Wider tires, reality?

[involutions]

Lots of people say something like, "You need wider tires to handle all that extra power," when you add a supercharger.

This probably SEEMS obvious, but... have you, or someone you actually know personally, ever gone wider only, with all other factors the same? Most people go wider and stickier at the same time. Just going from the OEM Pirellis to Michelin PSS in the same size made a HUGE, HUGE difference for me.

My specific question is, do wider tires in the same brand, style, and diameter, at the same temperature, really give more STRAIGHT LINE traction?

Also, where is the point of diminishing returns? When does it become not worth it to go any wider? Will you get the same amount of extra traction going from 10" wide to 11" wide that you will get by going from 8" to 9"? How about going from 11" to 12" or 12" to 13"? You get the idea.

I am talking about tread with, not sidewall width. For example, some 295/35/19 tires have a wider tread than some 305/35/19 tires.

Many of us have also read that wider tires simply make a wider, but shorter, contact patch, meaning the actual patch surface area does not change. Others say even if the contact patch did get larger, since traction is a function of weight per units of area, you would only get more traction by adding weight, and the contact patch area won't matter. There is a tire reviewer on youtube who points out that wider tires offer better cooling when cornering hard during a race on a track, but I'm talking about straight line acceleration on the street without doing burnouts to warm the tire before flooring the pedal. Not many people actually do that in the real world. At least not where I live.

So, is there anyone here who has FIRST HAND experience going wider, all other factors being the same?

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[raptor17GT]

i'd suggest you answered your own question but did some quick digging and found the following links.

https://www.physlink.com/Education/AskExperts/ae200.cfm

https://www.tyrereviews.co.uk/Artic...ou-more-grip-225-vs-255-vs-285-wide-tyres.htm

https://www.roadandtrack.com/car-culture/buying-maintenance/a21776425/wider-tires-more-grip/

 

[involutions]

i'd suggest you answered your own question but did some quick digging and found the following links.

https://www.physlink.com/Education/AskExperts/ae200.cfm

https://www.tyrereviews.co.uk/Artic...ou-more-grip-225-vs-255-vs-285-wide-tyres.htm

https://www.roadandtrack.com/car-culture/buying-maintenance/a21776425/wider-tires-more-grip/

Thanks for the reply.

Yup, I found those, too. That's actually the Youtube reviewer I was referring to. He is reasonably scientific, and seems pretty thorough. But like he said in the video, the BMW used in the test didn't have enough power to really break the tires loose. He also affirmed what I was saying about just buying stickier tires.

Since that's about the only real-world information I could find, I was hoping someone with hands-on experience would have some anecdotal information to share.

 

[SDAMike]

Great questions. I am wondering the same thing. ie. are 285/35/19 tires enough for a boosted car if they are sticky tires. (The wheels I want only come in 9.5" wide so 285 is the max size from what I can tell)
If you find your answers, please post up!

 

[Andrew@Lethal]

Lots of people say something like, "You need wider tires to handle all that extra power," when you add a supercharger.

This probably SEEMS obvious, but... have you, or someone you actually know personally, ever gone wider only, with all other factors the same? Most people go wider and stickier at the same time. Just going from the OEM Pirellis to Michelin PSS in the same size made a HUGE, HUGE difference for me.

My specific question is, do wider tires in the same brand, style, and diameter, at the same temperature, really give more STRAIGHT LINE traction?

Also, where is the point of diminishing returns? When does it become not worth it to go any wider? Will you get the same amount of extra traction going from 10" wide to 11" wide that you will get by going from 8" to 9"? How about going from 11" to 12" or 12" to 13"? You get the idea.

I am talking about tread with, not sidewall width. For example, some 295/35/19 tires have a wider tread than some 305/35/19 tires.

