Are there any benefits from having wider tyres other than the reduced wear and degradation rate?

Given tyre pressure is constant, the contact patch shape will change if a wider tyre is used, but with an identical surface area. Does that really have much effect?


[Modified by ckkl, 2:53 AM 2/4/2003]

 

I learned wider is better

But a hooser 205 might be different in width than a kumho 205

Wider tires will provide a wider contact patch, and allow you more traction for road racing, autocross applications. It also depends on rim width too,

Im far from an expert, someone else might say different than I

 

Quick reply!

Yeah, tyre compound definitely plays a huge role, but I'm trying to see the logic in it so let's assume the identical compound on a slick tyre (so that the tyre tread pattern doesn't come into play). Both running the same pressure, same overall rotational circumference, comparing tyre A with tyre B, where B has a wider tread...

Why is a wider contact patch better? (Remebering that the contact patch size is identical.)

I know a wider tyre is bad in standing water --> increased risk of aquaplaning.

 

Think of it likes this:

Wider tire (contact patch):

[======]

Narrower tire (contact patch):

[===]
[===]

Now moving left to right on your screen, which do you think will grip better? I may be wrong, I'm certainly no expert on this subject.

 

tire size is generally restricted by wheel width, allowable modifications to the car, and spacing under the wheel well. But generally, you will want to run the widest tire you can fit on the rim/under the car.

 

So your saying the contact patch actuallys shortens with the use of a wider tire?

 

To answer the original question, assuming your suspension can accomodate it, more rubber on the ground produces more friction. More friction = more grip. More grip = go faster.
-Adam

 

Re-read the post...

 

Why wouldn't the wider tire look like this:

[======]
[======]

or are you just assuming it decreases in the other direction. I have no idea how the contact patch is altered but i don't think it'd decrease because of a wider tire.

 

I dont think RJ works, he's on here to answer all our questions 24 7


But wider is better, does 8 inches stick better than 7 inches of contact?? yep, u bet it does... Remember those tires are your key to speed and staying on the road. the more there, the better, just dont go overboard.

Now if i could only fit 225's on my teg.... hmmm

 

You can. 15x7 wheels +38mm offset, spacers as necessary. Karl and Scott ran 225/45/15 hoosiers all last year (quite fast i might add).

 

It's a slip angle thing. I'm sure Scott (RR98ITR) can explain further. He's very, very good at that.

While that is a true statement, a wider tire does not increase the total area of the contact patch vs a narrow tire.

 

Ahhhh this sounds interesting! I hope Scott turns up soon...

 

pick up the book on race car vehicle dynamics written by Milliken...

http://www.amazon.com/exec/obidos/AS...855011-3901421

 

HMMMMM
Does hoosier make an STS legal tire??????

I was going to run 205 50 r15 azenis on some 15x7 wheels 35mm off(moded to 38mm)

hmmm Got me thinking.....

 

nope, but for STS you're better off with falkens, bfg KD's, kuhmo MX/712's, etc, etc...

and a 205 falken is very wide for its size, not sure about the others (if they are sold in 225/45's even). Besides, the falkens are cheap too.

 

Read the rulebook... this question and others just like it have been asked like a bazillion million times. STS requires a treadwear rating of 140 or more. Hoosiers are around 0 (read: zero.)
-Adam

 

Yea i know, 225 is the widest and 7.5 rims for my class, Got the rules just triing to deceide on a rim/tire combo.

205 falken azenis is where Im goin

 

Because a contact patch's overall size depends on the weight of the vehicle and the pressure of the tires. The narrower and wider tires will both have the same overall area of contact patch (in my example it is 6 equal signs.


[Modified by JMU1337v0.2, 12:57 PM 2/3/2003]

 

but if you use the same vehicle, weight, and tire pressure, and you fit a larger tire.....

 

This is what I'm thinkin too.. I would believe that because of the pliability of the tire then the actual contact patch itself would increase in size. At least a little. ??

 

Yup that's what I used to think too -- make the tyre one inch wider and you get an extra inch added to the dimensions of the contact patch.

The tyre increases an inch in width but if you run the same pressure, you have to pump more air into the tyre, since it has larger volume. If it reaches the same pressure as the narrow tyre, the contact patch will be the same surface area.

Another way to think about it:

Tyre pressure is measured in PSI which is obviously pounds per square inch. So a 2000lb car with 200PSI total tyre pressure (i.e. 50PSI per tyre) would have a total contact patch area of 10 square inches (i.e. 2.5 square inches is the contact patch of each tyre).

i.e. 2000lb car = 200PSI pressure in the tyres x 10 square inches of contact patch

The actual width of the tyres only affects the shape of the contact patch.

My question is: what is the benefit of the wider shaped contact patch, which you get from running wide tyres? (There's definitely benefit!)

Someone mentioned slip angles, which I have no idea about and I'd like to know more...

 

the force pushing down on the tire (vehicle weight) and the force resisting it (tire pressure) remain constant, therefore the contact patch would have the same area. however it would be wider and as such the contact patch would become wider and shorter, but with the same area. now, with the wider tire, you could possibly lower the tire pressure which would increase the contact patch area. thus you get monster trucks with wicked huge tires, low tire pressures and huge contact patches.

nate

 

I always thought it was the stiff sidewalls that allow you to run a low pressure without the rubber flexing and wanting to peel off the rim. Does the tyre width also play a part?

 

if you have more area to spread the weight over you don't need as high of a force.

nate