Rail 7 Chain ring keeps loosening

GrahamPaul

E*POWAH Elite World Champion
Nov 6, 2019
1,127
1,088
Andalucía
But it keeps coming undone! Surely a drop of locktite would do the job

If it keeps coming undone, is it possible that the freewheel hub cone is tightening up and giving you a bit of over-run which reverses the chain tension?

The rear hub on my missus' bike converted itself into a fixie recently which makes me wonder whether this is a possibility. Of course, I might be musing complete and utter bollocks...
 

protowheeler

Member
Sep 10, 2019
46
31
England
I've been researching this a bit. The BBT-18 comes in octagonal format so you can't use a 36mm socket with it. Instead I will need to buy a 36mm crows foot open spanner to use my torque wrench. The cheapest one of those I can find is 55€. Ouch!

This Unior one uses 1/2" ratchet drive. I'm sure there are other brands that have a similar thing. Trek carries Unior maybe they can order you one if you can't get it from Unior direct.
8 Tooth Cartridge Bottom Bracket Tool - 1671.2/4 | Unior USA
 

WilkyWay

Active member
Dec 26, 2019
120
102
Durham UK
This is what I made, patent pending...
6547383B-DC39-42C9-92A6-E5E2EA3555FF.jpeg
20EDF2BE-BC21-4EC1-9E5C-92F0C8F17FD4.jpeg
 

GrahamPaul

E*POWAH Elite World Champion
Nov 6, 2019
1,127
1,088
Andalucía
This Unior one uses 1/2" ratchet drive. I'm sure there are other brands that have a similar thing. Trek carries Unior maybe they can order you one if you can't get it from Unior direct.
8 Tooth Cartridge Bottom Bracket Tool - 1671.2/4 | Unior USA

Thank you! Found it on a Spanish site. Same price in euros as you pay in $. Methinks someone is being a little naughty here given that it's a Slovenian company. I guess we're paying lockdown markup. :unsure:
 

brizi2003

Active member
Nov 20, 2018
236
147
Whickham, Newcastle upon Tyne
Interestingly I saw a review about the Trek Rail, can't remember where, and they complained that the chain ring kept loosening! Also my Kenevo Lockring torque spec is 50Nm - I know its a different bike!
 

Paul Mac

E*POWAH Elite World Champion
Patreon
Subscriber
Jul 9, 2018
997
1,046
Uk
WilkyWay I don't believe you made that?
Prove me wrong and make another, then send to me for inspection ?
 

WilkyWay

Active member
Dec 26, 2019
120
102
Durham UK
This was the mk2 version. The mk1 was made from thinner wall steel and wasn’t up to the job.
It’s just a steel cylinder with The teeth cut in, welded to a 1/2” socket, then turned on a lathe to smoothen it and buffed.
Happy to take some more pictures for anyone who wants to make one.
 

kermaperuna

Member
May 2, 2020
3
0
FINLAND
Hello,

I have the same problem with my Rail 7.

- Do I need to remove the right side crank arm to tighten the chainring lockring

- Does it require any special tools to remove the right side crankarm?
 

Manicm

Member
Apr 23, 2020
38
3
Birmingham
Mine went today :( proper loose, given it a wash and checked it over, the locking but just keeps spinning, should it be clockwise? Or anti clockwise? Or is it a case of stripping the crank off then securing the nut?
 

kermaperuna

Member
May 2, 2020
3
0
FINLAND
Mine went today :( proper loose, given it a wash and checked it over, the locking but just keeps spinning, should it be clockwise? Or anti clockwise? Or is it a case of stripping the crank off then securing the nut?
Tighten it counter clockwise. You have to take the crankarm off first to tighten the lockring with a proper tool.

Remove the crank nut with 8mm allenkey. Then use crank-puller (ccp-44 is what i used) to remove crankarm. Tighten the chainring lockring counter clockwise with proper tool ( I used BBT-18). After that put the crank arm + crank nut back and tighten with 8mm allenkey.
 

Philly G

Well-known member
Jun 29, 2020
692
517
New Zealand
Is anyone not bothering with the o-ring? Difficult to torque up the lock ring without the o-ring bunching up, at which point it is surely no longer doing its intended job. Seems to me everything should work just fine without it?
 

Philly G

Well-known member
Jun 29, 2020
692
517
New Zealand
There’s definitely no o-ring on mine. It was either never fitted or fell of when it came loose. ??‍♂️
It cant be that important then, I can't work out what function it's supposed to have. I did read somewhere on here that some mechanics aren't bothering with it either ?
 

Manicm

Member
Apr 23, 2020
38
3
Birmingham
As I don’t have the tools I took the hour drive to the bike shop I got the bike from, all I can say is great service, offered me the software update and sorted the chainring out, shouldn’t come loose again. All sorted all there and then which I wasn’t expecting! Bring on the next ride!
 

EMTB Forums

Since 2018

The World's largest electric mountain bike community.

556K
Messages
28,104
Members
Join Our Community

Latest articles


Top