# upside down forks?



## 1Slippy (Jan 20, 2012)

just wondering why mountain bike's specially DH you dont see very many upside down front suspension. I remember back in the late 80's all the motocross\supercross bike went to the inverted front suspension.


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## boogenman (Sep 22, 2006)

THey lack lateral stiffness.


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## mtbnozpikr (Sep 1, 2008)

boogenman said:


> THey lack lateral stiffness.


That's up for debate but I won't start it. I used to run a Marzocchi Shiver and loved it for the absolute plushness of it. Manitou Dorado is also a great inverted fork you actually see on the WC circuit today. Fox even had one last season (prototype) on Gee Atherton's bike on at least one race.

One large positive of the inverted design is the fact that the seals remain lubricated so static friction is kept to a minimum.


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## crossup (May 13, 2009)

The main reasons why you dont see so many are 1)traditionalism, there are still people who will tell you suspension does not belong on bicycles much less some hi tech unsidedown gimcrak... 
2)urban legends...see post #2\
3) untill Fox or RS endorsed it all us fanboys wont buy them...dumb but truer than you might think

But my take is simple, they're quite superior and thats why virtually all motocrossers and many street bikes have them...its all race bike trickle down. My first set was on a '96 RM-125 and they were awesomely stiff. 
The only reason I wouldnt run one, assuming it dampened well, would be if there was a significant weight penality. I hope to check out the Dorado sometime..not exactly orgasming over the plushness of my BOxxER WC 

MAVERICK - Maverick Fork Technology
Fox Prototype Inverted DH fork - World Exclusive - Pinkbike.com
Manitou Suspension Forks & Bicycle Components for Mountain Bikes


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## crossup (May 13, 2009)

Another HUGE advantage is a significant decrease in unsprung weight which makes controlling the wheels motion that much easier and more responsive


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## csermonet (Feb 2, 2009)

One concern that I would have is the stanctions being closer to the ground, making them closer to rock strikes and other things of that nature. To my knowledge dirt bikes dont really ride the kind of gnar terrain we do, I imagine the majority of the riders stay on groomed tracks or in the desert, the dont necessarily blast rock gardens and the like. I could be talking out of my ass though. Has any that has spent significant time on a Dorado/Shiver/inverted fork have any problems with this?


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## mtbnozpikr (Sep 1, 2008)

csermonet said:


> One concern that I would have is the stanctions being closer to the ground, making them closer to rock strikes and other things of that nature. To my knowledge dirt bikes dont really ride the kind of gnar terrain we do, I imagine the majority of the riders stay on groomed tracks or in the desert, the dont necessarily blast rock gardens and the like. I could be talking out of my ass though. Has any that has spent significant time on a Dorado/Shiver/inverted fork have any problems with this?


Valid point but I'm not sure that's a huge issue. The shivers had stanchion guards bolted to the front which guarded against such potential impacts. The dorados also have shields to protect them. When I had my shiver I also had Lizard Skins fork boots over the stanchions to protect a bit more.


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## csermonet (Feb 2, 2009)

I have seen those I just dont know how tough they are. Also, i have seen steve romaniuk not run any shields at all in quite a few of his vids, so maybe its really a non issue


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## crossup (May 13, 2009)

The answer to that question is this question: how often do you hit your fork lowers now? 
As to groomed tracks.. sure but have you ever taken the roost from a 450 on a track with rocks in it? Its enough to make you wonder why no one gets killed from it...I've taken rock hits in the shoulder hard enough to rip my hand from the grips. 
So bottom line, the protectors work pretty well to keep the PAY ATTENTION NOW... S T A N C H I O NS from getting beat up



csermonet said:


> One concern that I would have is the stanctions being closer to the ground, making them closer to rock strikes and other things of that nature. To my knowledge dirt bikes dont really ride the kind of gnar terrain we do, I imagine the majority of the riders stay on groomed tracks or in the desert, the dont necessarily blast rock gardens and the like. I could be talking out of my ass though. Has any that has spent significant time on a Dorado/Shiver/inverted fork have any problems with this?


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## csermonet (Feb 2, 2009)

crossup said:


> The answer to that question is this question: how often do you hit your fork lowers now?
> As to groomed tracks.. sure but have you ever taken the roost from a 450 on a track with rocks in it? Its enough to make you wonder why no one gets killed from it...I've taken rock hits in the shoulder hard enough to rip my hand from the grips.
> So bottom line, the protectors work pretty well to keep the PAY ATTENTION NOW... S T A N C H I O NS from getting beat up


I apologize for my wrong spelling. And yes I have taken some roost its pretty burly ****. As far as hitting my lowers, it happens, not every run but it definitely happens. Mine have the battle scars to prove it.


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## crossup (May 13, 2009)

Ok then, no USD forks for you my friend! Probably the most compelling reason they are only seen on DH racers...
Kinda wish I hadn't seen this thread..was doing fine ignoring the Dorado...hmmm 260gram weight penality....just lost more than that going from a WTB Prowler 2.5 to Hans Dampf 2.35... I'm hearing a little voice chant "Manitou Manitou"


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## csermonet (Feb 2, 2009)

haha id love to give them a shot though, interested to feel the damper and the difference being inverted. have only heard good things about them. anyone want to trade theirs for a 40? o_0


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## mtbnozpikr (Sep 1, 2008)

csermonet said:


> haha id love to give them a shot though, interested to feel the damper and the difference being inverted. have only heard good things about them. anyone want to trade theirs for a 40? o_0


Technology has improved a ton and Fox has arguably the best damper on the market (FIT). My shiver was a 2002 model and while it was really plush and lacked a lot of static friction, it was a bit underdamped. If you were going to go for one, I would suggest a more current model so basically you've got the dorado to choose from if you plan on using it for DH.


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## csermonet (Feb 2, 2009)

Definitely not looking to swap my fork out anytime soon, especially for something older like a Shiver. Id love to give a new Dorado a shot, if i liked the way it rode more than my 40 I would be swayed to switch. As of now, coming off a 32mm Boxxer Race and now riding a 2011 40 FIT RC2 i absolutely LOVE it. Im no suspension guru by any stretch of the imagination so I am sure I could get some more performance out of it but I am loving it thus far.


