Hard to hard to find tall skinny tires...

[CapriRacer]

Originally Posted by roflwaffle

Have you tested the donuts RR in order to see if there's a significant difference between them and a small LRR tire? Besides, at best you could pick up a few mpg at 70-75mph if you cut the rolling resistance in half compared to whatever is on there now. If you cut the drag coefficient in half like basjoos did, you'll gain 20+mpg at 70-75mph, and there won't be any worries about undesirable operation.

Based on what I know about tires, using donuts to improve fuel economy is futile. There is no attempt by the tire manufacturer to control RR - or wear or traction or ride or durability. It's all about cheap. They use substandard materials in these tires because they only need to go 50 miles at 50 mph.

You'd be further ahead (and a whole lot safer) selecting tires where the feature IS RR!

[roflwaffle]

We should sticky your post meng!

[rmay635703]

Originally Posted by CapriRacer

Based on what I know about tires, using donuts to improve fuel economy is futile. There is no attempt by the tire manufacturer to control RR - or wear or traction or ride or durability. It's all about cheap. They use substandard materials in these tires because they only need to go 50 miles at 50 mph.

You'd be further ahead (and a whole lot safer) selecting tires where the feature IS RR!

I have a very old set of 12" 125 donuts on the front of my C-car (used to be all 4 wheels), so long as the car is VERY light the tires wear OK but only have as much grip as a half worn summer tread. One tire on the c-car has a weight capacity of about 800lbs more than the entire car weighs.

Donuts do have a very low rolling resistance, at least mine do but that is because they are like driving on a hard rubber tire, the inside including under the tread is 3ply with nylon, with all the air let out the tire doesn't compress very far

[CapriRacer]

Originally Posted by rmay635703

.......Donuts do have a very low rolling resistance, at least mine do.........

The reason you have good RR is because you are only using 25% of the load carrying capacity. ANY tire has good rolling resistance at that level.

[Frank Lee]

There's an echo in here here here here...

[Christ]

You hear it too, eh? Eh? EH?