Any advice on how to install the BBSHD with the shifting cable running along the bottom of the BB and the chainstay?

[FMercury]

I'm about to pick up a new Trek FX 3 as a donor bike. Before I install a BBSHD on it I want to try and address as many issues immediately. I noticed that the shifting cable on the FX 3 is similar to my Trek Checkpoint. the shifting cable runs inside the donwntube, then emerges at the base of the downtube and runs along the bottom of the bottom bracket, and then along the bottom of the chainstay.

Here's a photo of the FX 3: https://i.redd.it/ggugp0zg1kz41.jpg

Here's a photo from below, of my Checkpoint so you can see how the cable emerges from the downtube and tuns along the bottom of the BB and chainstay: https://i.imgur.com/m0x9NqO.png

Any advice on how to install the BBSHD with the shifting cable running along the bottom of the BB and the chainstay? Will the shifting cable cause any issues on the install/be in the way of the motor?

Thanks in advance!

 

[Patchogue]

Will the shifting cable cause any issues on the install/be in the way of the motor?

I don't see why it should cause any problems. It all depends on the bottom bracket diameter that you're using. If it's a regular BB68 then you should be fine. And regarding the sensor, just install it on the chain stay like it's supposed to be.

The only thing that I would recommend to you is to get a torque bar or build a stop bump rubber or nylon so if the motor rotates it doesn't smash your down tube channel.

 

[Thomsontouring]

Having built around 10 BBS02 and BBSHD bikes, I agree that the biggest danger is the motor getting loose and banging against the down tube. One of my bikes came back with the shifter cable totally munched between the tube and the motor. I've added a spacer on a couple of builds, and always wire tied the cable along the chain side of the downtube rather than the middle. I've also invested in a two-foot extension to the spanner wrench so the motors are REALLY tight. That has helped the most.

 

[Hyak]

Had the same dilemma. Either the cable gets bent more than I would like or the motor hangs too low and might catch a curb. Decided to drill a hole in the top side of the base of the down tube to route the cable over the top of the BB and on to the chain-stay. This would provide a good cable path and keep it out of the motor's way. I carefully filed the edges of the hole to remove burrs and prevent stress cracks from forming in the aluminum. 1,500 miles later, no issues.