# the PVD twenty eight inch mtb



## pvd (Jan 4, 2006)

PVDtwentyeightinchmtb!!! Lean and fu*king mean!

Built for showing at SSWC08 in Napa. See you folks there!

see full write up: https://www.pvdwiki.com/index.php?title=PVD_Skinny_Puppy


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## Walt (Jan 23, 2004)

*Love it!*

The chainstays are really neat - did you do those bends yourself, I assume?

Tight chainring clearance - but given the angle of the stays, I imagine you can run as big of a ring as you want!

85 psi? Is that a misprint?

-Walt



pvd said:


> PVDtwentyeightinchmtb!!! Lean and fu*king mean!
> 
> Built for showing at SSWC08 in Napa. See you folks there!
> 
> see full write up: http://www.pvdwiki.com/index.php?title=PVD_Skinny_Puppy


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## pvd (Jan 4, 2006)

Yup, I do my own bending from straight tubes. I hate the shape of the prebent tubes.

The chainring is close, but adequate. Spacing the chainstays so far apart at the bb makes the rear end incredibly stiff so I can use nice light tubes.

85psi is max, my bad. That's what they say. I curently have 60 in them, but the first ride is tomorrow. I can work out pressures and gearing final numbers then.

http://www.panaracer.com/eng/products/speclist/mtb.html#l


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## MMcG (Jul 7, 2003)

That looks like a fun bike. Nice work.

I guess calling it a 28" saves you from your Anti-29er stance eh?


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## pvd (Jan 4, 2006)

Yup.


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## jay_ntwr (Feb 15, 2008)

This is exactly why I'd like to see you making those 92mm BB shells for consumption by the rest of us. I'd like to do something very similar to that in the BB/Chainstay. It's nice to see it already done in real life before I get started though.


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## pvd (Jan 4, 2006)

Shimano P/N for the XTR Press-In BB's: SM-BB91-41A


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## SuspectDevice (Apr 12, 2004)

Got to love what the wide bb's allow. We're building a batch of cruisers right now that use the same bb setup. Finally, 2.0 tires on the back of a race cruiser, for those days you just want to huck the dirtjumps. I'm building them for some Shimano sponsored racers (actually a few of them are in Beijing right now...)


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## Thylacine (Feb 29, 2004)

Nice 29er


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## pvd (Jan 4, 2006)

Thylacine said:


> Nice 29er


FU !

email me direct about me getting you those bb's.

-p


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## MichauxYeti (Nov 10, 2005)

Your welding appears to have improved a lot. Nice looking bike!


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## CharacterZero (May 19, 2004)

Is that a 650B?


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## D.F.L. (Jan 3, 2004)

You machined off the granny bosses for chainstay clearance?


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## pvd (Jan 4, 2006)

D.F.L. said:


> You machined off the granny bosses for chainstay clearance?


Yeah. I wanted a shimano crank, but I didn't want it to look like the crank wasn't clean. I also needed the clearance. All it took was an $80 end mill.


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## pvd (Jan 4, 2006)

MichauxYeti said:


> Your welding appears to have improved a lot.


actually, this is some of the worst welding i've done to date. I was on medication, bugging out in my head, and rushing. not a good mix. The welds are pretty lumpy. my road bike has much cleaner welds. this bike was built in 3 days after work using really cheap tubes. i was trying to get it done and painted in time for SSWC.


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## Schmucker (Aug 23, 2007)

CharacterZero said:


> Is that a 650B?


No, it's a 29er.

I like how using the 92mm BB shell allows for road bent stays to work for monstercross style applications simply by spacing them further apart (and some light manipulation).


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## Francis Buxton (Apr 2, 2004)

Great looking fork. You really got a good aesthetic out of it. One of the better segmented forks I've seen in a long time.

Personally, I'm not so sure about limiting yourself to smallish tires on a bike built for 700c wheels, but it's your bike and not mine. 

Looks good.


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## MMcG (Jul 7, 2003)

Francis Buxton said:


> Great looking fork. You really got a good aesthetic out of it. One of the better segmented forks I've seen in a long time.
> 
> Personally, I'm not so sure about limiting yourself to smallish tires on a bike built for 700c wheels, but it's your bike and not mine.


He's anti-29er so he has to do that.


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## Schmucker (Aug 23, 2007)

MMcG said:


> He's anti-29er so he has to do that.


But he's running 29x1.75s on there, and it looks like their is room for at least 1.9s. Ah, but if he calls it 700x45 it's okay. He might end up building a bike that has some 700x55s.


