MachSchnell

Anybody know proper torque specs for assembly of a 3 piece wheel? I'm assuming it should be put back together with a similar tightening procedure to a regular lug tightening pattern, working crosswise in a star fashion...but I want to make sure I have the torque spec'd properly to avoid leaking or tightening the wheel out of round...

TIA

joey bagadonuts

Here's a quote from one of the moderators, Bill Gregory, who was advising me on the purchase of some BBS racing wheels, the type with magnesium centers:

[quote] If you get them, you may want to get a torque wrench with a needle/scale dial gauge, with a foot inch scale, so you can torque the bolts to 145 foot inches, which is around 12 ft lbs. Those bolts come loose over time - I check the torque after each days run, prior to the next event. <hr></blockquote>

Hope that helps!

MachSchnell

That definitely helps, thanks very much!

A930Rocket

joey bagadonuts,

[quote] If you get them, you may want to get a torque wrench with a needle/scale dial gauge, with a foot inch scale, so you can torque the bolts to 145 foot inches, which is around 12 ft lbs. Those bolts come loose over time - I check the torque after each days run, prior to the next event. <hr></blockquote>

Glad to hear this, as those are the wheels I use on my '87 930 at the track. I've also heard that they are one time use bolts (as in stretch bolts). Not sure how this plays into re-torquing them repeatedly though?

Also, I was told to pull them apart, inspect for cracks, etc. and reassemble every year.

Jim

Danno

Also would be a good idea to use a little blue Loctite as well. Since there are no lock-washers or locking mechanisms of any kind, vibration can loosen those bolts and cause your rim-halves to flex. This increases the loads on those bolts and causes them to fail from fatigue.

This happened on my BBS Race wheels because the bolts were too loose on the front rims. They worked themselves loose and started snapping. Replacing ALL of them with new bolts, Loctited and tensioned to the correct torque solved this problem for good.

Bill Gregory

[quote]<strong>I've also heard that they are one time use bolts (as in stretch bolts). Not sure how this plays into re-torquing them repeatedly though?</strong><hr></blockquote>

I just had a head snap this weekend when I retorqued one wheel, which is probably the 5th time I've retorqued them (after replacing with fresh bolts). I use a dial gauge, so over torquing wasn't the cause. Although BBS doesn't recommend loctite when assembling, when I replace the bolts this winter, I plan to loctite them in.

A930Rocket

If you use Loctite, can you retorque them, breaking the "bond" and have the same results and/or benefits of the Loctitie?

I've always felt that once you break the Loctite free, you've lost it's integrity/strength.

Jim

Bill Gregory

[quote]<strong>I've always felt that once you break the Loctite free, you've lost it's integrity/strength.

</strong><hr></blockquote>

I would agree with that. The purpose of using Loctite would be so one wouldn't have to retorque the bolts on a regular basis. Doesn't mean you don't inspect them frequently.