[Closed] Help fitting BB

You need to check if your new BB is normal or italian thread. (was the crankset a real bargain?) If not italian thread (rarer and unlikely) it will be fine. I wouldn't worry about the width of the whole bottom bracket or whether the threaded bits on the bb cups are longer (they probably are a bit), you just need to screw it in the right way with the plastic sleeve in, and with the correct number of spacers for the width of your bottom bracket shell. (explained in the instructions) And use loooads of grease everywhere.

Julian
thanks for the tip on grease, the threads seem really tight on the first few turns then seem to stop turning altogether, don't want to overtighten and damage threads on bb or in frame.
Crankset is from Merlin so will call them in am.
Richard

If it doesn't go in nicely then stop! A new bb in a nicely threaded frame should go on by hand for the first few turns at least. If you bought it from merlin its certainly the right thread, but maybe your old bb was cross threaded and mashed up the threads a bit. I would be asking a good bike shop to have a look and see if the bottom bracket shell needs chasing through/retapping.

Don't use grease!!

Use anti-seize.

The cups thread is "handed" Richard, one will only fit on nearside and one only on offside. Same thread pitch etc just one left handed and one right handed so try putting them in on the opposite sides and they may well be fine!

slx cups say left and right on them

Thanks chaps will have another look in daylight.
Richard

And they have thread lock compound on them

They don't make SLX in IT 70 Italian thread, that's a road standard!
But I agree that they should screw in by hand for a few turns until they hit the threadlock.

Thread shouldnt be differen but you may need some spacers

Skyline-GTR - Member

They don't make SLX in IT 70 Italian thread, that's a road standard!

Indeed they don't. But in the original post states slx cranks and shimano bb (didn't say which one). So I raised it early in case he was mistakenly using a roadie bb and about to kill his bb threads with it. An unscrupulous ebay/forum seller could have supplied a visually very similar roadie bb instead, or he could have bought the bb separately and just though 'ah, HT2, that'll do". I bet a few folk here have mistakenly battled with fitting roadie bb's to their mountain bikes. One prolific user of the classifieds/stranger to the other 2 forums here sold a few as 'HT2' as a 'bargain' recently, neglected to mention on a mountainbike forum that they were ultegra...

Having bought the whole lot from Merlin though (mentioned this a few posts in) it is certain that even if its oem it will have the right BB. I expect that with new correct BB, the problem is with the bb shell/threads or even the fitting of the previous BB.

Update.
Thanks for all the advice in earlier posts.As a newbie to swapping bits and pieces I find this forum invaluable with suggestions.

Merlin very helpful and confirmed it was correct BB.

1. Lots of thread lock compound which was fouling.
2. Existing BB was slightly cross threaded by previous owner of frame.
3. LBS very helpful and suggested that with a gentle amount of encouragement new BB would thread up and now turns beautifully.
4. New cranks fitted and with 1 drive side spacer the gear changing is sweet.
First upgrade that I have fitted and instantly feel the difference.

Regards

Richard

Nice one. It's a good feeling when you sort something like this!

Make sure that when you preload the bearings using the plastic cap that you only do it finger tight, just enough to take any slack up (similar to adjusting your headset). Too tight will kill the bearings quite quickly.

Thanks for the tip on the plastic cap.
Richard

Hey guys may I just resurrect this thread with another SLX crankset fitting question.

I too am going to get one of Merlin’s cheap slx deals, but do I need any special tool to fit them.... (the merlin website recommends a little plastic thingy??)

Thanks in advance

I think this tool is for the plastic cap that covers the bearings.I did not use a tool referring to Bigyinns advice above I just tightened it finger tight, no issues so far.
Richard