Just bought a 05 Anniv Z with 2800 miles. Orig owner put 245's on the front vs 225 and 265/35's on back vs 245/45 stock size. He did this back when new but has hardly even driven it. Any guess how far off speedo is and if VDC will be affected ? Thx. Keith

 

245/?/18 on the front?

 

congrats on the purchase especially only having 2800 miles on an 05, enjoy

 

Yeah that was pretty confusing to understand....

edit... ok after reading it a couple more times now i get it. So thats new tires on the stock wheels?

 

well you probably just need to buy a fresh set of rear tires to straighten it all out.

 

based on your rear tire size increase, your speedo is reading 5.5% too fast. use this calculator: http://www.1010tires.com/tiresizecalculator.asp

 

decrease , and slow, not fast. Not to mention how that will effect VDC

 

The whole concept of the fast/slow thing is actually pretty confusing the correct term for the OP's situation is it's "too fast."

His speedo will be from 5.2-5.5% too fast depending on actual diameter, PSI, tire condition etc.

If his speedo was reading 60 MPH, he's actually going slower (56.9 MPH) so his speedo is reading faster.

 

A tire calculator will tell you the difference between a 245/45-18 and a 265/35-18...Its quite a bit, a 265/40 would be a better fit. 245/40 is good for the front.

 

exactly

 

Sorry, doing thus from my iPhone at the beach. Yes the original owner kept the stock rims and put the 245/45-18 on the front and the 265/35-18 on the rear. Strange isn't it. He told me the car looked like it needed more tire. LOL. Any safety issues with the rims and these tire sizes. I have not heard any rubbing noise coming from the ft or rr but have not driven it more than 15 miles or so. Suggestions? Leave them alone and correct at replacement time or should I correct now? I'm surprised the vdc light has not come on based on the different rolling circumferences of ft and rear.