Warning to Yuba Owners - don't use large rotors

[ohzee]

maybe I'm the only one that gets his humor,

. All I want is peace in the Middle East..... and a blow job.

Ill 2nd that.. I think we have a new quote for the quote page.

I knew you were kidding.. I do love my yuba.. I just need to figure out a strong moderately priced front fork now.

off to take a ride

 

[spinningmagnets]

I suspect for a solid front fork, a Surly fat-tire fork will prove to be a safe choice. http://surlybikes.com/parts/category/forks

As far a suspension fork, what are some proven options on then Yuba? perhaps something that is adjustable for stroke, since normally most people want a long front suspension to soak up bumps, but a Yuba might need a shorter stroke so it doesn't throw off the rake of the frame too much?...

 

[Philistine]

Myself and Boostjuice have the same Yuba frame, and have compared our setups, he is running Boxer triple clamp type forks. I was surprised at how well his bike handled, I would have thought such long forks would have had a bigger impact on geometry and handling. But I think I will just go with quality touring XC suspension forks of some kind. The problem is the head tube is so long I presume I will have to buy new forks to get a pair with a long enough steerer? (ie, I doubt any second hand ones will have a long enough steerer)?

Maybe I should get a pair of pure titanium suspension forks, then I can fill them with gold? At least then I could at some point sell those for an Interceptor:

 

[liveforphysics]

This fork was what I ran on Agni bike. It would let me stoppie a heavy long bike at speed with a heavy rider with out giving me any issues.

DMR trailblade is what it's called. They still break if you put them through enough, but they tend to fail gracefully when they go, which was part of why I got it.

http://www.universalcycles.com/shopping/product_details.php?id=9874&category=703

 

[Philistine]

I like the fork Luke,

It screams at me "get the frock out of my way, I am a fork, I hold wheels while they spin".

I also think it would be a really good strong replacement fork for my Yuba.....

 

[heathyoung]

We need some perspective..... All I want is peace in the Middle East..... and a blow job.

Not in that order I hope Or is that in order of how likely they would be... :|

 

[Philistine]

Not in that order I hope Or is that in order of how likely they would be...

Like all meaningful things, humour is fundamentally temporally located. Discovering the mechanism of a joke at the very time that you are actually enjoying it viscerally, is like that moment when you fart at the same time as you come in a girl.

 

[mdd0127]

Some great material in this thread....unlike whatever it was yuba made that fork out of!

Thanks for the new sig line Kiwi!

 

[Kiwi]

What us Appocaloptimists need is LiAu04 A whole new meaning to "taking off with the loot."

 

[Chalo]

Myself and Boostjuice have the same Yuba frame, and have compared our setups, he is running Boxer triple clamp type forks. I was surprised at how well his bike handled, I would have thought such long forks would have had a bigger impact on geometry and handling. But I think I will just go with quality touring XC suspension forks of some kind. The problem is the head tube is so long I presume I will have to buy new forks to get a pair with a long enough steerer? (ie, I doubt any second hand ones will have a long enough steerer)?

It depends on who used the forks and for what bike, doesn't it? But it's true that the age of de rigeur suspension has resulted in almost all newish MTBs being set up with really stumpy head tubes.

If the fork is from a decent aftermarket manufacturer, e.g. Marzocchi, Rock Shox, or Manitou, you can probably have them press out your old steer tube and install a new one. I had Marzocchi remove a bent steel steerer from my fork and press in a super thick aluminum one meant for downhill and dirt jumping. I think they charged me $60 for that.

Swapping to an extra strong steer tube makes sense for the bike you have in mind. XC forks tend to have modest thickness aluminum steer tubes, which are not really suitable for tandem and cargo bike use. So if you get a cheap deal on a good XC fork and the steer tube is too short, you can get a twofer by replacing the steerer with one that is both longer and stronger.

If you do buy new, I recommend a short to medium travel fork that is configured for strength and set up with a firm spring rate, like the Marzocchi Dirt Jumper series. The DJ3 takes a normal 9mm axle and has a strong steer tube, stiff springs and matching damping. The current model features 100mm, but some older ones had 80mm.

Chalo

 

[Philistine]

Thanks Chalo, appreciate the tip, my bike knowledge is limited as best, so do appreciate the info. Cheers, Phil.

 

[mdd0127]

Chalo suggested a great fork. The Marzocchi DJ3 is a beast of a fork. I had one on a Kona Shonky dirt jump bike and it survived many 8 foot + drops to flat without even flinching. I have no style and land like a box of rocks too so the bike/fork didn't have an easy life!

 

[GMUseless]

I had been looking at the fork for my Yuba for a while. It was one of the few forks I could find with a crazy long steerer tube (270mm) required on the Mundo, and is under US$250.

 

[teklektik]

[/URL]

Hopefully you can see what I mean by this pic it was hard to capture with my subpar phone camera.

I see it. I see it on my bike too, there is a concave surface on the fork at the bend, a result from rolling the tube. Yes, basically a "start to collapse here" point.

Hmm - late to the party again... I just bumbled into this thread which is pretty interesting.

So - to dial back a few pages: I got my v4 off the very first container to arrive and the forks do not have the indentation - they are smoothly convex on the exterior without even a hint of flattening. There is at worst some minor flattening on the inside of the bend from the mandrel. This suggests to me that there have been manufacturing variations after the first run that may have played a role in this failure distinct from other participating issues with design or quality control.

