Rolling resistance: Tyre diameter vs width...

[Rower4VT]

Contact patch is mostly dependent on tire pressure and vehicle weight. Doesn't sound like it could be completely true...but it is. There are websites out there that explain the math of it. Like a bicycle, taller, narrower, higher-pressure tires provide for lower rolling resistance.

Check out Continental Vanco tires. I think I'm getting a set of 195/70R15 to replace my 205/60R15. The Vanco tires are built for small delivery trucks and heavier vans. They handle higher pressure, have a stiff sidewall (better handling), and the tread is designed for lower rolling resistance. Some of the Vanco models I believe are rated at 65-70psi. Might give a bit rougher ride, but I bet you coast a lot further than you could before.

[theholycow]

Originally Posted by Rower4VT

Contact patch is mostly dependent on tire pressure and vehicle weight. Doesn't sound like it could be completely true...but it is. There are websites out there that explain the math of it. Like a bicycle, taller, narrower, higher-pressure tires provide for lower rolling resistance.

I've been saying that for years.

Unfortunately, it may be untrue. In the last week there have been experiments and measurements by one gassavers.org user that may show that it's wrong, and I found some reference material that says it's wrong too. If it is wrong, I can't say I understand why, but it is what it is.

Take a look at the links in my sig about tire pressure and tire width. It's all in those.

[CommodAnt]

Originally Posted by Rower4VT

Contact patch is mostly dependent on tire pressure and vehicle weight. Doesn't sound like it could be completely true...but it is. There are websites out there that explain the math of it. Like a bicycle, taller, narrower, higher-pressure tires provide for lower rolling resistance.

Check out Continental Vanco tires. I think I'm getting a set of 195/70R15 to replace my 205/60R15. The Vanco tires are built for small delivery trucks and heavier vans. They handle higher pressure, have a stiff sidewall (better handling), and the tread is designed for lower rolling resistance. Some of the Vanco models I believe are rated at 65-70psi. Might give a bit rougher ride, but I bet you coast a lot further than you could before.

I'm wondering if the stiffened sidewall = more weight. I read that shaving 1kg of each wheel was the equivalent to shaving 10kg off the entire car as far as accelleration is concerned.... I suppose that also applies to decelleration, so it might not be such a bad thing. 70psi will be one hell of a rough ride.