Bicycle Mechanics - 34 vs. 26 chain ring

Hi. I'm getting a compact double on my next bicycle, and I'm trying to decide between a 34t and a 36t chainring; cogs will probably be 12-23 or 12-26 (only difference there is that the 23 has a 17 in place of the 26).

I've crunched the numbers (thank you, Sheldon Brown: http://www.sheldonbrown.com/gears/), so I know what ratios each chainring provides. What I don't know is what they're like in everyday use. The 36 seems like it would be more practical, especially in that the jump down/up from/to the big ring would be less dramatic. But, most everyone seems to offer 34t (36t is rare), so perhaps there's some meaning to that.

Any observations based on experience you can provide are welcome.

Thanks, and have a happy new year.

David

It really depends on what your climbing needs are. For me I would choose the 36 because is would offer closer ratios with a 50 big ring and the smaller differential should mean better shifting performance and less chain rub on the side of the big ring. With a 34 there is a greater tendency for the chain to rub the inside of the big ring when the chain is running on the smaller cassette cogs.

Al

Tell us more where do you live and how many hills/climbs. If you go with the 23, there may be times when you'd enjoy having the 34 for a little broader range for climbing. Me'd takes the 34.

Just go with the stock compact - 34/50. Your fitness is the bigger factor, 2 teeth +/- don't really do anything unless you care too much about a specific cadence and/or wish to output a specific wattage on climbs of a mile or longer. In other words, just ride...and enjoy.

Your fitness is the bigger factor...

Agree wholeheartedly. In my first complete year of riding (2005), I jumped up at least 2 gears or more on the longer / steeper climbs on my routes, and dramatically improved cadence as well.

However, I'm still avoiding any "real" mountain routes here in CO because I just don't think I'm geared low enough to avoid leaving my knees in little pieces along the shoulder.

Personally, I think a 36 would be low enough for 99% of the riding I would do here in CO, but I realilze that doesn't mean anything to anyone else in any other place. You've just got to get some miles in to determine what feels good and what you think you'll be capable of spinning in the long term. Good luck.

Depends on the mountains/hills in your area. You can go with either and your rear cassette can be selected for the killer hills. If you are truly in the mountains like here in Boulder and an old fart like me you will be wisest to go triple. I have both double (39/53) and triple (30/40/50) and my cassettes are 13/29. I select the bike for the ride I am programming for that day. See if you can try both and select the one that feels best. I've tried the compact and couldn't get used to the large jumps but thats just me. Good luck.

Thanks for all the input. I'm a 40-something returning rider, in good fitness, but not exceptionally strong. This coming season (starting today, when I mount the rollers) will be my first full season of riding in quite a while. I live in very hilly terrain in the Nashoba Valley area of Massachusetts. My current setup is a 53/42 with a 14-28 6-speed (yes, it's old).

With a standard double (53/39) and either a 12-26 and 12-27 cassette, I can match the lowest gear that I ride today, and that's adequate, but not optimal: Like I said, I'm not that strong, so I find myself somewhere between spinning and mashing on longer/steep climbs (not sure what cadence).

Luckily, with fesh new year's snow on the ground, I have more time to contemplate the perfect setup. (There is such a thing, right? ;)

Happy new year, all.

David

I'm 63yrs, weigh 225lbs, and find a triple the best choice. I ride in the Front Range of the Rocky Mountains and like to ride in the high mountains. I'm not fast, but can ride up almost anything with the triple including Mt Evans and Trail ridge road, both over 12K ft. Ride what feels right for you. Take the time (and $) to find a LBS that will check out your riding position and help optimize it for you. If you have a local Serotta dealer they seem to do the best job. After 50 years of riding I took the time and was able to make some subtle changes that made my riding more comfortable and less stressful on my poor old joints. Good riding in 06.