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## Whafe (May 27, 2004)

I am all for inverted forks, it enables my long travel big hit 29er to have a fork!

I have a 2011 Dorado, have no issue with stiffness, in fact its stiffer than a honeymooners chopper


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## mtbnozpikr (Sep 1, 2008)

Whafe said:


> I am all for inverted forks, it enables my long travel big hit 29er to have a fork!
> 
> I have a 2011 Dorado, have no issue with stiffness, in fact its stiffer than a honeymooners chopper


Nice...


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## Gurney (Apr 7, 2007)

The Dorado is a very under-rated fork IMHO. The 04 that I had was easy to work on and performed better then my 2011 Boxxer R2C2. I would like to hear how the White Bros Grove 200 performs. I believe there are some board members here who have them, you guys wanna speak up.


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## lelebebbel (Jan 31, 2005)

crossup said:


> 2)urban legends...see post #2\


The "lack of lateral stiffness" is not an urban legend. A fork using the same sort of axle, but lacking the bridge of a traditional fork will be less stiff than that traditional fork, that's just physics. 
The way to improve stiffness is to strengthen the axle or to increase axle diameter.
The shiver didn't go quite far enough there, so it was quite flexy, and that's why everyone thinks "USD = flexy". I haven't tried the Dorado but I hear they are better.

Note that Moto USD forks have steel axles, usually also 22 or 24mm diameter, with big-ass clamps on both sides. That's why they are stiff.

One of the few other relatively popular USD forks for MTBs is the Maverick. Note that they use a 24mm/27mm axle and a welded lower crown to improve stiffness.


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## csermonet (Feb 2, 2009)

That Maverick fork that you posted lelebebbel isn't a DH fork if im reading correctly, its a 6in enduro/am fork, similar to what spesh was using on one of their trail bikes i imagine. All that stuff on that site looks sketchy to boot. 24mm axle, welded crown, and lockout? Not cool. As far as REAL forks go, I would be interested to know how the White Brothers Groove rides as well, looks good and I think its competitively priced as well.


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## crossup (May 13, 2009)

Give me a break, USD forks don't have to lack in stiffness....only poorly designed USD forks are that way. AS you pointed out, some are good, some are not.
The lack of a bridge just means one has a bigger engineering job...if the design prevented getting stiffness equal to bridged forks, I doubt they would be so dominant in the moto world and think, when have you seen a bridged moto fork?. So in principal your point is valid but in RL its moot.

Also the point we're discussing is actually just plain false..as in lateral stiffness is determined by many things but not by lack of a bridge. Now TORSIONAL stiffness, thats what we are really on about...

The urban legend comes in that people turn a few(bad) examples into a stereotype.
All you're doing is explaining how the legend got started and then say in effect its true because people equate flex and USD.. circular logic if I ever saw it

I responded to a straight out misstatement by correctly labeling it and as far as I'm concerned your post just confirms it  sorry



lelebebbel said:


> The "lack of lateral stiffness" is not an urban legend. A fork using the same sort of axle, but lacking the bridge of a traditional fork will be less stiff than that traditional fork, that's just physics.
> The way to improve stiffness is to strengthen the axle or to increase axle diameter.
> The shiver didn't go quite far enough there, so it was quite flexy, and that's why everyone thinks "USD = flexy". I haven't tried the Dorado but I hear they are better.
> 
> ...


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## lelebebbel (Jan 31, 2005)

crossup said:


> Give me a break, USD forks don't have to lack in stiffness....only poorly designed USD forks are that way. AS you pointed out, some are good, some are not.
> The lack of a bridge just means one has a bigger engineering job...if the design prevented getting stiffness equal to bridged forks, I doubt they would be so dominant in the moto world and think, when have you seen a bridged moto fork?. So in principal your point is valid but in RL its moot.


1. I never said moto forks lacked stiffness. I pointed out that they DON'T, because of the much stronger axle used in motos.

2. there are plenty of moto forks with bridges. In fact, you could buy a bolt on bridge to re-fit on the (bridge-less traditional) fork of the BMW F650GS. I believe the bridge came standard on later models. But again, moto forks (no matter if USD or nor) don't usually need the bridge because they have much stiffer steel axles and stronger clamps, holding these axles.

3. Again,* I am not saying USD forks are less stiff in general* - I AM however saying that they need a stronger axle to achieve the same stiffness. The lower legs of a fork are only held together by two things, the bridge and the through-axle. If you remove one of those two things without sufficiently strengthening the other, you end up with a fork that is less stiff - simple as that. 
The Dorado seems to do a better job there than the Shiver did.



> That Maverick fork that you posted lelebebbel isn't a DH fork if im reading correctly, its a 6in enduro/am fork, similar to what spesh was using on one of their trail bikes i imagine. All that stuff on that site looks sketchy to boot. 24mm axle, welded crown, and lockout? Not cool. As far as REAL forks go, I would be interested to know how the White Brothers Groove rides as well, looks good and I think its competitively priced as well.


Never said it was, either. I posted it as an example of design measures to increase torsional stiffness on an USD fork.


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## crossup (May 13, 2009)

not seeing where I accused you of #1 but by saying the lateral stiffness legend is true(referrring to USD, see the OP), you include moto forks as USD is the fork type not tthe type of use.

bridged moto forks? sure, common -NOPE and you pointed it out, not necessary 
. And while, my bad, I didn't specify long travel off road, thats whats comparable to DH and germane to this conversation. I will give you credit that BMW is generous with travel and along with MAICO, may have sparked the move to leading axles, long travel and other improvements but otherwise not germane. 

I think we are basically in agreement on the main points and dont need to keep up the you said, I said schtick. You obviously understand physics and bikes so no need to go there, the rest is semanics and trying to converse on a forum


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## Danke (Sep 19, 2005)

Dirt bikes had upside down forks for years. Then they went back to right side up forks.

Why? The USDs were heavier and "too stiff". Great on a sport bike on smooth pavement with Hp to burn but on really rough ground the compliance of the right side up paid off. Plus with the change to 4-strokes saving a bit of weight paid off.

