# Pros and cons to reversed forks?????



## Mountain biker 41 (Oct 13, 2007)

Well, the title says it all. I now see/notice more and more bikes with reversed forks. What/Why are they becoming more popular?(IMO)Do they soak up smaller bumps?Do they last longer? thanks


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## scabrider (Oct 3, 2004)

what, exactly, are "reversed forks"...


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## Karupshun (Jun 13, 2006)

scabrider said:


> what, exactly, are "reversed forks"...


he may be thinking inverted forks, but those aren't becoming more popular


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## scrwscrnnms (Jun 27, 2005)

???


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## scrwscrnnms (Jun 27, 2005)

It sounds stupid if it were a longer travel fork or bike...possible crown to downtube collision? Like turned backwards?


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## LoozinSkin (Jun 29, 2004)

I think hes talking either about inverted forks like the defunct dorado or shiver...

or he's talking about the reverse arch that manitou does....


Either way I would'nt say either could be deemed new or popular.


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## tibug (Dec 5, 2006)

LoozinSkin said:


> Either way I would'nt say either could be deemed new or popular.


True, but it certainly should be!...I love my Shiver...

Tim


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## scrwscrnnms (Jun 27, 2005)

shivers are sick....manitou blows!


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## suicidebomber (Feb 10, 2007)

inverted forks? more MX than MTB, methinks.


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## scabrider (Oct 3, 2004)

inverted forks are chill. i was just trying to be silly earlier.inverted forks are more popular for mx though, not so much for mtb. but they do have a nice ride to them, i would use one if i had the choice...


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## suicidebomber (Feb 10, 2007)

MX and Supermoto too. Husqvarna factory team runs 'em Shivers!


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## Jayem (Jul 16, 2005)

They are used on motos because the excessive amount of fork travel on motos doesn't leave enough bushing overlap with a non-inverted design, and with motos the fore-aft strength is important (think about motos flying through the air and landing (sometimes casing) on big dirt ramps), so the bigger upper-tube size of the inverted fork is also a benefit here.

You can't really make comparissions though with motos, if the motos use non-inverted forks they don't have brake arches, so both designs get their laterall stiffness from massive tubes, clamps, and axles.

With mountain bikes, there aren't really any advantages to running an inverted design, the only real tangible benefit is better lubrication on the legs, and while tangible, it's pretty small, you also have a worse situation if the seals give out and the fork leaks oil over your brake.

There are some myths associated with the inverted forks though;

One is that they are better because there's less unsprung weight (perhaps better bump absorption). If anything this effect is due to the lubrication, not the unsprung weight. When you do the calculations (taking into account the entire unsprung weight, tire, tube, rim strip, rim, brake rotor, brake caliper, lower stanchions, axle, etc) the difference with an inverted fork is 10% or less. If you can feel a 10% in unsprung mass then good for you, but I would say this isn't going to make an ounce of difference to anyone. 

Another is that they are stiffer. They may end up stiffer fore and aft, but this is due to the bigger sized upper tubes and clamps. If you then compare to a fork like the fox 40 that has 40mm stanchions (upper tubes), those benefits get negated because the 40 simply has huge tubes as well. You don't see this fore-aft stiffness issue being very important these days anymore though., as no one is making serious forks with 28 and 30mm stanchions now, and the crowns/steerer interface is generally reinforced enough.

One thing that is not a myth is the lack of tortional rigidity. Because there is no brake arch to prevent twisting, you need to go to some pretty extreme measures if you are to make it as stiff as a non-inverted fork. A good example of this is the maverick DUC32 fork, it has a welded lower crown that joins big bulged upper tubes. This makes a pretty rigid structure, but it also relies on a much bigger axle with the hub. In this sense, the inverted fork is NOT an efficient use of material and will weigh more than the equivalent convenional fork (assuming someone dumps as much development into one). Even so, many users of that particular fork find it to be flexier than other decent single crown forks. The bottom line remains that these forks are used when not enough bushing overlap would remain with a conventional design (such as a fork with much more travel). The inverted fork is in this sense more "efficient" in it's use of materials, but at this point there is really no alternative. 

You can see the progression with the mtb forks, the marzocchi shiver had 35mm stanchions, the manitou dorado had 30mm stanchions (first version). As forks increased their stanchion size, the manufacturers did not have to resort to the inverted design, because the increase in stanchion size increased the bushing overlap area back to what would be acceptable. Keep in mind that an 08 marzocchi downhill fork has 38mm stanchions, the fork 40 has 40mm stanchions. 

