Originally Posted by
cyccommute
Pick any speed you like. Yes, a bike that is pulse braked is going to go faster than one that where the brakes are dragged for any given road or slope. That’s the reason people drag their brakes…to keep the average speed lower than if they let gravity and air resistance determine the speed. It’s not an “unfair advantage” but a fact of the two approaches to braking.
Stop with the “magic blanket” stuff. I never said anything about some “magic blanket”. The rim that does not have friction applied to it has a higher heat outflow than the rim that is undergoing constant friction. No friction…i.e. no braking…results in more heat being pulled from the rim by air flow than if the rim is under constant friction. To use your (bad) analogy in the proper way, if you have a hose constantly running water into the top of your pool and draining water out of the bottom but not enough to drain away the water being added, the pool overflows. If you pulse water into the pool when it has emptied a bit, then don’t put water in until the level drops again, you don’t overflow the pool.
Just to be clear, the hose constantly running water into the top of the pool is analogous to dragging the brakes.
First, I misread your point. But, to be fair, you are misreading mine as well. If you are constantly braking to keep the speed at 35mph and not slowing for corners, the pulse brake scenario only needs to slow to that same 35 mph for a corner, so the heat input on the pulse braking isn’t that much greater than the constant braking scenario. The difference is that once the pulse braker slows, friction isn’t being applied. No friction means an overall rim temperature decrease.
On a long descent like the one you (partially described…no distance yet), I’d probably not touch brakes for a very long time. If anything, I’d probably be pushing the pedals to get to a maximum speed. Any speed control on my part would be minimal and/or relying on air resistance. My rims wouldn’t get hot because I wouldn’t be using the brakes at all. The pulsed braking strategy doesn’t lose meaning just because the road doesn’t have corners. If I had to stop or slow for some reason on that kind of downhill, I would still brake hard and then get off the brakes.
Your argument is simply absurd. No, a bike that is drag brake is NOT necessarily going slower than a bike that is pulse braking. A rider can drag as hard or lightly as they like, just as a rider and pulse as hard or lightly as they like. The rider is in control of the brake lever. The rider can do what their brain desires.
The entire premise of this discussion is that the cyclist with the HIGHER AVERAGE SPEED will reach the bottom of the descent with cooler rims, REGARDLESS of the differing approaches to timing the brake usage. From my very first post in this thread, many days ago, I've repeated this OVER AND OVER AGAIN. Have I somehow failed to communicate clearly? I say this in every post I write. How is this not getting through???
Let me lay it out again for the umpteenth time for you:
- The descent is a 10 mile downhill at a steep 20% slope. The run has many tight turns but the road surface is good.
- Rider 1 practices pulse braking. In the straights he maintains a natural terminal velocity of 60 mph. In the corners he slows to 40 mph to avoid crashing. At the bottom of the descent his computer shows an average speed of 50 mph.
- Rider 2 is a pro rider. He has pro technique and balls the size of watermelons. He is able to anal pucker bomb down the entire descent at the natural terminal velocity of 60 mph, never touching his brakes once. He is simply that good, he is a downhill God. However on this day he wishes to experiment with drag braking. He uses one pinky finger to drag his brakes the entire way down. At the bottom of the descent his computer shows an average speed of 59.5 mph. His one pinky drag braking slowed him down by 0.5 mph compared to no brakes at all.
- The wheel temperatures of both cyclists are now measured.
- Which cyclist has cooler rims? The pulse braker or the drag braker?
Please answer so we can put this debate to bed and end this discussion thread.