c2dweller

I've just installed Bilstein B6/HD & H&R greens and I'm about to set ride height. I want to start with RS +5mm - but need to offset this for the 16 in wheels.

I am running standard tyres - 205 55 on the front and 225 50 on the rears so this calculates to be 631.9 & 631.4mm diameter wheels

A 17 in wheel would be - 205 50 on the front and 255 40 on the rears so this calculates to be 636.8 & 635.8mm diameter wheels

To get to the centres I halve the above dimensions. For the fronts I then need to aim for RS +5m -2.5mm and for the rears RS + 5m - 2mm.

Does this sound right?

Thanks, Lee

sml

Sounds like you are on the right track but does it need to be so perfect to the mm?

Seems like the majority suggest to change the perfect ride height to corner balance anyway, so it cant be that important (although I went for perfect ride heights and skipped the corner balance).

altarchsa

Sounds logical to me. But if you're getting that exact, would loaded different size tires and wheels (car on the ground, half tank gas, etc.) result in the same measurement differences as casting measurements? Probably talking fractions of millimeters, forget I brought it up.

I'm planning the exact same setup so I hope you get a knowledgeable answer.

c2dweller

When I started out I thought the difference would be bigger - bit dissapointed that it turned out to be just a few mm. I guess this doubt made me post the question in the first place.

I'll get it set-up correctly in the long term, just want to put a few miles on to make sure nothing else needs to be raplacing to match the uprated suspension.

Cheers, Lee

PNine64

If the difference in overall tire diameter was any more than negligible then wouldn't it throw many things off (speedometer, ABS??, etc)?

sml

Another quick thought ...

there is probably about 5mm of treadwear on tires ... so with new tyres your car should be 5mm lower ... compared to worn tyres where the car would need to be raised 5mm.

i haven't heard of anyone doing this.

c2dweller

Good point about tread wear! I wonder how many people think of this when they set-up RS height +5mm with worn tyres