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forum
Removing crankset and bottom bracket help
Hi all. My bottom bracket is creaking, hoping it's just needing some grease, however, after removing the hex connection I'm unsure where to do from here, can anyone advise please?
https://ibb.co/7kb7NS4
https://ibb.co/B4ftsHt
https://ibb.co/XCvBTyY
https://ibb.co/F3HXVdv
Ta
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14 comments
It looks like an alloy frame there, so electrolytic corrosion is the likely reason it's so difficult to remove. As an alternative to grease for reassembly it is worth considering pigmented varnish jointing compound (Duralac). Any grease will eventually dry out, unless you dismantle and reassemble regularly, so using jointing compuond instead is a long term solution to the corrosion problem when you want to fit and forget.
And lots of grease or assembly stuff when installing the new one.
If you're needing to remove the BB after you've removed the cranks be prepared for plenty of swearing and skinned knuckles. You need another tool for the splines (the square castellations on the first image)
Strongly recommend getting one like this with a central locator pin, which will stop it going askew. This was the best option for me with a particularly recalcitrant factory-fit (and factory-torque) square taper BB. Tool plus my entire 18st stood on the handle after a night soaking in WD40 (the BB, not me) was what was required.
https://www.gym-fit.co.uk/Bottom-Bracket-Removal-Tool-Square-Taper-Type-...
The other option is to get a socket one which has spanner flats on it like this
https://www.wiggle.co.uk/lifeline-bb-tool-octalinksquare?lang=en&curr=GB...
And then clamping it to the crank spindle with a bolt and a couple of big washers like this
https://www.instructables.com/Seized-Bottom-Bracket-Removal/
And using an adjustable spanner (or ring spanner if you've got a big enough one) to apply enough torque to remove it.
It's not a difficult job, just requires the right tool and brute force rather than any particular skill.
One final tip: drive side (chain side) is a reverse thread. Easy way to remember - push the tool handle towards the front of the bike.
If the square taper has a hole all of the way through, a wheel qr can be put though and tightened to keep the removal tool square when giving it some wellie, to avoid destroying the splines on the cup when it slips, as it will when giving it the said wellie.
Yep, this works very well, as long as the BB removal tool has spanner flats. Quite why some of them don't I don't know but I seem to have two of the beasties, which is why I ended up getting the one with the attached handle and locator pin.
The 'instructables'…'use a pipe (a scaffold tube will do nicely)'
Yep, been there!
A 'Mechanical Advantage' I believe
I have had some difficulties before, taken her to the LBS and they put the tool in their big vice, and used the frame to get the "mechanical advantage".
Thanks everyone, I'll get that part and see how it goes
Do the cranks feel floppy, in which case if they're square taper cranks you have a crank problem? Unless your bb is very graunchy, it isn't worth messing with. If it's that bad it probably needs replacing.
Creaking is something to live with, and think about a new bb eventually. I've taken them apart and greased them, but it's a short term fix.
Like this!
Once the cranks are off, then it's one of these. It looks like it's a Shimano copy, but check the number of splines is the same - your first photo looks like between 9 and 10 o'clock there's a bigger gap.
If it's standard English BSA threads, it's the opposite of pedals - the right hand side is a left hand thread. You've probably got a sealed unit in there - check how smooth it's running - you could replace it if it's old.
The bottom bracket may need some welly, e.g. setting up in a vice if it's stiff - just don't end up doing yourself or your bike a nasty. A Replacement Shimano unit like UN 300 should be right - the width of the body should be 68 mm for a road bike, and you need to check the spindle length.
Creaks are one of cycling's mysteries and can be coming from a range of places, and they only usually occur when you're underway so locating them can be tricky.
Just need a standard crank arm extractor tool. About £5-10. A common tool stocked at any local bike shop.
Plus some muscle as it may well have been tightened to 50Nm +
There's plenty of videos on YouTube showing you how to use one.
Definitely 'oddly satisfying' to use