[Figgs_1979]

So I am cruising the site, searching around and it seems like no one is running this setup. 245/35/19 and 285/30/19. These 2 tires match in diameter perfectly. THE BEST PART is you only have to upgrade the rears.

So who is running this setup? Taking delivery of a 2019 CPO this week and this along with Macht schnell springs is my first upgrade.

Talk to me people!

[DanG]

The most common tire choice (other than stock sizes) is 255/35/19 and 275/35/19 on 437s.

[Carrera2RS]

You will increase understeer, with a stock car usually match the increase front and rear

Depends how hard you drive the car and if its more traction or handling your after I guess

[Figgs_1979]

Originally Posted by DanG

The most common tire choice (other than stock sizes) is 255/35/19 and 275/35/19 on 437s.

Why? Is what I am asking.

The setup you mentioned has the front tire at 0.5" smaller diameter than the rear.

I have read the countless threads and most common but why hasn't anyone done the setup I've noted.

I ran 245 35 19 and 285 30 19 on my xdrive 340i with 437m wheels. This setup is in the rear is only .25" smaller. Than the stock 265 on the m.

The most ideal setup other than square would be to match the diameter.

This to me seems like the most feasible daily driving wide tire set up.

[Figgs_1979]

Originally Posted by Carrera2RS

You will increase understeer, with a stock car usually match the increase front and rear

Depends how hard you drive the car and if its more traction or handling your after I guess

My setup for the noted sizes includes Macht schnell springs. A modest 1" drop. This is just a daily driven car.

Just was curious why others haven't ran this setup. It just seems right. Front tire is stock and rear is 0.25" smaller diameter. But both diameters are equal with the setup I noted. I don't believe you'll get much understeer or even notice it daily driving.

[///MPhatic]

Originally Posted by Figgs_1979

So I am cruising the site, searching around and it seems like no one is running this setup. 245/35/19 and 285/30/19. These 2 tires match in diameter perfectly. THE BEST PART is you only have to upgrade the rears.

So who is running this setup? Taking delivery of a 2019 CPO this week and this along with Macht schnell springs is my first upgrade.

Talk to me people!

There are a couple of reasons.

First there's the balance. The stock balance of the car is quite specific with a 15mm tread width difference front to rear (the OEM front PSS star spec runs wide, the rear runs skinny), even though the tires are listed as 20mm apart (245/265). This gives the M2 the most playful driving dynamics of any modern BMW while still being safe, and people are unwilling to mess with it. Part of that is also rake, and the stock rake is nearly 13mm.

The tire size you're suggesting in the most popular tire for the car (the PS4S) has a 38mm tread width difference front to rear, and no rake at all, which will take a huge toll on the handling dynamics.

The second reason is that BMW guys, as a whole, aren't ones to rock the boat in this way from what I've seen, they usually stick to what's tried and true, and are usually better for it.

I mean, run what you want, it's your car, but if you want to preserve the playful nature of the car then stick as close to a 15mm front to rear tread width and 13mm of rake.

[Fabb]

Originally Posted by ///MPhatic

There are a couple of reasons.

First there's the balance. The stock balance of the car is quite specific with a 15mm tread width difference front to rear (the OEM front PSS star spec runs wide, the rear runs skinny), even though the tires are listed as 20mm apart (245/265). This gives the M2 the most playful driving dynamics of any modern BMW while still being safe, and people are unwilling to mess with it. Part of that is also rake, and the stock rake is nearly 13mm.

The tire size you're suggesting in the most popular tire for the car (the PS4S) has a 38mm tread width difference front to rear, and no rake at all, which will take a huge toll on the handling dynamics.

The second reason is that BMW guys, as a whole, aren't ones to rock the boat in this way from what I've seen, they usually stick to what's tried and true, and are usually better for it.

I mean, run what you want, it's your car, but if you want to preserve the playful nature of the car then stick as close to a 15mm front to rear tread width and 13mm of rake.

Never thought of the rake perspective. If I run 18 square, I would have 0 rake. Wonder how much will that impact the driving experience

[SEAT TIME RULES]

Originally Posted by Figgs_1979

Why? Is what I am asking.

The setup you mentioned has the front tire at 0.5" smaller diameter than the rear.

I have read the countless threads and most common but why hasn't anyone done the setup I've noted.

I ran 245 35 19 and 285 30 19 on my xdrive 340i with 437m wheels. This setup is in the rear is only .25" smaller. Than the stock 265 on the m.

The most ideal setup other than square would be to match the diameter.

This to me seems like the most feasible daily driving wide tire set up.

You don't have to match diameter's from front to rear. ABS on sports cars cars can handle at least a 5% diameter change. I've seen higher as well. The only advantage to an matching OEM diameter is no speedo delta..

[///MPhatic]

Originally Posted by Fabb

Never thought of the rake perspective. If I run 18 square, I would have 0 rake. Wonder how much will that impact the driving experience

I have no idea, but there are enough people on this board that have done it that I'm sure you could get a pretty good idea asking them.

[Figgs_1979]

Originally Posted by SEAT TIME RULES

You don't have to match diameter's from front to rear. ABS on sports cars cars can handle at least a 5% diameter change. I've seen higher as well. The only advantage to an matching OEM diameter is no speedo delta..

I know youn don't have to just seems more logical.

[ZPrime]

Originally Posted by Figgs_1979

I know youn don't have to just seems more logical.

It's not an AWD car, so like others have said, it doesn't matter for anything beyond stability control / handling.

And BMW engineered the car with a specific set of tire sizes for a reason.

What exactly the reason is behind the 245/265 choice, instead of 255/275... only BMW knows, and good luck getting that answer out of anyone there.

I'm leaning to 255/275 just because they tend to be more available and a little cheaper than 245/265 (for whatever reason). My set of PS4S in stock size are about ready to be replaced, hence I'm in here doing research...

[Carrera2RS]

Originally Posted by ZPrime

It's not an AWD car, so like others have said, it doesn't matter for anything beyond stability control / handling.

And BMW engineered the car with a specific set of tire sizes for a reason.

What exactly the reason is behind the 245/265 choice, instead of 255/275... only BMW knows, and good luck getting that answer out of anyone there.

I'm leaning to 255/275 just because they tend to be more available and a little cheaper than 245/265 (for whatever reason). My set of PS4S in stock size are about ready to be replaced, hence I'm in here doing research...

The stock car is marginally more understeer biased than oversteer for obvious reasons. I think going one size up or marginally more track on the front will be better than visa versa. I have no doubt 245 285 will work but I'm with you and moving to 255/275 when my 245/265's were out. especially as I am now on 9.5/10.5 rims