Now they've flipped back again to USD on dirtbikes. Who knows, maybe MTB forks will follow.

The weight penalty on a bike though is the problem, and to a lesser degree the vulnerability of having the slider at the bottom. For all the abuse dirt bikes get the riders don't tend to stop for a break and leave them lying flat in the dirt!


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## crossup (May 13, 2009)

ALL good points. The flip flopping is pretty funny from the marketing standpoint.. I bought the first year Suzuki went USD...'96(oops, looks like '95 was first year). For '97 they went back as you said and IRC around 1999 back to USD. And while the USD was massively stiff, the ride was inferior at least until the second gen USD's BUT the cool factor was almost worth it alone 
While I can't say that those USD were heavier, the weight was not a concern as the bike was at the AMA minimum weight(194lbs) and so a lighter fork would only have mean adding weight somewhere else. Just one brand but I'd bet the others were right there too.


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## William42 (Oct 29, 2006)

I love the "dirt bikes do it, it must work perfectly for bicycles" logic that people vomit every time a discussion like this comes up. 

Which is why everybody is running moto tires right? they grip better at high speeds, they last longer, and its harder to get a pinch flat! Its perfect! 

The thing is, the NEW dorado reasonably stiff (the old one was more noodly, and the shiver was a noodle), because its got a solid axle system and HUGE clamping area on the upper crowns. But its still not as stiff as a non-USD design like a boxxer or 40 or 888. Its simply easier to engineer a fork for light weight and stiffness with the non-inverted design. 

The reason motos can get away with inverted designs is because they can weigh 20 lbs and have 60mm stantions with 40mm hubs. 

Big clamping area+oversized hubs work just fine for inverted, but then its difficult to engineer with the weight and all.


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## recitio (Dec 22, 2011)

Has anyone done a side by side or long term comparison test of the Dorado vs Fox40 or 888Evo?

Would love to hear opinions.


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## mtbnozpikr (Sep 1, 2008)

William42 said:


> The thing is, the NEW dorado reasonably stiff (the old one was more noodly, and the shiver was a noodle), because its got a solid axle system and HUGE clamping area on the upper crowns. But its still not as stiff as a non-USD design like a boxxer or 40 or 888. Its simply easier to engineer a fork for light weight and stiffness with the non-inverted design.


You brought up some good points but Manitou makes (at least they used to) two versions of the dorado: the Pro and the MRD. The dorado pro which most people refer to is made out of aluminum but the MRD features carbon fiber construction. Carbon fiber's specific stiffness is much greater than that of aluminum so I wonder how those two forks stand up side by side.


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## .WestCoastHucker. (Jan 14, 2004)

.....


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## NEPMTBA (Apr 7, 2007)

Ah, technology...

... I would like to see linkage forks added again also, but there is only so much to go around and in the case of Moto, contracts with Showa, KYB dominate the field, prolly the same with MTB, Fox, Rockshox...

The forces are much greater with Moto hitting steep faced SX jumps and I still don't understand why they sell this to the gen public, most guys trail ride or rec race and never need that type of stifness, I do see a trend with off road Motos going back to Chromo frames, a good thing as they give and take to woods trails much better than stiffy aluminum.

But, then again anything with enough prototyping can be made to work for the intended application.

Just my take...
...ride whatevea ya like!


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## Uncle Six Pack (Aug 29, 2004)

crossup said:


> Another HUGE advantage is a significant decrease in unsprung weight which makes controlling the wheels motion that much easier and more responsive


I don't think you will get much less unsprung weight than a typical magnesium lower... especially if that USD fork gets a beefier axle and bits to hang some adequate brake calipers and guards for the stanchions....

Seriously, this topic comes up a few times a year and always stirs the same old arguments.

Personally, I would love to see the lefty-type roller bearings in a more standard (2 legged, 20mm axle) chassis... would give up a half-pound or so to have bearings rather than bushings in there.


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## crossup (May 13, 2009)

Ok, I only took aerospace engineering in college, what do I know?
Let's see what our beloved PINKBIKE says about FOX's prototype USD forks as see on Gee's ride(once):
Pinkbike's take: Massive news from Fox. While the inverted slider is still obviously very much in the prototype stage, they were confident enough in it to let Gee put in a practice run at the US Open for all to see - that speaks volumes. There are many advantages to an inverted chassis, including less unsprung weight that allows the wheel to track the ground better, as well as far more fore/aft rigidity. The old argument of inverted forks having less torsional flex needs to be thrown out the window as it is far less relevant than most believe. Keeping in mind that the fork is well into its travel when being ridden, which stiffens the inverted chassis up greatly, the cliche test of pinching the front wheel between your legs and twisting really has no bearing in real world applications. It is also interesting to note that many forms of motorized sport actually build in a degree of lateral flex to allow the wheel to follow the smoothest line through a section - especially when leaned over in a corner - which allows it to track better in the rough. While the upside down versus right side up argument could go on forever,



Uncle Six Pack said:


> I don't think you will get much less unsprung weight than a typical magnesium lower... especially if that USD fork gets a beefier axle and bits to hang some adequate brake calipers and guards for the stanchions....
> 
> Seriously, this topic comes up a few times a year and always stirs the same old arguments.
> 
> Personally, I would love to see the lefty-type roller bearings in a more standard (2 legged, 20mm axle) chassis... would give up a half-pound or so to have bearings rather than bushings in there.


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## Uncle Six Pack (Aug 29, 2004)

crossup said:


> Ok, I only took aerospace engineering in college, what do I know?
> Let's see what our beloved PINKBIKE says about FOX's prototype USD forks as see on Gee's ride(once):
> Pinkbike's take: ...


You are an aerospace engineer, yet you go to pinkbike's propaganda, uh, I mean, publicity for info? About a fork publicly ridden for one practice run?

All I was responding to was the claim of "less unsprung weight". If anyone can give exact mass of say, a boxxer lower vs dorado lower (stanchion), along with axle weights and whatever else (unsprung) is necessary to go along for the ride, we could actually settle this one, but have never seen it.... I suspect it is nearly a wash and, if anything, a rather high dollar per gram savings. Please, prove me wrong.

