What is easier?
 

Which bike is easiest to ride up a 20% grade? A road bike that weighs 19 lbs with a low gear of 29.6 gear in. Or a touring bike that weighs 30 lbs with a low gear of 18.4 gear in. Same speed and cadence.

To go the same speed and cadence you would have to be in the same gear, so the bike that weighs 11 pounds less would be easier.

Your right. Both bike climbing at 6mph

It would depend on if you're strong enough to push the higher gear and if you're a spinner or a masher. 11 pounds is a lot on a bike when you start climbing.
Normally a lighter bike is easier on a hill but when you get to 20% some people will need a granny gear. At what point the weight becomes less of an issue I don't know, but I have climbed on a 60 pound loaded touring bike while I weighed 220.

The doctor was his mother.








It was a trick question, right?

The super low gear of the touring bike is not needed if you're going 6 mph, so the lighter bike would be preferred at that speed. The lower gears are needed when you're only able to climb at about 3 mph and the choice is between riding at that speed in a low gear or walking at 2 mph with a bike that doesn't have a low enough gear.

The lighter bike's going to be substantially easier at 6mph.

The 29.6 gear inch works out to a cadence of about 70, which is not that low for climbing.

You'd be spinning the 18 inch gear over 100 rpms to keep up 6mph, which is likely higher than desired cadence for most people.


So no real gear advantage for the heavy bike, and adding the 11 pounds is going to take approximately 12 watt more to climb a moderate hill at 6mph than the lighter bike.

According to Sheldon Brown's calc 90 RPM puts you at 4.9 MPH in the lowest gear of the tourer and 7.9 MPH in the lowest gear of the roadie. That's a pretty significant difference. 11 lbs up a 20% grade requires roughly 15 watts for the same speed according to http://www.noping.net/english/. Although it will take slightly more effort to get the tourer up the hill at the same speed, it allows you the possibility to comfortably ride at a slower speed.

If you are talking about a sustained 20% grade, I would say the lower gearing wins for sure.

No. I'm serious.

If you can maintain 6mph up a 20% grade for any distance, you don't need anything lower than a 39/27.

Because your FTP would be over 500 watts.

Can't have the same speed and cadence with different gear inches. Cadence x gearinches x 0.0254pi = speed in meters per minute.

A friend of mine was having trouble getting up the 20% long grades with his 30lb touring bike that has a low gear of 20 gear in. He is buying a 19lb road bike with a low gear of 30 gear in. I wasn't sure the road bike would be easier on a long 20% grade.

It would depend on your weight, but yeah would require world-class W/kg.

I kinda made the assumption that the OP was talking about a semi-long 20% grade and that 6mph was being optimistic. Hence the recommendation of the lower gearing.

Your posts are a little confusing. If your friend is having trouble climbing 20% grades at 6mph then he could just ride slower. More likely he is already climbing slower or the grade is 10% not 20%. To get a reasonable answer you would need to provide more accurate details. For example, what is a 'long' 20% grade. There are few, if any, 20% grades longer than a mile. If he really is struggling up hills in the lowest gear on his touring bike he will have more trouble with the road bike with higher gearing even if it is 11 lbs lighter.

OK, which is heavier: a pound of feathers or a pound of lead? Or a pound of gold, for that matter? ;)

It would depend on what he is having trouble with. If he's in low gear, and can't hardly push the pedals around or his legs are giving out, then the other bike is a step in the wrong direction. if he's going right on up, and is NOT in low gear, and thinking "man, this thing is a tank, wish it were lighter", then he's likely on the right track.

It sounds like the lighter bike will be easier on a short climb but, the heavier bike bike with lower gears will be easier on a long climb with some 20 % sections. I was trying to find a watt calculator on line, but none of them took gearing into consideration .

Thanks for your help everybody

I should have said 4 mph. He did have to walk up a few hills with his 30lb bike with a low gear of 20

Generally, walking hills means you're out of fitness, out of gears, or just used the wrong gear and toasted your legs prematurely. The first two options call for lower gearing, not higher gearing on a lighter bike. The third option calls for riding more hills and figuring out what work best.

Personally, I prefer not to walk hills, but if I need to, I'm not afraid to stop and rest on the way up, either.