[racingfast]

I ran my Z at an autocross & put my 315's on the rear with no problems. I was told that the smaller diameter will screw up the computer as it doesnt understnad why the wheel is spinning faster than it should. ANy imput on this? thanks!

 

[DJWorm]

It will only give you erronious speedo readings....but who cares what the speedo says in an autocross. BTW putting 17's on the rear will raise your effective rear end ratio from 3.42 to around 3.56. Should help the acceleration but may not be legal in Super Stock. But may be in other classes. If you're keeping the 17's on the rear for street use you may want to reprogramm the computer so the reading is accurate. But then if you run the 18"s again it will be off until you reprogram it. Can't have your cake and eat it to.

 

[DJWorm]

It will only give you erronious speedo readings....but who cares what the speedo says in an autocross. BTW putting 17's on the rear will raise your effective rear end ratio from 3.42 to around 3.56. Should help the acceleration but may not be legal in Super Stock. But may be in other classes. If you're keeping the 17's on the rear for street use you may want to reprogramm the computer so the reading is accurate. But then if you run the 18"s again it will be off until you reprogram it. Can't have your cake and eat it to.

 

[racingfast]

thanks DJ---someone said their ABS & trancton cont went haywire when they did this..perhaps a coincidence... Its raining in PA here and my first event is today. .guess I will be running street tires. Brian

 

[Cape Cod Bob]

someone said their ABS & trancton cont went haywire when they did this..perhaps a coincidence... Its raining in PA here and my first event is today. .guess I will be running street tires. Brian

Ran 17" grandsport rims and autox tires on my 97 for 2 years and never any ABS or traction control problem.