going square how did you like it?

boosted180

Did you start with 19" wheels stock? If so, going down to 18" wheels and staying with the 40 size sidewalls on the tires, did you notice a difference in overall diameter? By the numbers, going from 245 40 19 (front) to 245 40 18 should decrease the overall diameter by about 1", which I'm tyring to avoid.

Did you notice a difference? Should I even worry about that?

Do you happen to have pics of your car on this setup?

PharmDZ

I have a set of hankook RS3's 275/35r19 on my stock Rays which I do like. I purchased the Enkeis which were 18" and went with a 275/40 to keep the same height because the car is lowered already and a smaller sidewall would make it an additional inch lower and I'd scrape everywhere.

ValidusVentus

One downside is that it will make your speedo read about 3% high. Possible upside and downside: effectively lowers the gearing on the car slightly.

Would be nice if more track tires were made in 275/40R18. Seems like 285/35R18 is pretty much the only option.

The difference in diameter between a 285/35R18 and a 275/35R19 is only .7" so ride height change should be only about .35"

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Mods: Dedicated caged track car, lots of things. ||| Valkyrie Autosport |||

boosted180

yes, that's exactly what I was concerned about also. I didn't want an inch lower b/c of the lower sidewall. thanks for the info.

boosted180

Yeah, I realize that it would only be half the calculated 1" difference since the wheel is mounted in the center. But even half an inch is way too much for me. In fact, I called Eibach today to ask if it's common for their springs to sag. When I first put them on 5 years ago, I was able to make it in and out of my driveway just fine. Now the front of the car scrapes, even if I'm very careful. And it looks lower also.

But I'm surprised that you went for 305 35 19 to 285 35 18 and you saw almost no difference in overall diameter/ height?? or did you mean 285 35 19 and 305 35 18, which would make more sense b/c the added width would add to the sidewall height a little and negate some of the change to a smaller wheel.

For my fronts, should I go with a 255 40 18 or a 245 45 18? (rears will be 275 40 18). The general rule of thumb is that when you go up or down 1" in wheel diameter, you compensate for that by adding or subtracting 5 to the sidewall number. But the width would affect the overall diameter also, so I was thinking I can stick with the 40 sidewall if I increase the width to 255 instead of the stock 245? And this will give me almost the same overall diameter?