Rings, Teeth & Cranks...HELP!

[Pedal Wench]

You asked about rear derailleurs and cassettte compatibility. I am running a 13-29 on my climbing bike with a short-cage derailleuer. So, you can probably go much bigger in the back with little problem.

With a compact 50-34 and my 13-29 cassette, I have gearing VERY similar to a triple, with little weight penalty. I have this on a bike that I'm setting up strictly for climbing rides. I have a 12-15 for flatter routes.

[bouncybouncy]

OK...did a little research and have an add on...

my rear is (i guess what you would say) is 11-23
it reads
11-12-13-14-15-16-17-21-23

so what you are saying is that i can get the double up front 34/50 then get a bigger set in the rear, maybe a 13-29 without having to change the derailer?

if so that may be the answer...

i knew there was a reason i went into photography instead of accounting...no wait, that deals with numbers too (and they are backward )...NO REALLY...you ladies are a HUGE help...this is starting to make sense! I almost want to go into the manliest bikeshop i can find and talk gear ratios just for an ego boost..hehe

[Pedal Wench]

For a roaring good time, play around here:
http://sheldonbrown.com/gears/

Plug in the numbers that you want to compare. I make up a wacky front crank so I can compare (30, 34, 39 for example) so I can see what I lose or gain with different components.

Shimano and Campy have different limits, and I'm not sure Shimano has a cassette comparable to my Campy 13-29. So, do some more homework on what's available in the components you are using.

[bouncybouncy]

Thanks a bunch!!! I have gone to his site before...in fact i posted a link to what he had done with the Surley Karate Monkey (my new baby )

...off to crunch some numbers...aaaaaaaaaaaaaaaaaa

[DebW]

OK...did a little research and have an add on...

my rear is (i guess what you would say) is 11-23
it reads
11-12-13-14-15-16-17-21-23

so what you are saying is that i can get the double up front 34/50 then get a bigger set in the rear, maybe a 13-29 without having to change the derailer?

You'll need to check your rear derailleur and find out the max sprocket size it can handle. Some derailleurs made for 11-23 won't be able to handle a 13-29. You can check the Shimano site, for instance, and for each model it will tell you the min and max sprocket sizes, the max front sprocket difference, and the total capacity in teeth.

[pkq]

Yup, the Shimano site will tell you all about compatibilities.

I run the 9-sp Shimano grouppo on my bike. Having ridden in PA for a few years, I would make two recommendations. The grades will be similar. One, I would avoid a triple. Two, I would keep your chainrings and change out your cassette with the largest gear you can get.

I began with a 52-39 chainring and 11-23 cassette bike from South Louisiana in the PA hills. It was tough but I hung with it.

I then tried the triple and cable tension was always an issue as were the adjustments on the derailleurs. So I decided to get a larger cassette for the 9-sp and wound up with a 12-27 cassette. The steepest grades are OK with the 27t gear on the back.

A compact will make it more difficult to gain high speeds on the flats. So, if you are going to ride flats, you will be glad you have the 53 chainring.