Do wider tires up front help handling? I've heard both. What's the truth?

-Rippin

 

YES... whoever tells you different is dumb. You are increasing the contact patch with the road and spreading the weight of the vehicle out a little more. There is a reason why NASCAR and indy cars have 12 to 15 wide tires. Just look at the tire sizes for new vettes and vipers. Now when it is raining this changes a little but I will get into that later.

 

I have always wondered why? Can you give us a short physics overview of rain and wide tires?

 

wider tires reduce slip angles.....

it is possible to go to wide... if you can't get a tire into it's optimal heat range, then you are basically carrying extra mass for nothing


how wide are you thinking about going?

in autocross, it is very common to see f-bodies with 315/35 hoosiers/kumhos that are very fast



"do wider tires up front help handling?" --

YES... i guarantee you will not see any competitive ESP f-bodies running stock size tires at Nationals



if you're asking about mismatching... like 315's in front and 275's in the rear.. well, i'd have to say that's just a way to tune a car to a driver's needs...

but it's a whole lot easier and cheeper to tune a driver to a car


don't mismatch... if you want bigger.. just go with bigger all the way around..... there are many other tuning adjustments that can be made

such as:
air pressure
rebound and compression adjustments
sway bars
spring rates

 

imagine being in a canoe...

you have your oar in hand....

the wide side of the oar offers a lot of water resistence when you stroke it through the water... so of course that's the end you're going to use to move around

now turn the oar over.... the handle of the oar offers much less water resistence when you stroke it through the water...



this relates to tires because using a wider tire is like using the big end of the oar... you get more water resistence and you can hydroplane easier

 

The wider your tires are the more of the vehicles weight is spread out over the contact patch. Meaning, that each squre unit of your tire is supporting a certian amount of load. The wider the tire the less load there is per unit area. Ice scaters have a really small contact patch on the ice with their skate, but that is because they are concentrating all of their weight onto a small area. This increases the contact load and actually melts the ice from friction. Now get on with tennis shoes and you slide all over the place because your weight is distributed over a larger contact area. There is not enough weight per unit ice to melt it and glide you along. Same goes for tires except you are not melting the road. The wider the tire the more water can build between the contact patch of your tire and road surface. You can support more of the vehicles weight with more water and hydroplane very easy. A narrower tire will not allow as much water between the contact patch because of its smaller contact area. Since the weight of the vehicle is now centered over a smaller area it can effectively push water away. tires do not need to be in their optimal heat range to produce grip. A tire whose compound is designed to soften and conform to the surface of the road will perform better when it is warm but that same tire will still produce grip when cold on any dry road surface. You are not just carrying mass.

True life example.
I was driving with 17x9's in my RS when I hydroplaned on an onramp going 30mph and slammed into a concrete divider.
I later that day drove in the same amount of rain the exact same spot to see what I hit and I was in a 2000 Impala that weighs more, has a higher center of gravity and whose tires are 1.5" less all around. I took the onramp 5mph faster and didn't slide one bit.

 

tire contstruction and air pressures being equal - the area of contact patch does NOT change, only the shape of the contact patch changes


so there isn't more or less weight per unit of area in the contact patch


IT'S ALL ABOUT THE SHAPE OF THE CONTACT PATCH

 

When you change the shape of the patch by adding more tire width you increase the total area which in turn distributes more of the vehicles weight. Now if you split the contact patch into a bunch of little patches and look at it that way than the area per patch does not change but the weight dissapation does. if you view the tire as having one unit of canotact patch than both area and weight distribution change as you add material. However, if you widen the tire by changing the shape of the origonal than your area stays the same. As soon as you add material by using a larger tire than everything changes.

 

this is a touchy subject, as rubber has some slightly diffrent properties than other matterals. i'll do a search here shortly, but i can't remeber if it was Karl Hunter, or someone else who really explained this in depth.

 

What is lacking in this conversation is tire width in relation to rim width. Fact: take a tire has a rim with range of 7-9". That tire will handle better on the 9" rim than it will on the 7" rim. Thus an 8" rim will handle better with a smaller tire than a larger tire.

 

SHIFTY, I know where you are coming from there if it helps. I understand what you are saying and I agree with the area concept. I guess we just have to understand that when it rains we need to take a little more caution than normal if we upgrade our tires.

 

No, You just need to get a tire that works great in wet or dry. Hence....

 

Tire compound and design aside you are correct. There are ways to overcome this though like AGood2.8 mentiong with tread design.

 

Who makes that tire?

 

i beleive that is the Goodyear.

http://www.tirerack.com/tires/tires....Eagle+F1+GS-D3

 

Yes it is a Goodyear F1 GS-D3. Sell for $145 each for 245/50-16's

Heres a comparison chart to Michilen Pilot's (Sell for $253!) And Brigstone Pole pos-03's that aren't made in a 245/50 16, only a 17" rim aplication for our cars.

Note: the wet traction ratings. Dry are just slightly less- wet blows them away by 1 full sec on a hot lap.

http://www.tirerack.com/tires/tests/...d3_charts.html

Edit/ also note: That test was done on a stock Lexus IS300 with lots of body roll and camber change. These goodyears will outperform the others on dry with a flatter contact patch. The other two tires have a stiffer sidewall and will perform better on just the edge of the tire. Goodyears design is better favored sitting flat because of the slip angle vs. tread pattern. Have the right camber specs (which that stock Lexus didn't) and they will grip better.