Physics of Descending
03-24-15, 11:19 AM
#101
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Don't mistake physics for personal preferences. Heavier riders can play with their tires too, and deflated tires don't actually increase traction... it softens the suspension. Big difference. Traction is governed by normal force and surface material. Full stop.
A bigger rider is less affected by surface irregularities; that is simply a question of increased momentum. A bigger rider certainly can decrease tire pressure; they just have to go to larger tires.
A bigger rider is less affected by surface irregularities; that is simply a question of increased momentum. A bigger rider certainly can decrease tire pressure; they just have to go to larger tires.
03-24-15, 11:31 AM
#102
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Love it...
So now here is the second thought. If you make your ride in a loop and return to the same point how much of your ride is either up or down hill?
So now here is the second thought. If you make your ride in a loop and return to the same point how much of your ride is either up or down hill?
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03-24-15, 12:42 PM
#103
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Elevation gain/loss will be same, but a early short 25%section and a long gradual downhill I suspect would be faster going down the gradual. Time wise for the loop I mean. I dunno..
If there are no apexes in this story then it's no fun, so there.
If there are no apexes in this story then it's no fun, so there.
03-24-15, 12:46 PM
#104
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I'm sure tire choice would make a difference as well
03-24-15, 01:22 PM
#106
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03-24-15, 02:02 PM
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03-24-15, 02:40 PM
#109
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I have an orange bike....it goes down faster. That's a proven fact.
03-24-15, 05:33 PM
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Just a few weeks ago I had to do my Saturday morning ride alone, because my usual friends were busy doing yard work, and when I got to the top of one of my favorite hills (used to be able to call them climbs before San Francisco) and a ...big... guy had arrived at the top some time before. We both started descending together and I had to put my face in my stem bolts peddling at 100 cadence to keep up with him riding down with elbows locked on the tops looking around casually. He had stock alu wheels and I was sporting by Boyd 60s. My jersey fits nicely and his was on its way to a parachute.
I don't need equations to tell me that weight on the descent makes a substantial difference.
I don't need equations to tell me that weight on the descent makes a substantial difference.
03-24-15, 07:14 PM
#112
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Just a few weeks ago I had to do my Saturday morning ride alone, because my usual friends were busy doing yard work, and when I got to the top of one of my favorite hills (used to be able to call them climbs before San Francisco) and a ...big... guy had arrived at the top some time before. We both started descending together and I had to put my face in my stem bolts peddling at 100 cadence to keep up with him riding down with elbows locked on the tops looking around casually. He had stock alu wheels and I was sporting by Boyd 60s. My jersey fits nicely and his was on its way to a parachute.
I don't need equations to tell me that weight on the descent makes a substantial difference.
I don't need equations to tell me that weight on the descent makes a substantial difference.
03-24-15, 11:22 PM
#114
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Yeah, I dig the karma of the uphill. Sometimes though, I end up next to Very large guys at 50+ miles of riding and I am somehow only then passing them on the 4th big climb
03-25-15, 04:41 AM
#115
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03-25-15, 08:08 AM
#116
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Bicycle Quarterly did wind tunnel tests and at 22 mph going to full aero tuck with no pedaling and the knees tucked into the top tube created a 7 % reduction in drag coefficient. Meaning if your downhill will take you above 22 on coasting alone than don't waste a lot of time and energy spinning a high gear; get small and let mother earth pull you in.
03-25-15, 08:59 AM
#117
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Bicycle Quarterly did wind tunnel tests and at 22 mph going to full aero tuck with no pedaling and the knees tucked into the top tube created a 7 % reduction in drag coefficient. Meaning if your downhill will take you above 22 on coasting alone than don't waste a lot of time and energy spinning a high gear; get small and let mother earth pull you in.
03-25-15, 09:06 AM
#118
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Neither right nor wrong, just a perspective.
FWIW reducing wind drag by 7% at 22mph is worth about 1 more mph. Someone who can turn his cranks effectively should be able to do better than that. (if he wants)
FWIW reducing wind drag by 7% at 22mph is worth about 1 more mph. Someone who can turn his cranks effectively should be able to do better than that. (if he wants)
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An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.
03-25-15, 09:25 AM
#119
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Time trialing and optimizing power, it might be a waste to push your speed downhill. But that would imply that you're time trialing with a 22mph top end ...
Seems like a full tuck would be worth more than 7% drag.
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