[lax01]

Coming back to this - looking for confirmation that someone has done 275/30/19 and 295/30/19 with M Performance Suspension (so lowered but at stock/port-set height). No camber plates.

Will 275/30/19 fit up front? Or is it better to go 265/35/19 & 285/35/19 to be safe?

Thanks

[VisualEcho]

Originally Posted by lax01

Coming back to this - looking for confirmation that someone has done 275/30/19 and 295/30/19 with M Performance Suspension (so lowered but at stock/port-set height). No camber plates.

Will 275/30/19 fit up front? Or is it better to go 265/35/19 & 285/35/19 to be safe?

Thanks

The 275/30 up front is the issue, and will rub for sure. The 295/30 you should be ok with.

265/295 will cause understeer, but if you're not hammering the car you'll probably be fine with it. But then you also have a rear tire that's .3 shorter than the front tire, and it's supposed to be .6 taller.

The safe bet is the 265/35 & 285/35 combo, but you could have a bit of rubbing with the 265 up front (some do, some don't).

[lax01]

Originally Posted by VisualEcho

The 275/30 up front is the issue, and will rub for sure. The 295/30 you should be ok with.

265/295 will cause understeer, but if you're not hammering the car you'll probably be fine with it. But then you also have a rear tire that's .3 shorter than the front tire, and it's supposed to be .6 taller.

The safe bet is the 265/354 & 285/35 combo, but you could have a bit of rubbing with the 265 up front (some do, some don't).

Thanks - Not 265/30 & 285/30? Assuming 255/35 & 275/35 is the safest bet to avoid rubbing?

[VisualEcho]

Originally Posted by lax01

Thanks - Not 265/30 & 285/30? Assuming 255/35 & 275/35 is the safest bet to avoid rubbing?

OK, first you need to remember that a lot of times when you shorten a sidewall you will widen the shoulder.

Take the 255/30 vs the 255/35 for example.

255/30 = 9.6 / 25.1
255/35 = 9 / 26

It's obvious that the 35 will be taller, but not as obvious that the 30 will be wider.

This doesn't happen every time, which is why it's always best to check the tire specs on Tirerack instead of using a calculator like willtheyfit.

I believe you were looking at the PS4S, yes?

If so, no 285/30 exists.

But let's imagine you chose the Firehawk Indy instead.

Have a look at the specs. Notice that your rake remains, but you're adding more width to the rear, giving you a slight understeer feel. Also notice the rear is nearly an inch wider...

[lax01]

Originally Posted by VisualEcho

OK, first you need to remember that a lot of times when you shorten a sidewall you will widen the shoulder.

Take the 255/30 vs the 255/35 for example.

255/30 = 9.6 / 25.1
255/35 = 9 / 26

It's obvious that the 35 will be taller, but not as obvious that the 30 will be wider.

This doesn't happen every time, which is why it's always best to check the tire specs on Tirerack instead of using a calculator like willtheyfit.

I believe you were looking at the PS4S, yes?

If so, no 285/30 exists.

But let's imagine you chose the Firehawk Indy instead.

Have a look at the specs. Notice that your rake remains, but you're adding more width to the rear, giving you a slight understeer feel. Also notice the rear is nearly an inch wider...

Yes, PS4S - and I actually meant 265/35/19 and 295/30/19 - but I'm guessing this is a pretty big delta from stock sizing

I'm just concerned, with the lack of ability to adjust camber - and with the M Performance Suspension (KW V3 from what I understand), that 275/30/19 will be undrivable

What's the best compromised tire size upgrade? You are basically saying 265/35/19 and 285/35/19 is that bet...assuming you rub the inside liner?

Thanks again

[VisualEcho]

Originally Posted by lax01

Yes, PS4S - and I actually meant 265/35/19 and 295/30/19 - but I'm guessing this is a pretty big delta from stock sizing

I'm just concerned, with the lack of ability to adjust camber - and with the M Performance Suspension (KW V3 from what I understand), that 275/30/19 will be undrivable

What's the best compromised tire size upgrade? You are basically saying 265/35/19 and 285/35/19 is that bet...assuming you rub the inside liner?

Thanks again

To maintain the balance of the car you're going to need to preserve the rake, and the 20mm between front and rear tire sizes.

So yes, the standard upgrade is 265/285/35 and yes, some users get rub on the inside with the 265, and some don't. When it comes to lowering, all bets are off.

I recommend setting up your suspension perfectly first, then buying tires to suit.

[lax01]

Originally Posted by VisualEcho

To maintain the balance of the car you're going to need to preserve the rake, and the 20mm between front and rear tire sizes.