But thanks for letting me know about your college degree and the (old) pinkbike article. Cool story.


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## ianjenn (Aug 1, 2004)

recitio said:


> Has anyone done a side by side or long term comparison test of the Dorado vs Fox40 or 888Evo?
> 
> Would love to hear opinions.


The DORADO we have has had over 200K vertical feet on it. She was rebuilt at around the 190K mark. Very fast riders. All of the testers wanted a DORADO after riding it. The fork is by far the most supple. It flexes more than a 40 but not as much as a Boxxer.


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## crossup (May 13, 2009)

You took me the wrong way Uncle.....I spouted manufacturers claims for less unsprung weight(pretty much all of them have made that claim) and you said you don't buy it. My response is I know airplanes,(despite the fact that the opportunities for weight savings seem obvious to me) not bikes so how about a PINKBIKE reporter? Mike Levy in this case. I thought the problem with PINKBIKE was that it was known for forum posters exaggerating etc, not that PINKBIKE itself has some adjenda to propagate misinformation.
I guess its like the guy who tells me I'm an idiot for believing correct information on Wikipedia because you cant trust stuff on the internet. 
Maybe since that baffles me, you could explain why riding a fork for one run changes anything? Especially since Mike seemed to be talking about USD not just that particular fork

Did I mention that most airplanes use USD suspension? of course we call them oleo struts but its only a name.
dang, that would prove what? Well that weight wise it seems USD can be the lightest
maybe that the benefits out weight the engineering challanges



Uncle Six Pack said:


> You are an aerospace engineer, yet you go to pinkbike's propaganda, uh, I mean, publicity for info? About a fork publicly ridden for one practice run?
> 
> All I was responding to was the claim of "less unsprung weight". If anyone can give exact mass of say, a boxxer lower vs dorado lower (stanchion), along with axle weights and whatever else (unsprung) is necessary to go along for the ride, we could actually settle this one, but have never seen it.... I suspect it is nearly a wash and, if anything, a rather high dollar per gram savings. Please, prove me wrong.
> 
> But thanks for letting me know about your college degree and the (old) pinkbike article. Cool story.


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## Lelandjt (Feb 22, 2008)

boogenman said:


> THey lack lateral stiffness.


Close, they lack stiffness when using an industry standard 20mm axle. They work great with a larger axle (Foes/Maverick) or with Manitou's hex axle. Not being compatible with standard hubs is a tough problem.

I've been using a Maverick DUC on my XC/trail/AM bike for 7 years now.


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## Pedal Shop (Dec 14, 2006)

csermonet said:


> One concern that I would have is the stanctions being closer to the ground, making them closer to rock strikes and other things of that nature. To my knowledge dirt bikes dont really ride the kind of gnar terrain we do, I imagine the majority of the riders stay on groomed tracks or in the desert, the dont necessarily blast rock gardens and the like. I could be talking out of my ass though. Has any that has spent significant time on a Dorado/Shiver/inverted fork have any problems with this?


when trying to get through this thread --- this is the main reason l think the bicycle world hasn't really gone full tilt with the concept


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## Uncle Six Pack (Aug 29, 2004)

crossup said:


> You took me the wrong way Uncle.....I spouted manufacturers claims for less unsprung weight(pretty much all of them have made that claim) and you said you don't buy it. My response is I know airplanes,(despite the fact that the opportunities for weight savings seem obvious to me) not bikes so how about a PINKBIKE reporter? Mike Levy in this case. I thought the problem with PINKBIKE was that it was known for forum posters exaggerating etc, not that PINKBIKE itself has some adjenda to propagate misinformation.
> I guess its like the guy who tells me I'm an idiot for believing correct information on Wikipedia because you cant trust stuff on the internet.
> Maybe since that baffles me, you could explain why riding a fork for one run changes anything? Especially since Mike seemed to be talking about USD not just that particular fork
> 
> ...


Yeah, so again, what is the unsprung weight savings FOR A BICYCLE?

And I have no problem with true info gleaned from the interwebs.... except you have to realize most of our beloved articles with info about bikes and components fall more into the realm of marketing than pure nonfiction.


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## crossup (May 13, 2009)

I think the most obvious place where savings can come from is that with standard forks the ONLY place you can mount dampening stuff if from the inside bottom of the lower as it must be connected (obviously) so that moving the lower moves the dampener in the stanchion. With USD, the mounted dampener is now in the upper. and therefore, sprung(unless the manufactures have done some weirdness, which is where being an engineer like me commenting on such can go wrong)
Same principal would apply to the sprung leg(the diff being the spring would sit in the upper,remember bike springs are rarely full (fork) lenght although with air suspension I see where there might be no unsprung change as the air cartridge can sit in the upper tube with std forks I believe

When we compare the two fork types weight wise we are basically comparing the weight of stanchion tubing with bottom axle clamps vs cast lowers(before we talk dampeners and springs as above). Now most of us are aware that cast mangesium is a good bit lighter than aluminum. So take a BOxxER, to me 20" of thin walled 35mm AL tubing has got to weigh less than 13" of cast mag at ~42mm. Factor in that USDs will require a leg bottom to hold the axle and brake and YES most of any weight saving is gone but that still leaves us with the dampener scenerio above.

Those who mention the need for larger axle etc need to know that contrary to common sense, that can easily reduce weight overall. Its physics and difficult to explain without involving math but the weight vs diameter vs strenght ratios of tubes improve as size goes up and wall thickness(weight)
goes down

And lastly being educated as an engineer probably makes me more savvy that the average poster here on such topics but beyond that I'm a LONG way from being an experience bicycle engineer and I'm not presenting myself as an expert, just someone who can see thru unsupported urban legends most times.
I thought it was pretty cool that the PB article brought up the lateral/torsional stiffness issue which as I've said is not the real issue with USD.


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## Uncle Six Pack (Aug 29, 2004)

crossup said:


> .... YES most of any weight saving is gone but that still leaves us with the dampener scenerio above.


That's all I was saying in my first response to you.... btw, throw in unsprung mass of stanchion protectors because unless you are a sponsored rider, you are gonna want them (most every used DH fork I have ever seen is way more beat-up on the lower half.)


