Same as Ray. Stainless standard issue nuts. No idea of the taper.
Am I worried?
No.
The studs are high tensile steel and bear the brunt of the forces involved. The nuts are there to hold the wheel in place and provided they are torqued correctly then little to worry about.
If I decide to replace a bolt/nut/screw then I consider stainless unless it is for an obvious safety critical component. It is then like for like.
I buy from well established and reputable suppliers.
ebay? Treated with great care! Cheap Oriental electric stuff! NEVER.
I concur with howard re the grades of steel. As a metallurgist in college we used to get books from Climax Molybdenum Company as textbooks. They were great books and free giveaways! Covering stainless steels with details of grades composition, heat treatment, uses etc.
For an individual to order a couple of stainless, heat treatable and hence stronger, ss bolts/nuts would be expensive. A2 and A4 are the general purpose grades, A4 prefered for marine use as better corrosion protection. YES..ss does corrode! Welding of ss is also an area for careful choice, perhaps more so than carbon steels.
