Aluminum Wheel Bolts

[chucked]

I am wondering if any teams have run aluminum wheel bolts/studs in the past.

I am looking into using 4 1/2" aluminum wheel bolts to replace the steel ones currently in use.

Also, I plan on using Aluminum Lug nuts. the hubs are aluminum and the rims will be either aluminum or magnesium.

So whats your experience with Al studs?

also, any recommendations on where to find such bolts?

Any Helpful comments are appreciated.

Thanks

[chucked]

I am wondering if any teams have run aluminum wheel bolts/studs in the past.

I am looking into using 4 1/2" aluminum wheel bolts to replace the steel ones currently in use.

Also, I plan on using Aluminum Lug nuts. the hubs are aluminum and the rims will be either aluminum or magnesium.

So whats your experience with Al studs?

also, any recommendations on where to find such bolts?

Any Helpful comments are appreciated.

Thanks

[Bernat]

I only have the experience with aluminium single nuts. The hub was also made in aluminium and we had serious problems to loose the nut after it was tightenend (it was not necessary to go ou to run, it happened just if you tried to loose it immediatly after tightening). We suppose it was because of the high friction coefficient in Al-Al. But we know other teams use the same combination, so we don't know how they do it.

[exFSAE]

Easy way to get into a lot of trouble. Bare aluminum galls very easily and will result in what Bernat described (threads will seize). You can anodize or hard coat everything.. which makes the manufacturing and thread tolerances a bit more difficult.. but will fix the galling issue. Using a lubricant (M1 from Starrett is good stuff) helps as well.

Even then, while initially it may work out well, it's a somewhat delicate part given that the base metal is so soft. If you're careful with it, you might have no problems. If you've got a bunch of inexperienced guys monkeying around on it, it will be easy to damage.

All out weight reduction is one thing, but with FSAE students I'd lean toward really robust, idiot-proof parts. If you want to take weight out though, you could make your own hollow studs as a start.

[Michael Royce]

A word of warning to teams entering Formula Student - the MSA (safety) scrutineers do NOT like aluminium wheel nuts. In fact, the Formula Student Supplementary Regulations (General Requirements) say "Aluminium wheel nuts may be used, but they must be hard anodised and in
pristine condition." The interpretation is they had better be purchased from a reputable aftermarket source AND they had better be brand new!

[flavorPacket]

Indeed. When we went to FSUK in 2007, we spent more than an hour in tech discussing our aluminum lug nut threads with the scrutineers. Our lugs were steel, however.

In our experience, the nuts wear out, even if hard anodized, and must be checked regularly and replaced immediately at the first sign of wear or cross threading. To us it was always worth it to save unsprung rotating mass.

[Adambomb]

I'm with exFSAE on this...more often than not the guy putting on the lug nuts will be some sort of ham-fisted newbie trying to prove something by tightening the lug nuts to 200 ft lbs. Not only that, but I've seen enough steel lug nuts and studs wear out on passenger cars (not to mention trouble with acorn nuts on Al wheels in general) that I sure wouldn't want to run Al on our car. Never mind Al's notorious galling problems. Although gun-drilling the studs does sound interesting.

[Hector]

We've run aluminum hubs with a aluminum center nut for many years now, without issue. I'm not sure why Bernat's nuts are seizing, but our takes approximately the same amount of torque to loosen and tighten.

The galling/wear concern hasn't really shown up. We replace the hubs each year, but even by the end of a long season of testing + competition + summer testing, they've never worn out or needed replacement. We do use some sort of antisieze on the nut, which we clean and re-apply after each day of testing. Maybe something to consider...

As far as running individual studs (as opposed to our single center nut) I have no experience. Make sure you give fatigue life a healthy factor of safety.