Trek Rail - Carbon Frame Crash Damage

[ColP]

Hi Mitch

If you said a stick caught the frame and the store acknowledged that, it would fall outside of warranty when it was reviewed - just to provide some clarification. But we'll certainly give your claim and any others a fair chance to be fully reviewed!

In my case, I assumed a twig might have caused it, as at the time I couldn’t think of another explanation. But there was nothing in the drive chain.

It would seem very strange that this identical problem is happening to so many people and causing exactly the same effect, including literally identical damage to the seat & chain stays, and the derailleur.

Could you also clarify why Trek have updated the documentation to change the UDH fixing torque to 25NM?
Was this information directly conveyed to Trek customers via the dealer network.

 

[Mitch@Trek]

Hi Mitch



In my case, I assumed a twig might have caused it, as at the time I couldn’t think of another explanation. But there was nothing in the drive chain.

It would seem very strange that this identical problem is happening to so many people and causing exactly the same effect, including literally identical damage to the seat & chain stays, and the derailleur.

Could you also clarify why Trek have updated the documentation to change the UDH fixing torque to 25NM?
Was this information directly conveyed to Trek customers via the dealer network.

It's hard to say what would have caused the damage, but I could see something jamming it and breaking away unexpectedly! Otherwise, the warranty team may be able to shed more light on it for you. Regarding the UDH, I don't see any conversations regarding the change to 25Nm for the UDH, most, if not all, that I see are printed at 25Nm. SRAM's UDH has been around for a few years now on many of our MTBs, but this specific dropout design is also seen on the Fuel EX, Slash, etc that also have a lot of units out there.

 

[Nautical Biker]

So, I'm finally home from work and have some time off. Time to get the bike fixed up with the new parts that came whilst I was away. I opted for the GX AXS upgrade kit rather than a new X01 derailleur. One question before I make a start, will I be able to remove the redundant shifter cable without dropping the motor?

 

[Orangie]

 

[Dave_B]

So, I'm finally home from work and have some time off. Time to get the bike fixed up with the new parts that came whilst I was away. I opted for the GX AXS upgrade kit rather than a new X01 derailleur. One question before I make a start, will I be able to remove the redundant shifter cable without dropping the motor?

I was able to.
Pull the shifter cable out of the rear triangle (where it exits the rear triangle to go into the front triangle) as this is a bit of a pinch point. You should then be able to pull the shifter cable out very easily.

 

[Nautical Biker]

I was able to.
Pull the shifter cable out of the rear triangle (where it exits the rear triangle to go into the front triangle) as this is a bit of a pinch point. You should then be able to pull the shifter cable out very easily.

Thanks, I'll give it a go today.

 

[CordlezToaster]

Can the GX AXS be wired in to use the internal battery?

 

[Nautical Biker]

Can the GX AXS be wired in to use the internal battery?

Not out of the box. I'm not sure if you can buy the battery adapter wire. Might also need a firmware update on your Bosch system?

 

[Mikerb]

A couple of points re the damage reported in posts above that may ( may not help) but would certainly raise questions for me if I was to look at a bike with a carbon rear triangle.
I believe all of the above involved mechs fixed to a Universal Derailleur Hanger (UDH).
1. The torque of the fixing bolt is set by SRAM at 25nm and etched onto the bolt head as standard. It will make no difference whether the chainstay is ally or carbon since in both cases the dropout itself is ally.
2. The UDH allows the mech to rotate backwards if the chain seizes or the mech is hit. The force needs to overcome the friction caused by the 25nm torque of the bolt fixing.

So my question is whether the chainstay ( or more to the point the fixing of the ally drop out into the carbon chainstay) gave way before the hanger was able to rotate? If so that would indeed point to a design flaw.

Apart from standardising hanger design the main feature of the UDH is its ability to rotate to avoid mech damage. Lots of bikes are now fitted with the UDH so it would be interesting to know if the damage for the unfortunate guys above was caused despite the UDH rotating or by the carbon failing to hold the drop out.

 

[Mitch@Trek]

Can the GX AXS be wired in to use the internal battery?

It can't. Currently, it is just an option on the EXe into the TQ system. No word on cross-compatibility for Bosch.

 

[billium]

Just caught Todays GMBNTech show and the first bit of news is a new prototype Trek Derailleur hanger design .
Perhaps they have realized their UDH has a serious issue/bug.

- starts at 0:45

 

[Mikerb]

I think you will find that is a SRAM AXS specific development. There is in fact no hanger. The AXS mech is directly bolted onto the frame. The fixing method does appear to use the same type of UDH torque bolt however. That enables the mech to rotate backwards if hit by something with force sufficient to overcome the 25nm torque.
A normal hanger is of course designed to break if the mech is hit from the front or side on. The torque bolt here takes care of knocks from the front and AXS detects sideways hits and automatically moves inward to absorb it. So those attributes make the hanger obsolete.....but only for AXS.

