Determining compatible BB?

[mrcharly-YHT]

Just noticed that cranks were wobbly on my CDF. Quick fiddle identifies that the problem is the BB bearings. This has happened before, then it went very quickly from slight wobble to unrideable.

Good thing I spotted it, as I was about to set off for a longish ride, with no prospect of assistance to get home.

Not sure how I identify a compatible replacement.
Crankset is a GRX.  Frame is old steel CDF.

I'm going to go and try to remove the BB.

[Sergeant Pluck]

If GRX it’ll be Shimano road rather than MTB.

I recently replaced a BB, GRX drivetrain, 68mm BB shell, with one of these:

https://www.sjscycles.co.uk/bottom-brackets/hope-stainless-steel-24mm-bottom-bracket-road-black/?src=00048%2F

[robgul]

Just noticed that cranks were wobbly on my CDF. Quick fiddle identifies that the problem is the BB bearings. This has happened before, then it went very quickly from slight wobble to unrideable.

Good thing I spotted it, as I was about to set off for a longish ride, with no prospect of assistance to get home.

Not sure how I identify a compatible replacement.
Crankset is a GRX.  Frame is old steel CDF.

I'm going to go and try to remove the BB.

If you get the crankset off and the BB out chances are that the details will be printed on the external cups and/or the sleeve between the two in the BB shell.   Don't forget drive side is LH thread!

[grams]

GRX is just standard Shimano road.

Any* vaguely recent non-weird steel road frame is extremely likely to be 68mm ISO.

There’s an extremely long list of BBS that fit this requirement, even from Shimano themselves; BB-R60 and BB-RS500 being the most commonly available.

There are however three different tools (just for Shimano) so buying one that matches the tool you have might become a requirement.

(* hello pedants)

[Lightning Phil]

If you don’t want to pay the Hope prices there is

https://www.sjscycles.co.uk/bottom-brackets/shimano-bbmt501-hollowtech-ii-bottom-bracket-english-thread-6873mm/?src=00048%2F

[Hot Flatus]

GRX is just standard Shimano road.

Any* vaguely recent non-weird steel road frame is extremely likely to be 68mm ISO.

There’s an extremely long list of BBS that fit this requirement, even from Shimano themselves; BB-R60 and BB-RS500 being the most commonly available.

There are however three different tools (just for Shimano) so buying one that matches the tool you have might become a requirement.

(* hello pedants)

The old style HT2 wrench (that also fits rotor lockings) can be supplemented with a cheap plastic insert to fit the more recent HT2 BBs.

[grams]

If you don’t want to pay the Hope prices there is

https://www.sjscycles.co.uk/bottom-brackets/shimano-bbmt501-hollowtech-ii-bottom-bracket-english-thread-6873mm/?src=00048%2F

That’s for MTB cranks which have a slightly wider spacing between the inner surfaces.

It can actually be used with road cranks if you retrieve a “Road” centre tube from an old BB (or omit the tube entirely) and use the right combination of the included spacers.

[mrcharly-YHT]

I've been stupid. I already had a replacement bottom bracket. Didn't fit it at the time because I didn't have the correct bottom bracket tool.

Job done now.
The one that failed has been on there for a long time.

[zigzag]

standard shimano bb's last a fair while, around 15k km in mixed conditions ime. i've used an aftermarket bb, which was few times more expensive and lasted few times less, go figure.

[Hot Flatus]

^ My experience too. I genuinely don't know why people bother with Hope BBs. They are functionally no better.

I had to replace a di2 cable in an 8 year old machine recently which necessitated knocking out a Shimano press fit Bb86. It was a shame because even after 8 years and probably 25,000 miles, it was still perfectly good.

[Sergeant Pluck]

I genuinely don't know why people bother with Hope BBs. They are functionally no better.

 

That’s exactly what I thought about the Chris King BB that I decided to replace with a Hope.