Heavier cyclists are quicker up hill?

[ColinJ]

Sounds like not a bad deal to me.

That's what my cousin said!

Assuming that they could do three 15-minute massages in an hour, it sounds like a nice little earner to me.

 

[greenmark]

Isn't this about the duration of the climb? Who can generate the most power/weight only until the climb is over.

Heavy riders like Peter Sagan can generate loads of W/Kg for 10 minutes or so, which is why he wins punchy climbs. But he doesn't last much longer than that.
Light ones will like Romain Bardet win on very long sustained Alpine mountains.

BTW on the Bespoke podcast someone mentioned that the top GC contenders like Froome, Bardet and previous winners tend to have a very close weight to height ratio of 2lbs per inch.

 

[screenman]

That's what my cousin said!

Assuming that they could do three 15-minute massages in an hour, it sounds like a nice little earner to me.

There you go then, just need some customers, insurance, training and a few other overheads and you have a business. I doubt these guys make a fortune doing sports massages.

 

[scotjimland]

The up side to this is that they're definitely faster going down hill .

are you sure about that ?

Newtons Laws of Gravity would say otherwise.

Ignoring the effects of air resistance, two falling objects of a different mass fall at the the same speed

Only air resistance affects the speed..

So If they are heavier and therefore bigger, they will have more air resistance so will actually fall slower.. ?

That's my understanding anyway.

 

[Milkfloat]

are you sure about that ?

Newtons Laws of Gravity would say otherwise.

Ignoring the effects of air resistance, two falling objects of a different mass fall at the the same speed

Only air resistance affects the speed..

So If they are heavier and therefore bigger, they will have more air resistance so will actually fall slower.. ?

That's my understanding anyway.

The larger/heavier rider experiences less drag (wind resistance) in proportion to gravitational force and therefore goes faster.

However, if the heavy cyclist was significantly less aero than the light cyclist then the result could be different. Therefore, even Drago should try and get in a tuck.

 

[vickster]

I'm too delicate for that now, and can't afford it anyway. My cousin had a massage after his Tour de Yorkshire sportive ride yesterday - £15/15 minutes!

That's not bad, although 15 minutes isn't enough to do both legs properly. I paid £35 for 30 mins recently when my neck seized up after crazy long weeks of desk work!

 

[Salty seadog]

are you sure about that ?

Newtons Laws of Gravity would say otherwise.

Ignoring the effects of air resistance, two falling objects of a different mass fall at the the same speed

Only air resistance affects the speed..

So If they are heavier and therefore bigger, they will have more air resistance so will actually fall slower.. ?

That's my understanding anyway.

Newton's law is correct in a vacuum where there is zero air resistance. All other things being equal a heavier rider will be faster coasting downhill (excluding of course in a vacuum) as their greater mass has greater potential energy.

 

[scotjimland]

Newton's law is correct in a vacuum where there is zero air resistance. All other things being equal a heavier rider will be faster coasting downhill (excluding of course in a vacuum) as their greater mass has greater potential energy.

nonsense

 

[huwsparky]

But the 100kg rider may be capable of making twice the power. Or more. I'm 111kg, and I'm pretty sure I can crank out more power than a 55kg rider of otherwise comparable age, health and fitness, simply because I am able to support the musculature to do so.

I've never disputed that. A few pro cyclist come to mind that have been around the 90kg mark.

 

[Salty seadog]

nonsense

Perform the famous experiment in this clip in your garden . I'll be kind and just make it a sportsman's bet than the hammer hits the Earth first . This is Because the hammer has a higher mass and therefore a higher potential energy .



The only situation where the rider with the lower mass would be faster downhill would be if his area was so huge that the increase in air resistance produced was in excess of their gain in potential energy over the smaller rider.

This is unlikely without putting them through a mangle.

 

[Drago]

Fatties are unlikely to roll downhill much faster, unless their skinny counterparts are made of feathers. However, they are able to benefit from their greater interita, so all other things equal will roll further.