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## Jayem (Jul 16, 2005)

lelebebbel said:


> The "lack of lateral stiffness" is not an urban legend. A fork using the same sort of axle, but lacking the bridge of a traditional fork will be less stiff than that traditional fork, that's just physics.
> The way to improve stiffness is to strengthen the axle or to increase axle diameter.
> The shiver didn't go quite far enough there, so it was quite flexy, and that's why everyone thinks "USD = flexy". I haven't tried the Dorado but I hear they are better.
> 
> ...


Yep, at least some decent info here.

Moto forks are inverted to retain enough bushing overlap and to deal with casing/forces associated with big double jumps. Thats it.

They are stronger fore-aft, but you can negate this to some extent by just using bigger stanchions. With the upper and lower diameters/crowns that motos use, torsion is not a huge deal, but its still flexier all things equal in torsion. The other benefits outweigh this.

On mountain bikes they make no sense unless you have 12" of travel. The unsprung weight thing is largely a myth, as when you do the math the amount saved is miniscul 66 lowers are like 3/4 of a pound as a example, and the total unsprung mass is high compared to what's saved. Add up the stanchions, dropouts, axle, lower internals+spring, hub, rotor, brake and mount, spokes, rim, tube, tire, etc... About the only real advantage dor bikes would ne the lubrication.

What makes them a good idea for motos does not make them a good idea for bicycles. Ive owned several different kinds of inverted DH forks. They werent bad, but they were noticably flexier. Ive even owned the shiver sc, haha, talk about a bad idea. That fork picked it's own lines and you hoped it all worked out in the end (sometimes it didnt). Scary as hell.


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## ianjenn (Aug 1, 2004)

Just wait all of em will be inverted in a few more years. Except RS but again I can crack one looking at it and rubber bands with oil spinning through it is not all to reliable or good at anything.


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## lelebebbel (Jan 31, 2005)

crossup said:


> I think the most obvious place where savings can come from is that with standard forks the ONLY place you can mount dampening stuff if from the inside bottom of the lower as it must be connected (obviously) so that moving the lower moves the dampener in the stanchion. With USD, the mounted dampener is now in the upper.


The 2011 and newer Fox 40 has the damper mounted in the upper and its a conventional fork. With a sealed damper design, it doesn't matter if the fork is USD or not, you can pretty much mount the cartridge either way.


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## crossup (May 13, 2009)

bad choice of words on my part.... my point was the cartridge etc must connect with the lower. So one could mount it high and use a pushrod to connect to the lower. That approach however has a weight penality obviously over a direct mounted system. Which would not be true of the USD...so my point was about unsprung weight and obviously, the Fox approach
would help that if the pushrod thingie is lighter than the dampener cart.

Referring to the inverted dampener:
"The FIT RC2 damper lowers un-sprung weight allowing the fork to react quicker"

Thanks for pointing out an exception...wonder how many more there are...:thumbsup:



lelebebbel said:


> The 2011 and newer Fox 40 has the damper mounted in the upper and its a conventional fork. With a sealed damper design, it doesn't matter if the fork is USD or not, you can pretty much mount the cartridge either way.


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## crossup (May 13, 2009)

I'm not sure I'd make that prediction but IF Fox makes one and people like it, I'd bet big money RS will follow and then they will become dominant until someone figures out how to make a conventional fork out perform it. Then the pendulum will swing back....



ianjenn said:


> Just wait all of em will be inverted in a few more years. Except RS but again I can crack one looking at it and rubber bands with oil spinning through it is not all to reliable or good at anything.


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## lelebebbel (Jan 31, 2005)

crossup said:


> I'm not sure I'd make that prediction but IF Fox makes one and people like it, I'd bet big money RS will follow and then they will become dominant until someone figures out how to make a conventional fork out perform it. Then the pendulum will swing back....


I agree - the same thing has been happening in the moto world for decades!

1955 Enfield Bullet


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## mtbnozpikr (Sep 1, 2008)

crossup said:


> I'm not sure I'd make that prediction but IF Fox makes one and people like it, I'd bet big money RS will follow and then they will become dominant until someone figures out how to make a conventional fork out perform it. Then the pendulum will swing back....


I don't think that's outside the realm of possibility.


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## ianjenn (Aug 1, 2004)

crossup said:


> I'm not sure I'd make that prediction but IF Fox makes one and people like it, I'd bet big money RS will follow and then they will become dominant until someone figures out how to make a conventional fork out perform it. Then the pendulum will swing back....


Fox has them in testing and they may become public. Marzocchi is rumored to be looking into it again as well again. The cost of production for invert is way UNDER have a molded lower end for the like of a Boxxer is just too expensive. Just for cost alone companies are looking into inverted designs.


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## htrdoug (Mar 19, 2011)

lelebebbel said:


> I agree - the same thing has been happening in the moto world for decades!
> 
> 1955 Enfield Bullet


That uses a conventional fork with shrouds covering the upper tubes. But yea,usd forks were in use about the dawn of motorcycle telescopic forks.
I'd post a pic of a BSA Bantam but I ain't got enough post count.


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## Panzer (Jun 7, 2011)

...and don't forget, they look the business too


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## 99sf (Nov 30, 2011)

that does look rad panzer


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## SV11 (Jan 2, 2011)

Panzer said:


> ...and don't forget, they look the business too


Cool fork, love the tyres, lol.


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## boogenman (Sep 22, 2006)

crossup said:


> The main reasons why you dont see so many are 1)traditionalism, there are still people who will tell you suspension does not belong on bicycles much less some hi tech unsidedown gimcrak...
> 2)urban legends...see post #2\
> 3) untill Fox or RS endorsed it all us fanboys wont buy them...dumb but truer than you might think


Its not a urban legend, it is the truth. I had 2 shivers and they were flexy as hell. Go find a bike with a shiver and grab the front wheel, it will twist side to side a lot. I don't get that much flex/twist with my Boxxer.

I did not elaborate into anything in my first post because I didn't want to get a forum war going but that has already happened.

