Bottom Bracket Complexity
 

Hey guys,

I'm deciding to buy a Dolan Pre-Cursa Frameset because it's a frame that I like and fits my budget/dimensions.

That being said, it will not have a crankset or bottom bracket -- I'll be transferring (hopefully) the bottom bracket and crankset from my other bike to the new one.

The problem is that the bike that I currently have was also a secondhand fixie that had a mix-mash of parts.

Anyone know how to check the bottom bracket specificity before having to take the bike apart and finding out?

I believe the current fixie I have has a Retrospec frame, although I haven't seen any branding of any sort besides the wheels.

Any advice regarding swapping parts from one bike to another would be appreciated! :)

It'll most likely fit, assuming it's standard size/threading. You will need a crank puller (assuming it's square taper) and the appropriate bottom bracket tool if you want to do the job yourself. It is kinda hard to tell which BB tool you need until you get the cranks off, though.

Measure the width of the BB shell part of the frame, only. It is likely to be 68mm wide on your old bike, meaning it is a threaded English BB. The new one looks to be the same.

Also, drop the chain, and see if there is any roughness as you turn the cranks. There is a lot of leverage, so it is difficult to feel (easier if you remove the cranks).

But, with the cranks on, also wobble the crank back and forth (perhaps towards the chainstays. Any wobble is bad.

If your bottom bracket is cup & cone, then there is some maintenance and adjustment possible including replacing bearings if needed. Other than roughness noted above, it is hard to tell if the bottom bracket has pitted without taking it apart.

If your bottom bracket is Shimano sealed, then they're not serviceable.

Some brands of sealed bottom brackets like IRD bottom brackets are theoretically serviceable, although I don't know if many people do it.

Thank you so much guys! I'm going to be bringing it into a bike shop to check with a mechanic if the whole swap is capable.

If it's the crank that came stock with the Retrospec I wouldn't bother pulling it off and installing it on the Dolan.