Hey everyone im sure this topic has been beaten to death but I cant really seem to find anything. Anyways I was thinking about picking up some 18x8.75 XXR 527's for my evo IX but im worried if I get 18 inch wheels it will affect my performance. Do you guys prefer 17 or 18 inch wheels?

 

With an 18" wheel there will be less tire sidewall flex while you're cornering, so that is a plus. The downside to an 18" wheel will be weight. On the street only, what tires you choose to run will likely be a larger factor in how the car handles than a 17 vs 18" wheel.

 

In theory, slightly more responsive cornering due to less sidewall flex, and slightly less straight-line traction from having less sidewall.

In practice, for a street car, no appreciable difference.

 

The extra sidewall on the 17" wheel makes them much quieter on the highway. Also, less prone to denting the wheel. I would consider those plusses for street driving.

 

Good points.

 

The other thing to think about is the additional cost of 18" tires vs. 17". That is the sole reason I've stuck with 17's but Im starting to reconsider since I want some wider rubber and there is far more availability in 18"

 

Was wondering about this myself, my friends all dis agree on it. One says no difference in ride comfort, the other says it will stiffen up noticeably. Nice to see some more input. Will the speedo read accurately with bigger wheels?

 

Tire diameter is what matters for speedo accuracy, not wheel diameter. With larger wheels you want tires with a narrower sidewall, which evens it out.

 

Play with this to see how speedo reading changes with tire size:

http://www.miata.net/garage/tirecalc.html

 

This.

 

i think 17in is good enough, you will also get better grip than a 18in