Pressfit BB installation

[citoyen]

To grease or not to grease? It's a Shimano BB71 (plastic) going into a carbon frame with metal lining in the BB shell.

This probably comes under FAQs and there are already all sorts of opinions on this matter on the internet but let's see how many different/contradictory answers the yacf panel can come up with.

I've already removed the old BB and cleaned the shell, got my bearing press primed for action, just waiting for the new BB to arrive in the post...

[firedfromthecircus]

Personally I would use a molybdenum disulphide based anti-seize in that application. I'm not saying I'm right, it's just what I would do. But then I wouldn't put a plastic BB in a Carbon frame, metal lined or not. And I wouldn't buy a press fit BB frame either, so you can take my advice for what it's worth. 

[citoyen]

I'm not a fan either but I inherited this bike so didn't have much say in the matter. I've only ever spent my own money on bikes with HT2 or square taper BBs.

[Hot Flatus]

Metal lining in shell? Then grease or locking compound to prevent creaking.

Bare carbon shell=No grease

[phantasmagoriana]

I used Loctite on mine, and it lasted a couple of years (which seemed ok for a pressfit BB). I've just replaced it with a Wheels Manufacturing threaded version, though.

[Torslanda]

What Phanta said. FSA or similar threaded shell, glued in place with the correct bonding agent, threaded BB & matching chainset of choice.

Cannondale's designers dickheads should be chain whipped for even thinking it up in the first place. Lambert/Viscount tried something similar in the 70s. Didn't work then, either...

[Hot Flatus]

Mine works. No issues.

I prefer HT2 though.

[citoyen]

Wheels Manufacturing threaded version

FSA or similar threaded shell

Interesting. I wasn't aware such things existed. I'll probably go down that route next time it needs replacing.

Am I right in thinking that any BB86 model would be suitable?

[zigzag]

i think the posters above were talking about pf30 bottom brackets. pf86/shimano design is a bit better as the bb shell is not likely to ovalise, causing bearing misalignment and creaks. light smear of grease on plastic cups should make the installation/removal easier and keep everything quiet.

[citoyen]

I'm assuming phanta was referring to something like this:
https://wheelsmfg.com/category-holding-bucket/bb86-92-bottom-brackets/bb86-92-outboard-angular-contact-bb-for-24mm-shimano-cranks-black.html

Not cheap!

[phantasmagoriana]

Mine's a BB86.

This is the threaded one I bought: https://wheelsmfg.com/bb86-92-outboard-angular-contact-bb-for-24mm-shimano-cranks-black.html

Haven't used it yet, though, as I only put it on the summer bike last week.

[phantasmagoriana]

I'm assuming phanta was referring to something like this:
https://wheelsmfg.com/category-holding-bucket/bb86-92-bottom-brackets/bb86-92-outboard-angular-contact-bb-for-24mm-shimano-cranks-black.html

Not cheap!

Yes, that's the one. I think I paid £47, which is a lot for a bottom bracket but if it lasts, then it'll be worth it. Could get a few standard HT2 BBs for the same price, though!

[citoyen]

 

[Torslanda]

I've been trying to find a conversion sleeve for BB86 (Shimano BB71/91) and failing. Maybe they don't have the same issues as BB30...

[zigzag]

I've been trying to find a conversion sleeve for BB86 (Shimano BB71/91) and failing. Maybe they don't have the same issues as BB30...

they don't make sleeves for bb86 as they would not fit due to a smaller diameter of bb shell (compared to, say, pf30)

[Torslanda]

BB30 has an internal diameter of 42mm, BB86 is 41. It's probably because the 86mm shell width won't allow an external bearing.

I love standards, there's so many of them . . .

[citoyen]

It's probably because the 86mm shell width won't allow an external bearing.

Yes, that occurred to me when you mentioned it earlier, but then I realised you were talking about BB30.

I love standards, there's so many of them . . .

At least you don't ever have to change a BB during a race, unlike wheels...