[kyleoc]

picked up a 325i with aftermarket M wheels
18” running 245/40 ZR 18 tires
and i have insanely bad tire rub. any bump or speed bump i have to literally slow down hard other wise im rubbing. are these type of wheels/tires too big for my clearance or are my shocks toast.

[mattanderson]

Hard to say without knowing the width and offset of the wheels, or which springs you're running.

245/40/18 is taller than stock, but I believe that's what Alpina used on the front of the E9x B3, so it should be possible with the right setup.

[krhodes1]

Blown shocks will make the car wallow and pitch and generally. They will not affect tire clearance at all. If your tires are rubbing, you have the wrong tires or wheels and tires. Or something is bent or otherwise broken.

[catlinsm]

I had blown struts that would rub when I hit bumps. My tires are 255/40/17. After replacing struts they don’t rub anymore.

[krhodes1]

Originally Posted by catlinsm

I had blown struts that would rub when I hit bumps. My tires are 255/40/17. After replacing struts they don’t rub anymore.

Unless your strut mounts and/or bump stops were bad, and you replaced them as part of the repair (as you should) blown struts do not in and of themselves affect suspension geometry at all. Struts only go up and down - blown ones go up and down more freely, and it is the bump stop that limits travel.

[Brandoch]

Originally Posted by krhodes1

Unless your strut mounts and/or bump stops were bad, and you replaced them as part of the repair (as you should) blown struts do not in and of themselves affect suspension geometry at all. Struts only go up and down - blown ones go up and down more freely, and it is the bump stop that limits travel.

Yes and no. New dampers are able to hold some weight, not a lot but some. With blown dampers the springs can sag slightly without the assistance. I'm talking like 1-2 mm here. Especially when not on a level surface.

[lookalikehuuh]

Can you give us more information on the wheels? What exactly are aftermarket M wheels? I assume they are just some random knockoff cast wheels with an "M" sticker on them, is that correct? Is it the front that rubs or the rear?

Can you maybe post a picture of the wheels and their profile (how much they extend out from the fenders? I suspect the offsets are not compatible with your car. Sometimes if you remove a wheel there might be numbers on the inside of the wheel that can give you the offset numbers for the wheel, but that is usually on quality wheels.

The tires on your car from factory usually have an overall diameter of ~25inches give or take a bit. The current tire size according to tire rack is nearly 26" so they are bit large for your car vs factory tire/wheel combination. Its likely that the combination of the larger tire size, and an improper offset are contributing to the rubbing.

There are lots of suspension components that can increase the ride height of the car. I recently did a refresh of the tophats for the front of my car and the ride height was slightly increased. New shocks/struts can also slightly increase the ride height because of the higher pressures of a properly charged strut vs blown, but usually they are not significant.

[krhodes1]

Originally Posted by Brandoch

Yes and no. New dampers are able to hold some weight, not a lot but some. With blown dampers the springs can sag slightly without the assistance. I'm talking like 1-2 mm here. Especially when not on a level surface.

If a few millimeters is causing rubbing, something is wrong.

And doesn't change the fact that damping doesn't change the suspension geometry. As I said, chances are the issue isn't the shocks, it's the bump stops and/or shock mounts allowing more travel than the suspension is designed for. And given the proclivities around here - the wrong tires and/or wheels on the car.