Bridgestone Announces Large Diameter Narrow Tires

[NeilBlanchard]

This is pretty cool!

News | Corporate | Bridgestone Corporation


Large & Narrow Concept tire
(Tire size: 155/55R19)

[niky]

You'd need some special rims to run that, wouldn't you? Most 19" wheels I know are around 8-9" wide. That tire comes out to about 6" wide. That gives you some sidewall stretch. Don't know if it's too much or okay, but I would think you'd need to use rims 7" or narrower with these tires.

Love the idea, though.

[Frank Lee]

Kind of like back to the future... like classic VW tires, and most anything '40s and older...

[redpoint5]

Interesting. The added benefit of the larger diameter and narrow width is 8% better traction in wet conditions. I wonder how the dry performance compares.

In science class they always teach that contact area doesn't influence grip or friction because the higher weight on the smaller contact patch equals out the equation. Why doesn't this work in practice? Race cars have enormous wheels.

[Frank Lee]

They need more rubber to dissipate heat.

[t vago]

Originally Posted by redpoint5

In science class they always teach that contact area doesn't influence grip or friction because the higher weight on the smaller contact patch equals out the equation. Why doesn't this work in practice? Race cars have enormous wheels.

Science class does not take into account the property of materials used in the grip/friction model. Rubber has a finite static coefficient of friction, and the smaller the surface area of rubber presented to the asphalt, the more likely it will be that the motive force spinning the wheels will overcome the static friction presented between the rubber and the asphalt.

(With wheels that are rolling on a surface, there is always a patch of static friction contact between the wheel and the surface, even if the wheel is moving - that is said to be traction. Overcome that static friction, and the wheel starts to spin freely against the surface - or it loses its traction.)

I'd like to be able to find some wheels to fit these kind of tires.

[niky]

It's heat. No matter how big your tires, the contact patch for the same pressure is exactly the same size. Narrower tires, however, have a long patch, which causes more carcass deformation than a wide patch, which causes more heat build-up.

Something Bridgestone touched upon in the press release. I guess they're getting around it with stronger sidewalls and higher pressures, which makes for a smaller contact patch.

The wet weather grip is no surprise. Wider tires hydroplane more than regular ones, and narrow tires tend to hydroplane less.

[sheepdog 44]

If you had some light weight rims, they'd be perfect for lowering highway rpm and getting better mpg. Which is hard to do with any currently available tire because they'd have both a higher rolling resistance and weight.

[Frank Lee]

No matter how big your tires, the contact patch for the same pressure is exactly the same size.

That's a popular but incorrect notion.

[niky]

Close enough for government work, as long as the tires are of the same type, construction and height.