Tire Sizing, KW V3, and spacer ?'s!

[bmw13]

I have coils on the way... not just for stance or performance but both... I want the car to actually handle/ function better than it is/ does now, not just look better!

I am currently set up with 245 up front and 275 in rear. I did possibly want to go up to 265F and 285R. My questions are:

-should I size up or stay the same? (What will be best for handling/ cornering??) car is stage 2 power wise...
keep 245F275R?
or size up to 265F285R

-will I rub?
with what I have now?
or going larger in both front and rear

-do I need spacers?
with what I have now?
or is going up in tire size enough?

[bmw13]

I think I will try 255F/285R and no spacers just like the Safety Car. I love that thing! Full spec list in video description!

[ozinaldo]

Can be very good really.

Just one thing to watch out: both Moto GP 1M and its "muse" E92 M3 GTS have this set up (with Pirelli PZero Corsa System tires) with a possible factory-tune in their DSC set up, since there is no stagger left like the stock 1M/M3. Both fronts and rears will have 26" of rolling diameter unlike the stock 0.5" difference.

I also want to believe that this is a non-issue but I can't say am 100% positive about that.

Otherwise, it is the dream tire-wheel combo.

[bmw13]

Originally Posted by ozinaldo

Can be very good really.

Just one thing to watch out: both Moto GP 1M and its "muse" E92 M3 GTS has this set up (with Pirelli PZero Corsa System tires) with a possible factory-tune in their DSC set up, since there is no stagger left like the stock 1M/M3. Both fronts and rears will have 26" of rolling diameter unlike the stock 0.5" difference.

I also want to believe that this is a non-issue but I can't say am 100% positive about that.

Otherwise, it is the dream tire-wheel combo.

so what do you recommend? I do not understand when you say .5" difference as well sorry suspension is SO new to me

[ozinaldo]

Originally Posted by bmw13

so what do you recommend? I do not understand when you say .5" difference as well sorry suspension is SO new to me

Stock car's 245/35/19 front and 265/35/19 rear set up has following overall diameters: 25.8" and 26.3", hence 0.5" stagger which corresponds to 807 revs per mile for fronts while the rears will be doing 790 revs per mile. This is what a stock 1M or M3's DSC "thinks" when it takes decisions if I may put it that way

When you pass to M3 GTS size tires on stock wheels which are the same wheels of 1M, the overall tire diameters will be 26" front AND rear so no stagger of 0.5", no difference or very little difference in terms of revs per mile. I don't have enough evidence to assume that stock ECU and DSC are flexible and adaptive "enough" to make this a non-issue. If you search M3 forums you will see there are people who did this and others who want to make this if and when Michelin releases 285/30/19 size PSS. You will also notice comments backing or doubting this particular tire size.

For the size of stock wheels and space in wheel wells, yes this got to be the dream (street) set-up.

I hope it is clearer now.

[bmw13]

Originally Posted by ozinaldo

Stock car's 245/35/19 front and 265/35/19 rear set up has following overall diameters: 25.8" and 26.3", hence 0.5" stagger which corresponds to 807 revs per mile for fronts while the rears will be doing 790 revs per mile. This is what a stock 1M or M3's DSC "thinks" when it takes decisions if I may put it that way

When you pass to M3 GTS size tires on stock wheels which are the same wheels of 1M, the overall tire diameters will be 26" front AND rear so no stagger of 0.5", no difference or very little difference in terms of revs per mile. I don't have enough evidence to assume that stock ECU and DSC are flexible and apaptive "enough" to make this a non-issue. If you search M3 forums you will see there are people who did this and others who want to make this if and when Michelin releases 285/30/19 size PSS. You will also notice comments backing or doubting this particular tire size.

For the size of stock wheels and space in wheel wells, yes this got to be the dream (street) set-up.

I hope it is clearer now.

It definitely is! Thanks! I have a better understanding now. Should I maybe witch tires then? But, I honestly am concerned now about the DSC. I do not run my DSC off as it is too risky for daily driving, but I do use MDM daily rain or shine. I do not want the traction light to come on anymore than it already does, that is for certain. Decisions, decisions...

[ozinaldo]

Originally Posted by bmw13

It definitely is! Thanks! I have a better understanding now. Should I maybe witch tires then? But, I honestly am concerned now about the DSC. I do not run my DSC off as it is too risky for daily driving, but I do use MDM daily rain or shine. I do not want the traction light to come on anymore than it already does, that is for certain. Decisions, decisions...

The DSC will likely be more intrusive, miscalculating the tire revs, on certain occasions at the very least. Can't be at such a level like I would call a huge and unacceptable difference but I believe can't be "no difference" as well, something got to be different. I decided not to do it myself and I will go next time either 255/275 35s front and rear like most do; or will see if I have the balls to do 275/30 front and 295/30 rear. I am leaning toward the simpler and mild upgrade, 255/275. I am OK with stock sizes anyway, as long as tires are PSS or something at that level so a mild upgrade could suffice. Both those sizes are much closer to stock set up than the one with 285/30 which also limits tire choice (no PSS for instance).

You have the KW which adds to complexity of this decision, especially if you are decided to go lower. As usual, it is very much to do with where and how you drive your car (track/DD or mixed), if you need to consider good tire manners in rain and also if you want to stay with stock wheels or not. A good 18" wheel shall give you yet another range of tire options to choose from.

Good luck

[Ender_]

I just had 265/30's mounted on the stock front wheels, no rubbing so far, it is pretty close, I have about a 1.5cm drop with the KWv3's.

My track rear tires are 285/35/18 - no rubbing.