[quoteI’d also be cautious of using 12.9 grade bolts as for this type of application the bolt could be a bit too brittle, 10.9 should be enough. [/quote]
Mark
I suppose the main message here is to use proper high tensile steel capscrew bolts and torque them up properly. It would probably also help if you ‘roughened’ the mating surfaces a little to help with friction and so reduce the shear forces on the bolts ?
Don’t they use 12.9 grade bolts in motorsport for suspension components ??
Not sure on the bolts in Motorsport but I remember when building a car at work a few years ago the olny bolts we could get at short notice to connect the subframe to the body were 12.9 and the ‘bolt expert’ said no way!
Regarding the bolts, we had a long discussion in our R&D department about this, I must add that they are mechanical engineers not automotive engineers or such
Anyhow the 12.9 bolt won according to our resident Doctor of Engineering -
To be honest I think the point is check them regular for coming loose ( the shim stacks compress, o rthe bolt gets a bit bent ), make sure the shank is well inside the hub and dont use stainless or plated 8.8 bolts ( they really do break easy ) and 10.9 would be fine - OH and change them every time you smack a kerb hard
For some people that means every lap…