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Gargamel
Original Poster
5,313 posts
130 months
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Morning,
I am still being nagged by my failure to complete my commute to work in under an hour.
Extreme measures are required. I am presently 90kgs, or 14 stone, which is probably too many. When I was a runner I was around 12 st 10lbs or 80 kgs.
My question would be what is 10 kg costing me in time per hour ? assume an average speed of 20 mph.
Any rough guides ?
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davepoth
19,862 posts
68 months
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Depends if you are 90kgs of fat or muscle really.
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TonyHetherington
30,864 posts
119 months
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Weight doesn't effect top speed, don't forget, it only effects acceleration (ignoring the fact that you may be bigger when heavier). So it depends how much stopping and starting you're doing (and therefore how much accelerating from 0) that your weight will effect. I've recently lost 5.5kg simply by eating slightly less. Same foods, just not quite as big portions. And I started off at 76kg, so it's not like I was big. Try that, you may see your times tumble 
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okgo
20,721 posts
67 months
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"Numerous studies have been performed to show just how much weight effects a cyclist. Bicycling Magazine published the results of a study from James C. Martin, Ph.D., assistant professor in the department of exercise and sport science at the University of Utah. Using the calculations from a 160-lb. rider on a 5 kilometer, 7 percent grade, he concluded that for every 5 lbs. added to a rider, it would take him an additional 30 seconds to ascend a steep climb."
So you can see from that roughly what it might cost you up hill...However on the flat your weight is much less relevant. Which is why many TT riders can afford to be a bit bigger compared to road riders.
It will be more effort to get your weight moving each time, but when at speed, to hold the speed will be no different really.
How far is the commute?
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Uriel
3,178 posts
120 months
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Stick 10kg of books/weights/baked beans in a back pack for one commute and see how you find it. Imagine the reverse.
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davepoth
19,862 posts
68 months
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Surely air resistance comes into play here if you're really bulky?
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Gargamel
Original Poster
5,313 posts
130 months
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okgo said: How far is the commute? Commute is 21.3 milesone way - and around 600 ft ascending on the way in, about double that on the way home... So the effect on climbing speed is pretty significant. I should imagine the aero effect of the size of my (expensively acquired, beer gut) to be relatively small ?
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daz3210
5,000 posts
109 months
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Gargamel said: Commute is 21.3 milesone way - and around 600 ft ascending on the way in, about double that on the way home...
So the effect on climbing speed is pretty significant.
I should imagine the aero effect of the size of my (expensively acquired, beer gut) to be relatively small ? Could the beer gut have aero advantage? I mean a slab front as opposed to a nicely rounded front must be less aero.
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crisisjez
7,491 posts
74 months
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I would be very very happy to get that in under an hour.
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Gargamel
Original Poster
5,313 posts
130 months
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daz3210 said: Could the beer gut have aero advantage? I mean a slab front as opposed to a nicely rounded front must be less aero. I always assumed greater mass meant faster top end speed when descending
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okgo
20,721 posts
67 months
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How rural is the route? Many start stop points?
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daz3210
5,000 posts
109 months
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Gargamel said: daz3210 said: Could the beer gut have aero advantage? I mean a slab front as opposed to a nicely rounded front must be less aero. I always assumed greater mass meant faster top end speed when descending Nope, from what I remember from physics at school, mass has no bearing on acceleration due to gravity, only aerodynamics and drag affect this.
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dangerousB
509 posts
59 months
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Forget the minutiae - for one reason or another, you're basically not working hard enough (putting out enough power) to achieve your target.
What's your current limiting factor - your lungs or your legs?
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Justin Cyder
6,028 posts
18 months
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davepoth said: Surely air resistance comes into play here if you're really bulky? Boardman was on the Olympics the other night saying that 80% of a cyclist's effort was spent punching a hole through the air. I tend to believe Chris Boardman, I think he knows a thing or two about cycling.
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swerni
19,836 posts
79 months
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Justin Cyder said: davepoth said: Surely air resistance comes into play here if you're really bulky? Boardman was on the Olympics the other night saying that 80% of a cyclist's effort was spent punching a hole through the air. I tend to believe Chris Boardman, I think he knows a thing or two about cycling. pah, amateur 
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Gargamel
Original Poster
5,313 posts
130 months
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okgo said: How rural is the route? Many start stop points? No I am lucky in this respect, I live out in the surry hills not far from Hindhead, so commute into Woking on the back roads. Only four sets of Traffic lights (all in the last 500 yards) I stop timing at the railway bridge in Woking as I don't want to take big risks through town. Only two junctioned right turns - one in Elstead and one in Normandy I often cycle the whole thing without unclipping. My feelingis I lose the times on the climbs, I really burn the house down on the long straights into Woking (Normandy to Worplesden) There it is definitly legs - on the climbs it is lungs !
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deeen
4,068 posts
114 months
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Gargamel said: daz3210 said: Could the beer gut have aero advantage? I mean a slab front as opposed to a nicely rounded front must be less aero. I always assumed greater mass meant faster top end speed when descending Hammer and feather... Anyway weight has a slight EFFECT on top speed, because it AFFECTS the rolling resistance. I would think the effect on your climbs is far more relevant though. Look how much effort people go to knock 1kg off the weight of their bikes, never mind 10! I like the above idea of sticking 10kg in a ruacksack, and see how much time it adds to your route. Also as above, I would be very happy with 20 miles in an hour on the flat, never mind a hilly route!
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Gargamel
Original Poster
5,313 posts
130 months
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daz3210 said: Nope, from what I remember from physics at school, mass has no bearing on acceleration due to gravity, only aerodynamics and drag affect this. Sorry I missed my from the end - yes I know it doesn't really. Speed is often confused with energy.
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okgo
20,721 posts
67 months
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What boardman said it right. But at these speeds c/da (drag) is not such an issue. And 10kg won't change your body shape that vastly really, especially not if its all in your belly.
Hmm, should be possible? Would you mind posting the route? I used to live in Tilford, and would be interested to see which way you go. Very lucky to ride around there, bugger all traffic and a great mix of terrain.
As dangerous said, its likely that you just need to improve fitness and power.
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swerni
19,836 posts
79 months
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okgo said: What boardman said it right. But at these speeds c/da (drag) is not such an issue. And 10kg won't change your body shape that vastly really, especially not if its all in your belly.
Hmm, should be possible? Would you mind posting the route? I used to live in Tilford, and would be interested to see which way you go. Very lucky to ride around there, bugger all traffic and a great mix of terrain.
As dangerous said, its likely that you just need to improve fitness and power. You used to be a fat knacker, you're much faster now you've lost weight
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