Originally Posted by
gauvins
Interesting data. Not clear how it translates to 50mm@50psi, though. The break points in their data occurs at much higher pressures, where the tire cannot absorb bumps in the road.
I may try to experiment this fall. Long path which is a mix of excellent tarmac and gravel. If I can get my power meter to work again, I'll report.
Keep in mind that the tire used in their test is 25mm. The break point applies to all tires but the pressure at which the break point occurs differs between widths. A 50mm tire at 50 psi is going to be some seriously rough riding. I think I had my 40mm tires at 50psi fully loaded on tarmac and I'm no featherweight. On gravel I went a lot lower.
Originally Posted by
Tourist in MSN
Thanks for the link. Interesting. But, they were clearly riding rock hard tires to get to the point where increasing pressure increases effective resistance. Riding an unladen bike (not touring weight), I do not think I ever get over 80 psi, I do 80 psi on the rear wheel of my road bike with 28mm tires, wider tires get less.
I did the super hard tires thing decades ago with tubular tires, but I can't remember when the last time was that I rode such tires. I am sure it is over two decades ago.
What I find to be the most interesting data point was the roughened concrete curve. It's clear that with 25mm tires there really isn't a pressure where you'd even get below the break point before you arrive at pinch flat territory.
It would be interesting to see that same test with wider tires etc. Even the lowest rolling resistances they got weren't actually that low. You'd expect a much better result from a GP4000 than 43W.