This time, they had their OWN test device. They built their own “treadmill like” device to measure the rolling resistance. No, they didn’t go to Conti this time.
The Schwalbe ZX’s now also use the (expensive) Vectran and improved a TON (both in RR & flat resistance) from their last test. The Specialized clincher Tony Martin flatted on twice? Yeah, similar RR than 4000S but zero flat resistance.
Edit: They used 100g butyl tubes for the test.
The GP TT (test winner) is around $46 on crc if you wanna get one.
The lighter bar on the top figure is the time until the tire flatted on a pulsating (dull) blade. The darker one is the force it took to drive a 5.5mm blade through it.
They also noted that because of their new test setup (which basically simulated real world road better than the previously used roll) the worse and good tires are closer together than before. Before they were around 20W better, now only around 10W.
I’m looing forward to trying a set of the Schwalbe Ultremo ZX tubeless. For my use, they look like the best combination of flat and rolling resistance.
"The lighter bar on the top figure is the time until the tire flatted on a pulsating (dull) blade. The darker one is the force it took to drive a 5.5mm blade through it. "
Second chart:
Rolling resistance. Dunno what the |----| part stands for… margin of error?
"The lighter bar on the top figure is the time until the tire flatted on a pulsating (dull) blade. The darker one is the force it took to drive a 5.5mm blade through it. "
Second chart:
Rolling resistance. Dunno what the |----| part stands for… margin of error?
Yeah, it’s some measure of the experimental/measurement error - without knowing exactly what the error bars are it’s hard to know what exactly to conclude. Is this the variation (max/min? 1 sigma?) in measurements from a single tyre, or some 95% confidence interval they got from sampling multiple tyres. I hope they measured several tyres for each model.
Also, I presume this is per tyre? So Conti TT is 2 + 2 = 4W better than my GP4000s? Hell, I’ll take 4W.
No sure where you have been getting data but the GP4000s hasn’t won RR in long time, if even ever. The Supersonic, Force, and GP4000rs have all done well though in their tests.
This time, they had their OWN test device. They built their own “treadmill like” device to measure the rolling resistance. No, they didn’t go to Conti this time.
…
They also noted that because of their new test setup (which basically simulated real world road better than the previously used roll) the worse and good tires are closer together than before. Before they were around 20W better, now only around 10W.
Well, duh (that’s directed at Tour, not you
When you measure Crr on a roller drum, the power required to deform the contact patch from the curved contact is higher than it would be from a flat surface at the same loading. Luckily, there are equations that allow one to easily equate a curved roller value to a “flat surface” value. That’s what I do when I measure on rollers. For example, the power required from a tire on a 4.5" diameter roller is ~5-6X what it would be for the same speed and loading on a flat surface.
That’s also why I call rollers “Crr amplifiers”
BTW, the VIttoria Diamante Radiale is an “interesting” tire. The supposed benefit of the “more radial” construction (it’s not a true radial) is potentially lower Crr. I got one of these tires and tested it on my rollers and the tread compound is VERY soft and the tire is a real dog. It’s also quite “squirrely” on the road. Fairly unsettling, in fact…
It would be interesting to see their treadmill setup. I wonder how they account for the extra drag from however they keep the surface “flat”? Sounds like they could’ve saved themselves some work and just used the roller-to-flat equations :-/
