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Old 03-17-2018, 06:55 AM   #15 (permalink)
RedDevil
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Racing bicycle tires cannot be compared to car tires. The shape of the contact patch, pressure on the tire, profile, construction, cross section are all completely different.

So Flo Cycling claims racing bicycle tires (with a extremely long and narrow contact patch) would have less rolling resistance if the patch was shorter and wider.
Sorry, I disagree wholeheartedly.
While it may seem logical at first glance it ignores what's really happening when the tire moves.

The contact patch is not static. As the tire rotates it shifts, obviously.
Now imagine the difference after shifting one inch. There'd be a new C-shaped section on one side while on the other side such a section is removed.
The total surface of the new section is the distance traveled times the width of the patch. That's the amount of rubber getting into contact with tarmac.

If the contact patch shortens and widens (assuming identical load and pressure) the C shape for the same distance will have shorter ends but a wider body. The surface still is distance traveled times width of the patch; as the patch is now wider, that area is also bigger; more new rubber getting in touch with tarmac, while the pressure is still the same.
That seems to indicate more friction for the wider tires, not less.
Now this was a simplified model; there are many other variables at play like the flexilbility of the tire, angle of attack on the contact patch, friction in the patch as the rounded tire progresses, etc.

Yet the truth is easy to find by looking at the tires used by professional road bicycle race teams. They typically use the narrowest tires possible at very high pressure.

As I wrote it is very hard to compare bicycle and car tires as they are fundamentally different. Yet, also on cars a wider tire does mean the contact patch area delta (change over a small distance) is equally larger, and so would be the rolling resistance.

Narrow tires with relatively high sidewalls and high pressure rule economy runs.
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Last edited by RedDevil; 03-17-2018 at 07:02 AM..
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