Wheel Hubs Torque

enio45 · Post by **enio45** » Sat Apr 03, 2004 8:53 am

I found out today that in the process of cleaning and stripping my aluminum wheels on the the 330GT (Aluminum Slots) my painter had taken the hubs off to do the job. I did not intend to have these removed but now that its done......... :?

My question is ....what is the proper torque spec i should use when putting these back on? Also, i think the studs were pinged originally to secure them properly?

Any advise ?

Thanks

Howard · Post by **Howard** » Mon Apr 05, 2004 7:25 am

I have the new correct nuts if you need

David Booth · Post by **David Booth** » Sun Apr 11, 2004 4:27 am

If you're talking about the 12 small nuts and bolts that attach the hub to the disc hat, Bill Badurski wrote a Technote article in Prancing Horse a while back, and specified 60 inch-pounds assuming clean, dry threads, and emphasized using new lock washers - a good practice in any critical fastener application. Don't add a washer under the bolt head.

Ferrari did not peen any bolt ends that I've ever seen. Lock washers, cotter pins, lock tabs and safety wire galore - but never a peened bolt.

Use a torque wrench and tighten in a criss-cross patttern. Legendary race-car mechanic Carroll Smith recommends taking any critical fastener up to tightening spec in two steps, and then going back and getting a second set of clicks with your torque wrench to be sure.

enio45 · Post by **enio45** » Mon Apr 12, 2004 8:05 pm

David, not sure we are talking the same - my alum wheels have 8 bolts that hold the inner hub to the wheel. The bolt heads have a end cut off to keep them from turning when fully seated in the hub, and on the nut side, it looked like the threads at the end were slightly pinged....not sure if im explaining this well.

Howard - are we talking about the same hub bolts??

Chris Coios · Post by **Chris Coios** » Tue Apr 13, 2004 9:19 am

Ed,

I think David is refering to the brake disc attachment to the splined hub that is part of the spindle assembly. If I understand this, the hub that you, Ed, are refering to is the hub that is the center of the wheel. I believe the square-hole wheels are actually real magnesium, not aluminum - pick one up without a tire on it and they are remarkably light weight. The steel hub center is bolted to the wheel casting. This hub takes the spline load and has the seat for the knock-off spinner.

The wheel center is indeed attached with a series of bolts found under the chrome ring, with the nuts on the back. The threads of the bolts are indeed peened over to prevent the nut from going away. While David's observation about Ferrari's approach to locking fasteners is I think generally correct, the square-hole wheels were made by Campagnolo (of bicycle component fame), not Ferrari. By the way, the straight-ear knock-offs were also made by Campagnolo, not Borrani. Hence the rule-of thumb that straight-ear knock-offs go with the square-hole cast wheels and Borrani angle-ear knock-offs go with the wire wheels.

If I recall, the bolts are 8mm, with the older design standard nuts that are 14mm across the flats (today the standard available is only 13mm across the flats). The bolts are probably marked 8.8 grade or the stronger 10.9 grade. There are standards for torque of fasteners of this shank diameter, thread pitch and strength grade. I would just use these standard specified torques, which are intended to give maximum holding power without overstressing the bolt/nut. A good hardware book or catalog often lists the torque standards.

Chris

enio45 · Post by **enio45** » Tue Apr 13, 2004 10:34 am

Chris, yes thank you, you are "right on" with what im trying to say ref the hub and wheel....and yes they are magnesium wheels with the square holes and the straight ear knockoff's.

It has been recommeded to replace the nuts if they have been removed -
Howard Pigdon in OZ had a group of these made at 8.0 grade i believe and has some available. Ill check into the torque spec and post it here if anyone else needs it.

Any other advise i should be aware of while im installing these?

Thank again for the information.....

enio45 · Post by **enio45** » Sun Apr 25, 2004 11:13 am

Hello again and more on the hub and torque specs,

Under closer inspection this weekend of the nuts and a torque check, several nuts i found were stripped.....which i believe was done as a result of using an air impact on them when the painter reassembled the hubs.

For me i think i should replace all of the bolt and nuts as ill never have the piece on mind driving the car - whenever i get to that point.

The bolts have a special cut on the head and use a thinner head.

Does anyone have an idea where one would go to buy these??

Thanks for the leads in advance........