street tire traction question

[Allforspeed]

TRUE STREET TIRES, which one will hook up better, 17 inch 245/45 or a 15 inch 235/60,


does the increased sidewall of the 15 inch tire overcome the width advantage of the 17 inch tire? i'm talking comparable true street tires, no DR's, at the strip, maybe some of your 60ft times on street tires would be cool

 

[super302]

15's will hook alot better than 17's

 

[Allforspeed]

so this holds true even for non slick street tires? i'm asking because it seems like dudes on 225/60 15's pull sub 2 second 60 foot times occasionally but i always hear that a wider tire will give better traction?! what 60 foot times have you put down on street tires and what size were they?

 

[Allforspeed]

i also just got a set of 17X9 cobra rims with tires for virtually free and am wondring if i should keep my 15's or if the 17's will offer more traction on street tires?

 

[super302]

are you really worried about traction or looks???

I would keep the 17's and throw on some nitto 555r's

the width is a factor, but not as big of a factor as many people think

a 245/45/17 will grip the same(if not better) than a 315/30/17

The sidewall has alot to do with it, along with the compound of the tire

 

[25thmustang]

Well I ran 245/45/17s at the track, and ran 2.0 60's all day. This was my first track experience on radials with a stick, and it went alright. The guys with the 15" tires (although they only had one pass on them) were stuck in the 2.1s+!

Its more about the compound than the width when comparing similar sizes!

 

[ramjetlx]

Im also running 245/45/17's and my 60 foot is a constant 2.0. My tires are Potenza S03's, but I have to heat them up before a run to get them sticky. And I also have a drag bag in the right rear spring set at 35psi. Thats seems to give me the most consistent 60 foots....

 

[deadlast]

small thread jack, but whats the widest, tallest tire you can put on an 18x9?

 

[super302]

small thread jack, but whats the widest, tallest tire you can put on an 18x9?

on a 9inch i wouldn't go wider than 275, height-i would go about 35/40....any more than 40 and it will look really tall

 

[Allforspeed]

i'm not really concerned with looks, the car is already kind of ugly was just wondering if either would make a noticable difference in traction, but it seems like they are pretty much the same with maybe the edge going to the 17X9's so i guess i'll put on the cobras!

 

[fiveohGT]

15s prob weigh less though

 

[85_SS_302_Coupe]

This is a sidewall issue. 17 inch tires have stiffer sidewalls as opposed to a 15 inch tire. Just like slicks, a street tire will wrinkle on launch, even if it's so little that you can't see it. 17s have little if any sidewall wrinkle, and break lose easier than a 15. In the end though, some practice and a decent street tire would pretty much level the playing field between the two.

 

[90mustangGT]

I went from 225/60R15 on 15x7 turbines to 275/40R17 Futura Ultra Z's on 17x9 Cobra R wheels. I was expecting to hook, considering they looked twice as wide in the back, nope, my street traction was about the same and worse at the track. Couldn't do much better at the track even with Nitto DR's. I would have swapped back to the turbines if they weren't so ugly. Today I traded my Cobra R's with DR's for a set of Welds even with standard radials.

 

[Michael Yount]

Too many variables to come up with just one answer - compound, wheel width, sidewall stiffness/speed rating of the tires, etc. One of the biggest issues that only one person has mentioned is the relative weight. The 17" combo will usually weigh significantly more - and it takes power to turn that additional weight. All else equal, the car on 15's will accelerate more quickly....simple physics.

 

[90mustangGT]

Too many variables to come up with just one answer - compound, wheel width, sidewall stiffness/speed rating of the tires, etc. One of the biggest issues that only one person has mentioned is the relative weight. The 17" combo will weigh significantly more - and it takes power to turn that additional weight. All else equal, the car on 15's will accelerate more quickly....simple physics.

Good point Michael but have you picked up a set of old-school centerlines latley? A buddy of mine had some and they were really heavy. I belive they were crome plated thick steel wheels.

I traded my Cobra R's for welds and wow what a weight difference.

 

[Michael Yount]

90Mustang - I was simply trying to point out that the 15" packages have the potential to weight significantly less; no doubt there are 'tank' 15 inchers too....so I editted to say the 17" will USUALLY weigh more. Thanks.

The same is true on the 17" end - lighter and heavier stuff is out there.

But if you seek light weight in either size, you'll accelerate, turn, stop more quickly. And there's lighter stuff available in the 15" and even 16" sizes than there are in the 17" size.

 

[90mustangGT]

90Mustang - I was simply trying to point out that the 15" packages have the potential to weight significantly less; no doubt there are 'tank' 15 inchers too....so I editted to say the 17" will USUALLY weigh more. Thanks.

The same is true on the 17" end - lighter and heavier stuff is out there.

But if you seek light weight in either size, you'll accelerate, turn, stop more quickly. And there's lighter stuff available in the 15" and even 16" sizes than there are in the 17" size.

I was just messin' with you, I knew that's what you meant, usually a 17 weights much more than a 15.

 

[crazypete]

Here's something I've always wondered on this issue:

Shouldnt taller tires (distance from ground to top of tires) make the car accelerate better since you now have a greater velocity at the contact patch due to the larger radius of the wheel? You get more distance for the same amount of tire revolutions.

 

[Biggeley]

Here's something I've always wondered on this issue:

Shouldnt taller tires (distance from ground to top of tires) make the car accelerate better since you now have a greater velocity at the contact patch due to the larger radius of the wheel? You get more distance for the same amount of tire revolutions.

A larger radius tire is going to change your effective gear ratio - less turns at the wheel per turns of the driveshaft. That may or may not make the car accelerate better, depending on whether or not it is beneficial to your setup to have less effective gear ratio.

Tire diameter makes a big difference in the effective gear ratio department.. Loosely calculated.. It's something like this:

Starting with 26" tire and 4.10 gear
27" tire -- effective gear ratio becomes ~ 3.90
28" tire -- effective gear ratio becomes ~ 3.73

 

[Michael Yount]

Pete - as Biggeley says, it's exactly the OPPOSITE effect from what you've stated. A taller tire is like putting less gear in; a shorter tire is like putting more gear in -- assuming traction characteristics of the two tires are the same.

So, with traction, you'll generally accelerate LESS quickly with a taller tire.