gear/shifting question
 

hello,

i have a road bike with a 52/42/30 front and a 11-24 9-speed rear. since it's rolling hills where i live, i am usually at 42 front - 19 rear and it can stay that way to cope with the rolling gradient road.

however there are a few miles that it is straight and my question is, to increase the pedaling efficiency i have to change gears right? what is better going for 52 on front and staying on 17/19 rear? Or staying on 42 but going down to 12 or 13 on rear. i tried both setups but it feels the same in terms of effort. but which gives a better mechanical advantage?

reason i ask is that i am not that strong to handle BOTH front and rear gear changes like going to 52 front and 12/13 rear. way too much effort for my age to pedal that hard.

You should be pedaling in order to maintain a cadence of 90-110rpm. Whatever gear you are in should allow you to maintain that cadence. Too much gear your cadence will fall off, to little and your cadence will be too high. The name of the game is "spin" and not trying to mash a single gear. That's what it sounds like you may be doing. This is regardless of your age. As you progress, you'll find you're able to spin bigger and bigger gears.

On the 42/13 or 12 you'll have a small loss in efficiency due to cross chaining and more friction on the chain links moving around the smaller cogs. If you were to run the 52/17 or 19 there should be less cross chaining and less chain resistance due to larger cogs but, the amount of efficiency lost is so small that it would only add up to about a second ot two over the course of an hour.