Many of us have also read that wider tires simply make a wider, but shorter, contact patch, meaning the actual patch surface area does not change. Others say even if the contact patch did get larger, since traction is a function of weight per units of area, you would only get more traction by adding weight, and the contact patch area won't matter. There is a tire reviewer on youtube who points out that wider tires offer better cooling when cornering hard during a race on a track, but I'm talking about straight line acceleration on the street without doing burnouts to warm the tire before flooring the pedal. Not many people actually do that in the real world. At least not where I live.

So, is there anyone here who has FIRST HAND experience going wider, all other factors being the same?

More contact surface = more traction. I recommend running the widest tire you can fit on your car without crazy modification. Tire material plays a huge factor as well such as radials vs slicks.

 

[EFI]

Yes more tire/pavement contact will provide more traction, it's simple physics.

There is a point of diminishing returns, but that point is achieved when you can no longer overpower the tires easily. Unless you are running pure drag radials in the 345+ you won't get to that point.

So yes, it's worth it.

 

[ahl395]

Tire compound matters more than width, but once you choose the best compound width will help you from there.

Wider = more surface area contacting the road. Usually you have to run a bit lower air pressure as well though which is something alot of people forget.

 

[involutions]

First of all, thank you for all of the replies from everyone.

While I am not arguing that a larger contact patch would give more traction, simple physics actually does not support it.

Simple physics would state that with a larger contact patch, the amount of total friction would be the same, but would be reduced per square inch because, with the same weight, it's distributed over a larger area. Of course, simple physics also does not take into account the nooks and crannies in the pavement, and how the soft rubber fills them, causing more grip.

AND, when you take negative camber into consideration, the outer edge of the tire is not contacting the road with as much force as the inner edge, exacerbated the wider you go.

AND, a wider contact patch means a shorter contact patch.

I would argue (while reserving the right to be wrong) that a wider tire does not give a larger contact patch. Just a wider, shorter one of the same area. (Excluding obviously extreme examples.)

I am more convinced that a stickier of the same width has more traction than a wider tire of the same construction.

Which brings me back to my question...

Is there anyone here who has FIRST HAND experience going wider, all other factors being the same?

Thanks!

 

[Angrey]

it depends.

If it's street/track radials, you're not going to experience a noticeable difference in traction between a 305 and a 315 or even 325 on track radials (for launch or straight forward grip).

You WILL notice a much larger lateral grip improvement on track radials.

Now, if you're talking drags or drag radials, it IS a noticeable improvement in forward grip.

Speaking from experience, you're not going to experience a noticeable difference 305/30R19's to 325/30R19's. There's just not enough sidewall and the compound isn't soft enough to make a difference. You'll roll them over easily with both.

With a better wheel/tire setup (say 15" or 16") on DRs or slicks, the incremental width increases make a huge/noticeable difference.

 

[ahl395]

First of all, thank you for all of the replies from everyone.

While I am not arguing that a larger contact patch would give more traction, simple physics actually does not support it.

Simple physics would state that with a larger contact patch, the amount of total friction would be the same, but would be reduced per square inch because, with the same weight, it's distributed over a larger area. Of course, simple physics also does not take into account the nooks and crannies in the pavement, and how the soft rubber fills them, causing more grip.

AND, when you take negative camber into consideration, the outer edge of the tire is not contacting the road with as much force as the inner edge, exacerbated the wider you go.

AND, a wider contact patch means a shorter contact patch.

I would argue (while reserving the right to be wrong) that a wider tire does not give a larger contact patch. Just a wider, shorter one of the same area.

Which brings me back to my question...


Thanks!

The weight is distributed over a larger area, that's a good thing. There's still plenty of weight to hold the tire on the ground and make use of the wider contact patch.

I think you are overthinking it lol. If wider wasn't better, exotic and fast cars would come with 195s. Why do you think the GT500 comes with 315s and a base Ecoboost comes with 235s?

 

[involutions]

it depends.

If it's street/track radials, you're not going to experience a noticeable difference in traction between a 305 and a 315 or even 325 on track radials (for launch or straight forward grip).

You WILL notice a much larger lateral grip improvement on track radials.

