I know they are both 16x7s. Currently have a set of tires mounted on S4 T2 wheels. Not too long ago I acquired a set of S5 T2 wheels with no tires. After reading through the FAQ, there was some info explaining that S4 T2 wheels are 4lbs heavier than S5 T2 wheels.


Prior knowledge tells me that lighter wheels is a GOOD thing, however it depends on the "moment of inertia". Does anyone have any info? Is it worth spending a couple bucks to have my friend swap the tires on the T2 wheels?

note: I do track my car, so that is why I'm curious if I will see/feel a difference on the track.

 

The moment of inertia depends on how the weight of the wheel is distributed. Since the wheels are the same size, the moment of inertia would differ mainly on the design of the face. It wouldn't be considerable.

In general, focus on weight when it comes to wheels the same size.

Weigh the wheels after removing the tire off of one just to make sure. Post up to confirm the weight difference for us if you don't mind.

Now if you were going from 15" to 19" diameter wheels with a similar width (hypothetically speaking) that weighed similar, then moment of inertia would matter a bit more. But it would matter in terms of accelerating and slowing down, not so much unsprung weight.

 

I would make your decision based on which one you like better

4 lbs won't be that noticeable...

 

Moment of inertia. In short, if you want to track your car and make it better, lighter is the best way to go. The moment of inertia is how much torque will it take to rotate an object. Is it more difficult to rotate an object of heavier weight than a light one? Yes it is, as with stopping. The lighter the wheel, the better (racecars have smaller wheels not only for price and availability; but for less mass. Formula 1 wheels are only 13").

Any feeling you'll have will be negligible; more confidence in yourself for just doing an upgrade rather than feeling the actual upgrade. To say that's worth something? Could give you an edge if your times start dropping.

 

seat of the pants might notice that the car feels a little better, but its only 16lbs, so its not going to be a big change.

however add a few small changes, and the car gets a lot sharper