Best P185/60R15 for traction. LRR a plus.

[severous01]

hahaha...185's and traction...good one

the best thing you can do for traction is go wider.

there's also not a lot of that tire size out there in different brands and they're all going to be an economy tire cuz they're for economy cars only. toyota is the only company i can think of that runs that size...well, maybe that old geo metro with aluminum wheels did...idk...either way, step it up a size and you'll get a lot more options

[sbergman27]

Originally Posted by severous01

hahaha...185's and traction...good one

My other car, with its P155/80R12 tires, seems to grip better on the ice an snow than the Yaris does. I'm not kidding. (Stock was P145/80R12, but those have been hard to find for a very long time.)

Keeping to a simplified physics model, frictional force is independent of surface area. But stopping on snow is not a simple system from a physics viewpoint. Lots of stuff going on.

Still, even going to something like a P205/55R15 only adds about 10% width, which is going to correspond to a < 10% difference in traction, since friction is, after all, and in general, independent of surface area. I suspect that tread design and material figures in pretty prominently compared to the limited range of width. Good snow clearing, taking advantage of opportunities for mechanical lock (as opposed to friction), and improved coefficient of friction change the *rules* of the game, rather than just adding a limited amount of (more of the same) width.

What *are* the limits, keeping the overall diameter within about 3% of stock, and without any scraping, for the Yaris anyway? Could it handle P225/50R15? That and P205/55R15 are the only close matches I can see with a 15 inch wheel.

P195/60R15 seems to be the widest *common* size. A 5% difference in width. 2% difference in overall diameter.

-Steve

Edit: Keep in mind, too, that the situation may be different for wet, M+S, and dry conditions. Then again, for years people have been letting air out if their tires in the snow, and swearing by it, despite the fact that Goodyear's testing has clearly demonstrated that practice to *reduce* traction on snow and ice.

[127.0.0.1]

Originally Posted by severous01

hahaha...185's and traction...good one

the best thing you can do for traction is go wider.

there's also not a lot of that tire size out there in different brands and they're all going to be an economy tire cuz they're for economy cars only. toyota is the only company i can think of that runs that size...well, maybe that old geo metro with aluminum wheels did...idk...either way, step it up a size and you'll get a lot more options

no.

traction rating on a tire is: how does it stop in wet ?
for any given tire size, AA is the best category for wet stopping.

wider tires wreck the AA rating. it may help cornering but doesn't
help wet stopping. unless it is a rain tire or happens to also be rated AA

wider tires ruin mileage
---
OP, stick with what you originally guessed. that is the tire

[sbergman27]

Originally Posted by 127.0.0.1

OP, stick with what you originally guessed. that is the tire

The width and/or the Michelin Energy Saver A/S?

As it turns out, P185/60R15 is, indeed, a weird size. The closest Energy Saver is P195/60R15. A 5% increase in tread width, and 2% increase in diameter. I do 95%+ of my driving on the Interstate highway. So the 2% increase in effective gearing is probably a help, if anything. And at 65 - 75 mph, air resistance dominates, accounting for something like 75% of total resistance at 75. As opposed to city driving, which is a mixed bag, but with air resistance figuring in decidedly less prominently.

Rotating mass is also less of a factor on the highway.

Still, I'd like to stay close to stock. And since I use the GPS and Scanguage as my speedometers, the 2% variance in diameter should be no tribble at all.

-Steve

[dingbat]

Originally Posted by severous01

hahaha...185's and traction...good one

the best thing you can do for traction is go wider.

Depends entirely on the conditions. I used to auto-x a car of similar weight and design to the Yaris. I used 185's for the winter series races because anything wider would not come up to temp. on a car that size.

[RETRO]

Yoko Avid TRZ.

[SilverBack]

To be brutally honest, you're only gonna find econo tires in 185/60 size and nothing better. You need to move-up a size to sport tires for better results. I recommend Falken Ziex ZE-502 in 195/50 for your stock wheels (assuming it's for daily driving only). The treads are much more grippier on both wet and dry roads and at the same time the rubber is hard enough to last much longer.

I've been running those same Falkens but in 205/50 (wider than 195 because I also Auto-X) for the last 15K miles and I've never been more confident on the road. Right now the tread depth is unchanged minus the minor scuffing from Auto-X. Definitely worth it!