I have an 05 5AT sedan and a friend is offering me his coupe 18s
now, will I have to recalibrate my speedometer for the change?
and are the coupe 18s comparable in weight to the stock 17s?

Thanks

 

i'm not aware that you can recalibrate the spedo on the G35.

 

No need to recalibrate anything... actually Cato is right..you can't really.

If you are running the coupe 18's the stock 225 and 245 sizes will be fine. If you are concerned on rotation then you can run 235/40 18 all the way around. The 235/40 is almost as close to stock 17" tire size.

As far as rim weight I am not sure about how much more, but there will be an increase. You are increasing the size of the rim and possibly the rubber.

 

235/45/18 is the ideal tire size as it is the OEM spec on the '05 sport. You will be perfectly flushed all around and no need for mods to make them fit.

 

Ya...what he said.

 

you can NOT recalibrate speedometer
you will be off by 2-4% (spedometer 60mph actual speed 64mph) depending on tire wear - I tested it using mile markers
after 15k you will be exact

 

If you don't care about staggered, then replace the tires with 235/45/18. The front and rear wheels of the coupe's 18s are the same size, 18x8. However, the offset is +30. If you are lowering your car, it might rub.

 

Here is a pic of my winter set up. 235/45/18 all around dropped on Eibach prokit and no rubbing anywhere.