Lug bolts in Stainless Steel?

[conandrum]

I cleaned up wheels, painted rotors and polished the hubs. In the process I stuck the wheel bolts in vinegar to clean them too. Unfortunately they came out nice and shiny, losing their protective black rust layer. Now they rust easily and in a brown red color - very visible and ugly.

So I found these stainless steel lug bolts by nicecnc https://www.nicecnc.com/products/14m...12-f13-2011-up


Is it recommended to even use stainless steel lug bolts? Stainless 304 is probably softer than pure steel due to the impurities added to reduce corrosion.

Would you recommend these or maybe some other alternative?

[jbash87]

I would not recommend using Stainless for wheel bolts. You are right that it is softer. It is also quite a bit weaker in tension and will deform more (stretch). Typical wheel bolts are either grade 10.9 or 12.9. I think BMW uses mostly 12.9. I wouldn't recommend anything under 10.9.

If you're curious, you can look up the standard material properties of many popular materials on matweb.com

[conandrum]

You are right jbash87. In their product specs they do not declare anywhere any kind of material grade or strength, except for "Cold-Forged & Heat Treated". I found that worrisome.

Having said that, today I also came across these ferrari T304 STAINLESS STEEL WHEEL BOLTS which also state nothing about material grade, except for "Cold-Forged & Heat Treated" again.
https://www.vmsracing.com/products/2...575-california

I don't think OEMs produce stainless steel wheel bolts otherwise I would have seen loads till now.
I think it will be safer to get new ones, or try bluing mine with heat/oil.

[jbash87]

Yeah their description leaves a lot to be desired from a material property standpoint. 304 can be heat treated to many different "grades". It's even a bit heavier than grade 10.9. Not sure it's the right choice for this application.

Heat and an oil bath would work, you can also try the bluing liquid. Project Farm did a whole video on this but I can't remember the outcome. Check him out on YouTube. Might save you the hassle.

[conandrum]

Originally Posted by jbash87

Yeah their description leaves a lot to be desired from a material property standpoint. 304 can be heat treated to many different "grades". It's even a bit heavier than grade 10.9. Not sure it's the right choice for this application.

Heat and an oil bath would work, you can also try the bluing liquid. Project Farm did a whole video on this but I can't remember the outcome. Check him out on YouTube. Might save you the hassle.

I was going to try to do the heat/oil bluing, but watched this just now and it put me off (@4:05).

...saying that heating steel to 500-600 degrees Fahrenheit (260-315 Celsius), may be hot enough to alter the temper of a heat treated part.

This means that the safest way is cold bluing but I have to shop online and wait for that.

I tried the boiling water method today and after an hour I gave up with mediocre results, which may be good enough for now.

Thanks for helping out.

[SlowX6M]

Do not under any circumstances use stainless steel fasteners, especially for critical application such as wheel or suspension bolts.

First of all, stainless steel fasteners are not as strong as Class 10.9 for metric or Grade 8 for imperial bolts that are normally used in automotive suspension applications.

Second, stainless steel fasteners are extremely prone to galling, and this is why you don't often see stainless steel fasteners being used anywhere besides marine applications where anti corrosion is the biggest priority. When threading stainless bolt into non stainless hub you probably wont experience galling, but you will damage the threads most likely after the very first use.

Furthermore, getting these bolts from a little known source, they could be made out of chinesium rather than 304 alloy stainless.

Get yourself a set of OEM lug bolts, and don't strip them from protective layer.

[jbash87]

All depends on the material. According to matweb the transition temperature for grade 10.9 (the closest we have for the stock bolts) isn't until 750degF so you would be well within the safe zone if you're only heating to 600degF and wouldn't be altering the heat treatment.