Bottom bracket and crankset

Before I started out building my bike I did a fair amount of research on a number of various subjects. One of them being, in what order do I assemble a bike? Luckily I found a guide on Park Tools webpage. One of the first elements to install, according to this guide, was the bottom bracket and the crankset, and so I did.

I had decided on going almost pure Shimano 105 components for the drivetrain and shifters. It’s what I have on my road bike where it has done the job just fine, plus I didn’t want to spend a great deal of money on Ultegra components for a bike that will experience some rough riding in mud and rain.

Bottom bracket

The bottom bracket is a standard 105 bottom bracket.

Furthermore I had bought a bottom bracket remover for installing the bottom bracket.

Armed with this. I was ready.

Here’s the bottom bracket.

bottom bracket

And here’s the bottom bracket removal tool, and some grease
bottom bracket removal tool and some grease

Mounting the bottom bracket is easy. Apply some grease, fasten the right cup which holds the center piece as well (there is an arrow showing you which direction to turn), fasten the left cup and that’s it. The most important part is to not overtighten the cups.

The final result


For the crankset, I had decided to go with the Shimano CX50 cross crankset which has 46 and 36 teeth chainwheels, as opposed to the normal 53-39 or 50-34 teeth chainwheels that you’ll find on a roadbike.

Here it is

(it will never be this clean again!)

Mouting it is described in the techdocs from Shimano and was almost as easy as mounting the bottom bracket. A bit of grease on the spindle. Push the part with the chainwheels through the bottom bracket and attach the left part. Tighten it, just a tad, and then mount and tighten the plastic cap (it must be done before tightening the left arm completely). Now make sure that the so called stopper plate (a little thingey that goes into the groove on the left arm) is in place, and tighten the bolts. I used a torque wrench to make sure that I wasn’t overtightening the bolts, Shimano recommends a torque between 12 – 14 Nm.

And that’s it, the bottom bracket and crankset was now installed.

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