track tire sizes for 18's

[Fen335i]

Hi Folks - I just recently picked up a set of 18" wheels for multi-use...going to use them for my winter set up for the next 4 months and then turn them into dedicated track tires next summer.

Wheels: 18", 8.5 front / 9.5 rear

I realize that a lof of you prefer a "square" set up...but given that I've got staggerred 18's, what would you suggest? I was thinking of going 255 front /275 rear and an R-compound tire.

Any recommendations (on both tire size and brand/model tire)?

[jml]

Originally Posted by Fen335i

Hi Folks - I just recently picked up a set of 18" wheels for multi-use...going to use them for my winter set up for the next 4 months and then turn them into dedicated track tires next summer.

Wheels: 18", 8.5 front / 9.5 rear

I realize that a lof of you prefer a "square" set up...but given that I've got staggerred 18's, what would you suggest? I was thinking of going 255 front /275 rear and an R-compound tire.

Any recommendations (on both tire size and brand/model tire)?

I've had good luck with NT01s. It's one of the better values out there. Not as sticky as a Hoosier, but it lasts about twice as long. They last me 4-6 DE days, and require a flip about half to 2/3rds of the way through. I am amazed at how gentle the minimal OEM camber adjustment is on front tires. More camber would be better, though you can get by with the -1.5 the OEM setup can deliver.

As to the sizes, I wouldn't go bigger than 255 to 265 on the front of that staggered setup. 275/35 rear is fine. You should seriously consider a square setup so that you can rotate front-rear.

[von_zoom]

Wheels: 18", 8.5 front / 9.5 rear

Whatever tires you decide on, make sure they will fit your rims.
vz

[JJM335]

I have R888's in 255/35 front and 275/35 rear on stock 18" rims.

[Paddy]

Originally Posted by JJM335

I have R888's in 255/35 front and 275/35 rear on stock 18" rims.

How is that setup working for you?

I'm thinking of getting Vred utracs for my stock 18 track/autox rims, but they don't have 245,265 in 40 profile, so I was thinking of going 255,275 35's

The other option is 245/40 255/40.

I'm thinking the 35's would be better...

.

[clubspec330i]

I have been using Nitto 265/35-18F & 275/35-18R for a while now. On a stock suspension, though the front has a little more gap than 245/40, it feels very nuetral. I will take it to Street of Willow for the first time this coming Friday December 18. Typically I would run my NT01 but it will be cold and a good test for NT05. On a lower car 255/35 will be ok but it will look like 4x4 on a stock car.

Good luck..

Mack

[M3V8Driver]

Originally Posted by von_zoom

Whatever tires you decide on, make sure they will fit your rims.
vz

Yeah, it is vital that they be 18" tires

[M3V8Driver]

Originally Posted by JJM335

I have R888's in 255/35 front and 275/35 rear on stock 18" rims.

That is the exact same setup I have waiting for my track wheels, but alas, it's too late in the season to use them here in PA, so they are just sitting there. If you want them, make me an offer.

[M3V8Driver]

Originally Posted by clubspec330i

On a stock suspension, though the front has a little more gap than 245/40, it feels very nuetral. I will take it to Street of Willow for the first time this coming Friday December 18. Typically I would run my NT01 but it will be cold and a good test for NT05. On a lower car 255/35 will be ok but it will look like 4x4 on a stock car.

Good luck..

Mack

Maybe, but it's not about looks with dedicated track wheels/tires. That gap between the tire and fender have no bearing affect on performance. In fact, one cold argue that more air moving around the tire will help keep its temperatures in check. It's all about performance

[Paddy]

Originally Posted by M3V8Driver

Maybe, but it's not about looks with dedicated track wheels/tires. That gap between the tire and fender have no bearing affect on performance. In fact, one cold argue that more air moving around the tire will help keep its temperatures in check. It's all about performance

Speaking of performance (for track/autox), which is better for a stock E90 M3

245/40/18 and 255/40/18

or

255/35/18 and 175/35/18

I'm trying to solicit some opinion about this in a few different threads but can't seem to get a definitive answer.
The sizes above are all that Vreds have in my range for an 18" rim.

From what I can determine the higher profile gives better ride quality, but I don't care about that so much.
Which setup gives better balance and traction?

I assume the latter because more width of rubber on the road and closer to stock width ratio for front/rear.

[M3V8Driver]

Originally Posted by Paddy

...which is better for a stock E90 M3

245/40/18 and 255/40/18

or

255/35/18 and 175/35/18

<<snip>>

From what I can determine the higher profile gives better ride quality, but I don't care about that so much. Which setup gives better balance and traction?

I assume you meant 275/35/18 in the latter example , but to answer your question, the rear width you listed in the first example is actually narrower than OEM (265). Now, balance is different than traction, and is only affected by tire sizing when dramatic changes from OEM are substituted (ie - squre setups). Traction is mostly dictated by overall tread width, which affects contact patch. The bigger the contact patch, obviously, the more traction. The sidewall isn't as important, at least when yo're only comparing 35 and 40 series (you will notice a negative affect in handling if you move to, say, a 60 series sidewall, becasue the tire will roll-over, causing overheating and chunking).

So, what it might really come down to for you is what tires are available in what sizes, keeping in mind only 35 and 40 series sidewalls. You can stick with OEM sizes, which might yeild limited options with certain brands, or "upsize" by a factor of one to 255/35/18 and 275/35/18 which will likely yeild a different set of limited options. The easiest route would be to go square setup, which not only yields more choices, but allows for rotating front/back, thus getting more usefule life out of the tires.

Hope this helps.

[M3V8Driver]

It is also important to keep in mind that 35 series profile tires aren't always going to provide less sidewall than 40 series profile tires. This is becasue it's part of a ratio (percent of width), so:
40% of 265mm = 106mm total tire sidewall, or 53mm top and bottom)
35% of 305mm = 107mm total sidewall, or 53.5mm top and bottom)

This also varies by manufacture due to the construction of the sidewall. With some manufactures, a 295/35 is taller than a 265/40.

[Paddy]

Originally Posted by M3V8Driver

It is also important to keep in mind that 35 series profile tires aren't always going to provide less sidewall than 40 series profile tires. This is becasue it's part of a ratio (percent of width), so:
40% of 265mm = 106mm total tire sidewall, or 53mm top and bottom)
35% of 305mm = 107mm total sidewall, or 53.5mm top and bottom)

This also varies by manufacture due to the construction of the sidewall. With some manufactures, a 295/35 is taller than a 265/40.

Thanks,
yes, I meant 275 in my original quote. I'm particularly interested in vredestein tires and am pretty limited by their selection for 18's. There is no 265/40/18 to match Stock rear tire.

So what you are saying is that the 35's in wider tire may have very little difference in sidewall height than the less wider 40's. That's interesting I never thought about that.
The vreds have a pretty good wear rating 280, so I think maybe I'll try the 255/35 and 275/35 to maintain the staggered setup.

Regarding balance, 275/255=1.078 versus 255/245=1.04 versus stock 265/245=1.081
(I have no idea if this calculation has any real meaning w.r.t balance) but it looks like the 275/255 is closer to stock balance.

Also 275/35 vs 255/40, the 35 profile sidewall is about 5mm (radius) shorter than the 40 profile, which is close enough for me.