For a while now I've been riding a 21-speed mountain bike. Climbing some of the hills around my area when tired is a no-go: I often end up walking up.

This is with a 24t small chainring and 28t large cog. On 26" tires that's about 22-23 GI.

A bit more about this bike: It is a 15" step-through frame, which due to my inseam, I've had to run the seatpost at it's limit. The handlebar is positioned so that I have to lean forward slightly. (I haven't bothered to adjust it). The tires do have knobs on the sides, but they are slick-centered.

That bike is now hung up for repairs that I can't afford at the moment.

So now I'm riding an old 10-speed road bike I picked up cheaply. If anything, the bars are actually lower relative to the seat than on the mountain bike. Typical of this style of bike, the small chainring is larger than the large cog, which while I haven't actually counted the teeth yet, I'm guessing puts 1st gear somewhere around 30 GI with 27" tires.

Tire pressure is about equal, as the old tires on the road bike have the same 35-65 PSI range as on the mountain bike, although the road bike tires are 1.25", and the mountain bike tires are 1.5" wide.

The weird part is, even when I'm tired, it seems like I can tackle more hill on this old bike, than on the mountain bike. I can only really chalk this up to some type of geometry difference, but what part, I don't know. Seat height is roughly out of the equation, as it's equal on both.

I'm planning on building a bike at some point for long distance traveling, and having experienced this major difference in hill climbing ability, I'm interested in measuring the bikes I have to determine what would be the best fit for me in building up a traveling bike.

Your input is appreciated.