Trek Domane+ - non_OEM solutions for Kiox mount, and lighting suggestions.

William - Bosch Team

Active Member

Hey Jim,

That light setup looks great, well done!

As Ebiker01 said, your drive unit is 4th generation (any Class 3 or 28mph max. assist DU with a full-size chainring is 4th gen.) For reference, some 2020, and maybe even some 2021 products will still utilize 2nd generation drive units, depending on OEM design. In other words, model year is not always a positive indicator of DU design.

All of our 4th generation drive units use (6) "Torx-40 Plus" fasteners. Torx Plus, or Torx+, is more of a specialty interface, and a bit more common in automotive. We used it as it allows more contact area for a given cross section size, which translates to the ability to achieve proper torque specs with a shallower bolt head. We did it for clearance. During re-installation, your bike shop should be sure to use a proper alternating sequence for tightening, and carefully torque to 20 Nm. It is also critical to note that the mounting plates attached with Security Torx, or tamper-resistant Torx, should not be removed under and circumstance.


New Member
Thanks again @William - Bosch Team . Excellent info.

Thanks for the tip on the Torx-Plus TP40. I just ordered a 3/8 socket in this size so I can put it on my torque wrench!

I'm not inclined to tinker with anything on the bike that I don't need to. Removing the mounting plates would not interest me at all, so no risk of me bodging that one up.

Having been an aircraft mechanic in a previous life, I'm pretty familiar with assembly techniques where torqued bolts and odd shapes are involved. As a general rule, I will always rotate and switch sides as I go through tightening a set of bolts.

The one real challenge with the bike (other than a few nerves over the Torx size) was trying to get the light wiring through the seat tube. There is some kind of proprietary DI2 battery mount that has the battery suspended from the area where the seat tube/top tube junction is. I can't find anything in any manuals about it, and got myself into a bit of a pickle when I accidentally pulled the Di2 wire out of it while moving things around installing the light. I could not figure out how to remove the thing at all. I finally ended up making an extra long Di2 wire attachment tool out of a piece of wood dowling and was able to get the wire plugged back in. And as I mentioned before, I had to fashion a fish tape tool out of a guitar string to get the light wiring fished through the tube.

Otherwise, nothing was terribly exciting.

Now if I can just get the guys at the Trek Shop to return my emails/calls about an appointment to get my firmware updated and the light settings changed so I can control them on the Kiox, I'll finally be done with this project.


William - Bosch Team

Active Member
Good call on the 3/8 socket! I forgot to mention that part. :cool:

That's really cool on being an aircraft mechanic. I bet your mechanical and problem-solving skill set is 11/10! There is something so satisfying about creating your own tool for a job (especially when it saves the $$$!)

That's a bummer on the shop response, though everyone is still very busy from what I understand. Not sure if this helps, but for the update/light setting adjustments you can go to any Bosch Certified dealer. Not sure what they charge for the services you need performed, but may save you some waiting time.