Now, if you're talking drags or drag radials, it IS a noticeable improvement in forward grip.

Speaking from experience, you're not going to experience a noticeable difference 305/30R19's to 325/30R19's. There's just not enough sidewall and the compound isn't soft enough to make a difference. You'll roll them over easily with both.

With a better wheel/tire setup (say 15" or 16") on DRs or slicks, the incremental width increases make a huge/noticeable difference.

Thanks for the info. I guess I could narrow the focus of my question to sticky street tires, maybe what tirerack.com would call "extreme performance" and not drag tires.

 

[involutions]

The weight is distributed over a larger area, that's a good thing. There's still plenty of weight to hold the tire on the ground and make use of the wider contact patch.

I think you are overthinking it lol. If wider wasn't better, exotic and fast cars would come with 195s. Why do you think the GT500 comes with 315s and a base Ecoboost comes with 235s?

Overthinking it, probably.
And yes, I agree, at least to a reasonable point that wider is better. Obviously a 2" wide tire wouldn't work out well. But is going from a 275 to a 305 better than going from a Michelin PSS to a Bridgeston RE-71R, both in 275, for example?

 

[barkingspud]

I have 315/30 MPS4S on the back and have no traction when getting into it from just about any speed up to 50mph if I have TC off. Only tire that helps is my MT ET Street R's

 

[Angrey]

First of all, thank you for all of the replies from everyone.

While I am not arguing that a larger contact patch would give more traction, simple physics actually does not support it.

Simple physics would state that with a larger contact patch, the amount of total friction would be the same, but would be reduced per square inch because, with the same weight, it's distributed over a larger area. Of course, simple physics also does not take into account the nooks and crannies in the pavement, and how the soft rubber fills them, causing more grip.

AND, when you take negative camber into consideration, the outer edge of the tire is not contacting the road with as much force as the inner edge, exacerbated the wider you go.

AND, a wider contact patch means a shorter contact patch.

I would argue (while reserving the right to be wrong) that a wider tire does not give a larger contact patch. Just a wider, shorter one of the same area.

I am more convinced that a stickier of the same width has more traction than a wider tire of the same construction.

Which brings me back to my question...

Is there anyone here who has FIRST HAND experience going wider, all other factors being the same?

Thanks!

yes, see my response. Street radials aren't going to reward you very much (forward) with a wider tire and bigger patch. They will however make a noteworthy change in lateral grip. Anyone who's ever driven a car on pizza cutters and then got into a car on wide tires can notice the difference.

Overthinking it, probably.
And yes, I agree, at least to a reasonable point that wider is better. Obviously a 2" wide tire wouldn't work out well. But is going from a 275 to a 305 better than going from a Michelin PSS to a Bridgeston RE-71R, both in 275, for example?

let's also not forget that maximum friction force (for both static and dynamic friction) is dependent upon the "normal load" or weight binding the two surfaces. This is why weight transfer and suspension makes a huge difference. If you ca shift the entire 100% of a vehicles weight/downward force to the rear tires, the amount of friction force is considerably increased. If you're on a high performance track/turn suspension that does not transfer weight well, improvements to the tire setup are going to be nominal.

So once you've maxed out the practical width of the tire, sidewall of the tire (for flex) and compound of a tire, the logical next step is increasing the downward force.

I personally don't like driving a car where you tap the pedal and stair at the tops of buildings. There's plenty of suspension solutions out there that attempt to provide a somewhat changeable suspension setup/solution while trying to launch vs trying to keep a stable ass end going around turns. (changing the dampening, spring rates (or using bags) etc).

Lots of guys focus on tires, but at the end of the day, you can only do so much with the tire, it's really the suspension and weight transfer that has more pronounced effects once you've basically maxxed out what the tire can offer.

 

[involutions]

I have 315/30 MPS4S on the back and have no traction when getting into it from just about any speed up to 50mph if I have TC off. Only tire that helps is my MT ET Street R's

Good info. How much power does your car have?

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