How much difference weight makes?
 

Just wondering how much bike weight and rider weight (fat) affects speed uphills? saying physical condition, grade and length of the hill being equal.

Thanks..
knotty

The weight of the rider initially makes the biggest difference. If you're a 220 lb. guy like me, dropping 10 lbs. off my frame is a lot cheaper than dropping the same amount off my bike.

But even if you are less heavy, if you haven't developed your climbing legs, that's what'll make the most difference.

If you want to see the difference, go here and punch in the numbers:

http://www.kreuzotter.de/english/espeed.htm

You could hold wattage steady, or speed, and see how it affects the other when weight changes.

Heck, let's say bike equipment is "equal" as well. Pick a lengthy hill you are used to and ride it in a normal steady fashion you are used to. Note your speeds, time, effort, etc. In a couple day repeat that same hill with the same kit on except for an additional 10lbs of lead weights in one of your water bottles (an old no longer used one). Record all the data and compare for yourself. Of course it will be a somewhat imperfect experiment but it will be accurate enough to give you an answer... ;)

BTW - come back and share your finding when you are done!

In my experience, a 10lb. difference is big. A trip with panniers takes me about 15% longer than a trip without panniers along the same route.

Weight makes a large difference. My commute got quicker when I consolidated my stuff to a single pannier.

Thanks guys, I'm starting again from a long, 15 year layoff and hills are giving me an unusually hard time, I can make it but much slower and lower gearing, same bike.

Besides being older, I guess, the biggest difference is the body weight. I'm still 15-20 pounds heavier today, but losing it rapidly and already lost 50, about 11 inches off the waist!

I was confused because I read somewhere (forgot where) that weight just makes a slight difference. I must have read it wrong.

NoRacer, I'll try out the chart, thanks.

knotty

Feel free to come on over to the Clydesdale and Athena forum as well if you want to hang with us phatt cyclists. :)

Set rewards for yourself -- those new bars for losing 20lbs, new saddle for another 10, new wheels for the final 10 (or whatever your numbers). That way you can reduce the weight off yourself and your bike, and be happy with both.

Once the hill becomes steep enough (5%? 8%?), power to overcome gravity dominates. Speed is proportional to 1/weight and time is proportional to weight. So lose 10% of the weight, and you go 11% faster and take 90% as long.

Assuming the same amount of power (which for body weight may be a big assumption).

Most likely it's also fitness. You probably don't have the cardiovascular fitness you had 15-years ago. Your power-output is less as a result. And losing 50-lbs would've lost some muscle and power at the same time as well. On the hills, it really comes down to power-to-weight ratio.

I have to really thank all your inputs, it has put me on a reality check. I tend to get impatient and think I've been expecting too much too soon. (started riding again 2-1/2 months ago) My mental image was of 15-20 years ago when hills were fun to see who would make it up to the summit first. I have to come back down to earth and just put in my time just riding. But, buying that 20 pound road bike will not hurt either, LOL!

Thanks!..knotty

If someone is riding for the purpose of getting fitter, a heavy bike works better than a light bike. But, assuming that the wheels and tires are of equal weight and quality, the performance difference between a 19 pound bike and a 29 pound bike on typical roads is so small that it is difficult to measure.

Of course, if you were climbing a mountain that took an hour, those 10 extra pounds would be meaningful. There is a difference between pushing 200 pounds of rider and bike up a hill, compared with 210 pounds. But, if that rider is trying to get fitter, that extra work will help him get fitter even faster.

It's enormously important. I was off the bike for three months last year from a combination of work stuff, then a gall bladder operation. My conditioning had to go downhill in that period, but I also lost about 30 pound. When I got back on the bike, I was short of breath and sort of weak, as you'd expect--but my climbing was better than it's been in years. I was a full chainring higher on one 1.5-mile grunt near my house--from the granny and big cog to the middle ring and big cog.

It depends on where you're riding - on flat terrain the primary obstacle you have to overcome is wind resistance and weight has only minimal effect. But on hilly ground when speeds are often 12-mph or lower, wind resistance is minimal and weight is the primary factor.

I'm 25, and I must have skipped that stage. :D Hills were never fun.

I had a funny conversation with a couple of friends once. We were doing a ride, some hills were coming up, and they were all exciting about them, while I complained about how much I hate the bloody things. Then once we hit the hills I get way ahead of everybody and get to the top first. My friends (who haven't really ridden much with me before) were all surprised. "For someone who doesn't like hills, you sure fly up them!" And I said "Yeah... I hate them so much, I just want to get the bloody things over with fast!"

And it's true, too. Though I don't usually fly up hills anyway, cause it's too hard. I just wanted to show off. :)

Power to weight is what it is all about....that is what makes a good cyclist a great cyclist...

FWIW When talking about the weight difference of bike components (in grams) it is not uncommon to hear in non-racing circles that weight makes a slight difference. But larger weight differences (in pounds) makes for a bigger difference.

Marco Pantani once had a comment along the lines of "I climb fast to make my suffering end sooner".