Where it gets real bad is with the single crown inverted fork, several companies have tried this, and most have given up. When dealing with an inverted design, that 2nd crown is absolutely critical to maintain the tortional rigidity, and if you design a single crown inverted fork you end up with something that is even more wastefull. These were very flexy forks and while the quailty of travel with my shiver sc was nice, there wasn't much point to a 5lb fork with 120mm of travel that wasn't very stiff. A fox vanilla or RS pike is a much better fork, in pretty much every way. 

So what it comes down to is that there's really no point to having them for mtb, the travel isn't extreme enough to warrent going to an inverted design, and the loss of the brake arch contributes significantly to increased flex with an inverted fork. These things can be designed around, but to give you an example the dorado DH fork with the stem was 8lbs, and it was the lightest. The shiver DC with the stem was 8.7lbs, my stratos S8 was a few pounds more than that. None of these forks were very stiff laterally. Some of them worked very well, and I definitely liked the shiver DC, it did it's job well. You just had to live with the fact that it was an 8.7lb fork and that it wasn't the stiffest fork out there. Other than that it did it's job very well. It's simply that the inverted design wasn't really warrented.


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## scotter (Sep 19, 2006)

advantage to inverted forks: nonconformity
disadvantage to inverted forks: nonconformity


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## Bobby Peru (Sep 8, 2004)

Wow, thanks Jayem! That was quite a read! I sill love my Shiver though. But that was a very in-depth and interesting post nonetheless!

I guess I am just used to my Shiver. The only other dual crown fork I ever owned was an '05 Boxxer Team. So my Shiver blows doors on that!

Someday I may get another dual crown fork, but in the meantime my Shiver is fantastic!


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## DSFA (Oct 22, 2007)

Jayem, that was quite the post...and fairly accurate but not quite, sorry. Your reasoning for why MX bikes run inverted forks has no reason to do with bushing overlap, it has everything to do with ground clearance at the bottom of the fork leg. As forks gained cartridge setups to separate the oil from the air (to prevent cavitation, that's foaming of the oil) and compression/rebound adjustments, the lowers started to overhang enough that once ruts formed on the track the bottom of the forks drug and to say the least hindered forward progress.
There really is only one reason for an inverted fork not to excel on in MTB usage since many moto forks actually have smaller axles than 20mm and now that disc brakes are common there is no issue there either. I think it comes down to the fact that bicycle forks need to be lighter and so use less material for the stanchion tube and if that was on the bottomside and you went down hard in a rock garden I could see some serious damage there since a bicyclist wouldn't put up with wrap around plastic guards like MX use or at least tough enough ones.
And Bobby...that Shiver is Sweet!


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## NorKal (Jan 13, 2005)

Jayem said:


> They are used on motos because the excessive amount of fork travel on motos doesn't leave enough bushing overlap with a non-inverted design, and with motos the fore-aft strength is important (think about motos flying through the air and landing (sometimes casing) on big dirt ramps), so the bigger upper-tube size of the inverted fork is also a benefit here.
> 
> You can't really make comparissions though with motos, if the motos use non-inverted forks they don't have brake arches, so both designs get their laterall stiffness from massive tubes, clamps, and axles.
> 
> ...


Don't you _ever_ shut up???

Hmm... guess not.


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## Jayem (Jul 16, 2005)

DSFA said:


> Jayem, that was quite the post...and fairly accurate but not quite, sorry. Your reasoning for why MX bikes run inverted forks has no reason to do with bushing overlap, it has everything to do with ground clearance at the bottom of the fork leg. As forks gained cartridge setups to separate the oil from the air (to prevent cavitation, that's foaming of the oil) and compression/rebound adjustments, the lowers started to overhang enough that once ruts formed on the track the bottom of the forks drug and to say the least hindered forward progress.


Actually, it was quite accurate, the reason those lowers were overhanging below the axle is that they had to make the fork "long enough" to keep that bushing overlap. It didn't have anything to do with the cavitation, it had to do with the overal length required for x amount of travel. So if you have a fork that has 12" of travel, you need say 6" of bushing overlap (arbitrary number), with a conventional design, you run out of length, so if you were to not extend the lowers past the axle, you might end up with 4" of bushing overlap, not adequate. The only way to regain that overlap is to increase the overal length of the fork below the axle (with a conventional fork). I'm not saying that cavitation is not important though.

