17x9 vs 18x9.5 for track use?
 

I'm stuck between the benefits of each tire. The 18x9.5s can fit a 265, but weigh a tad more. The 17x9s are lighter, but are usually ran with a 245. Which is more important to you, lighter weight or more tire width?

18x9.5s http://i.imgur.com/6vyGtWx.jpg

17x9s http://i.imgur.com/NglXW58.jpg

i am running 17x9 right now with a 245/40
i am planning on running 18x10 and 285/30R18 because everybody else does that who is competing in time attack and if i dont have the same level of rubber on the road i wont be competitive. it is what it is.

That's what I've noticed. I'd be right in the middle with 18x9.5s. That's what I'd prefer.

Honestly? If you're new to tracking stick with stock tires and wheels. You'll learn a ton about slip angles. People are too quick to put on sticky tires when starting to track.

I've been on track, no worries. I beat the snot out of my stock tires and suspension before upgrading. I'm just curious about everyone's opinions on the matter.

But did you learn to be a better driver. Throwing a car around is one thing however learning car control is another issue. Beating the snot out of your equipment is no gauge of being a good driver.

Of course. There's always things to take away from every session. It'd be extremely naive to throw a car around without the intent of taking something away from it. I'm not here to discuss my driving, though. I'm here to discuss whether or not members prefer a wider tire or lighter wheel when it comes to wheel sizes.

Mmm stock power with 285?? Im run 17x9 with 245/40 and next i would go with a 255/40.

i wouldnt go over 225/40R18 on stock power.

i was 0.4 seconds slower on 245 than 225 on stock power.

with stock power the width and compound will prevail. You can never go wrong with a good 17x 225 for these cars.

17in tires being cheaper is a big reason to stick to 17s. 17x9 with a 200TW 245 or 255 is a lot of tire for an NA car.

Do you have that much power to need a 265 or wider tire? I know experienced drivers who have said they’re faster on a narrower tire.

225's on a 17x8 at stock power, unless you're only looking to be competitive in autox, then 17x9 with 245's.

Not talking about me in this instance. Just curious as to what everyone prefers.

I personally went with 18x9.5 with a 265 wide tire to accommodate for more power. It also looks better in my opinion :)

The other tire option is 255/40-17

I can't say for sure, but in the same tire the 265/35-18 will probably be a bit faster.

However, the 18s will be more expensive. Looking at stuff like a re71, rt615, rs4 etc, it's like 40-50% more.

So you spend a lot more money for minimal gains. Unless you are trying to race time attack competitively, in which case you should probably use all the tire the rules allow, I think I'd stick to the smaller wheels.

So you aren't talking about yourself in this instance but you want our opinions about the difference between the two?

Are we having a conversation for the sake of conversation or an actual discussion about pros and cons to help you make a decision?

Every time I've gone wider I've gone faster thru the corners. It usually end up in faster lap times as almost all of the tracks (with the exception of 1) I run at are small and twisties with almost no straight whatsoever. The widest I've gone is 245 in 9". Im going to 255 in 9" this year because the tire I want is either 235 or 255.

So in my experience, all the way to 245, wider = faster around the track. YMMV.

What kind of tire?

- Andrew

200tw. This is mainly for the sake of general comparison, not for me necessarily. I'm interested in the extra width vs less weight debate

I'll jump in the muddy water...

255/40 is the largest recommended 17. And because there is no 265/35/17 Or 275/35/17, getting a wider tire means getting larger wheels.

It's been discussed, but street tires are terrible for AutoX. R compound is the way to go, and may have a lower utqg than 200.

Big money has to be spent to get better wheels for competition than the RPF1. 17's seem like the logical conclusion.

17x9.5 forgestars are available for 335 each. Which is half way to a rays or volk wheel.

And in conclusion: Weight vs width. You have to have a reason to care about grams and tenths of seconds. To many variables here to have a real debate. You do not need extra width till you have extra power. A 255/40 Toyo r888 weighs 26lbs, a 265/35 18 weighs 28lbs.

Had a set of 245/40/18 on my stock power 86 with suspensions before, really didn't like it. Yes it gives a lot more grip compare to the stock tires, but I felt like I couldn't turn the car using the throttle anymore (not sure if this make sense).

Personally... I’d choose weight savings every time.

Any street tire class in autox requires a 200tw tire... even if they're not really 200 in reality (like the RE71R, Rival S 1.5, etc).

True r compounds put you in a class that requires a ton of other mods to be competitive, and if you're in that type of class you'll want to be on Hoosier's.

So this is not for you, but a general discussion.

All else being equal, 18x9.5" will net you ZERO benefits on the track, because the tire you run will be way too much grip for track.

The only reason to go that wide and large is if you have a brake kit requiring 18" wheels for clearance, and you make enough power or have enough aero enhancements to take advantage of 255+ width tires. Otherwise, 17x9" is plenty width for a NA powered car. Hell, with stock engine you should basically max out at 225 or 235 width tires.

The only type of track you will see benefits from running 18x9.5" is if you are running Ebisu-type circuits where it's a glorified karting track.

-alex

I sometimes wish for brake and wheel manufacturers to decide on some common standards for brake clearance. It would have SO simplified wheel choice if there had been some known index specced for both brakes & wheels instead of current situation, where one can at most use fitment templates, if such exist (for example, i since long wanted to find nice set of 15 wheels that would fit over stockers, but of course, no one had made such template for stock brakes).

I went from 18's staggered to 17's squared and was a huge difference on track and day to day driving. I ended up going with wedssport tc105n which is one of the lightest 17x9 on the market. would highly recommend those wheels with 245/40 or if you want more tire you can run a 255/40

http://www.roadandtrack.com/car-cult...ransformation/
FR-S tire test
215/45-17 Michelin Primacy HP: 1:29.3 lap time
215/45-17 Dunlop Z1 *spec: 1:27.0 lap time
235/40-18 Dunlop Z1 *spec: 1:27.6 lap time