285 35 19 vs 285 30 19

[bsmf8x]

I got 437m rims oem suspension on my bmw m4 f82

Oem tire sizes currently 255 35 19 and 275 35 19

My front tires still have a ton of life left (prob good for almost another year)

My rear tires are shot. Down to the wires. Getting new tires this week, lol.

I'm looking to go wider in the back, I want the meaty look from the back (might be just me but 285's look a lot meatier than 275 even if it's only a small size difference).

Should I run 285 35 19 or 285 30 19? 285 30 19 is closer to 255 35 19 in terms of diameter. I don't track it but I don't want my DSC to bug out when I drive the car hard. It's so intrusive as is.

I'll prob change the fronts to 265 35 19 next year and my rears will def be shot by then lol, so idk what to run for the time being with 255s up front.

I don't track the car but I do drive it hard if that matters.

And no, I don't care if my rear wheel looks like the diameter is less with a smaller side wall on the 30. I'm also getting a much better deal on the 285 30 19 due to a closeout sale.

Thanks.

[N1rve]

Originally Posted by bsmf8x

I got 437m rims oem suspension on my bmw m4 f82

Oem tire sizes currently 255 35 19 and 275 35 19

My front tires still have a ton of life left (prob good for almost another year)

My rear tires are shot. Down to the wires. Getting new tires this week, lol.

I'm looking to go wider in the back, I want the meaty look from the back (might be just me but 285's look a lot meatier than 275 even if it's only a small size difference).

Should I run 285 35 19 or 285 30 19? 285 30 19 is closer to 255 35 19 in terms of diameter so I think it won't upset the car but not sure. I don't track it but I don't want my DSC to bug out when I drive the car hard. It's so intrusive as is.

I'll prob change the fronts to 265 35 19 next year and my rears will def be shot by then lol, so idk what to run for the time being with 255s up front.

I don't track the car but I do drive it hard if that matters.

And no, I don't care if my rear wheel looks like the diameter is less with a smaller side wall on the 30. I'm also getting a much better deal on the 285 30 19 due to a closeout sale.

Thanks.

I don't think there's any cons for 285 30 R19 except a different speedometer rating and that it'll look off. I think you'll have more oversteer because the shorter sidewall would be stiffer for a 30 ratio vs a 35 ratio. I'm not sure if more oversteer is a plus or minus for you. But then you're also increasing the width in the rear than the front so that would increase understeer. So, I am not 100% sure what will happen in your case haha.

I have 265 35 R19 and 285 35 R19, it's softer than stock with the taller sidewall and increased my ground clearance. Grip is better than 255/275 MPS4S. I've had both lol.

[2sporty]

I don't think there's any cons for 285 30 R19 except a different speedometer rating and that it'll look off and your traction control won't work as properly anymore because it can't get the intended readings. Oh yeah, there's also this thing called a limited slip diff that depends on overall diameter to be a certain amount. Oh wait, so there are cons.

[BitchinManWheels]

265 35 R19 and 285 35 R19
Make you and your car happy!

[bsmf8x]

Originally Posted by 2sporty

I don't think there's any cons for 285 30 R19 except a different speedometer rating and that it'll look off and your traction control won't work as properly anymore because it can't get the intended readings. Oh yeah, there's also this thing called a limited slip diff that depends on overall diameter to be a certain amount. Oh wait, so there are cons.

Same shit with 285 35 19, what's your point?

You typed that whole thing up without answering my question of whether 285 30 is better or worse than 285 35 just to add your smartass comment at the end.

[2sporty]

Originally Posted by bsmf8x

Same shit with 285 35 19, what's your point?

You typed that whole thing up without answering my question of whether 285 30 is better or worse than 285 35 just to add your smartass comment at the end.

285 35 is better, but if you were smart, you could have just used an overall diameter calculator available anywhere on the internet and compared to the stock sizes to find that answer.

[MineralWhiteF80]

I would go 285/35 tire in the rear for a couple reasons. That is what I am currently running (255/35/19 front and 285/35/19 rear) and I have zero issues. I'm not sure exactly what tire brand/model you are wanting to go with so I'll use my Michelin PS4S tires for my examples:

Not all 285 wide tires are actually the same width so you need to think more about actual measurements/specs for a given tire and compare against your current setup.

285/35 has a wider tread width than a 285/30 but overall width is the same, so a 285/30 will look narrower from the back, and actually measures the same as some 275/35 PS4S models.

The 285/35 has a beefier sidewall that gives the 'meaty' effect and make the tire look even wider. The 285/30 will trick your brain into thinking the tire looks smaller and narrower. A 285/30 tire will look like a rubber band on the rear and will be even smaller than the front tire.

