[BASELINE]

Just wondering if anyone has made 265/35-19s fit up front...

If so what wheels and offset... lowered?

[Kabrich]

Originally Posted by BASELINE

Just wondering if anyone has made 265/35-19s fit up front...

If so what wheels and offset... lowered?

You do realize tire brand and model play a part as well?

[BASELINE]

Originally Posted by Kabrich

You do realize tire brand and model play a part as well?

I know... sounds like some have run 275 up front too

[Polo08816]

Originally Posted by BASELINE

I know... sounds like some have run 275 up front too

But why though....

[BASELINE]

Originally Posted by Polo08816

But why though....

Mechanical Grip...

This one particular guy ran a 275 square setup and tracked the car.

[Polo08816]

Originally Posted by BASELINE

Mechanical Grip...

This one particular guy ran a 275 square setup and tracked the car.

First, wider doesn't necessarily mean more mechanical grip. If you want more mechanical grip, you need to step up to an Extreme Performance Summer Tire or a Streetable Track and Competition Tire.

BMW felt a 265 width tire was sufficient on the 2017 M3/M4 Competition Package.

Also, did the guy running a 275 width tire have to roll his fenders? I suspect he did.

The bottom line is if you're using a 255 width Extreme Performance Summer Tire or Streetable Track and Competition Tire and feel there is not enough grip up front, then sure, I guess you could move to a 275 width tire which may require fender rolling. It's just not a common track setup. My guess is because 255/265 is sufficient with the proper compound and there are diminishing returns afterwards.

[BASELINE]

Originally Posted by Polo08816

First, wider doesn't necessarily mean more mechanical grip. If you want more mechanical grip, you need to step up to an Extreme Performance Summer Tire or a Streetable Track and Competition Tire.

BMW felt a 265 width tire was sufficient on the 2017 M3/M4 Competition Package.

Also, did the guy running a 275 width tire have to roll his fenders? I suspect he did.

The bottom line is if you're using a 255 width Extreme Performance Summer Tire or Streetable Track and Competition Tire and feel there is not enough grip up front, then sure, I guess you could move to a 275 width tire which may require fender rolling. It's just not a common track setup. My guess is because 255/265 is sufficient with the proper compound and there are diminishing returns afterwards.

I get all that. Stepping up to a high performance summer compound is a given when going up in tire sizes and rims...at least for me; otherwise what's the point. I want a winter set of wheels/tires and a summer set.

All things being equal a greater contact patch is going to give you more grip. My E90M3 came with 245F and 265R, in the summer I ran 265/295...way more grip!!

I'm not sure if he rolled fenders. He states he didn't, ran a 10 inch wheel all around and lowered.

[Polo08816]

Originally Posted by BASELINE

I get all that. Stepping up to a high performance summer compound is a given when going up in tire sizes and rims...at least for me; otherwise what's the point. I want a winter set of wheels/tires and a summer set.

All things being equal a greater contact patch is going to give you more grip. My E90M3 came with 245F and 265R, in the summer I ran 265/295...way more grip!!

I'm not sure if he rolled fenders. He states he didn't, ran a 10 inch wheel all around and lowered.

Well, there's nothing in the formula for friction (grip) that specifies contact patch as a parameter for friction.

friction = coefficient of friction * force

In actuality, your contact patch area is primarily determined by tire pressure (and tire construction to an extent).

Assuming same amount of force and tire pressure, you're just getting a shorter, but wider contact patch with a wider tire. Now because the contact patch is wider (not larger), it may have an effect with regard to slip angles, but my guess is that you're really getting to the point where the returns are very insignificant beyond 255/265.

It's just not worth the effort at that point, especially if it requires you to roll the fenders.

[BASELINE]

Originally Posted by Polo08816

Well, there's nothing in the formula for friction (grip) that specifies contact patch as a parameter for friction.

friction = coefficient of friction * force

In actuality, your contact patch area is primarily determined by tire pressure (and tire construction to an extent).

Assuming same amount of force and tire pressure, you're just getting a shorter, but wider contact patch with a wider tire. Now because the contact patch is wider (not larger), it may have an effect with regard to slip angles, but my guess is that you're really getting to the point where the returns are very insignificant beyond 255/265.

It's just not worth the effort at that point, especially if it requires you to roll the fenders.

I get how the variances in tire pressure, rolling diameter and tire construction all have an impact on the overall contact patch. Again "ALL things being equal", you're not going to convince me that a wider tire won't offer a larger contact patch. And from what I understand the guy running 275s had NOT rolled or modified his fenders or wheel wells in any way.

Having said that.... I would surmise and agree with you to an extent that a 275 wide tire might offer a diminishing return for what 95% of drivers are using these cars for over say a 255 or 265, after all the difference between a 265 and 275 are measurably small. And at what point does the added weight of a bigger and heavier tire (adding rotational inertia) plus the added rolling resistance pay off in incremental lateral grip if you actually won't need that grip in the first place?

The right answer is dependent on what and how each plans to use the car.