More Parts, Different Bike

Tyler dropped by today with his aluminum steed. It had a few issues that needed to be addressed.

First up, the small chainring had broken, so he was running on only one speed up front. Due to it apparently being a bit of a peculiar crankset he wasn't able to source a replacement chainring, so instead he ended up with a whole new crankset and BB that then needed installing.

I had thought he had an actual Shimano crankset, but upon closer inspection it turned out to be a clone of some sort. So, the Shimano crankset end cap tool I had him 3d print didn't end up getting used, as the end cap on his cranks actually just used a hex wrench instead.

We did need to use a BB wrench to remove the old bottom bracket, and luckily that was a tool already in my arsenal. Threaded bottom brackets can sometimes really be stuck in there, but luckily for us it wasn't too tough to extract the old one. After tidying up the threads a little, the new one spun in nice and smooth.

Upon sliding in the new crankset, there was a little bit of confusion as to how things were lining up. Tyler's bike is a hybrid, which means that it's a bit of a peculiar mix between road and MTB standards. The BB is a road-standard 68mm spacing, while the rear axle is (I think) the MTB standard 135 (the old QR spacing).

The previous crankset appeared to be spaced out quite wide to match the chainline up with the wider MTB axle, but the new crankset was a road-specific model, and so it was sitting quite a bit more narrow on the bike.

In fact, it was sitting narrow enough that I started to have some doubts about whether the front derailleur would be able to properly shift the chain down onto the small ring. That was, mind you, before I remembered that front derailleurs have limit screws, and I should probably wind them out a little before giving up in despair.

Thankfully once I backed out the limit screws I was able to verify that the derailleur would have enough swing, so we were back up and running again. With a little twiddling and twaddling I was able to get the front shifting nicely, and we were good to go. With that part at least.

The next part would be less complicated, but quite a bit more work. Somehow Tyler had managed to break a few spokes on the front wheel, so after some faffing about at the bike shop and a bit of miscommunication and parts shortages, he managed to come home with a set of new spokes and nipples rather that a repaired front wheel. Thus it would be our job to do the swap.

Out came the old spokes, easily enough. I let Tyler do most of that work. Then, because it takes a bit of know-how to do I did the job of lacing up the new spokes in the correct pattern, as well as bringing the wheel up to tension and trueing it.

Once the wheel was round enough and straight enough I proceeded to impress Tyler with my amazing tire mounting skills, where I popped the tire onto the rim without anything but my bare hands, and without exerting much effort at all, and it was just a matter of putting the wheel back on the bike and sending him out for a test ride.

At least, until I noticed how loose his headset was. Turned out that his steerer was just slightly too long for the stem and the number of spacers he was running, and so the top cap was bottoming out against the top of the steerer rather than preloading the headset bearings like they should be. I tossed in another spacer for him, snugged up the preload, and then sent him out to take a test ride.

Apparently the test ride was a success, because he came back in one piece with no new injuries, and had no complaints about the performance of the bike.

All in all it was an enjoyable afternoon of tinkering, and a pleasure to get his bike back up and running smoothly again.