The BB on my roadie has died a creaky, playey (it’s a word!) death and I’m looking to pop a Hope bb in there. I’ve got GPX cranks so understand I need to use a Hope GPX conversion shim thingy. Anyone had any experience of using these? Do they affect the reliability of the bb at all (which is the main reason I’m looking at Hope)?

nope, they’re easy to install and do not affect anything other than stepping down the i.d of the l/h cup.

Yes I have one on my FS MTB, easy to fit and totally reliable. Even a YouTube Vid on fitting.

Perfect, cheers guys.

They are a bollocks to get back out of the bearing, mind, unless you modify one of the tophats.

+1 file a notch in one of the top hats so you can get a drift/screwdriver in when you come to remove them.

So file a little notch into which part of the shim? The top-hat part of the top-hat, or the rim part of the top-hat… Not sure I’m making sense any more.

you get two tophats in the kit. Take one and sit it on the workbench as if it was a top hat on someone’s head. Now file a notch, the size of a small pea, out of the top of it.

When you fit the two tophats to the NDS bearing you press one in from each side, so the notch is in the middle. When you come to remove the tophats, say when you need to swap out the bearings, you can get a screwdriver in the notch and tap the tophat out. Once you have one tophat out, then other is easy to tap out.

Without the notch, you can’t get anything in between the two tophats, so you’re stuffed. I filed two notches in mine, opposite each other, just to make it even easier to tap the tophat out. Just make sure the edges of the notch are smooth, so you don’t mark the crank axle with any burrs.

so how do you remove them if you’ve installed them without filing a notch in? i’m currently using gxp cranks but will be moving over to shimano on my new bike and want to swap the BB too as it’s only a few months old. am i stuck?

Very carefully use a hacksaw on them!

Excellent advice. Many thanks reggie.