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## jmoote (Aug 31, 2007)

Looks like a fun ride, and the aesthetic turned out great. I have to wonder why you went with the 30 degree stem instead of a more typical 5 to 10 degree stem with spacers. To me this resembles the upward pointing quills so characteristic of cheap department store bikes, on an otherwise really classy looking bike.


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## pvd (Jan 4, 2006)

Schmucker said:


> No, it's a 29er.
> 
> I like how using the 92mm BB shell allows for road bent stays to work for monstercross style applications simply by spacing them further apart (and some light manipulation).


This is a mountain bike, not a monstercross bike. Take a look at the print.

It is not a 29er. The wheel diameter is 622mm + 2 X 45mm. Almost exactly 28 inches. There is not enough clearance to run anything with a 29 inch OD. It is not a 29er.


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## pvd (Jan 4, 2006)

jmoote said:


> I have to wonder why you went with the 30 degree stem instead of a more typical 5 to 10 degree stem with spacers. To me this resembles the upward pointing quills so characteristic of cheap department store bikes, on an otherwise really classy looking bike.


How does the stem angle change how the bike works? I don't understand what you mean. Did you look at the dimentions in the print?


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## jmoote (Aug 31, 2007)

It doesn't change how it works. +30 degree stems have gone out of style - that's all I was saying.


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## brant (Jan 6, 2004)

jmoote said:


> It doesn't change how it works. +30 degree stems have gone out of style - that's all I was saying.


Style is over-rated.


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## Thylacine (Feb 29, 2004)

From a purely functional standpoint, it makes no sense having a huge headtube just so you can have a 'fashionable' 5º rise stem. The straightest route between two points is a straight line and all that.

In fact, I like the look of the front end. The bike actually reminds me quite a bit of the older WTB Phoenixes with that front end, and I like the blending of the old with the new in terms of looks.

Anyway, PVD is doing this for his own edification, not to pander to the "mtbr 'check out my tick-the-boxes' new bike!" crowd, so I applaud his no compromises approach.

At least it's not another fixie or 5 grand 'commuter'!


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## Walt (Jan 23, 2004)

*Agreed!*

I've always thought it was hilarious that people would use zero rise stems, spacers, and riser bars, when a riser stem and flat bar is stronger/lighter/cheaper.

Of course, the selection of even halfway decent flat bars sucks, especially if you want something 26+" wide with some sweep. And everyone knows it's cooler to look moto with your risers.

-Walt



Thylacine said:


> From a purely functional standpoint, it makes no sense having a huge headtube just so you can have a 'fashionable' 5º rise stem. The straightest route between two points is a straight line and all that.
> 
> In fact, I like the look of the front end. The bike actually reminds me quite a bit of the older WTB Phoenixes with that front end, and I like the blending of the old with the new in terms of looks.
> 
> ...


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## Peter E (Feb 16, 2004)

you did the right thing. The head tube is already on the long side (ecstatically), 1-2" of spacers and/or a hi rise handle bar would sure look ugly. If that is the height you want for your handlebar, that’s the best looking solution


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## Thylacine (Feb 29, 2004)

Salsa 11 degree Pro-Moto flat bars are all the bar anyone could ever need. Big fan.


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## pvd (Jan 4, 2006)

Chromag FU Bars. 28", 10 Degree bend, 31.8

http://www.chromagbikes.com/products_oversize.html

The FSA I've got right now are just a little too narrow at 23.6". I will be replacing them with FU bars cut to 26".

-p


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## Francis Buxton (Apr 2, 2004)

Thylacine said:


> Salsa 11 degree Pro-Moto flat bars are all the bar anyone could ever need. Big fan.


+1 on the Pro-Moto.


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## eMcK (Aug 22, 2007)

Bike looks great, but I'm unsure why you built it around a skinny low volume tire that is as heavy as or heavier than many full size 29" knobbies?


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## pvd (Jan 4, 2006)

M.o.i.


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## eMcK (Aug 22, 2007)

MOI, hmm. It wouldn't be hard to build up a 29er wheel at less weight, such as: rim like the Notubes 355 (~410 grams) and a lightish 29er tire (~600 grams). You've got a ~480 gram rim and a ~680 gram tire combo going on there. 

How is this going to change MOI to your liking? I just want some more info on your thinking here.

Also, you should get those BB shells on the market.


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## Thylacine (Feb 29, 2004)

Moment of....._my arse._


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## teamdicky (Jan 12, 2004)

Ohhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh.....

