Tapered or radius wheel bolts on bbs

So I’m changing my steel rims for some bbs alloys, and I need to buy some longer wheel bolts.

I’m not sure which to order, the wheels are bbs, no mention of vw or bmw just bbs on the wheels themselves.

I just did a quick google search and found bmw use tapered whilst I know vw use radiused ….

Any ideas guys?




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Shove a ball of blue tack down the hole. Take it out and see what shape it is. Might work, give it a go.

Yep what he said.

Another 'test' is to place a bolt from the steels through the holes and pull on the thread side of the bolt. Give it a wiggle. If it moves a lot then it's probably not the correct bolt head type.

TBH in MOST cases alloys have tapered head bolts not radius bolts. But that's a rule of thumb. Radius bolts TEND to be used on steels only.

I've used this chap in the past

Home

You'll have to phone him to have a chat about bolts though

Ian

Cheers guys.

So I had a closer look. I puffed a light spray of paint on a radius bolt, stuck it in the wheel and turned it, then looked at the marks left.
Did the same with a tapered boot.

I came to the conclusion that the wheels are designed for radius bolts. Also the tapered bolt is wiggly  in the hole whereas the radius bolt seems more snug.

Looking at the bolts I'd come to the exact opposite conclusion.

The radius bolt only seems to catch in a single place whereas the tapered seems to have caught all across it's surface.

Does the surface in the hole feel dished or flat?

Might be worth popping in to a tyre place that sells wheels and get their advice.

Ian

If you look closely the tapered bolt only contacts at the beginning of the thread… I had another look today, and its definitely wiggly in the hole whereas the radius one is snug,,, and has a bigger contact



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Steve1973 said

Shove a ball of blue tack down the hole. Take it out and see what shape it is. Might work, give it a go.

I'm thinking I might go and source some bluetack!,

Looking at your pictures, I'd say they were radius.