Is smaller better when it comes to wheel size?

https://www.youtube.com/embed/1aEX5dD1IT0

Bigger might be better when it comes to fast food combo sizes, but can the same be said of wheels?

Here’s why we downsized the wheels on our 997 Porsche 911 project car from 19 inches to 18 inches.

Presented by CRC Industries.

MadScientistMatt
MadScientistMatt UltimaDork
4/2/23 7:58 p.m.

This seems like a category where there should be a just right size, and either bigger or smaller would slow you down. Older cars often had wheels that were too small for maximum performance, but it wouldn't surprise me if a lot of newer cars made their wheels too big.

LanEvo
LanEvo Dork
4/3/23 12:42 a.m.

I've tested 15-, 16-, and 17-inch wheels on my racecar (Mercedes 190E 2.3-16) and found 15" was clearly faster. This was mainly down to a smaller overall tire diameter, which was a better match to the trans/diff ratios. There's also a significant savings in weight and tire costs. 

wspohn
wspohn SuperDork
4/3/23 10:14 a.m.

Adding unsprung weight is never the best way to go in terms of handling. The big wheel movement is style driven, not performance oriented.

Older cars had some odd choices - V8 powered cars with 13" wheels that didn't have room for adequate brakes and such.  Today we go overboard the other way .  Is there an ideal compromise size? Maybe 15", maybe a bit larger, but no one needs some of the huge wheels chosen for fashion rather than performance that we see today.

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) GRM+ Memberand MegaDork
4/3/23 10:27 a.m.

brakes should be sized for vehicle weight, intended usage, and maximum speed.

wheels should be just big enough to clear the brakes.

fight me.

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