Wheel size in relation to 0-100 and fuel economy in action

[ben yip]

I have spend so much time to dig this article up, most people just talking about it with no concrete evidence. I am not a big fan of large wheels at all, I can lost almost 0.2 second in 0 to 100, and hence the reason why light weight wheel is so important in tracking, which is my next mod

What surpises me is in 0-100mph, 0.7 seconds are lost, so why not fit 15 in drag racing then!!

http://www.caranddriver.com/features/10q1/effects_of_upsized_wheels_and_tires_tested-tech_dept

Edited July 12, 2011 by ben yip

[Seby123]

that really is pretty interesting...but i guess also expected that heavier wheels will cause the times to go up.

like the article says, most people choose big wheels for asthetics and looks, same with me, but my wheels turned out to be lighter than my stock, steel wheels.

as to fitting 15" in drag racing, i reckon some people do this, look at professional dragsters, they barely have rims, either a small diameter on the rear or small width on the front. thanks for sharing :)

[Buff Hamster]

Nice find on the article. I guess i won't upsize to 18" now :( . Stay with stock 16".

[DJKOR]

I'm no expert on the subject but I would imagine that you have to work out the right balance. On one aspect, as wheels get smaller in diameter their width tends to be reduced. Reduced width then equates to reduced tire width. Reduced tire width can account for reduced traction. When on the track, could this reduced traction potentially be significant enough to make the drop in diameter and weight negligible? I dunno.

One can counteract that reduced width issue by getting smaller diameter wheels whilst maintaining width... or even increasing. But then an increase in width equates to more metal, when then means more weight.

I guess then what would be ideal would be a wheel with a relatively small diameter but a larger width and of a lighter weight design so that in that case you can benefit from a wider tire whilst getting the benefit of a lighter weight wheel. That all said though, the optimum width all comes down to the car so it can vary quite a lot in terms of what would suit best. I'd be guesing a more avid track goer would know what works best.

As said, people tend to go larger wheels more for looks.... unless of course you are running large brakes and need the clearance. When you are on the street though, light weight wheels won't be overly to advantageous, so why not have the best of both worlds and have a separate set for the track in which you can put some nice semi-slicks on them, and then a fashionable wheel for use on the road.

as to fitting 15" in drag racing, i reckon some people do this, look at professional dragsters, they barely have rims, either a small diameter on the rear or small width on the front. thanks for sharing :)

I think you will find that they don't put smaller diameter wheels on dragsters for the purposes of having lighter wheels. Top fuel dragsters being an example put out power and torque in the range of several thousand HP and Nm. The wheels on these are smaller due to the requirements of the tires and traction. Ever seen a slow motion video of it? More sidewall equals more flex, and more flex reduces wheelspin.

[Steven]

With dragsters the smaller diameter wheel also helps with side wall pressure, but is a precise balance between side wall pressure and wheel torque - they put out so much torque that it's not uncommon for the wheel to spin INSIDE the tyre

[Hiro]

Formula 1 cars also only run 13" wheels because the sidewall flex of the tyre is actually part of their suspension design. If the move the 17-18" wheels actually goes ahead (it has been on the cards for a few years now) they would need to completely re-design the suspension of the car to match the stiffer lower profile sidewalls.

For sporty road cars though, sidewall flex is a bad thing, hence why larger diameter wheels and lower profile sidewalls can provide more cornering grip - as long as the wheel is light enough, the change in rotational inertia should be minimal as well (note, 18" chromies are _not_ "light enough"). You'd be surprised at how light some 16-17" wheels can be - the 16x6.5 205/45/16 wheel and tyre combo I have on the AE102 at the moment weighs roughly the same as the stock 14x5.5 175/65/14 factory steel wheel combo, yet I have an inch wider and 2" larger diameter wheel and 30mm wider tyre. The 17x8" wheels that we had on the Snoarer weighed only 9kg each (without tyre). I've yet to weigh the 17x7 Lite-5s that I'm putting on the AE102, but I'll do a comparison to the 16s when I swap them over and I wouldn't be surprised if the 17s are lighter again (the 16s aren't a particularly "lightweight" design).

In short, there is no hard and fast rule about "smaller is better" etc. It comes down to the design of the wheel, design of the tyre, the purpose to which you wish to use them, and the car itself (obviously you can't replace factory 18s with 15s with the same overall rolling diameter and expect good handling).

[Buff Hamster]

Actually stuff fuel ecc. 18" here i come