Tires & Sizing to get the most grip

[bubbajan21]

So I've just finished up my S50 swap and now I'm looking for some new wheels and tires to look for the most grip possible (within reason, no I do not want to run slicks if I'm looking for the most grip). The car has E30 M3 5-lug, H&R Sports, Blistein Sports, ST Swaybars, etc. so the suspension is pretty well-sorted. My last swap car (also E30 M3 5-lug) was on 17x7.5" Alpina Kopis with 235/40 Star Specs all around. As far as grip and handling, I LOVED the setup, but I would be hesitant to do it again because those star specs got so incredibly loud as they aged that for a DD, it was just unpleasant on the highway.

I'm pretty set on running Apex ARC-8's. I'm thinking 17x8" et20 fronts, and 17x8.5" et20 (concave) rears. Fenders will be rolled and pulled and spacers will be used to get the wheels where they need to be.

Now comes the questions. Tires, what tire and what size should I run? Please keep in mind this is an S50 DD looking for maximum (reasonable) grip along with a civilized tire that has good road manners (namely noise). So my options (as far as I'm aware) are as follows;

Toyo R1R's - My main draw to these is that I could run a 235/40 17 on the front and I could stuff a 245/35 17 on the rear without issue. This is a very appealing option to me as I'd love to have 245's out back, but I have given pause to these as I've read a lot of less than stellar reviews on these tires. Car & Driver rated them #7 out of 9 in a recent comparo and I've read a lot of not so good things about them. As much as I like the idea of 245's, if I can have more grip from a 235, then so be it. These are the only tire available in 245/35 17, so if it's not these, then it's back to a 235. These are the cheapest tire available by quite a large margin which is somewhat of a factor.

Bridgestone Potenza RE-11 - These are the most expensive tire available, but everything I've read is that they are a great and very grippy tire. Tire rack rated them number 1 in their testing and they seem to be an excellent tire in the wet and the dry. I know it's not really a big consideration, but they are the heaviest tire by a margin of 1-4 pounds per tire. The price is a bit of a turn-off to me, but if they're just an amazing tire then I'll consider it.

Dunlop Dirrezza Star Specs - Great tire, extremely grippy wet and dry, I know this from experience. The biggest drawback is noise and I am very hesitant buy another set knowing how noisy they get. Still an option, but I definitely wouldn't mind something a bit quieter.

Michelin Pilot Sport PS2 - A great tire that I've had on cars in the past. The lightest tire here (again, I'm aware it's not a huge consideration). They are a very quiet tire which is appealing and they are excellent in the wet and the dry. They are in the "max performance" category on tire rack which is a step down from the other tires here, but they rate right on par with all of the other tires here.

So if anyone has any experience, feedback, thoughts, concerns, etc. on any of these tires positive or negative, I'd love to hear it. Really one of my biggest questions is is it worth running the R1R's in order to gain 10mm of width on each rear tire or will I have more grip with a better tire in a slightly narrower width.

[bmwguy325is]

R1rs are going to wear pretty fast compared to the bridgestone or dunlop.

[Cronopoulos]

Check these out as well -

http://www.tirerack.com/tires/tires.jsp?tireMake=Hankook&tireModel=Ventus+R-S3

[Boise]

FWIW, Car and Driver just did another performance test of summer performance tires

http://www.caranddriver.com/comparisons/monsters-of-grip-nine-summer-performance-tires-tested-comparison-test

[fronton]

You do not need more than 225 in the rear for 240hp if you are running summer performance tires and I'm not sure why you'd want 235 up front. What is your reasoning for this much tire?

[bubbajan21]

R1rs are going to wear pretty fast compared to the bridgestone or dunlop.

I hadn't thought about that, that is very true. Hmmmm, definitely a consideration.

Check these out as well -

http://www.tirerack.com/tires/tires....el=Ventus+R-S3

They don't come in the sizes I'm looking for and they don't seem to rate very well in the wet.

FWIW, Car and Driver just did another performance test of summer performance tires

http://www.caranddriver.com/comparis...omparison-test

Wonderful link! :up: Oh I would LOVE to get a set of those Michelin Supersports up under my E30, Tire rack rates them as the best tire ever with 9's across the board for everything. Unfortunately I would have to drop down to a 215/45 or maybe even a 205/45 to get them to fit under the E30 which is significantly smaller than I'd like to run. If they come out with these with slightly shorter sidewalls I will absolutely be running these on my E30.

You do not need more than 225 in the rear for 240hp if you are running summer performance tires and I'm not sure why you'd want 235 up front. What is your reasoning for this much tire?

Maximum possible grip for acceleration, turning, and braking plus an aggressive look and stance.

[jeffmn8]

Just a reference, I had very little issues fitting 235/40/17 and 245/40/17 Front/Rear on my car with slightly rolled fenders. I have an mcoupe suspension setup with 17x8.5 et38 rims, 10mm spacers in the front and none in the rear.

[bubbajan21]

Just a reference, I had very little issues fitting 235/40/17 and 245/40/17 Front/Rear on my car with slightly rolled fenders. I have an mcoupe suspension setup with 17x8.5 et38 rims, 10mm spacers in the front and none in the rear.