So yes, the standard upgrade is 265/285/35 and yes, some users get rub on the inside with the 265, and some don't. When it comes to lowering, all bets are off.

I recommend setting up your suspension perfectly first, then buying tires to suit.

yeah, I guess I can't really setup the suspension perfectly since I can't adjust camber which would (obviously) resolve a lot of my concern around the front sizing

Anyway, thanks - think I might got 265/35 and 285/35

[PilotxERAU]

Originally Posted by lax01

yeah, I guess I can't really setup the suspension perfectly since I can't adjust camber which would (obviously) resolve a lot of my concern around the front sizing

Anyway, thanks - think I might got 265/35 and 285/35

Anyone rolled the fenders? I am running 275/30 PS4S F and 295/30 R on BBS-FIR's (9.5'" front 10.5" rear) lowered both front and rear to a bit more than 1 finger gap from bottom of fender to top of wheel at lowest points (corner balanced so not symmetrical). I am on MCS suspension (-2.5 camber front, -2.0 rear) and will get some rub over bigger bumps in rear and in some front rub on certain geometries when turning and hitting bumps. It is not as bad as I would have thought for this amount of lowering but I feel like a slight fender roll all the way around would eliminate any rub completely and be ideal. Wonder if anyone has gone down this road. I am a bit leary about doing it but I have seen some metal expert shops do some amazing work in that respect.

[G80BSM]

For anyone who is interested, PS4S 275/295 -30 on stock wheels and suspension don’t rub. The car handles and hooks way better than stock. However, the steering does feel just a tad bit heavier compared to stock. These are just my preliminary thoughts but I will report back in a couple of weeks.

[ssabripo]

Originally Posted by S.111

For anyone who is interested, PS4S 275/295 -30 on stock wheels and suspension don’t rub. The car handles and hooks way better than stock. However, the steering does feel just a tad bit heavier compared to stock. These are just my preliminary thoughts but I will report back in a couple of weeks.

Any rubbing in the front on full turn? that's my concern at the moment.

I'm currently doing 295/30 rears (- 1.1% from stock) and 265/30 (- 1.9% from stock) on fronts, but I want to try to maintain closer diameter and rake, so I'm hoping to try to go 275/30 (-1.2% from stock), but there is too many people reporting rubbing at full turn. with current setup I'm at -0.8% delta front/back.... if i would be more certain of no rubbing, the 275/30 would be ideal to mitigate the delta to -0.1% front/back.

My other option being considered is to go 285/30 rear ( - 2.3% from stock) and 265/30 (- 1.9% from stock), for a total delta of -0.4% between front/back.

[VisualEcho]

Originally Posted by S.111

For anyone who is interested, PS4S 275/295 -30 on stock wheels and suspension don’t rub. The car handles and hooks way better than stock. However, the steering does feel just a tad bit heavier compared to stock. These are just my preliminary thoughts but I will report back in a couple of weeks.

Not a bad play for stock height, and you shouldn't have any rubbing up front unless you're really hitting it hard in turns. But you definitely induced some additional understeer.

Originally Posted by ssabripo

I'm currently doing 295/30 rears (- 1.1% from stock) and 265/30 (- 1.9% from stock) on fronts, but I want to try to maintain closer diameter and rake, so I'm hoping to try to go 275/30 (-1.2% from stock), but there is too many people reporting rubbing at full turn. with current setup I'm at -0.8% delta front/back.... if i would be more certain of no rubbing, the 275/30 would be ideal to mitigate the delta to -0.1% front/back.

My other option being considered is to go 285/30 rear ( - 2.3% from stock) and 265/30 (- 1.9% from stock), for a total delta of -0.4% between front/back.

You guys with your percentages.

Stop looking at that crap, it's meaningless. TIRES ARE NOT PERFECT, and they all vary a bit.

Willtheyfit.com is ONLY good for wheels/offsets, not tires.

Calculate what you need by finding the maximums, then getting all the new specs from tirerack, using TW and OD.

[ssabripo]

Originally Posted by VisualEcho

You guys with your percentages.

Stop looking at that crap, it's meaningless. TIRES ARE NOT PERFECT, and they all vary a bit.

Willtheyfit.com is ONLY good for wheels/offsets, not tires.

Calculate what you need by finding the maximums, then getting all the new specs from tirerack, using TW and OD.

I'm not sure why you are saying this. Of course "tires are not perfect" and they have different widths and measurements... FOR WIDTHS! for overall diameter, they are absolutely accurate!

the reason to be concerned about overall diamater is the impact on the car's rpm, speed, etc, which affects several aspects of the ECU's calculations including DSC and MDM and rev-matching among other things.