 

[torabora851]

My turn with the carbon frame
I think that this is a design issue, as for all bikes I owned, the hanger snapped first to protect the derailleur and the frame. What amount of force should be applied to crack the thick derailleur neck?

 

[ilostmypassword]

My turn with the carbon frame
I think that this is a design issue, as for all bikes I owned, the hanger snapped first to protect the derailleur and the frame. What amount of force should be applied to crack the thick derailleur neck?

View attachment 100696 View attachment 100697

The YouTube video explains why this is happening. Sadly all it needs is some tension on the unit that flicks up and hits frame. Weird that it's not done out of the box by Trek! Good luck with warranty.

 

[Nautical Biker]

My turn with the carbon frame
I think that this is a design issue, as for all bikes I owned, the hanger snapped first to protect the derailleur and the frame. What amount of force should be applied to crack the thick derailleur neck?

View attachment 100696 View attachment 100697

I feel your pain! I think there is a compatibility issue with the design of the dropout and the UDH.
The UDH is designed to rotate out of the way if it is hit with enough force but the shallow frame dropout allows it to rotate almost 180 degrees, which is why the derailleur ends up embedded in the frame.
Older hanger designs would have snapped and left the derailleur hanging by the shifter cable, not stuck in your frame or cassette!
I have fitted 'armour' (ie a shit load of rubber padding and electrical tape) all along the seat stay on my bike to provide some cushioning and stop the derailleur become embedded in the frame if this happens to me again. I also check the hanger bolts are tight with a torque wrench before every ride. I am considering putting a dork disk back in behind the cassette too, to prevent the mech ending up wedged in there if the worst happens.

Good luck with repairs, I hope Trek offer you a good crash replacement discount or warranty repair. I got a very speedy response from them.

 

[torabora851]

Unfortunately, Trek refused to take responsibility for that problem. Their response:

" The UDH derailleur hanger has done exactly what it's designed to do - to rotate under excessive force in an attempt to save the derailleur. Unfortunately, the force put through the derailleur & hanger at the time of the incident was far too much for any of the hardware to handle."

I previously had two broken derailleurs, one on a Merida and one on a Norco bike and both without any damage to the frame.

I'm pretty disappointed with the design issues of this bike. A big part of the price of any bike is the RnD, and I feel that I just wasted my money on the RnD part of that bike, considering issues with the battery fitment and the problem with the hanger.

 

[JP-NZ]

Unfortunately, Trek refused to take responsibility for that problem. Their response:

" The UDH derailleur hanger has done exactly what it's designed to do - to rotate under excessive force in an attempt to save the derailleur. Unfortunately, the force put through the derailleur & hanger at the time of the incident was far too much for any of the hardware to handle."

I previously had two broken derailleurs, one on a Merida and one on a Norco bike and both without any damage to the frame.

I'm pretty disappointed with the design issues of this bike. A big part of the price of any bike is the RnD, and I feel that I just wasted my money on the RnD part of that bike, considering issues with the battery fitment and the problem with the hanger.

So are they helping with replacement of the rear triangle at all?

If you gave me the option of:
1. Broken/Damaged carbon frame
2. Broken/Damaged Rear Derailleur

Its a pretty bloody simple answer.

 

[torabora851]

So are they helping with replacement of the rear triangle at all?

If you gave me the option of:
1. Broken/Damaged carbon frame
2. Broken/Damaged Rear Derailleur

Its a pretty bloody simple answer.

I have:
broken rear derailleur, damaged rear triangle, the steel cable is torn off, and the twisted chain.
And an almost untouched hanger ( 25$ ) Great work UDH

Yeah, they give me a 20% discount on the seatstay replacement.

 

[Nautical Biker]

The best thing you can do is take out some accidental insurance cover once you have the bike repaired. That's a lesson I learned the hard way too!

 

[StarLord]

Man, still within the 30 day return period on my new Trek 9.7 Carbon and this is giving me second thoughts.

 

[davosaurusrex]

Was thinking of getting one despite the battery fitment issues but reading this has just removed it from the list, plenty of deadfall on my local trails!

 

[JP-NZ]

900km on my Rail 9.8 not an issue apart from some creaks I solved with grease and re-assembling the rear axle

 

[Sophie777]

I suffered a minor disaster this weekend whilst riding up at my local trail centre in Hamsterley Forest. I manged to snag a branch whilst descending and it got pulled up into the derailleur and through the rear wheel. I stopped as quickly as I could but the damage was already done, half a dozen bent spokes, the chain twisted over on itself in two places and trapped behind the cassette (can't help thinking a dork disk would have prevented that!) and the derailleur half exploded and embedded into the carbon seat stay. The hanger did not give way, it rotated in the dropout, allowing the mech to come up over the cassette. Shit happens I suppose but the bike is still new and I'm super disappointed that I have manged to inflict this much damage on it so early into ownership.

