Brand new 9.9 1 mile riding and frames is damaged due to rear mech hanger

[CJaMTB]

when was the alignment tool actually invented ?

The Park Tool V1 has been around at least 15 years, probably longer.

 

[Stihldog]

Torque settings another would be engineers like to throw about.

I agree. There seems to be a measurement tool for everything …with little tiny numbers. Next tool on my list is a magnifying glass(Old School Style) or a x10 monocle. .

I know my distance ancestors didn’t use a measuring device or story pole to chip away at the cave opening …they managed. But I ride an eMTB and lose sleep if I hear something strange coming from my bike. My never ending search for perfection causes unnecessarily close tolerances.(I have a problem).

 

[Mikerb]

The SRAM UDH is part plastic and part metal. The shaft and securing nut are metal, the actual hanger section is ABS. Obviously you can only fit the UDH if the bike was designed for it. Unlike most other hangers it bolts through the chainstay and is held in place by c 24nm torque applied to the securing 8mm bolt. Other designs usually include additional securing screws to keep the hanger in place and are made of ally.There are however non OEM versions of the UDH which are made of ally such as the PILO D798 ( over twice the price!!)

I cannot help thinking Trek have messed up by using the UDH design at least on their carbon frame versions since the UDH is designed to rotate if subjected to fairly extreme force like a chain jam, yet on the carbon Trek chainstay they have included a "carbon stop" to keep it in place. Maybe the carbon chainstay cannot support the full torque specified by SRAM and so Trek included a stay to reinforce its placement in the correct position. If however the arrangement is not sufficiently torqued.......or there is a chain jam, the hanger is merely going to rip the stay off which probably means the chainstay is a write off.
I assume there is no stay on the ally versions of the Trek??

 

[Binhill1]

J

Which proves what..? Old school or ignorant, could be either... Not being cheeky, just saying.

Just that not everyone needs a special tool to repair things . Some great mechanics out there.

 

[Binhill1]

I agree. There seems to be a measurement tool for everything …with little tiny numbers. Next tool on my list is a magnifying glass(Old School Style) or a x10 monocle. .

I know my distance ancestors didn’t use a measuring device or story pole to chip away at the cave opening …they managed. But I ride an eMTB and lose sleep if I hear something strange coming from my bike. My never ending search for perfection causes unnecessarily close tolerances.(I have a problem).

Exactly its a bike not a space ship. I remember when i used to go to Charlie Rhalph my repair guy he was a custom frame builder . My chain ring was worn he said turn it round the other way youll get a couple more years out of it. All changed now . Enjoy yourself anyway and dont let the buggers on this forum annoy you gŕrrrr

 

[CJaMTB]

J

Just that not everyone needs a special tool to repair things . Some great mechanics out there.

No they don't, but sometimes the special tool makes for a much easier and neater job, which is what a customer is paying for. Anyone can grab a mech and bend it back into shape, but that weakens the mech and risks damage to the more expensive component (the mech). Using the mech hanger tool removes that risk and achieves a perfect result every time. Right tool for the job.

 

[Stihldog]

Lately my preferred method of crash is OTB,
( more airtime, unpredictable landings, lifetime experience and spectacular videos.). Haven’t bent a derailer hanger recently. A trail-side fix was needed that time but when I got home I checked the alignment again with the tool. If/when I remove a derailer I usually check the hanger alignment with a tool. It’s kinda easy. So is a visual check but not as accurate.
I’ve installed the AXS GX derailer a while ago and thank gawd I haven’t smashed that yet but the benefits may outweigh the risk. I’ll cross the “bent derailer hanger bridge” when I get to the next crash, lay down, trail-squirrel or poor judgment moment.

 

[Bomble]

The SRAM UDH is part plastic and part metal. The shaft and securing nut are metal, the actual hanger section is ABS. Obviously you can only fit the UDH if the bike was designed for it. Unlike most other hangers it bolts through the chainstay and is held in place by c 24nm torque applied to the securing 8mm bolt. Other designs usually include additional securing screws to keep the hanger in place and are made of ally.There are however non OEM versions of the UDH which are made of ally such as the PILO D798 ( over twice the price!!)

I cannot help thinking Trek have messed up by using the UDH design at least on their carbon frame versions since the UDH is designed to rotate if subjected to fairly extreme force like a chain jam, yet on the carbon Trek chainstay they have included a "carbon stop" to keep it in place. Maybe the carbon chainstay cannot support the full torque specified by SRAM and so Trek included a stay to reinforce its placement in the correct position. If however the arrangement is not sufficiently torqued.......or there is a chain jam, the hanger is merely going to rip the stay off which probably means the chainstay is a write off.
I assume there is no stay on the ally versions of the Trek??

I sucked a stick into my derailleur while powering up a hill, it jammed and snapped the derailleur and the whole lot spun into the top of the chainstay/seatstay. The hanger didn’t bend or snap but had enough force to ride over ” the stay” without damaging that area at all. The damage occurred where the derailleur impacted the top of the chain and seat stays.

 

[CJaMTB]

Does sound like this Trek design is not good! I know the UDH is being used on a bunch of other bikes, e and otherwise, but haven't heard of this issue before, so is it just an issue with the Rail?

 

[Hamina]

Does sound like this Trek design is not good! I know the UDH is being used on a bunch of other bikes, e and otherwise, but haven't heard of this issue before, so is it just an issue with the Rail?

Well on the other hand we don't know really the size of the possible issue: Is it just one bike, two bikes, all Trek bikes or all UDH-equipped bikes.

 

[Bomble]

Well on the other hand we don't know really the size of the possible issue: Is it just one bike, two bikes, all Trek bikes or all UDH-equipped bikes.