Moto bikes use them because they can have bigger axles, bigger stanchion tubes and bigger crowns. On a DH you are going really drive up weight to get the stiffness needed.

Fox has made a inverted DH fork. Gee used it for 1 run at the Windham WC last season and rumor is that he hated it. I think it is safe to assume he hated it because it was flexy. It only makes sense that if Fox was going to try out a new fork like that the only change would be a chasis change with Gee's regular 40 internals inside the new fork.


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## ianjenn (Aug 1, 2004)

boogenman said:


> Its not a urban legend, it is the truth. I had 2 shivers and they were flexy as hell. Go find a bike with a shiver and grab the front wheel, it will twist side to side a lot. I don't get that much flex/twist with my Boxxer.
> 
> I did not elaborate into anything in my first post because I didn't want to get a forum war going but that has already happened.
> 
> ...


*A DH bike weighs 40LBS an MX bike weighs 250.
A DH rider maybe makes 1HP MAX an MX bike makes 60
A DH bike MAYBE does a 50 foot jump in a race an MX bike does 120 footers*

The differences in forces between the two are IMMENSE. Showa knows what they are doing. There is a reason Manitou went to them with chassis suggestions.


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## boogenman (Sep 22, 2006)

ianjenn said:


> *A DH bike weighs 40LBS an MX bike weighs 250.
> 
> *


*

That is exactly why they are not on bicycles yet.*


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## crossup (May 13, 2009)

feel free to ignore all the Dorado owners who say they're less flexy than Boxxers(lets not even count the 32mm Boxxers from the past which would be fairer to compare to Shivers).
And of course Shivers flex the most of USD's so lets use them to prove the point....
And while you're at it, lets tell all the motocross guys who rode huge factory works Showas etc(non USD)and drop the bike, find the front end is tweaked and straighten it by twisting the bars while holding the front wheel between the knees, that only USD flex much. Not talking crashing off a 120' jump, just washing the front end out at 10mph. 


Why am I wasting my time, this topic attracts every closed mind here


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## .WestCoastHucker. (Jan 14, 2004)

crossup said:


> ...Why am I wasting my time, this topic attracts every closed mind here


it also attracts self professed know-it-alls...


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## Uncle Six Pack (Aug 29, 2004)

.WestCoastHucker. said:


> it also attracts self professed know-it-alls...


awesome


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## The Haunted (Jul 10, 2009)

I have yet to find any problems with my 2010 Dorado apart from the brake hose that cut its way through the guide pretty fast. Stiffness is really not an issue and the damper work wonders. The ride is firm and doesn't dive while still being smooth through high speed chatter. give me a Dorado over a 40 anytime...


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## retrofred (Jan 19, 2004)

So I own a new white bros groove 200 and can say that I am very happy with it, but I've only had for two months. Only had two runs on it do to work. I've owned shivers and a dorado in the pass and can say it feels way better than the shiver. Don’t remember the dorado much so it must not of impressed me much. Looking forward to putting the groove through some use and once fully broken in give a full write up on it sense its not seen very much. 

Sent from my SGH-T989 using Tapatalk


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## crossup (May 13, 2009)

at least we agree on something 



.WestCoastHucker. said:


> it also attracts self professed know-it-alls...


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## SV11 (Jan 2, 2011)

ianjenn said:


> Showa knows what they are doing. There is a reason Manitou went to them with chassis suggestions.


Yeah, but Manitou let themselves down by using a carbon fibre chassis, and as everyone knows, carbon fibre does flex.


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## retrofred (Jan 19, 2004)

I will agree on that one. The whole concept of a carbon legged fork is cool, but I think its better left to the XC crowd. 

Sent from my SGH-T989 using Tapatalk


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## mtbnozpikr (Sep 1, 2008)

SV11 said:


> Yeah, but Manitou let themselves down by using a carbon fibre chassis, and as everyone knows, carbon fibre does flex.


Carbon has many pros and stiffness is one of them. The specific stiffness of carbon is about four times that of aluminum and the fact that it is a composite material means that it can be laid up to accomplish pretty much whatever people want it to do. Carbon does have some drawbacks (price, impact resistance, ...) but stiffness is not one of them.


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## crossup (May 13, 2009)

Thank you for stopping the start of yet another urban legend ...can you imagine building a million dollar F-1 chassis using CF to save a little weight, if you thought it would be flexier than aluminum? Let's remember CF is also 2x stiffer than STEEL. Few materials can equal CF in that arena



mtbnozpikr said:


> Carbon has many pros and stiffness is one of them. The specific stiffness of carbon is about four times that of aluminum and the fact that it is a composite material means that it can be laid up to accomplish pretty much whatever people want it to do. Carbon does have some drawbacks (price, impact resistance, ...) but stiffness is not one of them.


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## recitio (Dec 22, 2011)

Friend of mine once mounted dirt bike forks on a beach cruiser. 

It was awesome. 

Ride down stairs and it just felt smooth, despite the hardtail.

I want 30lb forks on my bike.


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## ianjenn (Aug 1, 2004)

As I eluded to earlier. 2013 Inverted FOX!


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## OneEyedHito (Jun 20, 2009)

ianjenn said:


> The DORADO we have has had over 200K vertical feet on it. She was rebuilt at around the 190K mark. Very fast riders. All of the testers wanted a DORADO after riding it. The fork is by far the most supple. It flexes more than a 40 but not as much as a Boxxer.


Ding Ding Ding, we have a winner! Real world experience speaks volumes. I can concur that my Dorado is worlds better than the Boxxer that I had, I didn't pay MSRP for either of them so the "You paid alot so you have to like it more argument doesn't hold here"....


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## Gurney (Apr 7, 2007)

ianjenn said:


> As I eluded to earlier. 2013 Inverted FOX!


Let's just say for arguments sake that you are correct, since we have already seen a prototype. And say some big name WC racer like Gwin, Hill, Peaty or who ever won a race with this fork. Could you imagine how all the naysayers would react, that would be some good comedy.