 

[shock]

I was taught in motorcycle safety foundation class to always use both brakes as well. Use the rear all the time and modulate the front. Locking up the rear is fine, it's what your supposed to do in an emergency. Locking up the front on the other hand, leads to accidents because the bike goes down very easily in that condition. So that's how I use 2 wheel bike brakes and have had no problems. As far as that fork picture, I've seen that happen to plenty of forks, but all of them involved in front end collisions. So this is either a huge flaw in the fork design/manufacture, or a huge flaw in the honesty of the poster.

 

[deVries]

So - to dial back a few pages: I got my v4 off the very first container to arrive and the forks do not have the indentation - they are smoothly convex on the exterior without even a hint of flattening. There is at worst some minor flattening on the inside of the bend from the mandrel. This suggests to me that there have been manufacturing variations after the first run that may have played a role in this failure distinct from other participating issues with design or quality control.

Very good observation. This either implies a design flaw in the manufacturing process that changed, or a new fork was used with different design & inherent flaw.

Either way, this leaves Yuba wide open to a lawsuit, IMO.

Hope they put a monster FF on there soon & be done with it. No sense in attracting lawyers to force a change that might destroy the company financially too. No more Yuba Mundos anyone?

 

[Chalo]

This either implies a design flaw in the manufacturing process that changed, or a new fork was used with different design & inherent flaw.

The most alarming thing about the failure documented here is the mode of failure. Strong or weak, forks should fail progressively and intact, and in my observation most of them do. Even if Yuba decide not to furnish a tandem-rated fork, they should switch to one that can bend without tearing or breaking.

My shop replaced a chromoly fork on a recently sold commuter road bike a couple of days ago. It had been in a major frontal impact that reversed the fork's rake and buckled its blades. But the fork absorbed the energy of the impact, and the rest of the bike was unharmed. Moreover, the failure was smooth and diffuse, without wrinkling, rupture, tearing, fracture or separation. To my mind, that's about the best scenario-- the fork withstands all normal loads, absorbs overload, spares the rest of the bike, and maintains enough integrity to support the bike and rider afterward. The only drawback I can see is that some nincompoops would continue to ride on it.

Chalo

 

[Hillhater]

The most alarming thing about the failure documented here is the mode of failure.

Why ? .. how did you think it failed

Strong or weak, forks should fail progressively and intact, and in my observation most of them do. Even if Yuba decide not to furnish a tandem-rated fork, they should switch to one that can bend without tearing or breaking.

Agreed..but this fork did remain intact , and there was no "tearing or breaking" that i can see.
Yes they need a better , stronger fork, but this didnt exactly "fall apart", it just bent badly.
..its just a crap design, poorly made with cheap materials and no QA testing to verify its suitability.

 

[amberwolf]

Agreed..but this fork did remain intact , and there was no "tearing or breaking" that i can see.

It is difficult for me to tell for sure, but the strong contrast/sharp lines at the point of the arrow I made in the pic below strongly suggest a crack/tear/break at that point, probably one that is horizontal at the side and vertical at the back edge, like a cross pattern.

Can't really be sure without a pic from behind.

 

[liveforphysics]

This either implies a design flaw in the manufacturing process that changed, or a new fork was used with different design & inherent flaw.

The most alarming thing about the failure documented here is the mode of failure. Strong or weak, forks should fail progressively and intact, and in my observation most of them do. Even if Yuba decide not to furnish a tandem-rated fork, they should switch to one that can bend without tearing or breaking.

My shop replaced a chromoly fork on a recently sold commuter road bike a couple of days ago. It had been in a major frontal impact that reversed the fork's rake and buckled its blades. But the fork absorbed the energy of the impact, and the rest of the bike was unharmed. Moreover, the failure was smooth and diffuse, without wrinkling, rupture, tearing, fracture or separation. To my mind, that's about the best scenario-- the fork withstands all normal loads, absorbs overload, spares the rest of the bike, and maintains enough integrity to support the bike and rider afterward. The only drawback I can see is that some nincompoops would continue to ride on it.

Chalo

I totally agree with you from a crash perspective. If you crash hard, it's fine for a fork to fold up to protect the frame, something has to give after all.

However, for any sort of braking use, the fork should never fold up ever no matter what IMO. No excuse for that.

 

[chaosbarbie]

Yuba clearlystates on their website, using any rotor larger than a 160mm on the front, and 180mm on the back is not recommended and voids the warranty.

It doesn't seem surprising that there was a failure if a rotor bigger than the one recommended was used.

 

[Punx0r]

Do you have a vested interest in Yuba?

 

[Alan B]

Yuba clearlystates on their website, using any rotor larger than a 160mm on the front, and 180mm on the back is not recommended and voids the warranty.

It doesn't seem surprising that there was a failure if a rotor bigger than the one recommended was used.

This argument doesn't hold water in several ways. But we've already covered that ground, reread this thread.

 

[anticarist]

Out of curiousity, was the fork that failed one of the new aheadset styles or one of the slightly older versions that had the threaded headset?

 

[boostjuice]

Out of curiousity, was the fork that failed one of the new aheadset styles or one of the slightly older versions that had the threaded headset?

Yubas use old-skool threaded headset type forks, but this has nothing to do with the failure point of the fork in this case.