Originally Posted by
GAtkins
Thanks to all who responded. Much appreciated. I thought I was correct, but wanted to make sure.
I currently have a bike with a triple (yeah, I know
) on the front at 30-40-50 and a 12-27 on the back.
I'm considering getting a new bike with a 50-34 chain ring and a 11-34 cassette. I'm not in the best shape, but getting there. I wanted to make sure I wasn't loosing anything on the low end. Looks like I will have a lower low-end and a higher-high end, but just slightly.
Thanks again.
Glenn
Frankly, going from a triple to a compact double isn’t an improvement in my opinion. You are trading a system with a pretty good arrangement for gears for one with lots of holes.
This is a comparison of your current triple with your proposed compact double. Look at the 17 gear and how it shifts across the two systems. The difference from the higher gear to the middle on the triple results in a 5 mph shift in speed. Your cadence won’t have to change much to keep up with the change in speed. The difference in the double is almost 10 mph. More importantly, you’ll have to increase your cadence to keep up with the speed change from about 90 rpm to nearly 120. It feels like you have lost a chain.
This comparison shows what you would get if you changed the 12-27 to an 11-34. You’ll get a lower low and it will probably be cheaper. For the double, you’ll need the cassette, crank, a new chain, probably a new derailer, and perhaps new shifters. If you keep the triple, you’ll need only the cassette and chain. You might need a new derailer as well but I would see if your current derailer works with an 11-34.
By the way, the gear calculator is one of the best I’ve ever used. It’s very easy to use and the comparison feature is really nice.