[ECPERFORMANCE]

No ever used 17-18 on there cars? or even different size tires on volks or rota wheels? I know you did, help me out.

come on guys I really want to get setup before the good weather gets here.

If you don`t want to help, can I at least get a link?

 

[ewalberg]

do a search man. it's been done for sure. I think it's a terrible idea going with 17/18's, but do what you like... i think people have gone 18's all around.

I'm going to 15/16's because i want a smoother less harsh ride, and i want a lighter faster setup. 15/16's with same overall diameter tires will be fundamentally faster. THe only thing you have to do is keep sidewall stiffness in mind depending on how you want it to ride.

My tires will be higher profile than stock becuase i want to maintain the original/proper overall diameter (or slightly taller).

 

[Viggen]

they did a comparison is I think sport compact a few years ago. They tested the same 205 width tire on a 15, 16, 17 & 18in tire. The 15's were the slowest with the 17's being quite a but faster with MUCH better controll/feel. The 18's had the highest speed through the turns but they were just that much harder to get rolling with the low powered 4 cyl fwd car (I cannot remember what it was) thus the speed down the straights was fastest with 17's.

Obviously it's not a really accurate comparison since the larger tires should of been wider which obviously would of been harder to accelerate but lateral grip should of been higher.

The only negatives I see with larger rims is tires are more expensive.... if you go to the track they are a lot more costly!!! Acceleration is slower however I bet the driver cannot tell the difference......

positives - handling/steering feel is better & it definantly looks a lot better! The new 911's are going to be arriving with 20in rims when the next get hit the market.

 

[ewalberg]

Didn't they do mini copper tests where the 17's were the slowest? of the 15/16/17 options?

I'm not disputing that the same tire on different rims might be faster with big rims. I think this test may prove nothing more than that you need to select the right tire... and that they DIDN'T select the right tire, they used the same tire in all scanerios. This proves nothing that perhaps the tire chosen had a too soft sidewall design for the smaller rim options.

I don't buy the speed down the straights was fastest with 17's for a minute unless it's due to entry speed onto the straight associated with better cornering. otherwise you're defying physics, or playing tricks with rim weights.

yes, if you're using relatively soft sidewalled tires to begin with then i think it's very normal that a 17" rim might be faster through turns than a 15" but it will accelerate slower and brake slower.

My point is if you put an APPROPRIATE tire on a 15" rims it will be faster than an appropriate tire on a 17" rims becuase the tread will still stay flat in both cases, and you will have a faster lighter setup.

If there does not EXIST an appropriate tire then you have to chose a rim to suite your tire needs, but I don't think that's the case here.

if you just wanna buy cheap-o tires or compliant tires and get better performance than yeah, maybe a bigger rim is the better way to go for cornering... but that's not my point... and i'll still maintain the 17" option will hurt your 0-60 and your 60-0 times.

If bigger rims were faster than you wouldn't see indy cars with small rims with like 8" of sidewall on the tires. You also wouldn't see Radicals and Formula Fords with more sidewal than our stock cars have.

Hasn't it been said here that the elise was basically designed around 15/16's but that the marketeers required 16/17 for cosmetics?

For my goofy purposes, I want the fattest possible tire on a wide rim with the most sidewall with the most grooves for water shedding, so i've got the most compliant set-up over bumps in the road (have you ever driven in san francisco?)... that way i'll have as much traction as i can get, be as least likely as possible to float off the raod, and be as least likely as possible to bend a rim. (i've got a lightly bent 17" rim on the back right now).