What am I missing with all the ultra-wide wheels & tires?

[Vdub]

Is everyone who gets 9"+ wheels & 245+ tires tracking a lot? I've been spending the last several weeks deciding how best to spend $2k on a new set of wheels. The wide ones definitely look better, but they weigh (and cost) soooo much more!

Due to the weight, I'm leaning on buying some lightweight wheels that are only 7.5" wide and putting Michelin PSSs on them in stock size of 215/45R17. They won't look as cool, but I feel like I'll actually notice a little bit better acceleration. Yeah, I'd get more traction with wider tires, but getting grippier tires in the stock size seems like it will be sufficient in 98% of cases.

So with my 2 cents out of the way, if you got super wide tires, what was your reasoning behind it? Do you really need the extra traction at the expense of weight & speed? Or was it just because they look cooler?

[Gunman]

My money is on "wider is better".

Very easy to over tire the 86. I went 17x8 with a 225. Weight, and rotating unsprung mass is evil, in my race car designing mind...even though I don't track the car.

[14stu]

If you don't track or autocross the car, you are just doing cosmetics. If you are tracking/autocrossing your car, then class rules and testing/comparing setups will quickly yield the optimum combinations.

There are a bunch of racers and a lot of hard parkers. The racers are almost all on 17" wheels (tires are much cheaper and the wheels are usually lighter), the show and shine guys like the 18"+ wheels.

A bunch of the autox/time trial classes make a 9" wide wheel the max for the twins.

[Pat]

You and I agree, Vdub. My ideal setup is an 8" wheel with 225/45-17 high-end tires. it's what I use for winter, summer and track. I also prefer a wheel with a significantly lower offset than stock, which is tough to find. I am very happy with my Kosei K4Rs.

[venturaII]

225/50-16 on a 7" wheel and +40 ET. Yeah, a 7 is a bit narrow for a 225, but man, they're light. And the car stays fun to drive.

[nikitopo]

Originally Posted by Vdub

So with my 2 cents out of the way, if you got super wide tires, what was your reasoning behind it? Do you really need the extra traction at the expense of weight & speed? Or was it just because they look cooler?

When people change their wheels, they change also the tires to stickier ones. So, they see they are faster but not so much because of the size. You can check a test made some time ago:

http://www.roadandtrack.com/car-cult...ransformation/

Most of the gains can be obtained by just changing the rubber and keeping the size same. In fact, the car was a bit slower with the bigger tires!

Where size matters is on the better heat energy dissipation. If you don't track at all, or track up to 5 laps per time then it doesn't really matter.

[G-Man]

I am 17x9 245/40 to stay in my autocross class(STX), but my dailies are also 17x9 cause they are pretty. If it rains i just use my dailies to run, so they are at least somewhat competitive.

also the road and track article sums it up pretty good. The wide stuff is better for lateral G's and autocross is all about low speed high G.

[imnotsureaboutbrz]

Originally Posted by Vdub

Due to the weight, I'm leaning on buying some lightweight wheels that are only 7.5" wide and putting Michelin PSSs on them in stock size of 215/45R17. They won't look as cool, but I feel like I'll actually notice a little bit better acceleration. Yeah, I'd get more traction with wider tires, but getting grippier tires in the stock size seems like it will be sufficient in 98% of cases.

I've put a set of 225/45/17 Michelin PSSs on the Stock PP wheels and they have been serving me great! They are only ~1lb difference between the 215s and you get 0.5" (6%) more contact patch and 225 is a better fit to the 7.5" wide wheel.

**Also food for thought since you are shopping the PSS: Contact patch gain vs rotational weight gains

size weight tread width
215/45 21 lbs 7.7"
225/45 22 lbs +1lb 8.2" +.5"
235/45 22 lbs +1lb 8.2" +.5"
245/40 23 lbs +2lb 8.5" +.8"
245/45 23 lbs +2lb 8.0" +.3"

[nikitopo]

Originally Posted by G-Man

also the road and track article sums it up pretty good. The wide stuff is better for lateral G's and autocross is all about low speed high G.

Lateral G is bit better, but the difference is small: +0.02 g. Another note is that the wider tires have a higher load index (91 vs. 87). This means a bit stiffer sidewalls that give an advantage in cornering and slalom. Overall, not the difference someone might expect from a 235 tire.

[Mr.ac]

Spending all that money and going with pss? Lol
Get a better tire. Unless you pay under $120 for each you are clearly getting ripped off.
For some odd reason people still think just because it's an oem brand it has to be better right? Wrong. That's just the sales rep pulling a fast on.

[DarkSunrise]

For auto-x, wider is better because you can add cornering grip without going fast enough to worry about drag/aero. STX is limited to 245 on 17x9 so it's the standard setup.

For track, you need to weigh the gains in cornering grip against the losses from drag/aero. Will be course-dependent but 225 on 17x8 is a good starting point.

For street, I don't think it really matters unless you're really concerned about fuel economy. I'd run the stock setup on cheap tires (215 on 17x7) just to have fun, but wide tires/wheels do look nice aesthetically.

[G-Man]

Originally Posted by DarkSunrise

STX is limited to 245 on 17x9 so it's the standard setup.

STX allows up to 265, if you are 2wd, only the AWD guys in STX are limited to 245. most of the guys in my club run 255/40

[DarkSunrise]

Originally Posted by G-Man

STX allows up to 265, if you are 2wd, only the AWD guys in STX are limited to 245. most of the guys in my club run 255/40

Ah ok I stand corrected!

[nikitopo]

Originally Posted by DarkSunrise

For auto-x, wider is better because you can add cornering grip without going fast enough to worry about drag/aero. STX is limited to 245 on 17x9 so it's the standard setup.

I don't think there is enough time to overheat a tire in auto-x. A narrower tire with same compound should provide almost same grip. Maybe you have better results because the axle track is a bit bigger and the suspension geometry is altered.