Question about track width effects on handling

[BadOne]

Assuming the only changes to the Supra are the following:

Wheels: Wider with greater offset
Front: 19x9.5 Offset +22
Rear: 19x10.5 Offset +35

Tires: Same type as stock (Michelin Pilot Sport 4S), but wider
Front: 265
Rear: 285

What effect should this have on handling? I'm assuming that since this will increase the front track width by a greater factor than the rear, the net effect will be less oversteer.

I'm also curious about what effect the wider track width should have on the suspension. I'm guessing that it will have less body roll due to the increased roll resistance, but the wheels will be further from the car so the net effect might be more body roll with a longer lever arm.

I'm fairly new to all of this and am trying to get a grasp of the subject.

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[2Cool]

Answering from a couple years of autocross and NASA HPDE events viewpoint, plus Google-fu.

Increasing track width lowers weight transfer, increasing handling. Increasing the front more will lead to more oversteer... which we already have a heaping helping of in our cars. You can make it up some with additional tread width in the back, or a stiffer rear swaybar, or spacers.

Keep in mind that you will give up daily driving comfort an wider tires, stiffer sways, springs, etc.

 

[1slow_mk5]

More rear sway = more oversteer not less all other things equal.

 

[Xxyion]

you have to consider what is your application. Are you looking for wider wheels for looks? For handeling? For better grip? In general a wider wheel means more tire to the ground which means more grip in almost every application. Body roll as far as i understand it, is more of a symptom of suspension rather than tire width. What you will feel is sidewall strength depending on your application as well as the type of tire you run with.

Also wheel width is less important than tire width when talking about grip. On a 10.5 width wheel, you can run anything from a 265 to a 305. Its how much tire you want on the ground and how much stretch or poke you want from your tires. Since our cars are staggered, my main practice is to keep the front tires the same separation in width to the rears as OEM. For me i'm running 9.5 in the front and 11 in the rear and i have 275 in the front and 295 in the rear.

The tire specs you listed should be fine and with the exception of more grip, the handling should feel largley the same until you start reaching the limits of the car.

 

[nibble]

I agree with @Xxyion on body roll. That is more of suspension setup than tire choice. see more info in my pewter supra build.

wider tire will give you more grip but not necessarily give you faster acceleration on straight. typically wider tires are heavier hence harder to rotate the wheel which in turn, it may be slower when accelerating. There's balance of power output and tire grip that you'll have to optimize.

 

[BadOne]

Thanks to all for the answers. I think I am beginning to understand the effects.

The wheel and tire setup was an amalgamation from what I've seen most people running for "Supra fitment", so I was curious what the resulting handling characteristics would be with the seemingly normal setups people are doing.

Currently I have OEM wheels with 265's in the front and 285's in the rear in an effort to maintain as much grip as possible when using all season tires for the colder months. So far, I've liked the results.

 

[white_turbo]

Aside from the track width, it is going to change your scrub radius. Depends on the spacer, it is going to affect braking stability.

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