Now I get it.
I rode with you (or at least that bike) at Tamarancho.

I was scratching my head after we talked, but I didn't ask the right questions I guess.
I kept thinking "Who's Peter Verdone?"


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## pvd (Jan 4, 2006)

eMcK said:


> How is this going to change MOI to your liking? I just want some more info on your thinking here.


In the last few years I have been focusing so much on design that I really don't care much about fancy parts. I try to spec parts that are light, cheap, AND strong. Yes! All three. There are now parts so nice coming from taiwan and japan that putting a solid, light bike for less cash is really easy.

The wheels were chosen to be cheap. Alex rims cost nothing and the slight aero cross section adds a lot of axial strength to the wheel. XT hubs because I didn't feel like ponying up for XTR. The tires are nothing fancy, but they fit the design goal. It is amazing how much 0.500" of radius on the wheel effects the MOI. The bike feels very light and quick to spin up, nothing like a 29er.

The XTR rotors were a splurge. I love those things.


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## MMcG (Jul 7, 2003)

WTF is MOI???


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## Live Wire (Aug 27, 2007)

MMcG said:


> WTF is MOI???


http://en.wikipedia.org/wiki/List_of_moments_of_inertia


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## eMcK (Aug 22, 2007)

pvd said:


> In the last few years I have been focusing so much on design that I really don't care much about fancy parts. I try to spec parts that are light, cheap, AND strong. Yes! All three. There are now parts so nice coming from taiwan and japan that putting a solid, light bike for less cash is really easy.
> 
> The wheels were chosen to be cheap. Alex rims cost nothing and the slight aero cross section adds a lot of axial strength to the wheel. XT hubs because I didn't feel like ponying up for XTR. The tires are nothing fancy, but they fit the design goal. It is amazing how much 0.500" of radius on the wheel effects the MOI. The bike feels very light and quick to spin up, nothing like a 29er.
> 
> The XTR rotors were a splurge. I love those things.


I know all about cheap parts, beleive me. I was just seeing if wheel diameter difference was enough for you to notice a diffrence between this and a 29" tire.

You work out a formula for this yet?


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## pvd (Jan 4, 2006)

The difference really is huge. I can also keep the wheels closer to center than the 29" stuff. The rear stay clearance allows for a lot more choices.

This bike is so much nicer than the 29er that I previously built. On that bike, even with SB8's, it felt so porky and cumbersome. This bike is much more peppy.

It does have drawbacks. It's obviously not that good in serious rock gardens. The lack of a front shock and the tire size make that clear. I see it being used for long rides that won't be very rocky.

The PVD2x2 will be installed this week. That will give me a singletrack and pavement gear. The PVD2x2 is a dingle that doesn't require chain tension adjustment with vertical dropouts. Essentially, paired magic gears. http://www.pvdwiki.com/index.php?title=PVD_Skinny_Puppy#Gearing


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## Thylacine (Feb 29, 2004)

pvd said:


> This bike is so much nicer than the 29er that I previously built. On that bike, even with SB8's, it felt so porky and cumbersome. This bike is much more peppy.


I think design and geometry has more to do with why you prefer this bike over your 29er.


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## pvd (Jan 4, 2006)

That may be true. I still don't like the big wheels though.


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## eMcK (Aug 22, 2007)

Some might say those wheels are "the big wheels".

I find it a little hard to believe that you can be riding such a comparatively heavy wheel/tire combo and be able to discern the difference between your wheel set-up and a lighter full 29" set-up.


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## pvd (Jan 4, 2006)

Give it a try. I was through speculating years ago so I started actually trying new ideas.


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## brant (Jan 6, 2004)

pvd said:


> Give it a try. I was through speculating years ago so I started actually trying new ideas.


Quite right. I just got back from one of the funnest rides in years with what must be the heaviest rear tyre I've run for a long long time...
42A Rubber Maxxis Minion DH 2.35 Supertacky.

Amazing how fast you can plough through rock gardens when you're not worrying about pinch flats or rim damage. Weheeeeee....


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## Live Wire (Aug 27, 2007)

pvd said:


> Give it a try. I was through speculating years ago so I started actually trying new ideas.


That's a fact, you don't know until you ride it.

So Peter, can you tell us what happened to fork #1? Must've been a hell of a crash!


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## coconinocycles (Sep 23, 2006)

pvd said:


> That may be true. I still don't like the big wheels though.


yawn. 700c is 700c. tire choice is tire choice. my LBS boss had a ross schafer made salsa with 700x45 smokes in 1990......... nice bike, though, PVD. practical. total agreement on the alex rims, too. most riders would be suprised at how many alex rims are sold with other company's stickers on them........ steve.


