Easy install of a tail light on a Trek XM700+

Jeff Backes

Active Member
If you own one of these bikes you have a front light, but no taillight. Well, that's pretty easy to fix. I purchased two parts, a "Bosch" and a rear cable kit.

1) Rear Rack
2) (Link Removed - No Longer Exists)
3) Cable Kit
4) An old credit card cut into strips

I removed the left crank with a puller tool.
I loosened the crash guard beneath the motor using a T-30 and a 4mm hex key
I then had access to the three left hand cover screws and removed them using a 2.5mm hex key
I removed the rear wheel
I inserted the plug end of the Cable kit into the third socket from the left toward the top of the motor
I snaked the cable behind the bracket holding the motor in place and out the back
I then ran the cable up the inside of the rear fender all the way around to the back
I cut an old credit card into strips about 1x3 cm and folded them into peaks
Every 10cm or so I inserted a piece of the credit card into the grooves on the inside of the fender to keep the cable in place
I drilled a hole in the back of the fender and fed the cable out the back
I found that the red wire in the cable was positive and so I soldered the Bosch cable onto the cable that came with the lights and covered all the wires in shrink wrap.
I turned on the head light and the rear light came on!!

Here are some photos of the completed project.

Let me know if you need any more information.



Here you can see the cable feeding into the inside of the fender. there was already an oblong hole in the fender that I used to feed the wire through.


You can see the little pieces of credit card holding the wire in place. It looks like crap, but if they are the correct size they seem to hold the wire in place very well, time will tell. The cable seems plenty durable.


Here is a picture of the light installed on the rear rack.

Chris Nolte

Well-Known Member
How to you reinstall the left crank? I have seen videos on how to remove it, but none for re-installation.
You should be able to press it on slightly with your hands, then install the bolt and tighten it into place. The left crank arm should be directly opposite the right crank arm.