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## crossup (May 13, 2009)

We should also consider that manufacturers dont blow RD and and resources on something everyone knows isn't better. You can bet for each attempt so far, engineers have said, I think I can make the compromises that will make this work. Because along with the other factors, every Shiver that people poo poo, leads to loss of confidence in that company and susquent loss of revenue. Sure theres some element of gambling here by the manufacturer, hoping to have the next trend setter, the next better mousetrap but its all up to us in the end and one can easily see the factors involved by just reading the posts from the haters, the uninformed and the misinformed here. Thats why you stick Gee on it and hope he likes it...that's one of the few arguments most of us respond well to.


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## boogenman (Sep 22, 2006)

Gurney said:


> Let's just say for arguments sake that you are correct, since we have already seen a prototype. And say some big name WC racer like Gwin, Hill, Peaty or who ever won a race with this fork. Could you imagine how all the naysayers would react, that would be some good comedy.


I don't think there are many naysayers on here. I certainly am not a naysayer by saying the reason Fox and Rock Shox don't have a USD in production is because they can;t build one that is better than what they have.

Here are 2 facts:
1. The Marzocchi Shiver was a friggin noodle. If you don;t believe that you probably also rode with 3.0 gazzalodis. 
2. I would ride a USD from Fox, Rock Shox or Marz if they could build one that is better than what they have out now.


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## Jayem (Jul 16, 2005)

It's just not an efficient way to make a chassi unless you NEED 8" of bushing overlap (not an issue when you have decently sized stanchions and only 8" of travel) or the extreme fore-aft strength of an inverted, but bigger stanchions on a regular fork can negate that as well.

How long has the 40 been produced? If there were inverted advantages, I'd assume fox would have jumped on it by now. Why is the shiver "so flexy"? It's not overly flexy for what it is, it has 35mm stanchions, massive uppers, big crowns, and if you want to make it stiffer, those things need to be EVEN bigger, or one-peice carbon fiber lowers+crowns (kind of like how maverick makes the DUC32), even then it's debatable whether it will end up as stiff without the brake arch. There's just no good reason to do it.


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## mtbnozpikr (Sep 1, 2008)

Jayem said:


> How long has the 40 been produced? If there were inverted advantages, I'd assume fox would have jumped on it by now. Why is the shiver "so flexy"? It's not overly flexy for what it is, it has 35mm stanchions, massive uppers, big crowns, and if you want to make it stiffer, those things need to be EVEN bigger, or one-peice carbon fiber lowers+crowns (kind of like how maverick makes the DUC32), even then it's debatable whether it will end up as stiff without the brake arch. There's just no good reason to do it.


I think that is a very reasonable and informed post although in my opinion (maybe it's the engineer in me) just the R&D is enough to pursue new designs because if we don't push the envelope, new products don't seem to get developed. Just out of curiosity I'd like to take a look at their finite element analyses just to see the stress and strain distributions throughout.


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## oakhills (Mar 30, 2004)

I've been riding the Foes XTD fork for 8 years now and it is very stiff and plows through everything like power steering. It is heavy, but the way it mows down everything in its path makes the extra weight worth it....


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## boogenman (Sep 22, 2006)

Katana said:


> I've been riding the Foes XTD fork for 8 years now and it is very stiff and plows through everything like power steering. It is heavy....


No one wants heavy, that is why they are still a rarity on DH bikes.

It sure would be nice to hear from someone @ Fox about the fork Gee used. I would like to know if they already did the R&D and scrapped the idea because it was too flexy or if the concept is still on the table.


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## oakhills (Mar 30, 2004)

boogenman said:


> No one wants heavy, that is why they are still a rarity on DH bikes.
> 
> I'd never want to run a 30 pound DH bike. Hence, the Foes fork is going on 8 years, one rebuild and has all the updated "works internals". Plus, I don't have to get the latest and greatest each season (Fox, RS, etc.), because the Foes fork is always the latest and greatest.


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## .WestCoastHucker. (Jan 14, 2004)

step away from the kool-aid brah...


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## boogenman (Sep 22, 2006)

Katana said:


> boogenman said:
> 
> 
> > No one wants heavy, that is why they are still a rarity on DH bikes.
> ...


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## boogenman (Sep 22, 2006)

.WestCoastHucker. said:


> step away from the kool-aid brah...


When did we start talking about 29'ers?


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## Lelandjt (Feb 22, 2008)

boogenman said:


> Katana said:
> 
> 
> > It will only be a matter of time until Fox can figure out how to get a USD fork to work on a DH bike with out being a boat anchor.
> ...


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## mtbnozpikr (Sep 1, 2008)

Pinkbike has an article about Fox's prototype inverted fork today. Fox's Prototype Inverted DH Fork - Pinkbike.com


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## boogenman (Sep 22, 2006)

mtbnozpikr said:


> Pinkbike has an article about Fox's prototype inverted fork today. Fox's Prototype Inverted DH Fork - Pinkbike.com


That about sums up what I was saying :thumbsup:


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## LenzRider (Feb 3, 2012)

yo white braddahs on a 29r


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## crossup (May 13, 2009)

While the article does lend support to those who say 'noodle fork' , I'm seeing a somewhat low budget approach when they use off the shelf 40 parts. The only way theres a chance of making the fork stiff enough where it isnt, is going to be to optimize everything to save max weight to allow extra beef ONLY where it will help the stiffness. To me its clear that they don't want to sink a bunch of money into an ok fork that may not do well in the market - and if it were to need a new hub for a monster axle, the market would be smaller as the price would go up. So they see how a knowledgeable rider responds to it with a standard axle. . 
If they make a USD fork that has superior attributes all the way around, sure it will likely catch on and become profitable. But make another Shiver and its just going to be that much harder to sell the real deal when you make it- the old bad reputation deal. 
I think FOX is playing the game very well, slowly perfect it without busting the bank, wait for public sentiment to swing your way and don't bet the bank on it. So prototypes and no adjenda beyond keeping an eye on the future.



boogenman said:


> That about sums up what I was saying :thumbsup:


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## mtbnozpikr (Sep 1, 2008)

crossup said:


> While the article does lend support to those who say 'noodle fork' , I'm seeing a somewhat low budget approach when they use off the shelf 40 parts. The only way theres a chance of making the fork stiff enough where it isnt, is going to be to optimize everything to save max weight to allow extra beef ONLY where it will help the stiffness.


