Rio
04-03-08, 11:40 AM
Hi All, I'm a looking at a bike with 42,32, 22 on the front and 12-27 on the rear gearing and wondered what you think of it for a commuter. Terrain is mostly flat with one or two good sized hills.
Bicycle Mechanics - gearing question
Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.View Full Version : gearing question
Al1943
04-03-08, 11:51 AM
That gearing should be good for commuting, especially for hill climbing. I wouldn't change a thing unless you plan to race downhill.
Al
Al
Rio
04-03-08, 11:52 AM
Thanks so much!
Bill Kapaun
04-03-08, 02:19 PM
I'll assume it's a MB with 26" tires?
IF SO, basically it should be very good, but you could probably "tweak" it a bit with a bit more of a "road" cassette. I doubt the cost would be worth it though.
Maybe something like an 11-21? That would give you a bit more "top end" and a bit more closely spaced flat cruising gears. The downside is that you may have to shift to the small ring more often and the bike would have to be equipped with a Compact FH to accept the 11T cog.
Other factors would also be in play, such as how steep are your hills and even crank length. 5MM difference in crank length can sometimes have a much greater effect than a 1 tooth difference on a cog. Going from "fat" knobby tires to "skinny" street tires can make an even bigger difference.
Even if you occasionally "spin out" on the 12T, it probably won't really effect your top speed as much as you would think.
IF SO, basically it should be very good, but you could probably "tweak" it a bit with a bit more of a "road" cassette. I doubt the cost would be worth it though.
Maybe something like an 11-21? That would give you a bit more "top end" and a bit more closely spaced flat cruising gears. The downside is that you may have to shift to the small ring more often and the bike would have to be equipped with a Compact FH to accept the 11T cog.
Other factors would also be in play, such as how steep are your hills and even crank length. 5MM difference in crank length can sometimes have a much greater effect than a 1 tooth difference on a cog. Going from "fat" knobby tires to "skinny" street tires can make an even bigger difference.
Even if you occasionally "spin out" on the 12T, it probably won't really effect your top speed as much as you would think.
HillRider
04-03-08, 03:44 PM
Unless your hills are incredibly steep and long, the gearing sounds unnecessarily low. A 22x27 low gear (21 gear-inches) is extremely low and probably over kill for any but the weakest rider or a very heavily loaded tourer.
The 42x12 high gear of 91 gear inches is probably adequate for flat terrain but could get spun out if you luck into a tailwind.
I agree with Bill Kapaun that a more road-like cassette would make the gearing more useful. A 12x23 or 12x21 cassette would keep the same high gear, still give a plenty low low gear and provide finer steps in the middle gears.
The 42x12 high gear of 91 gear inches is probably adequate for flat terrain but could get spun out if you luck into a tailwind.
I agree with Bill Kapaun that a more road-like cassette would make the gearing more useful. A 12x23 or 12x21 cassette would keep the same high gear, still give a plenty low low gear and provide finer steps in the middle gears.