The 285/35 is only changing diameter over stock by 0.3 inches whereas the 285/30 will be going down in size 0.8 inches.

As for traction control differences between a 275 and 285 wide rear tire paired with a 255/35 front, I think any change in sensitivity is very small and largely the internet and forums make this change out to be wayyy worse than it is. I've never seen any factory bmw published information explaining how different tire diameters affect traction control sensitivity. But, a worn out tire and a brand new tire have a larger diameter difference than what you are planning on changing, so even a complete stock car would suffer the same traction control intervention changes.

I notice my traction control comes on far less because I have better grip out in the rear with 285/35. After 6 heat cycles on the track, my 285/35 PS4S tires have SOO MUCH more grip it's crazy. I used to be able to spin the tires in 1st, 2nd, and 3rd under hard acceleration. After the heat cycling, I can barely spin the tires in 2nd gear, if at all. The car just squats and goes.

Pics of 255/35 front and 285/35 rear: KWv3 coilovers and 15mm spacers all around.

[Conissah]

Why do you want the rear tire height to be closer to the front? You should be more worried about the percentage difference between front and rear and not throwing that off too much. With a 255/35 and a 275/35, the rear is larger by 2.3% in diameter, you change the rear to a 285/30 and that goes to -1.2%, meaning the rear is smaller by 1.2%. That's a delta of 3.5% overall. I can't say for certain but that sounds like it would throw your TCS off. If you run 255/35 and 285/35, the rear is 3.5% larger, so a delta of 1.2%, which sounds much more reasonable.

I'm currently running 265/35 and 285/35 for reference, have absolutely no desire to run a 30 sidewall. The whole point of me dropping from 20" wheels to 19" was to gain some extra rubber. I definitely wouldn't want the rear tire to be shorter (in terms of height) than the front, that would look super goofy.

[bsmf8x]

Originally Posted by MineralWhiteF80

I would go 285/35 tire in the rear for a couple reasons. That is what I am currently running (255/35/19 front and 285/35/19 rear) and I have zero issues. I'm not sure exactly what tire brand/model you are wanting to go with so I'll use my Michelin PS4S tires for my examples:

Not all 285 wide tires are actually the same width so you need to think more about actual measurements/specs for a given tire and compare against your current setup.

285/35 has a wider tread width than a 285/30 but overall width is the same, so a 285/30 will look narrower from the back, and actually measures the same as some 275/35 PS4S models.

The 285/35 has a beefier sidewall that gives the 'meaty' effect and make the tire look even wider. The 285/30 will trick your brain into thinking the tire looks smaller and narrower. A 285/30 tire will look like a rubber band on the rear and will be even smaller than the front tire.

The 285/35 is only changing diameter over stock by 0.3 inches whereas the 285/30 will be going down in size 0.8 inches.

As for traction control differences between a 275 and 285 wide rear tire paired with a 255/35 front, I think any change in sensitivity is very small and largely the internet and forums make this change out to be wayyy worse than it is. I've never seen any factory bmw published information explaining how different tire diameters affect traction control sensitivity. But, a worn out tire and a brand new tire have a larger diameter difference than what you are planning on changing, so even a complete stock car would suffer the same traction control intervention changes.

I notice my traction control comes on far less because I have better grip out in the rear with 285/35. After 6 heat cycles on the track, my 285/35 PS4S tires have SOO MUCH more grip it's crazy. I used to be able to spin the tires in 1st, 2nd, and 3rd under hard acceleration. After the heat cycling, I can barely spin the tires in 2nd gear, if at all. The car just squats and goes.

Pics of 255/35 front and 285/35 rear: KWv3 coilovers and 15mm spacers all around.

Originally Posted by Conissah

Why do you want the rear tire height to be closer to the front? You should be more worried about the percentage difference between front and rear and not throwing that off too much. With a 255/35 and a 275/35, the rear is larger by 2.3% in diameter, you change the rear to a 285/30 and that goes to -1.2%, meaning the rear is smaller by 1.2%. That's a delta of 3.5% overall. I can't say for certain but that sounds like it would throw your TCS off. If you run 255/35 and 285/35, the rear is 3.5% larger, so a delta of 1.2%, which sounds much more reasonable.

I'm currently running 265/35 and 285/35 for reference, have absolutely no desire to run a 30 sidewall. The whole point of me dropping from 20" wheels to 19" was to gain some extra rubber. I definitely wouldn't want the rear tire to be shorter (in terms of height) than the front, that would look super goofy.

285 35 it is, thanks.