Trek Rail Chain Guard (broken and fix)

DJRumble

New Member
Jan 24, 2021
7
10
Australia
Last weekend I snapped a chain on my relatively new Rail 9.8. I changed up to a lower gear while starting an ascent and hitting a big root. The power down while chain was at such angle tore open the linkage. Lesson learned. Change gears before the hill.

What happened when chain snapped was as I pedalled, the chain knotted and then plowed through the *e Thirteen chain guard. The guard part was fine but arced piece it connects to snapped at what looks like a clear design weak point. Picture of broken part attached.

These things are impossible to get in Australia. Huge wait time and cost.

So I busted out the trusty Fusion 360 and made a new one that has more material around the weak points.

I 3D Printed it with tough PLA material. It come out perfectly. Printed an extra as a spare to carry as well. Only had one ride so far and works perfectly.

I will put it up on thing-verse soon. PM me if you want the STL file if you are in the same boat as me.
Chris

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BigMark

Well-known member
Feb 10, 2020
89
496
91737
I have a 2020 Rail 7 with 9300 miles, not sure when mine broke. Using the manual can't find the part number. Can someone provide it please, my new Faro Trek dealer was no help and did not feel it was an essential part...

sprocketthing.jpg
 

BigMark

Well-known member
Feb 10, 2020
89
496
91737
I normally get 3000 miles per groupset including the 9100 chain so I must be doing something right. The clay here may be a game changer though. Richard likes to type in all caps, don't be a dick!
 

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