Trek Rail 5 2020 - Rearhub service

[Hamina]

After 500km the rearhub of my Rail 5 seems to come to an end. Problems started when chain started to drop off from front sprocket.

OEM SRAM SX chain was at 0,5% -> replaced with GX chain.
OEM SRAM SX cassette was missing one tooth -> replaced with new SRAM NX cassette.

With new (and old) NX cassette there seems to be play in the driver/freehub. When driving in biggest gear with quite normal pedal pressure the freehub seems to pop-off one teeth forward (I don't know the correct word in english). I think it might have to do with the play and the fact that torque from smallest cog causes pawls loose the grip.

Trak Rail 5 hub specs:
Freehub/Driver: Formula DWG--137
Driverside: Xero 15267 LU 15x26x7mm
Non-Driverside: Xero 6902-LU 15x28x7

The inner diameter is 29,5mm if you want to build your own tool from socket.

Play:

Trek Rail 5 - 2020 - Formula DWG-137 hub

www.emtbforums.com

Some instructions how to disassemble the hub:
Hi Lo rear disc hub service/replacement- Mtbr.com (bearings are different)

Potential spareparts:
COMMENCAL | HUB AXLE KIT FORMULA AX-2139 the hub axle
Free hub bodies - Shop One of these could fit

I'll try to fix it by changing new bearings and report back. I'll add some photos when I get the freehub open.

 

[Hamina]

Removed one thin shim inside the freehub and handtightened the freehub. Play seems to go away. Washed everything with IPA and put new grease inside.

Made a tool from 21mm socket


This is what's inside. 3 shims: 2 thins + 1 thick.


The freewheel pawls. Seems to be ok

 

[themonkster]

My rear hub on my Rail 5 had been making a rough noise for a while. I asked my LBS to have a look while they were looking at my gears and updating the firmware.

They changed the bearings in my rear hub. Its come back super quiet. I've attached a picture of the parts that were removed with the invoice.

Don't know if this helps anyone.

 

[Hamina]

Bought a new OEM freehub. Seems to function correctly but there’s still aldready little play when pushing cassette on sides. Interesting to see how long it last. Hopefully until I get some decent hubs and rims.

Changed also the other bearing (6902), but only because I accidentally broke it.

W547627 is the product code
Hub Bontrager 1248

The old one was not good without all the three shims, but could be if one would be just a little thinner.

 

[Djlcater]

My rear hub on my Rail 5 had been making a rough noise for a while. I asked my LBS to have a look while they were looking at my gears and updating the firmware.

They changed the bearings in my rear hub. Its come back super quiet. I've attached a picture of the parts that were removed with the invoice.

Don't know if this helps anyone.

View attachment 37285

I had mine replaced under warranty as well, seems like it’s a common fault with that hub!

 

[themonkster]

I had mine replaced under warranty as well, seems like it’s a common fault with that hub!

Mine wasn't replaced under warranty. I'd done 900 miles on it.

 

[Hamina]

I think that the freehub play could we fixed if one of the shims would be just a little thinner.

I'll try to keep this wheelset alive couple of months and replace them with DT Swiss 350 + EX511 set. The OEM wheels will be good for commuting with slicks and when selling the bike.