Practicality of wider tires

[SuperTom]

Originally Posted by Aluma007

I've recently upgraded to 225/45/17 conti extreme contacts( similar to Pilot sports 4s) from 22k miles on stock primacies. Drove over 1000miles the day after they were mounted for a road trip and have driven around town on normal routes for about two weeks now. First thing i noticed...who moved my seat up? crank side handle down...nope. LOL! It raised the car up enough to throw off my perception...now I'm thinking I need some yellows. Second thing i noticed...who messed with my steering wheel? Feel has changed drastically. Its a little numb and has more weight to it. Feels like the wife's 2018 civic hatch with 18's (235/40/18). However, it has way more grip than it needs up front. Rear still shudders when I drive it from standstill, but it's much less than stocks and rear end doesn't break loose at any time now. very stable feel. Third thing I've noticed...car rolls over a little more than before on hard cornering. fourth thing...mpg's have dropped by about 2-3 (about 30-50miles less per tank) from what I could tell on a long trip I took vs same trip a couple months ago. Fifth thing...This particular tire has 7.6inches of tread and is mounted on an 8in wheel. side walls are almost vertical and look very good compared to the stocks which have an almost 45 degree stretch to its 7in tread on 8in wheels. Overall, I like the stability and the amazing comfort and quiet these tires provide, but I think a max performance tire is probably too much tire for these cars stock. I'll probably go either to an ultra high performance or keep the 215/45 next time...

That's because you went almost a half inch taller .4" with that size. If I ever go wide it will be 245/40/17 will keep the diameter ~the same

[RayRay88]

Originally Posted by 86 South Africa

Width and grip are not correlated when looking for outright performance.
This has been debated many times and proven over and over (there’s a few good YouTube videos explaining this somewhere).
Grip comes primarily from tyre compound. Wider tyres of similar compound will generally last longer, but will not do much to add grip when cornering etc.

Toyota has said many times the OE tyres where chosen for fun (and probably cost and longevity).

Most people seem to think wider = grippier for some reason, but I reckon the trend is more to do with looks. Particularly on street cars.

Grip in a straight line? Probably not. But a wider tire, of equal compound, will always give you more lateral grip, provided you can overcome any negatives associated with weight, drag and get them up to temperature.

[churchx]

RayRay88: except if on wet. Wider tire will always aquaplane at lower speeds due need to pump more litres of water out of way. And in winter or on gravel/mud, when skinnier tire has more chances to dig through to grippier surface due higher pressure per contact patch. For daily driven car (even more so - driven year round at any weather/season) i'd rise importance of wet grip by few notches.

[RayRay88]

Originally Posted by churchx

RayRay88: except if on wet. Wider tire will always aquaplane at lower speeds due need to pump more litres of water out of way. And in winter or on gravel/mud, when skinnier tire has more chances to dig through to grippier surface due higher pressure per contact patch. For daily driven car (even more so - driven year round at any weather/season) i'd rise importance of wet grip by few notches.

I agree 100%, its just that people confuse all the factors associated with tire size choices and just conclude that wider tires do not give you more lateral grip. That in it self is a false conclusion.

[Icecreamtruk]

People saying that for track usage, in the dry, wider tires do not give you more lateral grip (tire compound staying the same) are the reason shit spread. You either havent tested this yourself and are just spreading lies, or you tested it but are incapable of properly extracting the maximum potential of the car. Also, people assuming better lateral grip is always going to give you better lap times...

Im tired of all this ...

[86 South Africa]

Originally Posted by RayRay88

I agree 100%, its just that people confuse all the factors associated with tire size choices and just conclude that wider tires do not give you more lateral grip. That in it self is a false conclusion.

