Just a quick question for my S2000 regarding tire and wheel size. I want to maintain or upgrade the handling characteristics of the car and looks are nice too. Should I stay with stock size wheel and go with R compound competition tires? Is there any truth to the larger the wheel the greater affect It has on acceleration? I am not interested in dragging the car but I will be putting it on the track and want to get into auto-x. The car is currently stock and the next upgrade following tires will be brakes.

-Reese-

 

There are two factors to consider: weight and overall diameter.

Obviously, the more weight you have, the lower your acceleration.

Also, the greater the diameter of the tire, the lower your acceleration.

 

Very true, but larger wheels are also usually fit with lower profile tires, keeping the overall diameter nearly the same.

 

As pfb mentioned a lower profile tire must be used to mantain overall tire diameter. This usually will result in less tire weight assuming you don't go with something like a 285/30 18. The OEM S2000 wheels are not overly light so it is possible to reduce the combined weight of the OEM wheel and tire. For example, and OEM tire and wheel weighs 44 lbs combined. I moved up to an 18x9 forged rear wheel with a 265/35 tire, combined weight of 42lbs. So, I managed to increase tread width, reduce overall weight slightly, improve steering feel, and it just looks a hell of a lot better. Just beware, that this will not come cheap, and few 18" wheels will fit properly on the S without rubbing/sticking out.

 

Clovis, so u don't feel any loss of acceleration?

 

No...think about it, less weight will result in greater acceleration not less. In addtion, I now have more cornering grip with a wider tire.

 

Clovis...I just read your sig...u have HREs...no wonder

 

There's another factor to be considered here. Wheels/tires have to be accelerated both laterally and rotationally. Weight is the factor in lateral acceleration, but rotational inertia is the factor in accelerating it rotationally.

A 16" wheel may weigh the same as a 18" wheel, but it will almost certainly have a lower rotational inertia. Adding the tire will tend to dilute this effect, but not negate it. How much of a factor is this? I dunno. Any of you physics weenies want to take some measurements, mangle some numbers and report back?

- Michael

 

Back from the dead !!! so here i am with ap2 oem 17 wheels
thining to upgrade to 18s will that slow me down if wheel weights are same or slightly lighter?
what im refering to is diameter
OEM tires 215/45/17 F 245/40/17 R
comared to 215/40/18 F 245/35/18 R
would diameter be the same on these to sets of wheels???? would that slow acceleration? thanks!!!

 

Depends on the tires & wheels. Help yourself out and learn how to look up specs on the manufacturers' websites or tirerack.com.

The answers to your other questions are in the post, so I'm not sure why you're asking. As far as modeling lateral acceleration and rotational inertia...good luck. General rule of thumb to avoid being *slowed* by wheel & tire changes is pay attention to weight (duh) & overall diameter (gearing effect) as pointed out above.