#31
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Quote:
http://flocycling.blogspot.com/2016/...ire-study.html In this study, they did wind tunnel tests using 20 different tires (some were the same model but in different widths) on one of their aerowheels, and also had rolling resistance tests done on the tires. They combined the aero drag with the rolling drag to come up with the overall best performing tire. If you take a look at their data, you'll see that tire rolling resistance was the biggest factor in wheel performance. The tire at the top of the list placed only 11th out of 20 on aerodrag, but was tied for 1st for rolling drag. Digging deeper into the data, some interesting things can be seen. The wind tunnel test was performed at a speed of 30 mph. At the yaw angles experienced most frequently by cyclists, the average drag experienced by the different tires varied between about 90 and 125 grams, which results in drag powers of about 12 - 16 Watts. The rolling resistance tests were performed at 35 kph (21.8 mph), and produced drags of between about 12 and 20 Watts. Scaling up the rolling resistance losses to 30 mph yields drag powers of between 16 and 27 Watts. So it can be clearly seen that even at 30 mph rolling resistance is greater than aero drag, and also that variations in rolling resistance between tires is greater than the variations of aero drag between tires. Since very few people spend a lot of time at 30+ mph, and because aerodynamic losses increase with the cube of speed (rolling resistance losses only increase linearly with speed), at the speeds most people ride rolling resistance losses will be proportionately even larger than aero losses than is shown in the test data. Flo Cycling designed their latest aerowheels around the 23mm Continental GP4000s (a natural choice as they had found that this tire was the most aero in a previous test of several tires). So it is not surprising that this tire had the lowest aerodynamic drag of all the tires in this test. But what they found in this new test is that not only did the GP4000s only place 4th when both aero and rolling losses were combined, but that the wider 25mm version of this tire was overall better, even though the wider version was not as well aerodynamically matched to the wheel. |
#32
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To get back to the OP's question
Tread is on the outside, so yes, it is mounted in the correct direction.
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#33
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[QUOTE=oldpotatoe;2296339]
Quote:
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#34
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This is how I've always thought about this issue:
If a tire has significant tread, and if you think that tread can help move water away from under the tire to the side, then you want the grooves to be pointed such that as the tire contact patch rotates the grooves allow the water to move outwards. That means that at the contact patch you would see a V as you look down (if you could see through the rim, and the bike is moving toward the top of the screen). If you imagine the tire rotating and the contact patch moving you'll see what I mean. You'll also see that a patch that is oriented such that the grooves look like this: ^ the water would tend to be driven toward the center of the tire, which is not what you want to have. Caveat: I'm not a tire manufacturer and don't really know if anything I've said above is correct, it just intuitively seems right to me. Last edited by Louis; 01-16-2018 at 10:09 PM. |
#35
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Quote:
With any tires, bike or car, the worst time to be on the streets is the during the first 10 minutes of a rain if it hasn't rained in awhile, especially light rain, the oil comes up off the road and layers on top of the water making it very slick. And of course as you all should know that painted and steel surfaces are very slick when wet regardless as to how long it's been raining. But don't get slick confused with hydroplaning. Hydroplaning with cars starts at 35 mph on average, wider tires it happens quicker which is why certain high performance cars suffer from hydroplaning before regular cars do, that and high performance tires are designed for ultimate traction on dry pavement and not wet pavement. Last edited by froze; 01-17-2018 at 04:49 AM. Reason: change |
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