I have read somewhere online that Trek Rails have a particular problem with the mech rotating in the drop outs, has anyone else suffered similar damage? I'm wondering if this is reason enough to inquire about a warranty claim.

I'm also looking into options for repairing or replacing the damaged seat stay, what do you guys think is the best course of action? (this is my first carbon frame bike!). I have added some pictures of the damage.

Lastly, replacement mech, like for like replacement (X01) or should I go for the GX wireless upgrade kit?

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I can empathize with you.
I crashed my carbon Specialized Diverge within a few minutes of purchase - on riding out of the bike shop
The frame cracked in 3 places: 2 cracks on the side of the crash, the 3rd on the opposite side.

Specialized, like Trek in your case, offered me a 20% discount on a new frame (carbon or aluminum), and on parts that needed to be replaced.
I don't think, as suggested in this thread, Specialized would have done better than Trek in trying to make you whole.

But if you purchased your bike with a credit card - you may have a 90 day warranty (even in the case of a crash) with your credit card company - so I would check with them.

Visa paid for my new frame (I chose aluminum) and damaged parts (minus 20%), and the labour costs to install the parts on the new frame.

The lesson I learned is to never choose a carbon bike again.

 

[Nautical Biker]

I can empathize with you.
I crashed my carbon Specialized Diverge within a few minutes of purchase - on riding out of the bike shop
The frame cracked in 3 places: 2 cracks on the side of the crash, the 3rd on the opposite side.

Specialized, like Trek in your case, offered me a 20% discount on a new frame (carbon or aluminum), and on parts that needed to be replaced.
I don't think, as suggested in this thread, Specialized would have done better than Trek in trying to make you whole.

But if you purchased your bike with a credit card - you may have a 90 day warranty (even in the case of a crash) with your credit card company - so I would check with them.

Visa paid for my new frame (I chose aluminum) and damaged parts (minus 20%), and the labour costs to install the parts on the new frame.

The lesson I learned is to never choose a carbon bike again.

I thought I had bad luck breaking the frame after a few months, straight out of the shop must have been sickening.
I tend to agree about carbon frames, as much as I love my Rail (now fully repaired and insured), I would not choose carbon again. Hopefully the bike will now last me many years though.
The shop I bought the bike from were fantastic, they gave me a great deal on replacement parts and I was also very happy with the discount offer from Trek. It was nice to be on the receiving end of very good customer service.

 

[Nautical Biker]

Was thinking of getting one despite the battery fitment issues but reading this has just removed it from the list, plenty of deadfall on my local trails!

To be fair, this kind of accident can happen on any bike. I would say that if you have a carbon frame fit plenty of chainstay armour and make sure you have your hanger properly torqued up. If you have a UDH, pay extra specal attention to this point. I think the deisgn of this device is flawed to be honest.

 

[Nautical Biker]

Man, still within the 30 day return period on my new Trek 9.7 Carbon and this is giving me second thoughts.

They are amazing bikes, great to ride. My experiences suggest to me that the Aluminium framed version will be more robust though.

 

[torabora851]

To be fair, this kind of accident can happen on any bike. I would say that if you have a carbon frame fit plenty of chainstay armour and make sure you have your hanger properly torqued up. If you have a UDH, pay extra specal attention to this point. I think the deisgn of this device is flawed to be honest.

Rail uses Shimano, and UDH is Sram's part, this is probably a kind of corporate war. SRAM's UDH destroy frames with Shimano derailleurs installed

 

[Wilbur]

I can empathize with you.
I crashed my carbon Specialized Diverge within a few minutes of purchase - on riding out of the bike shop

Dang, that’s unlucky..

 

[ilostmypassword]

I can empathize with you.
I crashed my carbon Specialized Diverge within a few minutes of purchase - on riding out of the bike shop
The frame cracked in 3 places: 2 cracks on the side of the crash, the 3rd on the opposite side.

Specialized, like Trek in your case, offered me a 20% discount on a new frame (carbon or aluminum), and on parts that needed to be replaced.
I don't think, as suggested in this thread, Specialized would have done better than Trek in trying to make you whole.

But if you purchased your bike with a credit card - you may have a 90 day warranty (even in the case of a crash) with your credit card company - so I would check with them.

Visa paid for my new frame (I chose aluminum) and damaged parts (minus 20%), and the labour costs to install the parts on the new frame.

The lesson I learned is to never choose a carbon bike again.

What did you do? That is terrifying. I've never owned a carbon frame and never will. Too expensive and to fragile for mountain biking. Clearly.

 

[Wilbur]

What did you do? That is terrifying. I've never owned a carbon frame and never will. Too expensive and too fragile for mountain biking. Clearly.

Nah, they’re fine on mountains, just don’t ride into door frames leaving the bike shop..