You don't need to be an 'investor' to invest in Singletrack: 6 days left: 95% of target - Find out more
Managed to break the mech hanger on my Rail 5, have rung around the local Trek dealers and nobody has one in stock. Got one coming from Trek but its from the Netherlands and going to take time.
It says its a UDH, but the shops say its not actually a universal hanger, anybody had any luck putting a SRAM UDH on a Rail? Be good to get going again before the year is out.
Pic of what you need? I've probably got one
As far as I know they are universal?
If you get one, you’ll need a torque wrench that works reverse thread, 25NM.
If they rotate they can take the derailleur into the frame and cause massive damage.
Only the bike industry could design a universal hanger that's not universal.
The trek one definitely looks like a UDH - the Nukeproof version is only £13...
If they rotate they can take the derailleur into the frame and cause massive damage.
I thought the point was that they were SUPPOSED to rotate, but no-one seemed to have clocked that if they rotated too far they'd trash the stay. Which I've heard of happening a few times.
Go for the Nukeproof one as it should fit if it is UHD.
It’s a UDH, but the bit that’s different is there’s a larger plate that covers the bearing on the Trek version due to the ABP bearing being exposed otherwise. A normal will work fine.
A couple of tips for when fitting yours, loosen your axle before tightening the hanger, and make sure the axle has plenty of grease on it, or it can bind and loosen the hanger when removing it (could be a factor in hangers rotating).
Thanks all, tried one I found in the local shop. All fitted OK, thought I'd cracked it, the axle thread was a different pitch so foiled at the last hurdle.
Good shout for the nukeproof, I'll see if I can get one of those to try while I wait for the Trek original.
This just happened to me on a trek. Broke the mech, but meanwhile the “sacrificial” UDH spun around (survived) and smashed my carbon frame.
Pretty annoying I must say.
Yep, that's why we're under strict instructions in our workshop,to make sure they're tight, and why I mentioned making sure the axle is greased. It can be a costly failure if you don't.
I bet the damage looks exactly like this
Earlier Rails had 20NM on the UDH, Trek have now changed it to 25NM
coatesy
Free Member
Yep, that’s why we’re under strict instructions in our workshop,to make sure they’re tight, and why I mentioned making sure the axle is greased. It can be a costly failure if you don’t
I'd this a trek specific problem or all UDH equipped bikes?
Ay Caramba! I timely reminder to buy a spare mech hanger for my Rail. I'm assuming that the damaged stay is beyond repair. Ouch.
So you can destroy your mech and the stays of your frame but the UDH survives, genius.
At least they're now a tenner at CRC/wiggle, swings n roundabouts.
Doubt it's a Trek specific issue, but they were our first experiences of UDH systems, and we've been making sure they're tight ever since.
coatesy
Free Member
Doubt it’s a Trek specific issue, but they were our first experiences of UDH systems, and we’ve been making sure they’re tight ever since.
Seems like a design oversight then as this is from the SRAM page about the UDH:
"It protects your derailleur against chain jams by pivoting back and out of the way, and slips slightly when encountering impacts"
I guess/hope that making sure it is torque'd to spec limits or slows this backwards pivot motion...
We were so close to being rid of the million different mech hangers there as well.... 😂
It’s like you’re looking at my bike but in red instead of black.
Sounds like this is a bit of a failure of design on trek’s part. Whist the UDH is supposed to move, as a non mech eng it sounds like it’s not been reinforced enough. Did you try taking it up with trek to see what they said? I did mine last week but haven’t taken it back in to get it sorted as it’s been Christmas break.
Yep, after a lot of negotiation they wouldn’t admit any kind of liability but I kept pressing them on why they’d increased the torque to 25NM.
Eventually they replaced seat & chain stays plus the UDH and even the rear mech.
So a good result overall.
It’s happened to loads of Rails, there’s a few EMTB forums threads on it.
Not just treks from what I’ve heard. Also saw similar on a Specialized where the hanger is not UDH but has similar issue
Blimey, another 7 minute Youtube video that could easily be 30 seconds long.
"look at this bolt"
"Make sure that the hanger is swung as low as it will go"
"tighten bolt COUNTERCLOCKWISE to the correct torque"
"Cross your fingers and try not to crash...."
The end.
I have also seen the threads of these hangers strip due to being plastic, so I wouldn't torque too tight either. It's not an amazing design....
Had them come on bikes straight from the factory with threads stripped, nowhere near as much fun & games as when they shear off flush as you check they're tight.
The Norco version (pre-UDH but similar design) on the current Sight was pretty funny. The axles kept seizing in the frame. Even with an allen key on both ends of the axle you couldn't release it. You had to take the rear triangle apart ha ha. We told the local Norco rep that the axle was the issue which fell on deaf ears even though he reported into the Head Office. Norco redesigned hanger again instead :facepalm: . Sure enough, the problem wasn't solved and a whole load of waste created. Finally they changed the axle....
Seems that some modern mech hangers snap instead of bending like the mech hangers of old. Worse design IMO.