I follow cycing and have never heard of this guy. I assume he broke the “athlete’s hour” using equipment like King Eddie used years ago. If so, then he had to use standard box shaped rims, etc.
The heavy wheel thing is very interesting. I wonder if it really helped or was simply a non factor. Obviously, if it did help then it would really only be applicable to velodromes or flat point to point time trials.
Actually I think a limited version of the same principle is used by some of the pro teams - you’ll have to search hard but on one of the cycling news stories about team DSC and their TdF wheels includes comments from Steve Hed about why some of the new wheels aren’t as light as they could be.
I think it was Sugino and others. I’ve got a Mavic Challenger rear disc wheel for the track, it is 2700 grams and nearly unridable it is so heavy.
This is very odd as rotating mass has to accelerate to rotate. I can’t beleive that conservation of rotational momentum overcomes the force required to accelerate it from an energy output point of view.
One of my best 40k TT’s was in the rain - on Shamals that had filled with I think a couple pounds of water. This was on a flat course and I just felt unstoppable…especially when I hit the brakes. I for one am certain that the extra weight in the wheels is what let me hold my speed so well.
I used to have a toy car with a fly wheel in it that I could send all the way down the hallway - the ones with plastic wheels never made it halfway. That’s about as far as I get.
I can see that being a bigger concern if there were repeated accelerations required, but–and correct me if I’m wrong–isn’t the Hour Record done on a flat point-to-point course? Thus, the energy expended for one acceleration (of say 1K) would be more than offset by the rotational momentum carried through the other 39K.
One of my best 40k TT’s was in the rain - on Shamals that had filled with I think a couple pounds of water. This was on a flat course and I just felt unstoppable…especially when I hit the brakes. I for one am certain that the extra weight in the wheels is what let me hold my speed so well.
This goes back to the thread and debate we had awhile back on efficiency. The heavy wheel reduces the actual speed variation with each pedal stroke which will improve the efficiency of the applied power. It may take an extra few seconds to get up to speed but this loss is insignificant if one is going slightly faster on the flat for an hour.
but then if this is done in a velodrome (it is, right?), wouldn’t there be hundreds of turns over the course of the TT? and isn’t a ‘change in direction’ what acceleration is? and wouldn’t accelerating a heavy wheel lots of times suck? i haven’t taken physics in a few years, and i’m torn over this. intuitively, a heavier wheel rolling better feels right and wrong. and i suppose we’ll now have to chuck in the 650 vs 700 debate as well?
accelleration is a change in velocity, which is a vector force, so there is a direction component to it. So yes, you would be changing velocity as you go round the velodrome even if speed is constant. I think the issue is that once you get the wheel spinning, you are not actually changing the velocity of the spin of the wheel much by turning the handlebars (or leaning into the turn).
Damn, I’m absolutely not a physicist, so I have no business even participating in this thread. when it comes to biking, I don’t know jack.
but then if this is done in a velodrome (it is, right?), wouldn’t there be hundreds of turns over the course of the TT? and isn’t a ‘change in direction’ what acceleration is? and wouldn’t accelerating a heavy wheel lots of times suck? i haven’t taken physics in a few years, and i’m torn over this. intuitively, a heavier wheel rolling better feels right and wrong. and i suppose we’ll now have to chuck in the 650 vs 700 debate as well?
-mike
Not sure of the physics of this as the change in direction acceleration is mitigated by the high bank of the track somewhat, I think. If it was a big deal, then the lighter wheel would be a big deal. Clearly it is not.
I think it was Sugino and others. I’ve got a Mavic Challenger rear disc wheel for the track, it is 2700 grams and nearly unridable it is so heavy.
This is very odd as rotating mass has to accelerate to rotate. I can’t beleive that conservation of rotational momentum overcomes the force required to accelerate it from an energy output point of view.
I wish I were smarter.
-SD
Rotating mass has to accelerate to change speeds, not merely to rotate. It takes no more or less energy to keep a heavier wheel rotating at a constant speed than it does a lighter wheel.
How is the flywheel effect a myth? Its physics - a heavier wheel will have a heavier moment of inertia (a phrase Ive never seen tossed around when discussing), and will be less resistant to stop spinning. All other things being equal, a heavier wheel will spin longer, and require less effort to maintain a higher speed.
I thought that’s why the weight of discs didnt matter - the aerodynamics are nice, but the moment of inertia over a long course helps too.