[bradsm87]

I'm planning to get aggressive offset wheels and cut it pretty fine with guard rubbing.

Has anybody got first hand experience of the difference between 100% stock and M3 FLCAs as well as alignment pin removed and tops maxed out inward. I'd imagine both mods would roughly cancel each other out in terms of the positioning of the top of the wheel?

Cheers,

Brad

[mlifxs]

not an expert but I've done both of these and here are my beliefs:

pulling the alignment pin should not change the fitment near the strut, as the wheel should move with the change in the strut angle. Pulling the pin and pushing the strut inward should create some extra clearance for fender fit.

adding the M3 wishbone doesn't change the positioning of the strut, but it does change the positioning of the wheel hub, pushing the bottom of the hub out and causing the top of the hub to move in (all relative to the strut). So it seems to me that you may loose a small amount of clearance to the strut, when you do the M3 wishbone. You will be adding clearance to the fender side.

[doogee]

Originally Posted by mlifxs

not an expert but I've done both of these and here are my beliefs:

pulling the alignment pin should not change the fitment near the strut, as the wheel should move with the change in the strut angle. Pulling the pin and pushing the strut inward should create some extra clearance for fender fit.

adding the M3 wishbone doesn't change the positioning of the strut, but it does change the positioning of the wheel hub, pushing the bottom of the hub out and causing the top of the hub to move in (all relative to the strut). So it seems to me that you may loose a small amount of clearance to the strut, when you do the M3 wishbone. You will be adding clearance to the fender side.

This is incorrect.

With both modifications, the clearance to the strut never changes.

But the top of the wheel will move into the wheel well quite a bit!

[mlifxs]

Originally Posted by doogee

This is incorrect.

With both modifications, the clearance to the strut never changes.

But the top of the wheel will move into the wheel well quite a bit!

okay, help me out with that. If the strut stays fixed at the top and the wheel moves into the well quite a bit, isn't the wheel moving closer to the strut? or is both strut and hub moving with the change in control arm length?

[doogee]

Yup! Both the hub and strut move exactly the same together.

[mlifxs]

Originally Posted by doogee

Yup! Both the hub and strut move exactly the same together.

thanks for that.

Sorry OP for the misinformation.

[NocturnalEVO]

With the pin removed, is camber all over the place as the car moves? Or will it be set to one setting specifically with the pin removed?

[mlifxs]

Originally Posted by NocturnalEVO

With the pin removed, is camber all over the place as the car moves? Or will it be set to one setting specifically with the pin removed?

for daily driving, my camber was stable, no noticeable movement with the pin removed. I'm now on camber plates, same comment. Camber plate vendor claims positioning should be stable as long as top mount fasteners are torqued properly, my guess would be same for the oem top hats. I don't know if high stress driving (tracking) would cause any change.

[mike-y]

Originally Posted by mlifxs

thanks for that.

Sorry OP for the misinformation.

actually I think you were right...

suppose the alignment pin is NOT changed and the strut remains fixed. adding the M3 wishbone and control arm increases negative camber by moving the bottom of the wheel outward, and the top of the wheel inward.

that is the only way to increase negative camber without moving the strut mounting location. So the top of the tire has to move inward, decreasing strut clearance a bit.

there is no other way around this. removing the alignment pin, and sliding the strut mount inward moves the entire assembly together (clearance is not affected). but changing the arms, changes the angle of the hub which will affect strut-tire clearance.

[doogee]

Originally Posted by mike-y

actually I think you were right...

suppose the alignment pin is NOT changed and the strut remains fixed. adding the M3 wishbone and control arm increases negative camber by moving the bottom of the wheel outward, and the top of the wheel inward.

that is the only way to increase negative camber without moving the strut mounting location. So the top of the tire has to move inward, decreasing strut clearance a bit.

there is no other way around this. removing the alignment pin, and sliding the strut mount inward moves the entire assembly together (clearance is not affected). but changing the arms, changes the angle of the hub which will affect strut-tire clearance.

No! lol.

The strut is bolted the the spindle and is in a fixed position. Take an actual look at the suspension to understand. The angle of the hub NEVER changes.

The ONLY way to change the strut to wheel clearance would be to bend the strut.

[doogee]

As you can see the strut (Yellow arrow) slides into the spindle. When changing the control arm (A), the entire assembly moves outwards.

[mike-y]

ah, so the strut pivots at the top as well then.

I guess I'm too used to my other cars with both upper and lower control arms, which the E90 does not have.

[doogee]

Originally Posted by mike-y

ah, so the strut pivots at the top as well then.

I guess I'm too used to my other cars with both upper and lower control arms, which the E90 does not have.

Yes sir

[mlifxs]

thanks for the benefit of the doubt mike-y, but I'm now persuaded on the "no change in strut clearance" aspect. I looked at realoem so yes strut and wheel carrier are fixed, and that is consistent with no loss of clearance.

but then...wouldn't you think that the top of the wheel is coming out as well...unless the very top of the strut is moving inward while top hat stays fixed? ...or what else gives?

[doogee]

The strut articulates in the strut mount. Think of it like a swing. I supposed you could argue the top might come outwards a little bit.

[bradsm87]

Longer control arms obviously prodominantly move the bottom of the wheel out but also the top slightly as well (anything below the strut mount linearly from 0).

The reason for my post is to make sure that sliding the tops in as far as the factory slots go will move the wheel tops in more than the amount the M3 LCAs move them out. Outer clearance is my concern and I'm aware that the strut/knuckle/hub/wheel is all fixed.

[doogee]

Originally Posted by bradsm87

Longer control arms obviously prodominantly move the bottom of the wheel out but also the top slightly as well (anything below the strut mount linearly from 0).

The reason for my post is to make sure that sliding the tops in as far as the factory slots go will move the wheel tops in more than the amount the M3 LCAs move them out. Outer clearance is my concern and I'm aware that the strut/knuckle/hub/wheel is all fixed.

Sliding the strut mount should make up the difference! I'd say you're good to go.

[mlifxs]

Originally Posted by bradsm87

Longer control arms obviously prodominantly move the bottom of the wheel out but also the top slightly as well (anything below the strut mount linearly from 0).

The reason for my post is to make sure that sliding the tops in as far as the factory slots go will move the wheel tops in more than the amount the M3 LCAs move them out. Outer clearance is my concern and I'm aware that the strut/knuckle/hub/wheel is all fixed.

I suspect that sliding the tops in move the wheel more (from visual) but I didn't measure to know for sure.

I now have camber plates at -2 camber up front. That definitely shows up visually as additional clearance. I'm 18" 9" wheels up front ET31 with 245/35/18 Conti DW and have plenty of clearance....I think I could easily go 255s on beefier tires with this amount of camber.

[john16443]

Originally Posted by mlifxs

for daily driving, my camber was stable, no noticeable movement with the pin removed. I'm now on camber plates, same comment. Camber plate vendor claims positioning should be stable as long as top mount fasteners are torqued properly, my guess would be same for the oem top hats. I don't know if high stress driving (tracking) would cause any change.

Camber pins removed, no M components installed, tracked car. No change in position of upper strut mounts/top hat after hard driving. struts were located all the way against the inboard slotted ends when I replaced struts last month.