Bottom Bracket and Crank Set
The next step for my single speed mountain bike beast build is to get the bottom bracket and crank set installed. I have received all the components necessary and will begin with the bottom bracket.
I am converting the bottom bracket from the 1 piece crank set that it came with, to a 3 piece square tapered bottom bracket. This will improve the ability to customize and update these components in the future if/when I decide to do so. Using the bracket adapter pictured, I am able to reuse the previously existing cups, that I left in the bottom bracket. The old cups cleaned up nicely and did not have any dings or scratches that would inhibit smooth rotation of well greased bearings.
I begin by greasing the inside of the cups, and packing the bearings. Do not be stingy here, you will want to roll grease between each of the ball bearings and make sure that there is plenty of grease. The last thing you want is to have to pull everything back apart and re-grease it again.
Installing the shaft of the bottom bracket, you will notice that there is a rib on the interior of the threads on only one side (pictured). This is the non-gear side, and the nut on this side will be installed completely to that rib. **Note** When installing the nuts be sure to check and recheck the smooth rotation of the bracket, do not over tighten or leave the nuts too loose, you need to find that sweet spot right in the middle.
On the non-gear side, only the one bracket nut is used. On the gear side, a washer with a guide notch (pictured) is installed, followed by another nut (pictured). Once you install the additional washer and nut, recheck the smooth rotation again. Bottom bracket installation complete.
The next step is the crank set/chain ring. As I mentioned this beast is going to be a single speed. So there is only 1 chain ring being installed, no derailleur, no shifting gears…simple, minimal and just right. In order to take full advantage I went with a 34 tooth oval chain ring.
There are a multitude of reasons on why I chose this style of chain ring and I will be writing a separate post explaining the science behind oval chain rings soon, so be sure to subscribe so that you don’t miss it.
First, I installed the chain ring onto the crank, if you notice in the picture of this particular chain ring you will see a triangle/arrow printed on one side of the ring, this is the direction that the crank is installed. If you get a brand that does not have this guide, you just need to know that the widest part of the ring should be vertical when the crank is horizontal. The reason for this will be explained in my oval chain ring post, so you will just have to take my word for it for now.
Attached the cranks onto the square tapered bottom bracket and secure them with the nut that was provided with the bottom bracket. Rinse and repeat with the non-crank side. Crank set installation complete.
What good is a crank set and bottom bracket without some way to power them…The last step for this assembly is to install the pedals. Most pedals are labeled as to which side they belong on, but in the case that they are not you just need to make sure that they thread in by spinning them towards the front of the bike. Right side threads in clockwise, and the left threads in counter-clockwise. The pedals can be tightened by either using an open ended wrench on the pedal side, or an allen wrench on the inside of the crank arm. Make sure these are nice and tight. Pedal installation complete.
Tools used for this step:
Allen wrench set
Total cost for this step: $94.03 (84.76 Euro)
Muc-Off Bio Grease – $13.30 (11.99 Euro)
3 piece bottom bracket adaptor kit – $17.75 (16.00 Euro)
34 Tooth oval chainring crankset – $42.99 (38.75 Euro)
RockBros pedals – $19.99 (18.02 Euro)
*Each component description is linked to the same or a similar component to the one I used, prices may vary.
Bike Build Rolling Total – $104 (93.75 Euro)