Now that would be interesting if I could fit 245/40 17 in the back because in that case I could run the Super Sports! :D That would put me at 245/40 17 in the rear and either 215 or 225/45 17 in the front. Hmmm, that's a bit narrow in the fronts and I don't want to set this thing up to be a drag racer. If they only made the Super Sports in a 235/40 17 I would rock that setup in a second with the 245's out back. Hmmmmmm, I've got some thinking to do. :)

[jeffmn8]

With street tires, you might even be able to fit 245s up front. I was running rcomps (bfg r1's) so they run slightly larger than normal.

[Apps]

I can't say that I don't like cars with the widest possible tires that will fit in the fenders. However, the width of a tire is inconsequential in how much "grip" it is able to deliver (in the dry). The rubber compound that makes up the tread area is the most important part here. Normally you will trade wear for all out "grip" and as you use this all out "grip" the tire will change. That is the chemical structure of the rubber will be adversely affected by the temperature at which it operates to create friction or grip. After a few cycles it will stop producing as much grip as it started with (design of the tire and compound will affect how drastically this falls off).

For those who believe that the amount of rubber in contact with the road varies based on tire size, consider that if the pressure and load on the tire stay the same then the area in contact with the road will also stay same (P = F/A, where P-pressure, F-force, A-area).

Just a consideration.

In the end it comes down to your priorities for the car. If you desire some capability in the cold...likely a high friction tire is not for you. Rubber has a transition temperature where it will change to a "glassy" material and produce very little grip. This temperature is much higher for high grip tires. If you would like wet performance you need a tread pattern that lends itself to the amount of performance you seek. Noise has other requirements....

and so on.

[bubbajan21]

I can't say that I don't like cars with the widest possible tires that will fit in the fenders. However, the width of a tire is inconsequential in how much "grip" it is able to deliver (in the dry). The rubber compound that makes up the tread area is the most important part here. Normally you will trade wear for all out "grip" and as you use this all out "grip" the tire will change. That is the chemical structure of the rubber will be adversely affected by the temperature at which it operates to create friction or grip. After a few cycles it will stop producing as much grip as it started with (design of the tire and compound will affect how drastically this falls off).

For those who believe that the amount of rubber in contact with the road varies based on tire size, consider that if the pressure and load on the tire stay the same then the area in contact with the road will also stay same (P = F/A, where P-pressure, F-force, A-area).

Just a consideration.

In the end it comes down to your priorities for the car. If you desire some capability in the cold...likely a high friction tire is not for you. Rubber has a transition temperature where it will change to a "glassy" material and produce very little grip. This temperature is much higher for high grip tires. If you would like wet performance you need a tread pattern that lends itself to the amount of performance you seek. Noise has other requirements....

and so on.

So by this logic, are you saying I'd be able to get power to the ground better via a 215/45 17 Michelin Pilot Supersport than I would via a 245/45 17 Toyo R1R assuming the Supersport has a better chemical compound for grip??

The logic of "if the pressure and load on the tire stay the same then the area in contact with the road will also stay same" can't be sound because I guarantee you if you have 2 tires with the same compound, same load, and same pressre next to each other, one with a 100mm width and one with a 300mm width, the wider tire will have substantially more grip as it may have the same contact area front to rear in contact with the road, but the width of the contact patch would be ~3 times wider. Aside from chemical makeups of tires, grip is to some extent a function of contact patch and there is no way you can convince me a 100mm wide tire has the same contact patch as a 300mm wide tire. I agree that chemical make-up of a tire is more important than the size of the tire, but to claim that "the amount of rubber in contact with the road does not vary based on size" seems far fetched to me.

[Nsquared97]

Figure I'll throw my $.02 into this.

First off, have you looked into the Kumho XS? I have no idea about their sizing and if it would work for you, but they are another decent option for max grip summer tires.

As far as the RE-11's, they are great tires (had them on a different car) but IMO cost too much and really aren't any better than other offerings.

Star specs seem to be a great tire, and are what I would pick. Great wet weather performance, and seem to be the best all around tire in that category.

Also, I would not listen to those Car & Driver articles. I looked through one, and a lot of their results don't make any sense. Instead take a look at the comparisons that Grassroots Motorsports has done on these tires, they know what they are doing when testing tires like this and have good driver's doing the testing as well.

[bubbajan21]

GRM Rated the Toyo R1R's at 4th in a review of 6 tires and the Star Specs at 5th out of 6 strictly based on performance in an autocross course :/

http://grassrootsmotorsports.com/articles/texas-toasted-tires-part-1/

[Cronopoulos]

RS3's are a great bang for the buck race/auto-x/naked driving tire.... I have used them on the track and auto-x... They get warm fast and they hold the heat well and are DAMN NEAR R-compounds when hot. This is just my opinion but I wouldnt hesitate to run these in the rain either despite what the reviews say.

Star specs take a little longer to heat up. When they get hot and pushed they get really greasy from my experience (lowered pressure as temps rose with no help).

The XS tires take longer to heat up but hold the heat better than most, great tire for warmer climates but pricey.

[bubbajan21]

RS3's are a great bang for the buck race/auto-x/naked driving tire.... I have used them on the track and auto-x... They get warm fast and they hold the heat well and are DAMN NEAR R-compounds when hot. This is just my opinion but I wouldnt hesitate to run these in the rain either despite what the reviews say.

Star specs take a little longer to heat up. When they get hot and pushed they get really greasy from my experience (lowered pressure as temps rose with no help).

The XS tires take longer to heat up but hold the heat better than most, great tire for warmer climates but pricey.

I'm looking for tires for a DD.