LS05

The bike is a 2018 Fuji Track, fixed gear, size XXL with a FSA sealed cartridge BB bearing. I purchased a SRAM Truvativ GXP BB to replace the FSA.

I want to do the work myself...Is there anything I need to be especially aware of?


Thank you.

veganbikes

The first thing is making sure you got the correct bottom bracket for your cranks. It looks like that bike stock was running square taper cranks (most likely JIS taper) which is usually the case for lower cost fixed gears and single speeds from most manufacturers. GXP is different standard entirely and is not compatible with square taper, ISIS or Octalink or other 3 piece cranks or 24/24mm 2 piece cranks but will work with 24/22 2 piece cranks of the correct size.

Once you have sorted the BB issue or the crank issue if you are changing cranks then you will want to make sure you are using the correct tools for the job and use good quality tools because they will last longer and not strip components as easily because they should have a solid grip on the part. I would also make sure you are greasing your threads and if using a two piece crank greasing the spindle on that crank (though if you stick with a square taper you may not want to grease or go very lightly as the grease could help push the crank further down the taper and damage the crank arms. I would recommend a torque wrench but I would recommend a torque wrench in just about every situation because there is nobody on the planet who can sense torque by feel. Yeah maybe you have done it a while and you can get it to the same spot and so far that spot hasn't caused trouble.but proper torque is always a good thing in case you are wrong or deal with someone of a different size who might test your hand guessing.

If you do have square taper cranks make sure you get the correct spindle length for your cranks, it is not so much dependent on frame but on the cranks but most likely Fuji would have spec'd the correct length so just measure that (or look at the BB usually it is marked and get one of that same length and taper. I really like IRD Defiant (QB-99) Bottom brackets for square taper I think they are some of the smoothest out there and if they have your size I would go for it. SKF also makes fantastic square taper BBs and René Herse Cycles sells them (SKF is one of the largest bearing manufacturers in the world).

However if you are reading this and the first paragraph gave you pause because you may have bought the wrong B.B. don't risk it head on down to your local bike shop and they can get it installed for you, they have the tools and the expertise and you can use that time for other things. Not that you should learn how to work on your own bike but your LBS is there for you for stuff like this so you don't have to make expensive mistakes.

TejanoTrackie 

You should NEVER put any grease on a square taper bottom bracket spindle. The recommended torque values are based on a clean ungreased spindle, which will minimize movement of the crank arm when tightened and allow the tension in the bolt to be maintained for a tight connection. The bolt threads, however, should definitely be greased, to get an accurate torque reading.

veganbikes

Every mechanic is a little different I have talked to some who do grease and some who don't. Grease does prevent seizing and makes removal easier but yes your point is 100% valid as well. I am I guess sort of agnostic on the whole thing but most of my stuff minus three bikes is all external bb cranks or one ISIS crank.

TejanoTrackie 

If you are worried about seizing, you can use anti-seize compound, which is not a lubricant, but instead an insulator to prevent galvanic action between the two dissimilar metals (steel spindle and aluminum crank arm). It is also very helpful to prevent seizing between an aluminum seatpost and a steel frame.

Rolla

GXP is its own standard, with a 24mm spindle diameter on the drive side that tapers to 22mm on the non-drive side. If your crankset isn't GXP, that BB won't work. The FSA crankset that I took off of my All City Super Pro had a 19mm spindle.

Installation is super easy if you have the right BB and BB tool (and crank removal tool if it's square taper). Maybe post a pic and show us what you're working with.

veganbikes

True that. Good option!