[obzen]

Went from stock 19" 442m 225/40 - 255/35 to 19" 235/40 -255/35 with ET30 square 8.5j. Stock m suspension rwd not lowered. I'm hearing little rub from from but only when I'm in sport mode. In Comfort full lock no rub? Should I be concerned ?

[HarryTee]

If you do use sport mode then you should be concerned.
But from your description, I think if you can find the place of rubbing contact, you may easily be able to bend the metal/plastic a bit to resolve it.

[obzen]

Edit: today I noticed it only rubs if I'm backing up, full lock, and turning right in sport mode. If I go left it doesn't rub. I wonder if it's because the front two tires have a bit different tread wear? They're sottozero3s

I'm gonna try and visualize where it's rubbing I think it should be ok to run this setup for a 4 months

[Skyhigh]

I am puzzled what I am missing here, but what has Sport Mode to do with it!?

[kern417]

Doesn't really make any sense but it's likely that you sitting in the driver's seat is reducing your clearance in the front right wheel well. Either way it should be fine but you can fix it if it's annoying.

[obzen]

Originally Posted by Skyhigh

I am puzzled what I am missing here, but what has Sport Mode to do with it!?

Maybe because the dampers are stiffer and somehow that contributes to less clearance on full lock? I'll mess around with it today and try to figure out why this is

[obzen]

Originally Posted by kern417

Doesn't really make any sense but it's likely that you sitting in the driver's seat is reducing your clearance in the front right wheel well. Either way it should be fine but you can fix it if it's annoying.

Could be this. I need to turn fulllock and look in the wheel wells to see where it rubs exactly. Weird that it only does it one way.

[Desertnate]

Originally Posted by obzen

Maybe because the dampers are stiffer and somehow that contributes to less clearance on full lock? I'll mess around with it today and try to figure out why this is

This would only apply if he has the adaptive suspension. Otherwise, nothing in the suspension changes when you go into sport mode. Even if we assume adaptive suspension, I'd think there would be less of a chance of any rubbing in sport mode because it is harder to compress the suspension with the stiffer setting. It isn't like suspension components change position depending on setting.

It's a head scratcher for sure...

[sqwinny]

Sport mode is odd, perhaps you are just noticing it now. You could always grab a quick set of spacers and you have more clearance.

[obzen]

Originally Posted by sqwinny

Sport mode is odd, perhaps you are just noticing it now. You could always grab a quick set of spacers and you have more clearance.

Going from stock 19x8J ET36 to 19x8.5J ET30 the wheels are more flush now so adding a spacer will push them out past 'flush' likely resulting in more rubbing

[Skyhigh]

Originally Posted by Desertnate

This would only apply if he has the adaptive suspension. Otherwise, nothing in the suspension changes when you go into sport mode. Even if we assume adaptive suspension, I'd think there would be less of a chance of any rubbing in sport mode because it is harder to compress the suspension with the stiffer setting. It isn't like suspension components change position depending on setting.

It's a head scratcher for sure...

Precisely!
Only the Adaptive Suspension is affected by the mode (Comfort vs Sport) and even that only changes the stiffness and response, not the height! Stiffer suspension means less bouncing, so less rubbing....

And the OP does not even mention Adaptive Suspension....

It makes no sense to me.

[obzen]

Originally Posted by Skyhigh

Precisely!
Only the Adaptive Suspension is affected by the mode (Comfort vs Sport) and even that only changes the stiffness and response, not the height! Stiffer suspension means less bouncing, so less rubbing....

And the OP does not even mention Adaptive Suspension....

It makes no sense to me.

Sorry for the confusion, turns out that ET30 upfront with 235/40 rubs a tiny bit on the front of the wheel well. It's very close, a couple mm would clear it. Downsizing to 35 sidewall instead of 40 this week.

Originally I thought it was only in sport mode but after looking closely it rubs in comfort mode too so that was a false report on my end. Does the speedo report wrong with downsizing the front sidewall to 35 since OEM is 40?

[Skyhigh]

Yes, it will.
You are effectively changing the circumference of the wheels.

[obzen]

Originally Posted by Skyhigh

Yes, it will.
You are effectively changing the circumference of the wheels.

aside from the speedo will there be any issues running 35 profile tires instead of the 40? I know a bunch of people run 35 in front but not sure if thats an x drive thing or what not. For RWD does it make any negative difference except for the speedo and ride quality?

[about94ninjas]

Originally Posted by obzen

aside from the speedo will there be any issues running 35 profile tires instead of the 40? I know a bunch of people run 35 in front but not sure if thats an x drive thing or what not. For RWD does it make any negative difference except for the speedo and ride quality?

I've been running 255/35/19 up front and I've had zero issues. It actually helped correct the speedo, which reads a couple mph lower from factory haha. I am using camber plates to help with the clearance tho

A 35 vs 40 profile in and of itself isn't going to affect much, sidewall and overall diameter is what you need to pay attention to.

[pauli18c]

How often do you drive around in reverse, at full lock, while only going right?

I would just drive it if it doesn't rub under normal driving conditions...

[obzen]

Originally Posted by about94ninjas

I've been running 255/35/19 up front and I've had zero issues. It actually helped correct the speedo, which reads a couple mph lower from factory haha. I am using camber plates to help with the clearance tho

A 35 vs 40 profile in and of itself isn't going to affect much, sidewall and overall diameter is what you need to pay attention to.

If 35 sidewall is within the diameter spec than I'm going to assume it's perfectly fine and not loose any sleep over it

[about94ninjas]

What paulie18c said. If you really wanna be sure, just go to a tire size calculator online, enter the stock size and then what you're running.

[BWbimmer]

Originally Posted by Skyhigh

Yes, it will.
You are effectively changing the circumference of the wheels.

Since the speedo is "connected" to the rear wheels and the rear wheels didn't change, I can't seen any circumference impact?

[about94ninjas]

Originally Posted by BWbimmer

Since the speedo is "connected" to the rear wheels and the rear wheels didn't change, I can't seen any circumference impact?

I believe BMW uses the front wheels for speed

[BWbimmer]

Originally Posted by about94ninjas

I believe BMW uses the front wheels for speed

So you are saying if you are doing a burnout, then the speedo stays at 0?
Then this must have changed with the F series

[about94ninjas]

Originally Posted by BWbimmer

So you are saying if you are doing a burnout, then the speedo stays at 0?
Then this must have changed with the F series

Couldn't find a burnout video, but found one doing a rolling burnout, and the speedo was reading 40mph at the top of 3rd lmao. I guess that's why f series have a specific "dyno mode"