Dry rear wheel bolts?

[Boxered]

Hi all, just had my rear wheel off for a puncture repair, noted that bolts and flange are a little rusty, but then remembered the manual saying the bolts must be free of oil and grease? is this correct, it goes against the grain to put the bolts back in in a rusty grease free state. Am I ok to copperslip them?

Confused of St Helens

Steve

[Rob B]

Mine are copaslipped and torqued up.

Right or wrong!?

Rgds, Rob

[Gromit]

Rob

Whatever you do, don't copaslip the bolts. The tightening torque also requires the bolts to be dry to 'grip' the threads - this is what an indepedent BMW mech told me (ie he wasn't doing the 'party line' thang).

If they're a bit rusty, a wire brush'll clean them up ok. In nearly 100k miles on R259's I've never had a rear wheel bolt seize through lack of greasing.

[winger]

Well i have to say I greased mine,both the originals and my collectors items that i use now,but the most important thing is to torque e'm correctly,cuz if you don't they come undone!!!! 105Nm

Chris

[adamski49]

Long answer
I copa-slip mine once and they last from then on - I've never had a loose one yet, let's be honest 105 Nm is bloody tight. This includes the five K series BM's I've had as well.

Having spoken to my local BM tech he said not to use copsalip on the wheel bolts... too late says I... take them out and clean them says he. (I haven't )

However he did say to use a drop of oil between the shims and the bolt to allow the two to move separately and give a true torque settting.

He also said to use a drop of oil on the threads of the spark plugs and not copaslip for a reason I can't recall

Short answer
No

Adam

[stempy]

What happens is that if you lube the thread, when you torque it up to the recommended without lube torque then you end up overtightening it because of the lubricant. Over tightened bolts stretch and could eventually snap!

yours

A Lurker

[Gromit]

What happens is that if you lube the thread, when you torque it up to the recommended without lube torque then you end up overtightening it because of the lubricant. Over tightened bolts stretch and could eventually snap!

yours

A Lurker

Oh yeah - that was the other reason I forgot to mention.

[Blackal]

What happens is that if you lube the thread, when you torque it up to the recommended without lube torque then you end up overtightening it because of the lubricant. Over tightened bolts stretch and could eventually snap!

yours

A Lurker

From experience of engine-building, If the reason was overtorquing - then a lower value would be given for the figure when using a lubricant. My own inclination was to molykote the threads (as I always do on car wheels) but the strict instruction by BMW not to - had me envisaging a wheel coming off at 70mph! But - without the lubricant - I have this paranoia that the galvanic action of the aluminium wheel and the steel bolt are doing more damage when unlubricated.

Tempted to use a low-strength nutlock compound though.

So the answer is.................. I don't know!

But, with a rear tyre only lasting 3000 miles or so - at least the bolts shouldn't be seized on?!?!?!