Aluminium sprocket nuts

[Tim Smart]

I was wondering if anyone has replaced their sprockets and used aluminium sprocket nuts? They are M12, so I bought some aluminium Pro Bolt nuts, but it says on the paperwork that aluminium nuts shouldn't be torqued up to OEM specifications, but it doesn't give what they should be torqued up to for this application? I know the settings for the sprocket nuts is 110Nm, which seems a massive setting, but its out of the BMW service manual. Does anyone actually know the answer?

 

[andybarsblade]

I had probolt sprocket nuts on my R1, never again

 

[Tim Smart]

How come Andy? That's good news

 

[andybarsblade]

Put them on the bike @40nm. 100nm for sprockets nuts was the OEM spec, no need for that what so ever.

Cracked within 1 month.

 

[RossHarper]

I've just replaced my sprockets and kept the standard nuts, but cos they're rusted makes the new silver sprocket look naff so was going to order some aluminium ones next week.

This is the only info on them from website.

Aluminium Sprocket Nuts Set of 6. Gold Anodised. 12mm. New
Lightweight Alloy Upgrade Rear Sprocket Nuts.
Stainless Steel Inner Threads For Optimum Strength

Don't know if I shall now with Andy's comment.

 

[fatbob]

Sounds like they have some sort of helicoil..........nasty

 

[Tim Smart]

They do have a stainless steel helicoil insert, but that shouldn't be a problem, have fitted them now anyway, so I will keep you updated Ross!!

 

[Tim Smart]

Just had a phone call from Pro Bolt they say ali nuts shouldn't be tightened past 44Nm.