Gentleman Cyclist
Guest
Bicycle weight seems to be something of an obsession on this forum and I have to wonder if everyone has taken leave of their senses? I realise this subject has been probably been done to death, but here goes my ten penneth……
Many of your less charitable contributors to these posts make it clear that to be with the "In-crowd" you must have the very lightest bicycle and do everything you possibly can to make your bike light. If you don't, not only is the bicycle you ride suspect.... but you must be a fool also.
In the world of Cycle Chat Light = Good; Heavy = bad. I should know dear readers for I ride a Pashley (and by God I love it!) and the distain of some for that small admission needs to be seen to be believed…..the bike and yours truly, weighing in at 100kgs (so please spare me the tourette's like blurtings…there’s good chaps!) In any case, at the risk of bringing down a storm of choice remarks I thought I’d dare to actually prop up my argument over weight with evidence.
First of all let me make it clear, weight is important. If it weren't, we would all be enjoying pleasant 200mile rides on 100kilo road bikes equipped with arm chairs and small car tyres. So despite the title, I accept that we should all ride modern, well-made, well equipped bikes.
BUT!......In truth what we are debating here is nothing more than just a few kilos. Bikes range from “commuter bikes” like my all-steel Pashley, to a super-light barely strong enough to negotiate a pot hole single speeder. In truth given the usual rider and bike combination giving a combined weight of say 82 kilos the difference in performance between bikes of differing weight may surprise you.
James C. Martin, Ph.D. an assistant professor of exercise and sport science at the University of Utah provides some interesting calculations that makes the issues of weight very clear.
He took a 5 kilometer hill of 7% grade as an example which is a good stiff climb (the legendary Stelvio climb averages 7.5%). He further assumed a 73kg rider who can produce 250 watts on a 10 kg bike. Given those circumstances it would take 19 minutes and 21 seconds for the rider to get up the hill. Now comes the interesting bit. For every 2kgs added the trip up the hill would take 30 seconds longer. So even on my Pashley on a really tough climb it would only take 22 minutes and 21seconds (a mere 3 minutes longer)
That means that even on a heavy old clunker like mine, I’d only be three minutes late for the jolly picnic at the top of the 20 minute climb. Just in time for the weight watchers to get the sandwiches and tea out!
The performance advantage of a light bike is clearest when the hill is steepest. When the road flattens out, those 30 seconds per kilo grow smaller and smaller and make no real difference on the level because as the speed of the bike increases, the greater resistance comes from the wind, tire rolling resistance, bearing drag, clothing….. less and less on the weight (on a downhill stretch it’s a slight advantage to have a heavier bike).
Variations in body weight being much greater make a much bigger difference. If that same 73kg, 250 watt rider on the same bike as in the first instance were to be 100kgs he would reach the top 6 minutes and 10 seconds later……..that is 3 minutes after me on the jolly old Pash….and I’d then have to ask my butler to have the “Bolly” chilled!
So don’t stress about bike weight my dear velocipedal chums…….lose weight off yourself!
Bottoms up!...heads down!
Many of your less charitable contributors to these posts make it clear that to be with the "In-crowd" you must have the very lightest bicycle and do everything you possibly can to make your bike light. If you don't, not only is the bicycle you ride suspect.... but you must be a fool also.
In the world of Cycle Chat Light = Good; Heavy = bad. I should know dear readers for I ride a Pashley (and by God I love it!) and the distain of some for that small admission needs to be seen to be believed…..the bike and yours truly, weighing in at 100kgs (so please spare me the tourette's like blurtings…there’s good chaps!) In any case, at the risk of bringing down a storm of choice remarks I thought I’d dare to actually prop up my argument over weight with evidence.
First of all let me make it clear, weight is important. If it weren't, we would all be enjoying pleasant 200mile rides on 100kilo road bikes equipped with arm chairs and small car tyres. So despite the title, I accept that we should all ride modern, well-made, well equipped bikes.
BUT!......In truth what we are debating here is nothing more than just a few kilos. Bikes range from “commuter bikes” like my all-steel Pashley, to a super-light barely strong enough to negotiate a pot hole single speeder. In truth given the usual rider and bike combination giving a combined weight of say 82 kilos the difference in performance between bikes of differing weight may surprise you.
James C. Martin, Ph.D. an assistant professor of exercise and sport science at the University of Utah provides some interesting calculations that makes the issues of weight very clear.
He took a 5 kilometer hill of 7% grade as an example which is a good stiff climb (the legendary Stelvio climb averages 7.5%). He further assumed a 73kg rider who can produce 250 watts on a 10 kg bike. Given those circumstances it would take 19 minutes and 21 seconds for the rider to get up the hill. Now comes the interesting bit. For every 2kgs added the trip up the hill would take 30 seconds longer. So even on my Pashley on a really tough climb it would only take 22 minutes and 21seconds (a mere 3 minutes longer)
That means that even on a heavy old clunker like mine, I’d only be three minutes late for the jolly picnic at the top of the 20 minute climb. Just in time for the weight watchers to get the sandwiches and tea out!
The performance advantage of a light bike is clearest when the hill is steepest. When the road flattens out, those 30 seconds per kilo grow smaller and smaller and make no real difference on the level because as the speed of the bike increases, the greater resistance comes from the wind, tire rolling resistance, bearing drag, clothing….. less and less on the weight (on a downhill stretch it’s a slight advantage to have a heavier bike).
Variations in body weight being much greater make a much bigger difference. If that same 73kg, 250 watt rider on the same bike as in the first instance were to be 100kgs he would reach the top 6 minutes and 10 seconds later……..that is 3 minutes after me on the jolly old Pash….and I’d then have to ask my butler to have the “Bolly” chilled!
So don’t stress about bike weight my dear velocipedal chums…….lose weight off yourself!
Bottoms up!...heads down!
