So i’ve got an Octalink crankset and the bolts will not stay tight, i’ve tried putting ptfe tape on the threads but they still come loose.

Could it be that i used the wrong grease when i screwed them in the first time? i greased the threads with some grease i got from the local motor spares shop, that i use to grease my tow ball. Don’t know what sort it is but it’s made by ‘Total’ and is red in a white tube!!!

Should i use thread lock?

You don’t grease the threads, but some threadlock might be a good idea. I have forgotten if its blue or red you want to use, use the one that will let you undo it after awhile.

PTFE tape isn’t a thread locker, if anything it’s a good lube! Don’t grease the threads, get a nice good quality threadlock.

Probably worn splines by now. If the splines are worn even if you tighten the bolts right up as the crank arm rocks on its spline it loosens the crank bolt.

~What grease you used will make no great odds. You could try threadlock but I doubt it will work. All my octalink bbs are coppaslipped

Nice one cheers, why did I think i should grease the threads!!

Think it’s blue thread lock that you can undo. trip to B&Q after work then.

I had the same problem with a set of octalink cranks. They’re Fit only for the bin I’m afraid. Worth giving the threadlock a go, but in my experience they’ll just keep undoing themselves at increasingly regular and more inopportune moments 🙁

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Greasing them is the right thing to do although coppaslip is better

Never ever assemble a spline or thread dry

TJ – it’s not that old and I don’t think the BB is knackered I only bought it in Jan!! Cranks are about a year old.

Maybe i’ll just have to keep tightening them up untill i can afford a new crankset.

Binners – bugger!

THIS is the very reason I went over to HT2. Guessing you’d rather avoid shelling out for new cranks though?

Never ever assemble a spline or thread dry

Most fastener torques are quoted dry, then modified for lubed (and rarely specified). You can’t make sweeping statements like that as they’re not universally true.

THIS is the very reason I went over to HT2. Guessing you’d rather avoid shelling out for new cranks though?

You’d rather spend time shelling out for new bearings instead like me eh! 🙂

Would love a new set of SLX cranks but unfortunatley the funds are not available at the moment (so says the missus!!). 🙁

I’m glad it’s not just me though.

Coffeeking – check that – all I can find is values for lightly oiled. Infact I found many engineering places stating you cannot specify a torques for a dry bolt as the friction is a variable. Lightly oiled is the norm

Coffeeking – check that – all I can find is values for lightly oiled. Infact I found many engineering places stating you cannot specify a torques for a dry bolt as the friction is a variable. Lightly oiled is the norm

I will, have to dig out my handbook – check back in a bit!

Coffeking – I think the thing is that a “dry bolt” in this context is actually one wiped with an oily cloth so “lightly oiled” not heavily greased

Run of weld round it. Sorted.