To your point, when I did my research on what tires to put on them, the first thing I did was look at tirerack's TW and OD, and this was exactly what was used for selecting the appropriate tire..... and now, the fine tuning has to do with the overall diameter dial in regarding the width of the side wall if you were to compare MP4S vs Indy Firehawk for example:


Left is indy's firehawk 500, right is the M4PS...The OD and RPM's are identical. So yes, the 265/30 vs 275/30 impact on rake and performance is most certainly important in terms of percentages.

[VisualEcho]

TW and OD are all that should be quoted, not percentages.

Treadwidth is the real shoulder, and should be within the 20mm difference spec'd by BMW to keep the balance correct.

OD will give you the placement of the shoulder, and rake values.

And for some of us, weight is always factored in as well, but we are the rare few.

[G80BSM]

Originally Posted by ssabripo

Any rubbing in the front on full turn? that's my concern at the moment.

I'm currently doing 295/30 rears (- 1.1% from stock) and 265/30 (- 1.9% from stock) on fronts, but I want to try to maintain closer diameter and rake, so I'm hoping to try to go 275/30 (-1.2% from stock), but there is too many people reporting rubbing at full turn. with current setup I'm at -0.8% delta front/back.... if i would be more certain of no rubbing, the 275/30 would be ideal to mitigate the delta to -0.1% front/back.

My other option being considered is to go 285/30 rear ( - 2.3% from stock) and 265/30 (- 1.9% from stock), for a total delta of -0.4% between front/back.

No rubbing at all, even at full turn. At full turn, the gap between the fender liner and the tires is almost the same as stock thanks to the smaller diameter of the 275/30's. There's a 1.5 finger gap between the tire and the strut mount. I took it for a spirited drive on some winding roads that also have huge bumps/dips and to my surprise, there was no rubbing at all.

I am going to get them rebalanced on Monday. While the tires are off the car, I will visually inspect them for any signs of rubbing as well.

The only reason I went with the 275/295 setup was, just like you said, to stay closest to OEM diameter and rake, and even the f/r stagger. I would've gone for 265/285 - 30's but they reduce the diameter of the sidewall even further and I didn't want that. Surprisingly, the ride is less harsh even though these 275/295's are 0.3" shorter than the OE spec PSS's, thanks to the better tire compound on the PS4S.

Originally Posted by VisualEcho

Not a bad play for stock height, and you shouldn't have any rubbing up front unless you're really hitting it hard in turns. But you definitely induced some additional understeer.


You guys with your percentages.

Stop looking at that crap, it's meaningless. TIRES ARE NOT PERFECT, and they all vary a bit.

Willtheyfit.com is ONLY good for wheels/offsets, not tires.

Calculate what you need by finding the maximums, then getting all the new specs from tirerack, using TW and OD.

No rubbing even at turns where the road dips and I'm really on it - not yet at least! It actually understeers much less when comparing it to the stock tire setup. The front end grip is just perfect now in my opinion. I'm running a stage 2 tune so the power is closer to the 470-480 whp mark and this tire setup is almost perfect for that.

[ssabripo]

Originally Posted by VisualEcho

TW and OD are all that should be quoted, not percentages.

what does thread width have anything to do with diameter and impact on the ECU's calculations on mdm/dsc, rpm, et al? and yes, percentages are absolutely important when determining the delta change from OEM. The car's multiple calculations are based on that.

[ssabripo]

Originally Posted by S.111

No rubbing at all, even at full turn. At full turn, the gap between the fender liner and the tires is almost the same as stock thanks to the smaller diameter of the 275/30's. There's a 1.5 finger gap between the tire and the strut mount. I took it for a spirited drive on some winding roads that also have huge bumps/dips and to my surprise, there was no rubbing at all.

I am going to get them rebalanced on Monday. While the tires are off the car, I will visually inspect them for any signs of rubbing as well.

The only reason I went with the 275/295 setup was, just like you said, to stay closest to OEM diameter and rake, and even the f/r stagger. I would've gone for 265/285 - 30's but they reduce the diameter of the sidewall even further and I didn't want that. Surprisingly, the ride is less harsh even though these 275/295's are 0.3" shorter than the OE spec PSS's, thanks to the better tire compound on the PS4S.

That's good feedback...exactly what I was looking for

When I kept the stock fronts temporarily while trying 295/30 rears, the understeer impact was palpable, and definitely not recommended. I thus tried 265/30, given some of the feedback on here of multiple folks having rubbing issues with 275/30 and even 265/35, albeit very few had posted they were still on stock suspension.
265/30 + 295/30 mitigated the understeer for the most part, but at the track, in hard cornering - particularly on tight turns, you could still notice a slight increase.