To be fair, since then I have broken chains/derailleurs and haven’t had the same issue. I think it was more a case of bad timing as when it dragged the stick in I was on a really steep hill stood on the pedals, there must be a hell of a lot of force going through it at the moment.

 

[Taff]

To be fair, since then I have broken chains/derailleurs and haven’t had the same issue. I think it was more a case of bad timing as when it dragged the stick in I was on a really steep hill stood on the pedals, there must be a hell of a lot of force going through it at the moment.

Just check it every ride if the wheel is out. Takes seconds to check that hanger torque or tightness. Riders have to be responsible for some daily/ regular maintenance.

 

[Bomble]

Just check it every ride if the wheel is out. Takes seconds to check that hanger torque or tightness. Riders have to be responsible for some daily/ regular maintenance.

The hanger spun even though it was tight but yes I always check over the bolts on the bike before the next ride, it’s surprising how often things loosen off.

 

[Binhill1]

Just check it every ride if the wheel is out. Takes seconds to check that hanger torque or tightness. Riders have to be responsible for some daily/ regular maintenance.

Just like we test air pressure and fluid levels and every other recommended things in life , switch of gas in house etc . Come on Taff

 

[Mikerb]

I have seen a few MTB videos where they recommend checking all bolts before a ride, but I wonder how people actually do that. Most bolts are tightened to a specified torque and some are threadlocked. In either case any disturbance of the bolt will either break the thread lock or change the torque.........both will then subsequently keep coming loose!! So really the only "check" that should be done is with a small allen key just to ensure nothing is really loose..........well below any torque figure..........and I would leave low torque screws/bolts that are threadlocked alone!
I admit I do not check any bolts..........the majority I have secured properly myself in the first place, and I have never had any come loose!!

 

[Binhill1]

I have seen a few MTB videos where they recommend checking all bolts before a ride, but I wonder how people actually do that. Most bolts are tightened to a specified torque and some are threadlocked. In either case any disturbance of the bolt will either break the thread lock or change the torque.........both will then subsequently keep coming loose!! So really the only "check" that should be done is with a small allen key just to ensure nothing is really loose..........well below any torque figure..........and I would leave low torque screws/bolts that are threadlocked alone!
I admit I do not check any bolts..........the majority I have secured properly myself in the first place, and I have never had any come loose!!

Totally agree when i check any bolt and it is not often , i cant recall one ever being loose. Saying that got back bike from dealer and took off crank before i used it and was surprised how easy they were to come off . Everyone definitely obsessed with torque values which i never heard of till Ebikes arrived. I am basing this on riding serious offroad since 1986 .

 

[Mikerb]

Do it once...and do it right! I check everything on a brand new bike. LBS dont get to play with my bike. I trust noone!!

 

[Binhill1]

Just check it every ride if the wheel is out. Takes seconds to check that hanger torque or tightness. Riders have to be responsible for some daily/ regular maintenance.

Well i was out yesterday dont know what actually happened. Only doing 5 mph probably less on beach stones maybe some tangles. Drive train gave a clunk lower jockey wheel bolt came out and the derailier to hanger bolt as well . Both stripped so new hanger and new derailier. Whether i picked something up and it jammed or dare i say a loose bolt i dont know .

 

[Stihldog]

Well i was out yesterday dont know what actually happened. Only doing 5 mph probably less on beach stones maybe some tangles. Drive train gave a clunk lower jockey wheel bolt came out and the derailier to hanger bolt as well . Both stripped so new hanger and new derailier. Whether i picked something up and it jammed or dare i say a loose bolt i dont know .

Lucky bastar…err I mean that sucks! Similar thing happened on my hardtail last year. Chain ate a stick and snapped the derailer and badly bent the hanger. Installed a handmedown from the rail and got a AXS GX. Problem solved

 

[Binhill1]

Lucky bastar…err I mean that sucks! Similar thing happened on my hardtail last year. Chain ate a stick and snapped the derailer and badly bent the hanger. Installed a handmedown from the rail and got a AXS GX. Problem solved

I wondered if i could have retapped but maybe not. I sold an unused 6 year old xt derailier and shifter last month for £100 so alls well. To be honest i cant remember the last time i broke one if i ever have.

 

[Stihldog]

I wondered if i could have retapped but maybe not. I sold an unused 6 year old xt derailier and shifter last month for £100 so alls well. To be honest i cant remember the last time i broke one if i ever have.

Sh*t happens. I’ve chewed through a couple of derailers in the past two years …but I’ve never had flat tire, yet.

 

[Taff]

Just like we test air pressure and fluid levels and every other recommended things in life , switch of gas in house etc . Come on Taff

Down to the individual. 10 seconds to check- weeks off bike if it goes wrong. Really don’t see what problem is.

 

[Asnowmobiler]

totally agree on the video the guy says torque to 25 nm which is to high for the carbon frame

my bike the bolt says 20 nm

it look like when mine was built the hanger was possibly sat on top of the stop peg so the hanger was at a angle which is why it moved so easy and the stop I think is completely broken off

NEW TREK RAIL 2020-2021 SERVICE MANUAL SUPPLEMENT
This is at the top of the forum page. Download it and you will see they upped the torque to 25 for the carbon bikes. My 2021 also read 20nm on the attachment bolt, but confirmed it should be 25nm and it's reversed thread. Mine was too loose from new and spun backwards, chipping the paint.

 

[BobMtnBkr]

Asnowmobiler brings up an important point. The enclosed video says the nut is a left-hand thread… So you need to turn it counterclockwise to tighten it (as opposed to the normal “righty- tighty”).