Suspension geometry.

[E-bmw]

In particular "track".

I am in the process of getting an r53 ready for track/daily duties & have come across an issue.

The coilovers that I have fitted have meant that the tyre sidewall JUST fouls the adjusters for the coilover.

It is only by a couple of mm but, I now need to fit wheel spacers and have a quandry that I would like assistance with.

Is wider better?

I could just go with 5mm spacers for the front only & that gives plenty of clearance, but then I think, would wider be better? And what about the rear to match?

What is the consensus with respect to geometry?

[GreenV8S]

Moving the wheel outboard is going to alter the position of the contact patch relative to the steering axis, so if it's right now then any change will make steering feedback and kickback worse.

You should aim to have more than just a couple of mm clearance because components and joints can flex a remarkably long way under load.

[E-bmw]

Thanks for that, I was assuming that would be the case.

As a test I fitted 1.5mm washers behind each wheel bolt & there was nearly 1mm of space, so 5mm spacers will be good.

[GreenV8S]

If you're using road tyres then a 5mm change to the offset is not IMO anything to worry about. Make sure you have enough wheel stud/nut engagement and if the wheel uses the centre bore for alignment make sure that the spacer passes this through - that might be a problem with a thin spacer.

[E-bmw]

I will be sourcing bolts longer by the wheel spacer width, so got that one covered.

On your second point, not sure I understand you.

The spacer will be 5mm, the centre bore of the hub is well over 5mm out from the disc face, so the fact that it is a thin spacer means there is still enough for the wheel to correctly align, whereas you seem to be saying that the thin spacer means there won't be any for the wheel centre to align on?

[GreenV8S]

The part of the hub which locates on the center bore of the wheel is usually quite shallow. Thicker wheel spacers would usually have a recess which locates on the hub, and have a shoulder which the wheel locates on. This is only possible when the spacer is thicker than the locating shoulder. The sort of thin spacer you're describing wouldn't have enough thickness for that.

[E-bmw]

Ah! Got you, well said, it looks like mine will be thin enough to leave a smaller lip there, so in a roundabout way, still work.

[CarsOrBikes]

My et48 wheels also just touched the adjusters, so I have used 11mm spacers (hubcentric) and longer bolts, since then I have upgraded to R56 bearings and wheel bolts which are significantly stronger which you'll identify with maybe when you recheck the bolts during a track day. I didn't need rear spacers.

[E-bmw]

I will keep that in mind too when I get that far, my hope is that by keeping the spacer as small as possible whilst still giving enough clearance will keep me away from that issue.