A serious wheel question that goes beyond weight and appearance...

[Jdogg180]

Wider rear wheels and tires will produce more understeer.

[jamal]

Unless you are tracking the car it's not really a concern.

Going to a wider rear tire on these things will result in more understeer.

The reason for a staggered setup has more to do with balance and temperature management than grip. If you are on a track and are trying to put a lot of power down on corner exit then a wider rear tire might work better because it has more rubber and can handle more heat and load. To go into it further would get pretty complicated. For the most part I like a square setup, even on a car with more power like a Z or a turbo S2k.

And it could be worse. I know a guy who put wider rear tires on the back of his accord.

[Draco-REX]

Wider rear wheels are used to help the engine put down power out of turns. Considering that our cars only make 151tq, there really isn't a need for larger rear tires. Going with a square setup will help keep the grip even front-to-rear. Going to a staggered setup will encourage understeer.

[DrDuquette]

I would think that going from a neutral non staggered car to a staggered would make the biggest difference in upsetting the balance. In a staggered I would think you would be setting up a neutral car to have more understear due to more tracking in the bak and less in the front? Am I wrong thinking this way?

Now if the car was built to be neutral in the staggered format but then to go an put an unstaggered wheel set up, I would think you would end up with oversteer.

Just imagine putting a pair of spare tires on the front or back of the car. I know that is drastic staggering, but do you see my point?

[boredom.is.me]

It is really cool readings everyone's explanation. I never would have really thought of oversteer and understeer being so related to width. Thanks guys.

Now if you chose much wider tires (on a square setup) than stock in both the front and rear, would this create more understeer? or is this directly related to the ratio between the front and rear?

[Metabrz]

Originally Posted by boredom.is.me

Now if you chose much wider tires (on a square setup) than stock in both the front and rear, would this create more understeer? or is this directly related to the ratio between the front and rear?

If you put on 'much wider tyres' on a square set you might not get understeer but the balance of the car will be disturbed due to the additional rotating mass of the set up - acceleration will be dulled but braking will probably better enhanced. So you can stop faster from going slower.....

Remember this is a small sports car we're dealing with. The wheel/tyre combo you choose should be suited to what you want the car for - show car / track work / street etc etc.

My advice would be that if you want to enhance the performance of the car by ONLY swapping out the wheels and tyres is that you keep the changes to a minimum. Look at rotational weight and look at putting on 225 or 235 section tyres. Putting on 19" with 255's......the car will be better served on the show car circuit than as a daily driver or back road / track weapon.

Of course if your plan is to supercharge or turbocharge it to 300 HP, look at wider rubber (as well as brakes, suspension etc) but remember that 19's can be a little precious (delicate) if pushed fast due to the lack of rubber between the rim the pot hole you just ran over.

The engineers who designed and built this car knew what they were doing. Improvements are best made incrementally.

[DrDuquette]

Wider tires would mean more grip assuming they are good tires. Just remember now it will be harder to get the back wheels to break loose so maybe harder to get the car into a drift. But also realize you will be going faster when the tires break loose. You should learn about the car first with stock tires before you increase your grip and speed.

[fatoni]

Originally Posted by Dave-ROR

I run 17x8s with 235/40/17s which made a huge difference.

Whether or not 18x8s with 235/35/18s would be better or not would depend on multiple factors. I'd guess the difference in performance would be marginal either way with an increase in harshness with the 18s.

when someone asks such a simple question i dont think its fair not to mention that most of that huge difference is compound and not size

[DrDuquette]

Originally Posted by fatoni

when someone asks such a simple question i dont think its fair not to mention that most of that huge difference is compound and not size

Exactly!!! Compounds and brands will make a big difference too.

[Dave-ROR]

Originally Posted by fatoni

when someone asks such a simple question i dont think its fair not to mention that most of that huge difference is compound and not size

I was assuming he'd pick the same compound/tire regardless of which size he went with, I would. :shrug:

I don't pick a size unless the tire I want is available in it

[DrDuquette]

That is great thinking. Looking into what tire before the wheels.

[Vracer111]

Originally Posted by boredom.is.me

The most used single description I have heard of for the FR-S and the BRZ is that they are "balanced" in terms of how they drive and handle.

It is common to put wider tires on the rear of a car. This adds a little in the looks depart as well as helps put power down better. With that said, would you want your front and rear wheels to be the same width? How would it effect grip between the front and rear?

The car was designed around same sized tires front and rear, changing tread contact patch (via different widths) would only upset the balance of the car with the stock suspension. You would have to change the suspension from stock to maximize benefit from such a setup, which would undoubtedly change the balance of the car. Stock suspension is setup very well from the factory...I see no need to mess with it at all until it's time to replace components due to wear.

Compound and taking a tire to it's maximum width wheel it fits is much more important to me for balancing the car than just getting wider tires. Wider tires are no good if the wheels you have aren't wide enough to minimize sidewall flex and keep the tread in shape. It's the main reason I stayed with the stock tire size but went with better tire compound and wider wheels for my track setup... besides the obvious weight component (wider tire sizes add 3-4 lbs at a location which will affect the handling/balance more than slightly overweight wheels). I am also not going for quickest time or driving 100% on the limit 100% of the time [this is my daily driver the bank owns after all!] where wider tires would provide more grip (but still at the expense of poise/balance). I am just wanting the car to be better balanced than stock while having a great time on track. Stock size sticky tires on maximum width wheels balance the car even better at the limit than stock because you can read the tires that little bit better with less 'slop' and you have noticeably more grip available. On the street though, Grippy stock sized tires on maximum width wheels for the size will make it seem more 'understeery' or less prone to kick the rear out but you still have excellent steering feel and response.

For me, maintaining the balance means the wheel/tire combination needs to be lighter than stock and the tires should gain minimal weight (not be more than ~2 lbs heavier than stock weight - because no matter how light the wheels, a heavier tire will mess more with the suspension feel than a lighter one.) The reason I went with Kumho XS's over Hankook RS-3's (besides being very familiar with the RS-3's, having always wanted to try the XS's, and the XS's being $14 cheaper) was they weigh less. Having put my FR-S on track last week, sticky stock sized 215/45-17 XS's on 15.6lb 17x8 Kosei K4R's are definitely better balanced than the car was stock... stickier tire compound, 8" wheel width chosen for the maximum tire stretch recommended, and ~4lbs less weight a corner all add up to something really impressive - impressive poise and control with very high level of grip!

[SUB-FT86]

So what you guys are trying to say is this car is in optimal handling mode stock?

[7thgear]

Originally Posted by SUB-FT86

So what you guys are trying to say is this car is in optimal handling mode stock?

is that really hard to believe?