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## eMcK (Aug 22, 2007)

While I haven't tried the tire you are running I have ridden extensively with Mutanorapor 700x44s, Mythos 700x42s and Schwalbe Black Jack 700x45s. I've tried this "new" idea.

Alex rims for the most part are way underrated. I've got huge miles on a 700c Adventurer including time on the back of an Xtracycle. Still straight as day one. Cheap too. Wasn't slagging off on the parts quality wise, they just seemed like a poor choice to attempt to change MOI on a 700c off-road bike.


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## teamdicky (Jan 12, 2004)

Moved.
Imadumbass.


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## teamdicky (Jan 12, 2004)

A ha.

Proof that the bike is silly non-sense.
Those little tires provided so little traction they wouldn't even stick to the ground.


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## pvd (Jan 4, 2006)

Live Wire said:


> So Peter, can you tell us what happened to fork #1? Must've been a hell of a crash!


That was a weird one. I've done forks similar to this that were much longer and put extensive time riding on them. Never a problem. This fork didn't last the day. I had done a bunch of goofy trials things in the parking lot, the tamarancho ride, then to the BBQ. I was about to leave when I decided to do a front wheel skid up to a group of friends. That's when the fork buckled. Never had this done before. Future versions will use straight gauge on the brake side and maybe a gusset beneith the tab.

Fork #2 looks much whimpier but is much more comfortable to ride. I rode it a bit and it seems to ride fine on the trail. I need to do a little more testing. This type of fork gets a little hairy on washboard at speed, but that isn't too common where I ride most. I did a lot of hard braking and front wheel skids to check that it wouldn't break like the other and it seems fine there. I do need to try some bigger drop offs now.


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## MMcG (Jul 7, 2003)

I just gott a say - that's a pretty cool bike and all, but your claims that just because you are using fat cyclorcoss tires on it vs lightweight 29er tires makes it "not a 29er" are ridiculous.

Why not just say the geometry choices you used on this particular frame suit you well rather than calling it a 28" wheeled bike? 

Pretty hard to pull the wool over the eyes of folks who frequent this particular forum and I don't think you are fooling anyone.


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## brant (Jan 6, 2004)

pvd said:


> That was a weird one. I've done forks similar to this that were much longer and put extensive time riding on them. Never a problem. This fork didn't last the day.


I was wondering about that fork before I had it pointed out in the thread that it had failed.

Firstly on this one, and the replacement, there doesn't seem to be much of a nod to the now-common "forward facing" dropouts - helping stop the axle moving under hard braking (and some say stopping the wheel prematurely ejecting, though I've never had that happen myself).

Secondly, the disc tab (which caused the failure)... On our steel forks we have an extended drilled rib which goes up the fork leg, as a result of some fatigue cracking we had when our forks were used by trials riders.

Heres a terrible quality pic which encompasses both...


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## pvd (Jan 4, 2006)

[email protected] said:


> On our steel forks we have an extended drilled rib which goes up the fork leg, as a result of some fatigue cracking we had when our forks were used by trials riders.


I'm with you about the extended rib. Once the fork broke, I could see all kinds of ways to reduce the possibility of it happening again. It's just so strange that it didn't happen to the other forks. The paragon tabs that I've been getting limit my options. I prefer not to cut my own, but if I don't like how the other solutions I may have to go that way. I figure that a back plate will be good, but I'm also concered about adding stress risers. I'm never been a fan of gussets for that reason.


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## pvd (Jan 4, 2006)

MMcG said:


> Why not just say the geometry choices you used on this particular frame suit you well rather than calling it a 28" wheeled bike?


It is not possible to use a wheel with a 29" diameter on this bike. It is not a 29er. The 28" wheels fit just snug. It's a 28er.

622mm + 2 * 45mm = 712mm ( 28.0" )

622mm + 2 * 57mm = 736mm ( 29.0" )

622mm + 2 * 32mm = 686mm ( 27.0" )


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## Thylacine (Feb 29, 2004)

Now THAT'S impressive!

On our rigid forks, we're using a triple bulge-butted seat tube as the legs, which are 28.6 x 0.9 at the disc mount, and 30.0 x 1.2 at the 'crown', and thinner in the middle. Seems to work well. I honestly don't think 1" legs are up to the task like they were pre 'long AtoC' and 'discs'.

Extending the disc mount to avoid that point loading is yeah, a good idea.


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