Question for Old Potatoe...

[jimbolina]

I have a NOS Super Record crankset that I'm installing on a Nuovo Record BB. I understand there is some controversy concerning how many ft lbs of torque to apply to the crank arm mounting bolts. Back in the mid '80s the Campagnolo tech (Jim Ingram) said 28 to 32 ft lbs dry. I have more recently heard that value isn't near enough.

I had earlier installed my other Campy Record crankset onto a similar BB at 30 ft lbs with a very light film of oil, with no issues - at least that I can tell.

My question is, is this 'newer' thinking correct and the torque value should indeed be significantly higher, or is the 30ft lbs spec still spot-on?

Also, with that thought, did I over-torque my other crankset with the lubricated spindle flats?

On a related note what sort of damage to a crank arm does modest over-torquing do beside bringing the arm closer to bottoming-out? Does it actually damage the arm (micro-cracking, etc) or just stretch or enlarge the hole a bit?

Thanks for your help with this...

[teleguy57]

You might want to edit the title to "Potatoe to have to get his full attention:) (you can do that by going edit, advanced...)

[lhuerta]

Don't over think it...32-35 Nm, NO GREASE on taper, if crank is firmly mounted before u reach 32-35Nm then stop...ur done

[oldpotatoe]

I have a NOS Super Record crankset that I'm installing on a Nuovo Record BB. I understand there is some controversy concerning how many ft lbs of torque to apply to the crank arm mounting bolts. Back in the mid '80s the Campagnolo tech (Jim Ingram) said 28 to 32 ft lbs dry. I have more recently heard that value isn't near enough.

I had earlier installed my other Campy Record crankset onto a similar BB at 30 ft lbs with a very light film of oil, with no issues - at least that I can tell.

My question is, is this 'newer' thinking correct and the torque value should indeed be significantly higher, or is the 30ft lbs spec still spot-on?

Also, with that thought, did I over-torque my other crankset with the lubricated spindle flats?

On a related note what sort of damage to a crank arm does modest over-torquing do beside bringing the arm closer to bottoming-out? Does it actually damage the arm (micro-cracking, etc) or just stretch or enlarge the hole a bit?

Thanks for your help with this...

Answered the other one. 30 ft-lbs on a dry spindle, what I have been doing for 30 years w/o ever having one of my or a customer's crank fall off or get loose.

[Mark McM]

I have a NOS Super Record crankset that I'm installing on a Nuovo Record BB. I understand there is some controversy concerning how many ft lbs of torque to apply to the crank arm mounting bolts. Back in the mid '80s the Campagnolo tech (Jim Ingram) said 28 to 32 ft lbs dry. I have more recently heard that value isn't near enough.

Campagnolo specifies a torque of 32 - 38 NM (23.5 - 28 Ft lb). The torque recommendations higher than this are usually offered by those who insist on installing their cranks with unlubricated tapers. (In other words, compensating for one error with another error.)

There is no technical justification for dry assembly of square taper cranks. Lubrication assures a more consistent press fit, and also requires less force to drive the crank onto the taper (less bolt torque), so there is less chance for damage - well, unless you over torque the bolt, that is.