With an inverted fork, you get far more overlap because the lowers simply go into the uppers and there's enough space in the uppers to give good overlap for extreme amounts of travel.

It has everything to do with the clearance below the axle, that is implied and the entire reason they don't just keep making the fork longer below the axle. It's about bushing overlap though, not cavitation. If you want to see this for yourself, do the math and figure out how much bushing overlap would exist if it wasn't an inverted fork (say for 13" of travel).


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## Jayem (Jul 16, 2005)

Bobby Peru said:


> Wow, thanks Jayem! That was quite a read! I sill love my Shiver though. But that was a very in-depth and interesting post nonetheless!
> 
> I guess I am just used to my Shiver. The only other dual crown fork I ever owned was an '05 Boxxer Team. So my Shiver blows doors on that!
> 
> Someday I may get another dual crown fork, but in the meantime my Shiver is fantastic!


I had a shiver too, and it was definitely one of the best forks that I've owned.


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## Jayem (Jul 16, 2005)

Khemical said:


> Don't you _ever_ shut up???
> 
> Hmm... guess not.


No, I force you to read all of my posts.:madman:


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## DSFA (Oct 22, 2007)

Jayem said:


> Actually, it was quite accurate, the reason those lowers were overhanging below the axle is that they had to make the fork "long enough" to keep that bushing overlap. It didn't have anything to do with the cavitation, it had to do with the overal length required for x amount of travel. So if you have a fork that has 12" of travel, you need say 6" of bushing overlap (arbitrary number), with a conventional design, you run out of length, so if you were to not extend the lowers past the axle, you might end up with 4" of bushing overlap, not adequate. The only way to regain that overlap is to increase the overal length of the fork below the axle (with a conventional fork). I'm not saying that cavitation is not important though.
> 
> With an inverted fork, you get far more overlap because the lowers simply go into the uppers and there's enough space in the uppers to give good overlap for extreme amounts of travel.
> 
> It has everything to do with the clearance below the axle, that is implied and the entire reason they don't just keep making the fork longer below the axle. It's about bushing overlap though, not cavitation. If you want to see this for yourself, do the math and figure out how much bushing overlap would exist if it wasn't an inverted fork (say for 13" of travel).


Sorry dude, twelve inch travel forks for mx have been around since the late 70's/ early 80's and while they had some overhang (around 2-4" depending on brand) once the cartridge forks came out in the late 80's and early 90's is when the overhang became enough of an issue to move to inverted forks, which had been around since the mid 80's (Steve Simons came out with aftermarket ones in I believe 82/83). The cartridge forks also came about when forks were growing in size from 38/41 mm to 43mm and up. Bigger stanchions necessitate larger lowers, which equals less clearance. 
And it's about the cartridges used to prevent cavitation not the cavitation itself.
So if you wanted to do a 13" travel fork (which has been done at the factory level but never to market) with a conventional fork, you would be correct about having to make the lowers longer to accommodate the travel but for what has been on available to consumers that hasn't been the issue.
So I'll give you that bushing overlap plays a part in long travel fork design, however it's not the number one reason for the change in mx forks from conventional to inverted forks.


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## SHIVER ME TIMBERS (Jan 12, 2004)

tibug said:


> True, but it certainly should be!...I love my Shiver...
> 
> Tim


Shivers are the best


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## NorKal (Jan 13, 2005)

Jayem said:


> No, I force you to read all of my posts.:madman:


And I DO read them. :madman:


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## kenneththecurtain (Jan 7, 2007)

I think its mainly the seals and bushings being soaked in oil all the time, USD forks are just so damn plush. I use shivers which are tasty, but a chum has a couple of white bros DH2/3 forks and theyre plusher than your mum. Like people say they flex a bit, but its not that bad or noticeable most of the time. Theoretically 888's should feel nicer than a shiver, but they just don't.

Also its a bit harder to scratch stanchions because they are out of the way a bit more and usually have guards. Saying that, I scratched a stanchion this morning off a pedal in the back of the car... Its a real shame, I'll be forced to buy a 3rd pair


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## NJMX835 (Oct 17, 2006)

C'mon people, no mention of the best inverted forks made for a downhill bike?

http://www.avalanchedownhillracing.com/dhf8forka.html

Now, who wants Kool Aid? :thumbsup:


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## rep_1969 (Mar 25, 2004)

I had a Shiver and LOVED it. I still swear that my Shiver was more plush than my 888RC. It's close, but still not as plush. Also, I never felt any of the "flex" that everyone always talks about, and I'm 200+ fully geard up.