I tend to agree. I posted the article before I actually read it (had to run to class). Upon reading it my first impression was that they would be much better suited to explore different materials such as composites. I like my Fox 40 a lot and don't plan on getting rid of it any time soon but if they are serious about the inverted design, there is surely more going on that we aren't seeing.


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## 1Slippy (Jan 20, 2012)

Panzer said:


> ...and don't forget, they look the business too


silly question but all that suspension and street tires?


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## Jayem (Jul 16, 2005)

crossup said:


> While the article does lend support to those who say 'noodle fork' , I'm seeing a somewhat low budget approach when they use off the shelf 40 parts. The only way theres a chance of making the fork stiff enough where it isnt, is going to be to optimize everything to save max weight to allow extra beef ONLY where it will help the stiffness. To me its clear that they don't want to sink a bunch of money into an ok fork that may not do well in the market - and if it were to need a new hub for a monster axle, the market would be smaller as the price would go up. So they see how a knowledgeable rider responds to it with a standard axle. .
> If they make a USD fork that has superior attributes all the way around, sure it will likely catch on and become profitable. But make another Shiver and its just going to be that much harder to sell the real deal when you make it- the old bad reputation deal.
> I think FOX is playing the game very well, slowly perfect it without busting the bank, wait for public sentiment to swing your way and don't bet the bank on it. So prototypes and no adjenda beyond keeping an eye on the future.


But, if you took that same engineering and R&D and poured it into a regular chassi that does not have the inherent limitations (the ones you are designing around), you'd get something even better, or the same for cheaper. That's the issue. Dumping money into the inherent problems that CAN be overcome is usually a waste. What are you going to buy, a $4000 6.5lb inverted fork that performs awesome, or a $1500 6.5 right side up fork that performs awesome?


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## William42 (Oct 29, 2006)

crossup said:


> While the article does lend support to those who say 'noodle fork' , I'm seeing a somewhat low budget approach when they use off the shelf 40 parts. The only way theres a chance of making the fork stiff enough where it isnt, is going to be to optimize everything to save max weight to allow extra beef ONLY where it will help the stiffness. To me its clear that they don't want to sink a bunch of money into an ok fork that may not do well in the market - and if it were to need a new hub for a monster axle, the market would be smaller as the price would go up. So they see how a knowledgeable rider responds to it with a standard axle.


Low budget? its an entirely different chassis - literally the only thing thats the same is the the damper and stantion diameter (which is bigger then anything else on the market).

Also, from the sounds of it, gwin and atherton liked the compliance of it for straight lining rock gardens, but felt it was too flexy in the corners. That doesn't mean its a noodle, that means they feel that the regular 40 has an advantage (which could be extremely slight). The main reason to cash in on an inverted 40 is to be ready if 29er DH bikes take off.


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## Panzer (Jun 7, 2011)

1Slippy said:


> silly question but all that suspension and street tires?


Not silly at all...
Urban DH


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## mtbnozpikr (Sep 1, 2008)

mtbnozpikr said:


> I tend to agree. I posted the article before I actually read it (had to run to class). Upon reading it my first impression was that they would be much better suited to explore different materials such as composites. I like my Fox 40 a lot and don't plan on getting rid of it any time soon but if they are serious about the inverted design, there is surely more going on that we aren't seeing.


I was going to suggest not only a new chassis made out of carbon to keep weight down and have remain competitive with regard to stiffness but also potentially carbon stanchions. It seems as if Marzocchi is already working on that and this time I read the article (Marzocchi Prototype Suspension First Look - Pinkbike.com). It seems as if Marzocchi is working on the inverted design as well and are going out of the box by potentially using other materials (carbon). It will be very interesting to see what they come up with over the next couple of years.


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## sandwich (Sep 24, 2005)

I'd like to chime with real world experience (gasp)...I rode an Avy DHF for 2.5 years and the only time I touched the exposed stanchions was removing the bike from the gondola at whiteface, on a friends pedal which was sticking out. I never damaged them in any wreck (which I had plenty of) nor in the car, nor anything else. I think that's largely a myth, but you do need to run fork guards for sure.

I will say that I think toying with the USD chassis has some inherent benefits, but teasing out the bad bits appears to be a challenge. Magnesium lowers (which MX bikes can't really use) with integrated dropouts probably put the unsprung weight theory to bed, as USD forks need machined and fitted dropouts attached to the stanchions, vs. forged/cast assemblies on RSD forks. I think the bushing overlap and better sealing are the best parts. Seals that push dirt away rather than just up the stanchion is a great system, although if the fork guys spec good seals that benefit can be reduced. In addition, you can get a lower axle to crown, and more flexibility with regards to axle setup and wheel size, as well as mud clearance if that appeals to you.

it'll be interesting to see what comes out of these developments. I really liked my Avy, but the weight, offset, and twisting in a crash were a huge negative for me, and I don't regret getting rid of it. I'd love to try a dorado, but I can honestly say that going from the DHF to a Boxxer WC was a phenomenal experience...I lost 4+lbs on the front end alone...that makes up for any difference in damping. I hope Zokes can pull it off, they deserve to have a dog in the fight with Fox and RS.


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## LenzRider (Feb 3, 2012)

sandwich said:


> it'll be interesting to see what comes out of these developments. I really liked my Avy, but the weight, offset, and twisting in a crash were a huge negative for me, and I don't regret getting rid of it. I'd love to try a dorado, but I can honestly say that going from the* DHF to a Boxxer WC was a phenomenal experience...I lost 4+lbs on the front end alone...that makes up for any difference in damping. * I hope Zokes can pull it off, they deserve to have a dog in the fight with Fox and RS.


I have to agree:thumbsup: this is my second upside down fork (had a Dorado) and the weight is a big issue, its like someone added a 10lb dumbbell to the fork although I'm the only dumbbell associated with my bike. I've had a Boxxer & a couple 888's and never had this much top heavy weight. However the positive side is that you seem to have more control
on the long descents than a regular dual crown, but again on twisty turns, it slows you down like trying to steer a Panzer tank. I guess there are always going to be pros and cons about them.


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