[Jzepp300]

Does anybody know if going from 17" to 18" wheels will slow my 98 cobra down and will it be noticeable just for daily street driving?

[GTRaptor]

All depends of the total diameter of the tire/wheel combination.

If you use a 245/45/17 it is the same as using a 245/40/18, more wheel, less tire sidewall.

[Cobra_Lynx]

The weight of the new rim/tire combo you're considering will play a big part too. As a bit of a colourful illustration, consider playing frisbee with a manhole cover; not only is it simply heavier, but it also takes much more effort to get it to spin. Obviously, the difference isn't going to be on that scale, but a heavier wheel/tire will affect your handling, and it will affect acceleration also. Now, you can get a light-weight 18" rim that weighs the same as a stock 17" one, but to go big and not add weight will cost a fair bit of money. On the other hand, the jammy lightweight rims have this habit of looking cool, so... Its up to you. You'll get a bigger contact patch, and they do look better in those gaping wheelwells, but I'd consider all the effects before you go putting money down. Good luck. Jim.

[Jzepp300]

I estimated about 30lbs. more with the new 18's versus the stock 17's...........will that really slow my car down? I will be switching back to the 17's for winter with the stock 17" cast wheels....will just be doing occasional street driving here and there.......just wondered if you will notice a big difference in the speed of the car.