Square taper BB torque

[stephenmarklay]

My new cheapo SS crank started to creek after a fee rides so I snugged it up a little and it was quiet. Today it was little loose again so I want to properly torque it it is a no name set and i am thinking around 38NM based on what I have seen.

Is that reasonable?

[Hindmost]

Are we torqueing the crank arm or the bottom bracket cups?

[aaronf]

Going on memory here, but 28-30 lb-ft is spec for Campy and Shimano crank-fixing bolt on a dry (non-greased, which will open its own can of worms, just search) spindle.
So yes, 38Nm (28.03 lb-ft) is a great place to start.
For further reference, Campy shipped their bolts with mild thread-lock applied and recommended grease on the shoulder of the bolt where it meets the washer that bears on the crank arm. Doesn't hurt to just grease both sides of the washer.

[zzy]

~40Nm is fine, but make sure you're locking down the drive/fixed side first. Sometimes if the threads are junky a bit of loctite can help but shouldn't be necessary.

[stephenmarklay]

Thanks everyone and yes it is the crank arm fixing bolts. I just might use a little blue loctite too. I probably would not on nicer equip but on this I may

[MrSmokey]

What about for old toplines??? same-ish??? Just be a little more tender, and start low?

[Dekonick]

What is your crankset?

I looked and it is 42 for Chorus 10. I have the books for 00-06. I really thought it was 38...

[stephenmarklay]

Originally Posted by Dekonick

What is your crankset?

I looked and it is 42 for Chorus 10. I have the books for 00-06. I really thought it was 38...

Thank you! Unfortunately, it is a generic crank that came on a Raleigh SS. So there is not going to be any documentation.

I did ended up at about 39Nm with some blue loctite. I will see how it goes over the next couple of days.

[cmbicycles]

I've always used 23.5 ft/lb for square taper crankarms... 50 for sealed BB cups. Cheap beater bikes and cranks sometimes only qualified for the gutenteit torque standard, Topline cranks got 19-20ft/lbs... and the few I saw with any regularity when I worked in a shop cracked eventually anyway

[Dekonick]

Originally Posted by cmbicycles

I've always used 23.5 ft/lb for square taper crankarms... 50 for sealed BB cups. Cheap beater bikes and cranks sometimes only qualified for the gutenteit torque standard, Topline cranks got 19-20ft/lbs... and the few I saw with any regularity when I worked in a shop cracked eventually anyway

They come from the factory with blue locktite on some of the threads on the bolts if I remember correctly. Typically I put some blue or green locktite on the first few threads, gently lube the washer, and use a torque wrench.

[oldpotatoe]

Asked and answered..I use 30 ft-libs, dry spindle, grease on crank bolt threads and on crank bolt washer BUT, for the OP..if the crank has gotten loose, it may have wallowed the crank flats and it may not ever stay tight..

For the loctite gig,really does little since loctite is best when applied and used wet..

[smontanaro]

Jan Heine mentions 25 nM for the Rene Herse cranks in this essay about whether or not to use grease: https://janheine.wordpress.com/2012/...not-to-grease/

[oldpotatoe]

Originally Posted by smontanaro

Jan Heine mentions 25 nM for the Rene Herse cranks in this essay about whether or not to use grease: https://janheine.wordpress.com/2012/...not-to-grease/

Undoubtedly because of the quality of the BB spindle and crank flats..'catching' on the spindle when assembling..sorry Jan, dry spindle..maybe wet on yours but on Campag and shimano...dry.

[stephenmarklay]

Originally Posted by oldpotatoe

Asked and answered..I use 30 ft-libs, dry spindle, grease on crank bolt threads and on crank bolt washer BUT, for the OP..if the crank has gotten loose, it may have wallowed the crank flats and it may not ever stay tight..

For the loctite gig,really does little since loctite is best when applied and used wet..

I am hoping it is still square. The crank never felt loose, it just creaked a bit. But I have ruined a crank before so we will see.

I used the WET loctite

[MrSmokey]

Originally Posted by cmbicycles

I've always used 23.5 ft/lb for square taper crankarms... 50 for sealed BB cups. Cheap beater bikes and cranks sometimes only qualified for the gutenteit torque standard, Topline cranks got 19-20ft/lbs... and the few I saw with any regularity when I worked in a shop cracked eventually anyway

...yea, knock on wood, i have had good luck so far, but know better. i got 3 sets of them and other old stuff with a bike i bought a few years ago and figured i would have killed the first set by now, just from riding them. I am not a lightweight, but probably having them on a titanium noodle helps.

thanks!

I think around 18-19ish what i set them with last time i put them on, I just did it by feel tenderly, and checked where it was... I remember the number looking a little low to me.

Actually ...I have probably become too complacent about them, I used to be kinda tender with the bike, and worry about them, and kinda forgot. I for the past year or so i just um... ride it. No big drops, but it gets hopped and hammered, i am probably asking for it.