One thing I still noticed as well was just a hint of lightness on the steering as compared to stock, so I'm glad you mentioned the 275/30 fronts actually made the steering heavier! I used to keep steering on sport plus lately due to this, but good to know you are getting heavier steering....exactly what I want.

I am putting the Carbahn tune next monday on my car ( ~550hp/567lb-ft crank...so ~490-500sh whp), so I think I'm gonna bite the bullet and give your setup a try once my tires are ready to be replaced in a couple of months. Worse comes to worse I may drop back to 285/30r + 265/30f

keep the pics and feedback coming please

[G80BSM]

Originally Posted by ssabripo

That's good feedback...exactly what I was looking for

When I kept the stock fronts temporarily while trying 295/30 rears, the understeer impact was palpable, and definitely not recommended. I thus tried 265/30, given some of the feedback on here of multiple folks having rubbing issues with 275/30 and even 265/35, albeit very few had posted they were still on stock suspension.
265/30 + 295/30 mitigated the understeer for the most part, but at the track, in hard cornering - particularly on tight turns, you could still notice a slight increase.

One thing I still noticed as well was just a hint of lightness on the steering as compared to stock, so I'm glad you mentioned the 275/30 fronts actually made the steering heavier! I used to keep steering on sport plus lately due to this, but good to know you are getting heavier steering....exactly what I want.

I am putting the Carbahn tune next monday on my car ( ~550hp/567lb-ft crank...so ~490-500sh whp), so I think I'm gonna bite the bullet and give your setup a try once my tires are ready to be replaced in a couple of months. Worse comes to worse I may drop back to 285/30r + 265/30f

keep the pics and feedback coming please

Happy to help

Fairly recently I drove an M3 on PS4S’s with the 265/295 combination and the understeer was noticeable but nowhere near as horrible as I thought it would be.

You are right, most people who tried to run 275’s upfront were either lowered or running wheels with a much aggressive offset. That’s why most of them had rubbing issues. I have a set of Apex EC7 coming soon and I’m fairly certain that 275’s with their 9.5” et 28 wheels will cause rubbing issues. If they rub, I’ll add camber plates.

I’ve only had this setup for a week and I’m loving it so far. So I’d say just give it a try. If you’re still on edge about the fitment, find a tire shop that’s willing to do a test fit. Plus, you’ll like the heavier feeling steering wheel .

Also, I got the wheels rebalanced today. I’m happy to report that there were no signs of rubbing anywhere on the fender liners or the tires. I’ve attached some pictures for your reference.

[ssabripo]

Originally Posted by S.111

Happy to help

Fairly recently I drove an M3 on PS4S’s with the 265/295 combination and the understeer was noticeable but nowhere near as horrible as I thought it would be.

You are right, most people who tried to run 275’s upfront were either lowered or running wheels with a much aggressive offset. That’s why most of them had rubbing issues. I have a set of Apex EC7 coming soon and I’m fairly certain that 275’s with their 9.5” et 28 wheels will cause rubbing issues. If they rub, I’ll add camber plates.

I’ve only had this setup for a week and I’m loving it so far. So I’d say just give it a try. If you’re still on edge about the fitment, find a tire shop that’s willing to do a test fit. Plus, you’ll like the heavier feeling steering wheel .

Also, I got the wheels rebalanced today. I’m happy to report that there were no signs of rubbing anywhere on the fender liners or the tires. I’ve attached some pictures for your reference.

that's awesome, thank you for sharing!! very helpful.

btw, since you are at it, any chance you can take some additional pics of the car's stance, specially in the front (from the sides, at angles, etc) similar to what you posted already but with better day light and background? when you get a chance of course

[G80BSM]

Originally Posted by ssabripo

that's awesome, thank you for sharing!! very helpful.

btw, since you are at it, any chance you can take some additional pics of the car's stance, specially in the front (from the sides, at angles, etc) similar to what you posted already but with better day light and background? when you get a chance of course

Here you go

[ssabripo]

Originally Posted by S.111

Here you go

man, that's the ticket right there!!

looks like I will be trying this next

[G80BSM]

Originally Posted by ssabripo

man, that's the ticket right there!!

looks like I will be trying this next

Cool! You won't regret it.

[lax01]

Confirmed - 275/30/19 and 295/30/19 fit with M Performance Suspension with Vorshlag Camber plates - no rubbing with -3* camber in the front and -1.9* in the rear (we didn't test out if the 275/30/19 fit with the M Performance Suspension (which was bottomed out on height) and stock top hats (and stock camber) fit)

I think I could potentially go 305/30/19 in the rear - and the front doesn't look that close either.