Bottom Bracket

thestrand

Although I have been cycling for a few years, I am not terribly experienced when it comes to changing parts, on the drivetrain in particular. I currently own a Felt F95 which has a mixture of sora and microshift, with an FSA chainring and bottom bracket.

As I am starting to ride a lot more recently, I am upgrading the whole groupset, to either 105 or some sort of SRAM.

The bike I currently have has a square taper bottom bracket, and I just wanted to check (because I can't find it anywhere on the internet) that the GXP or BB-R60 ones that come with shimano/sram will be compatible for my frame, before I go out and spend hundreds of pounds on components that I might not be able to use.

Thanks

dj58

Your BB shell should be threaded ISO/English 1.37" x 24 TPI and be 68mm wide. You are considering changing from a internal square taper type BB to an external type Shimano or SRAM type BB, depending how much finishing was carried out on the BB shell, it may need to be faced, see link below.

http://www.parktool.com/blog/repair-hel ... ng-bts-bfs

As long as you use the matching manufactures BB and crankset, be that the Shimano 105 SM-BBR60 or SRAM GPX you should be fine.

JayKosta

Many people have trouble when changing the BB - squeaks and creaks, getting all the parts to 'line up' correctly, etc. And you'll probably need some special tools and skills to make the change.

If the current BB and cranks / rings are not causing any problems, I wouldn't change them. I don't think you'd notice much improvement.

Upgrading the brakes, shifters, derailleurs, will make a noticeable functional change.

Jay Kosta
Endwell NY USA

thestrand

Thanks to you both for your advice, its reassuring to find out that all of the options are still available!

What I am planning to do is buy a groupset as a whole, and then only install the chainrings when my current one becomes worn, as that seems cheaper than buying everything but the BB/chainset individually.

keef66

thestrand wrote:

Thanks to you both for your advice, its reassuring to find out that all of the options are still available!

What I am planning to do is buy a groupset as a whole, and then only install the chainrings when my current one becomes worn, as that seems cheaper than buying everything but the BB/chainset individually.

I've been worrying about chainring wear for 8 years now; still no sign of them wearing out yet...

bobones

One of my bikes is a 2011 Felt F85 which originally had a square taper BB. That has since been replaced, first with Shimano Hollowtech II, then FSA and now SRAM GXP. I did not get the frame faced as most modern frames will already be well enough prepared and I have never had any problems. I think you can safely change it as anything for English threaded/BSA frame should work with the appropriate chainset and be lighter than your current setup.