 

[Alan O]

I'd love to be able to believe that we fatties are faster uphill, but sadly I have the laws of physics and a lifetime of experience to shatter such illusions

 

[ColinJ]

I can assure you that big, heavy riders can go down steep hills faster than skinny, light riders (assuming simple descents with no braking required) ...

I had a laugh in Spain once. I was slogging my way up a long switch-backed climb and I looked down a few bends and saw a fit-looking cyclist racing up towards me. It turned out to be a young woman - very petite, and very fit. She slowed briefly as she passed me, smiled and said "Keep going it's only about 800 metres to the top!" then she shot off and left me for dead. I looked up the hill and saw her go over the top and begin her descent. A couple of minutes later I got up there and set off in pursuit. I went past her at 70 kph just before the bottom of the hill and then meandered along the flatter road at the bottom to give her a chance to catch up. When she came alongside me she was red-faced from her exertions. She told me that she'd been spinning out in her 53/13 and asked how I'd managed to catch her. She didn't believe me when I told her that I'd hardly had to pedal...

The basic reason is that the frontal (drag-producing) area of a rider increases much less quickly than (gravity-loving) mass with increasing size of rider.

An example to illustrate the phenomenon - a square-sided solid box with sides 1 metre long weighs 100 kg. If you double the lengths of the sides then each face would now be 4 square metres instead of 1 square metre, but the mass would now be 800 kg instead of 100. That's 8 times the accelerating force but only 4 times the drag-inducing area.

Going up a steep hill we can virtually ignore drag. A fit rider of mass 100 kg may very well not have 50% more power than a fit rider of mass 66.7 kg, in which case Ms/Mr Skinny has an advantage over Ms/Mr Big.

 

[Kajjal]

I can assure you that big, heavy riders can go down steep hills faster than skinny, light riders (assuming simple descents with no braking required) ...



The basic reason is that the frontal (drag-producing) area of a rider increases much less quickly than (gravity-loving) mass with increasing size of rider.

An example to illustrate the phenomenon - a square-sided solid box with sides 1 metre long weighs 100 kg. If you double the lengths of the sides then each face would now be 4 square metres instead of 1 square metre, but the mass would now be 800 kg instead of 100. That's 8 times the accelerating force but only 4 times the drag-inducing area.

Going up a steep hill we can virtually ignore drag. A fit rider of mass 100 kg may very well not have 50% more power than a fit rider of mass 66.7 kg, in which case Ms/Mr Skinny has an advantage over Ms/Mr Big.

Being a 100kg, 2m tall wind break , if you use real life figures as I am not 2m wide and tall, does being heavier still give me the advantage ?

My experience is I am much faster downhill on hydraulic disc brakes, compared to rim brakes which I appreciate is another difference.

 

[Kajjal]

If you want to get some theoretical values you can use this calculator. https://www.gribble.org/cycling/power_v_speed.html

If you put the weight of the rider in kg, and the gradient in the parameters box on the left, then enter a miniscule power in the box at the bottom (eg 0.001 watts) you'll get the terminal freewheeling velocity.

So ... accepting the defaults for everything except weight and frontal area and assuming a -7% gradient, and using riders of 50, 75 and 100kg, we now need to calculate their respective frontal areas. The calculator defaults 0.509 m^2 for the 75kg rider, so I''ve gone for .4 and .6 for the 50 and 100kg riders respectively (related to mass ^2/3)

And the results for the terminal freewheeling velocity are (according to the model and my dodgy frontal area calculations) ...
50kg area .4 ... 56 km/h
75 kg, area .509 ... 59 km/h
100 kg area .6 ... 61 km/h

Of course if the riders actually start pedalling or, heaven forbid, braking all bets are off.

As for me, I weigh just over 90kg and I descend all hills braking like hell. I went down Toy's Hill on Saturday (familiar to Kent residents). As I came to the crossroads below the village, cautiously looking out for people coming out of the side roads, a couple of blurs whizzed past, as some racing snakes zoomed down. There are huge signs warning cyclists to be cautious on that descent.

Thanks taking the time to reply, at 100kg I am faster downhill , but not uphill