I'm about to pull the trigger on a set of Dunlop Star Specs. The wheels I have are 16"x7". Can't decide between a 205/55 or 225/50. Both have a diameter of 24.9". 225's weigh 2lbs. more. Car is lowered on H&R springs, 1" up front, .75" in the rear. Any recommendations?

 

what offset are the wheels?

 

42mm

 

gschiel,

What are you doing with the car?

Is this a MCS? R56 or R53?

 

The 225/50/16 is molded to optimally fit an 8" rim, although it will fit a 7".

Another 205 size option is 205/50/16. It's a little bit smaller than OE tire size diameter rather than larger (24.1" vs. 24.9"), and it weighs 4# less than the 225/50/16 (22# vs. 26#).

 

Sorry I guess my first post was a little vague. I've got an R53. Looking to get into auto-x this year. Not worried about trying to meet the requirements of any classes, just looking for advice before I spend the money. I would prefer to go to a 205/50 to help with gearing but I'm not a fan of wheel gap and I don't want to spend the money on coilovers until I can afford the ones I want. Basically is the wider tire going to make a noticeable difference in handling? And would have a tire size larger than stock affect gearing much?

 

A sticky street tire (like the Star Spec) is the first step in gaining grip. A larger contact patch provides more grip, but a lot is involved in getting maximum contact patch, including suspension, wheel alignment, and tire pressures.

One of the ways of getting more tire contact patch is to mount wider tires, which works up to a point. I don't know exactly where that point is, because I've never used more than one size wider than OE. I may be increasing contact patch a bit, but I also notice a small loss in steering precision when the tire looks even slightly too wide for the wheel. However, national level AX'ers in stock classes often mount impressively wide tires for their rim widths, but they're from another planet.

The 205/55/16s would be about .8" taller (larger in diameter) than the 205/50/16s, so the car would sit/ride about .4" higher with 205/55/16s. That much change in the center of gravity would probably not be noticeable.

The taller tire would also result in slightly higher effective gearing (not usually an advantage in AX), but that difference would also be small.

In short, given your car, your AX driving skills, and your Star Spec tires, the small differences in tire width and diameter we're mulling over should make a comparatively very small difference in your times.

If I'm right about that, within the narrow range you're considering, you could just get the tire size you want to drive on everyday, or the size that you find more attractive on the car.

 

with +42 I would expect the 225s to fit - however I do not run 16" and so cannot guarantee it...

pity there's not 225/45 available

I personally am on the fence with 7" rim width - I've run 225s on my 15x7 including the RS3, and the R1R. At present I am running the R1R.

I've also run the 205/50 Z1 (two seasons) and found it to be a very effective alternative.

I don't think either is a bad choice, but I'd expect the 225/50 to have a slight edge. Are you ever on the limiter in 2nd during competition?

Cheers,

Charlie