I've read numerous posts here with people talking about bigger diameter wheels hurting acceleration. This to me seems like total BS. I can understand that bigger diameter tires will hurt acceleration because it is essentially making your gearing taller. However, everyone i've seen running 18" wheels is using tires that are within .1" of the factory diameter so the wheel size should have no bearing. Can someone please explain the physics behind this??

-Steve

 

The reason why people says that is because 18" wheels usually weigh more then 16" making the car slower. If you get good 18" wheels that are lighter then the stock ones then it will be slightly faster.
Another reason if because the bigger wheels will cause traction problems when launching because of the lower profile tires.

 

ok that's what i thought, basically there is nothing that inherently makes an 18"er slower than 16". It wouldn't make sense to me any other way. How much do the stock wheels weigh?

-Steve

 

there are more factors to consider as well....alot depends on how the weight is distributed around your entire rolling diameter...

 

Bingo- we have a winner. The reason people say that larger wheels will make the car slower is because generally the mass is moved farther away from the center of the wheel. The farther way the mass is away from the center the more force it takes to move it. Do this take a sledgehammer and choke up on the handle and spin it around in a circle. Now grip it at the very end of the handle and spin it around again. Harder right? This is the same thing a car is trying to do when you move to a larger wheel. Of course if you go to lighter wheels you will be able to offset this somewhat, but even if the wheel is lighter it may not be enough. Someone else around here can probably give a better explanation - like UL. Or I could try and dig out some of my old Physics or Statics & Dynamics books.

Also you can go to this tread for some good information: https://www.s2ki.com/forums/showthread.php?...p?threadid=7388