gota911

Gary,

I, too, recall reading "somewhere" (here on RL maybe?) that our lug nuts are aluminum.

As for your question: "What are these black nuts that Suncoast sells and what is the link?"

Here is the link you seek==> Suncoast OEM Bolt/Lug Nut

As shown in the SUncoast pictures, even when new, the bolt heads look like dog ****! Rusty lug nuts are embarrasing!

simsgw

Boy, that's for sure. Especially because I didn't notice until I was wiping down the wheels before judging began in a concours d'elegance.

Thanks for that link. I'll go check those out.

Gary

simsgw

Okay, I'll get a set of those for next time I take the car in for service. Notice that bronze collar they mention? That's to deal with the problem of dissimilar metals I mentioned. That keeps the steel from touching the aluminum lug face on the wheel.

Gary

Edgy01

Years ago Porsches all came with aluminum nuts. But that ended about the time Porsche started going with cast wheels--early 1990s. These bolts today are definitely ferrous iron/steel.

Dealing with the different materials coming in contact with one another is simple. In the aviation business we installed steel rivets in aluminum wing skins 'wet with sealant' to minimize corrosion. In the case of these lug/bolts I would just lightly coat them with a little Antiseize.

simsgw

I never got into the manufacturing end, Dan, but I'm pretty sure that technique has been dropped in favor of specialized coatings on the fasteners and/or glue. (Pretty fancy 'glue' as you know, but basically still glue.)

Thanks for explaining where we got that impression of aluminum nuts. Now I won't have to go thumbing back through all my Porsche books. I don't think we need to worry about the current ones though. Their anticorrosion measure is pretty simple, just expensive. (You know. Like a flat six that puts out 400 hp in a hole the size of a big suitcase.) According to the technical description at the Suncoast site, they use lug bolts, not nuts, and the bolts are constructed with a bronze collar right under the head that prevents contact between the steel portion and the wheel. The steel still corrodes and certainly the process will go faster for short periods when the wheel is continually wet in that little recess, but the corrosion will be a surface effect and won't affect the structural integrity of the bolt.

Doesn't look pretty in any case, but it sounds like the only permanent fix would be new bolts because these have their finish wiped off by the installers for my tires. New bolts and a special socket that I persuade any mechanic to use when he touches my wheels. That would do it. Otherwise, the pretty finish of new bolts will last only until they're used to bolt on a wheel, which would be rather futile.

Gary

jhbrennan

When I was cleaning my OEM lugbolts a few years ago, I too was curious about the metallurgy - using my grade-school science, I applied a magnet to the lug bolts and at least was able to confirm pretty quickly that they weren't aluminum.

RollingArt

You talking about these Ti lug bolts?

These were a screaming deal for those looking for lug bolt redemption. I haven't done any weigh-ins yet, but my understanding is they should shave off 1 pound per wheel. That's a nice side benefit.

I don't quite understand the design. The center of the nut section was hollowed out and then filled back in with a threaded plug? A lot of extra machining for no weight savings. Maybe designed for smuggling spy microchips across the border.

gota911

Phil,

Not sure if those are the same Ti lugs or not. I don't think the lugs I was interested in had the center plug, but maybe they did.

BTW, I'm not looking to shed weight, just looking to shed rust!

Fin Fever

your pics are a little fuzzy so I cannot be sure, but it looks to me as though the center plug has a reverse thread. If that is the case, it would explain the purpose of having the center of the lugbolt drilled out and reverse-tapped. I love just about anything overengineered, who makes those bolts?

Alan C.

A fellow rennlister wanted Ti bolts for his car and found a source in China to produce them.

There was a minimum order number and I believe that explains the extra sets he recently sold.

I've got a set in the garage and they are interesting. Currently I have chromed bolts and I haven't convinced myself that the Ti bolts would look that much better.

gota911

Alan,

I sent you a PM.

Alan C.

If you are worried about the small contact area of a steel wheel bolt mounted to the wheel you must be positively horrified about the wheel area mounted to the iron rotor hat.

To make a broad statement that a high tensile grade 8 steel alloy is stronger than a stainless bolt is not correct. Once you leave the austenitic stainless alloys, 304, and move into the duplex and martensitic grades you can see some very high tensile properties.

jhbrennan

Come on man...you're taking all the fun out of this - conjecture and opinion are so much better to post about than science and fact

gota911

Bawhahahahah!

Alan C.

Wow, I just looked at one of my wheels and it is nearly cracked in half at the pad surface. Had I only read this thread first I would have had new hubs machined from unobtanium to avoid the problem.

Better?