Race Face X-type external bottom brackets are fitted with notoriously poor bearings; an engineer friend who I ride with once suggested they might actually be made of cheese. My Blur came with one such bottom bracket, and after a particularly muddy lap of Llandegla as part of Fearless earlier in the year it became completely seized. I replaced the bearings then, but not the plastic top cap which keeps most of the grime out, meaning the new bearings last about ten months before clogging up again. I’ve just replaced those, and thought I’d record the process here for anyone else who wants to try it.
1) You’ll need two new bearing cartridges to replace the ones you’re going to take out. The size you need is 6805 2RS. The 2RS just means that there is a rubber seal on each side. If you’re buying based on actual dimensions, the width is 7mm, internal diameter 25mm, external diameter 37mm. You can get generic ones quite cheaply on eBay, or pay a fortune for bike-specific ones which will almost certainly be identical. Don’t forget to get a couple of plastic top caps too; look out for the postman though as mine were a little over-packaged.
2) Remove the cranks and spindle from the bottom bracket, probably exposing much much in the process.
3) Remove the cup from each side of the BB shell using a bottom bracket tool.
4) Ignore the warning which says “Do not disassemble“. It’s more…guidelines than actual rules.
5) The first thing to do is remove the old bearing cartridges from the cups. The best way I’ve found to do this is using a punch. If you look through the shell from the threaded side, you’ll see the lip of the cartridge just poking out.
6) Get a punch onto the lip and then hit with a hammer until it pops out. It’s probably easiest to carefully clamp the cup in a vice while you do this. I don’t have a vice in my workshop (shed) yet, but found I was able to just cup the cup in the palm of my hand and use the fingers to hold the punch. I only needed some sharp whacks with a tap hammer rather than anything particularly hardcore.
Don’t try and whack it straight out or the cup forces the punch out and makes it slip off the cartridge lip. Take a shallower angle to avoid this, and encourage the cartridge out.
7) The cartridge will start to emerge from the cup. Don’t try to whack it out from one side in one big go; work around in circles so that it comes out parallel to the cup.
8) Eventually the cartridge will pop out. If you’ve been careful, you won’t have trashed the cup in the process.
9) You now need to fit the new cartridge into the cup. There are probably all kinds of different ways of doing this (again, easy with a vice I should imagine), but I used a decidedly low-tech one. I offered up the new race to the cup, between two bits of wood and gave it a whack with a claw hammer. A couple of blows were all it took to get the cartridge most of the way in. This only works so far though, as once the edge of the cartridge is level with the edge of the cup you can’t hit it any further in. To get the cartridge in all the way, it needs to go further and be a bit recessed. I therefore placed the old, knackered cartridge between the wood and the new cartridge, and gave it another whack. This is just enough to drive the new cartridge fully into the cup.
10) So there you have it, a nice shiny new cartridge in the cup, ready to go. At this point you can also fit the new plastic top cap – it’s a simple push fit.
11) Repeat for the other cup, then screw them back in to the BB shell, fit the cranks and marvel at how smooth the action is.
There you have it; it’s not terribly difficult or high-cost, but definitely makes a heck of a difference and is miles cheaper than buying a new bottom bracket each time yours starts crunching.