BIGGER WHEELS = SLOWER CAR???, can you say INERTIA??? Options

[pflau]

just wondering.... do bigger wheels make the car accelerate slower and stop longer because of the greater rotational inertia??? yes I know big wheels make steering more responsive.. so maybe going from 15 to 16 makes sense.. but 17 and 18???? do some people sacrifice performance for look???

phil

[97GTinKC]

I think the stock 15x7 GT wheel is closer to 18 lbs., I sold a set recently and seem to remember 18. I am getting ready to swap a couple of tires around, will post the weight of the stock wheel then.
On my wife's digital bathroom scale, the stock 15x7 wheel with worn Michelin Pilot 205-55-15 is 34.2 lbs. while one with most of its tread left (had one tire replaced) comes in at 36.0 lbs. so wear can change things by a couple of pounds also.
Michelin doesnt list weight on their web site, but Continental does, their Extreme Contact 205-55-15 is 21 lbs. while a 215-40-17 is 20.9 lbs. and the Conti Sport Contact in 225-45-zr16 is 18.9 lbs. while the 265-35zr18 (which is 24.3" tall) is 23.7 lbs. (all tires have the same approx diameter 23.9 for the 1st 3 and 24.3" on the 18), so weight can vary between models and same approx. sizes even in the same brand.
36 lbs is probably a good baseline to start from. If a person stays in the same height range as stock(23.9" diameter) , and the same approx stock weight (36 lbs wheel and tire combo) they could run 17 or 18 inch and probably not lose any performance. As far as the weight being concentrated farther out from the center affecting anything, I think it would be too hard to calculate. does it really make a difference accelerating 2 differently shaped masses of the same overall diameter and weight? I agree if you go taller, you will take a performance hit, (even 1 inch will make a noticeable difference and affect the speedo)
And remember wear can account for a few pounds of rubber, so a few pounds either way probably wont make a noticeable difference.