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## rep_1969 (Mar 25, 2004)

NJMX835 said:


> C'mon people, no mention of the best inverted forks made for a downhill bike?
> 
> http://www.avalanchedownhillracing.com/dhf8forka.html
> 
> Now, who wants Kool Aid? :thumbsup:


It better be for $1895!!!


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## NJMX835 (Oct 17, 2006)

rep_1969 said:


> It better be for $1895!!!


Not to be a shill, but that's only a little more than any of the 'World Cup'' forks & with all the options too.

Plus, they LAST, most of the folks that I've known who own them have had them for years & years.

They are somewhat heavy & expensive, that's one drawback, but IMHO the performance, quality & customer service you get.more than makes up for it.


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## Mountain biker 41 (Oct 13, 2007)

sorry 4 the confusion...yes I mean inverted forks. In my area and on the internet, Im seeing more and more "inverted" forks. Why I ask is cause there is/was(not sure) a ad in classifieds for 125 or 175 bucks...and i was wondering y so cheap(besides the fact they are 01s or 02s) Everyone whos *owned* them, y did you get rid of them?

Ps..I posted in DH cause these ones have like 170mm travel


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## Pistol2Ne (Apr 2, 2006)

SHIVER ME TIMBERS said:


> Shivers are the best


I like wet noodles too


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## Raptordude (Mar 30, 2004)

Jayem said:


> They are used on motos because the excessive amount of fork travel on motos doesn't leave enough bushing overlap with a non-inverted design, and with motos the fore-aft strength is important (think about motos flying through the air and landing (sometimes casing) on big dirt ramps), so the bigger upper-tube size of the inverted fork is also a benefit here.
> 
> You can't really make comparissions though with motos, if the motos use non-inverted forks they don't have brake arches, so both designs get their laterall stiffness from massive tubes, clamps, and axles.
> 
> ...


PhD. Thesis right there.

Inverted Forks are RIP.


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## rep_1969 (Mar 25, 2004)

I got rid of mine because I sent it in for service, they told me it was pretty much trashed. They gave me a killer deal on a 888rc that I couldn't pass up.


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## wyrm (Jan 19, 2004)

NJMX835 said:


> C'mon people, no mention of the best inverted forks made for a downhill bike?
> 
> http://www.avalanchedownhillracing.com/dhf8forka.html
> 
> Now, who wants Kool Aid? :thumbsup:


Ya what about... these forks.

The Showa.... which proved that the inverted was not dead on the race scene.
And the New Dorado which will be on the race scene for 2008.


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## NJMX835 (Oct 17, 2006)

That new Dorado looks pretty sweeeeeeeeeet! 

You have any better pics of it?

As far as the Showa goes, unobtanium doesn't count, lol

(I wish they'd start making mtb forks for the unwashed masses though)


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## wyrm (Jan 19, 2004)

NJMX835 said:


> That new Dorado looks pretty sweeeeeeeeeet!
> 
> You have any better pics of it?
> 
> ...


The only thing I know about the New Dorado came from the guys at I-bike. The only thing the same as years previous is the name. Everything else is different. They went with a 38mm sanctions. This is to solve the stiffness prob and the wear of bushings. They couldn't say much with the dampening.


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## DSFA (Oct 22, 2007)

If Honda actually starts marketing bicycles and components I guarantee there will be a very high quality inverted fork on the market. And soon after I'd bet on models from Fox and Marzocchi, along with a refined Manitou Dorado.


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## rep_1969 (Mar 25, 2004)

DSFA said:


> If Honda actually starts marketing bicycles and components I guarantee there will be a very high quality inverted fork on the market. And soon after I'd bet on models from Fox and Marzocchi, along with a refined Manitou Dorado.


You know it's funny. I heard something like Honda didn't want to get into the DH bike thing "to the general public" because of profitability issues. I don't know, something a long those lines. (Im sure someone has the real scoop.) But hell, a top of the line DH bike cost just as much as a sweet azz crotch-rocket and probably more than most Motorcross bikes.

I don't see why they wouldn't get into the DH scene publicly. They'd probably make a zillion bucks.


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