Sigh,

[chaoskaze]

Originally Posted by rvoll

So, while thinking about this thread, I'd like to present a definition:

https://www.urbandictionary.com/define.php?term=ricer

So what percent of "ricer" are you? I went up from 215's to 225's, so I'm probably 5% there.... I could argue that these are much better tires, which they are, but I could have put on 215's.... Oh, well.... Here's a proposed list:

Add an intake -- 10%
Add headers/exhaust -- 20%
Lower car -- 10%
Wide tires (235+) -- 15%
Expensive rims -- 20%
Big spoiler -- 15%
Stickers, etc -- 10%

Yes i went from 45% to a good 20% in the last 7 months

[Aluma007]

Originally Posted by SuperTom

That's because you went almost a half inch taller .4" with that size. If I ever go wide it will be 245/40/17 will keep the diameter ~the same

I knew it would, but didn't quite know how to quantify what it'd look like or what to expect as for the feel and other factors. There was a sale so I went for it. LOL. IF anything, I've been clearing bumps and driveways/inclines I'd scrape the stock bumper on even with the new HT autos lip I installed recently.
Roads are horrible around these parts so the extra height is nice in that respect. Just have to get used to the lifted eye level feeling...ugh. I miss the go kart eye level.

[RayRay88]

Originally Posted by 86 South Africa

Sigh,

That video is totally useless. It’s a bunch of stopping distances on a bunch of different cars with different tires and sizes. Sure he draws a lose correlation but it has nothing to do with lateral grip. A skinnier tire will give you more front to back grip hands down. Not arguing with that. See funny cars. But lateral grip is a different story.

[86 South Africa]

Originally Posted by RayRay88

That video is totally useless. It’s a bunch of stopping distances on a bunch of different cars with different tires and sizes. Sure he draws a lose correlation but it has nothing to do with lateral grip. A skinnier tire will give you more front to back grip hands down. Not arguing with that. See funny cars. But lateral grip is a different story.

Dude. I’m not gonna get into an internet argument with you. Google some stuff... I too used to think wider = more grip. Then I watched and read some stuff... educayshun teaches you to read good and about stuff. Do it.

[86 South Africa]

If anyone is really interested;

However a rubber type is a lot softer than metal, and a road is a lot rougher than a metal plate. Even at low loads the tyre deforms to key into the irregularities in the road, so increasing the load has a lesser effect. That's why you get the sub-linear dependance described in the Wikipedia article.

And anyway, if by "grip" you mean grip when cornering, the grip isn't just controlled by the contact patch area.
...the reason why wider tires are chosen is because they last longer than thin ones!


Italics cos it’s quoted from a couple of sources and not my original words.

https://en.m.wikipedia.org/wiki/Tyre_load_sensitivity

[Stang70Fastback]

Originally Posted by 86 South Africa

I too used to think wider = more grip. Then I watched and read some stuff... educayshun teaches you to read good and about stuff. Do it.

Wider DOES = more lateral grip (to a point) when you account for everything. It isn't as simple as arguing that the contact patch is the same. Otherwise people wouldn't be running wider tires in autocross events.

Also, Engineering Explained annoys the shit out of me. He does a great job of explaining some fundamentals, but his tests are never anything CLOSE to properly scientific. I wouldn't mind that so much if people understood this, but instead people treat his test results like gospel, whereas any proper researcher would LAUGH at the suggestion that his test results were truly accurate. It isn't his fault, as he doesn't have the resources to do a proper test, but that doesn't mean we should just ignore the fact that some of his tests are almost silly in how unscientific they are. They're just meant to be interesting tests that attempt to get some sort of standardized result, but they're FAR from accurate, and they are always hawked as the be-all, end-all of a debate.

The video you linked is a particularly egregious example.

[gtengr]

Originally Posted by 86 South Africa

I too used to think wider = more grip. Then I watched and read some stuff... educayshun teaches you to read good and about stuff. Do it.

Are you running 195's on 6.5" wheels or similar?

[RayRay88]

Originally Posted by 86 South Africa

If anyone is really interested;

However a rubber type is a lot softer than metal, and a road is a lot rougher than a metal plate. Even at low loads the tyre deforms to key into the irregularities in the road, so increasing the load has a lesser effect. That's why you get the sub-linear dependance described in the Wikipedia article.

And anyway, if by "grip" you mean grip when cornering, the grip isn't just controlled by the contact patch area.
...the reason why wider tires are chosen is because they last longer than thin ones!


Italics cos it’s quoted from a couple of sources and not my original words.

https://en.m.wikipedia.org/wiki/Tyre_load_sensitivity

It's not just about the tire load, it has much to do with the shape of the contact patch on a wider tire. A wider contact patch has more lateral stiffness than a narrow/tall contact patch during cornering.


Education and knowledge is infinite, it's up to you to decide not to stop once you have seen a poor youtube video.