Bicycle Mechanics - Newbie Question: Difference between 24" and 26" tires?

Hi all!
As you can tell from my question, I'm totally new to cycling. I'm thinking of buying a used 80s Specialized Rockhopper for communiting around town (about 10 miles a day). I foundthis bike for $195 at this local non-profit cycling center. It is in great condition and has a 17" frame with 24" wheels, which is just right for my 5'1" shortness.
So here's my question: what's the difference between a 24" and 26" wheel? (Besides 2 inches...) I've been riding my roomates Raliegh M-80 this whole time, with a 26" wheel and I was wondering if the 24"wheel will be that much of a difference. Are the mechanics in riding it different? Is it that much more difficult to find replacement wheels/tires/tubes and stuff?

Any info would be greatly appreciated!
-amy

Well, there's the gearing. It has to be different to account for the tire diameter, because the tire is like the final gear in the drive system.

I'm thinking the ride of a 24" wheel will be just a bit stiffer, as the spokes will be shorter and flex less.

The whole bike should present a lower profile than the 26" wheel bike, but whether this is noticeable in terms of wind resistance at riding speeds is questionable.

Besides the gearing (for a given gearing range, the 24"-wheeled bike will be approximately 0.92 as large of a gear as the 26" wheeled bike), the fit is the main thing that concerns you. And at 5'1" the fit will be better for you, I htink. Presuming you can ride it beforehand, test it out, make sure it feels good.

Of course, you'll have to buy diff tires and tubes, and the selection of tires will be smaller for 24" wheels because fewer bikes use them.

Besides gearing and other things mentioned in the previous two posts, bear in mind if you ever take it off road, you will have a harder time clearing obstacles with 24"ers, although all else equal the 24" wheels will be stronger. There has actually been a development in the XC mtb world to 29" from 26.

24" tires will require a search but a google on 24" bicycle tires turned up a variety of sources. This may be a bmx size, check the tire itself for the fine print- somewhere it will have the actual/real size on it probably though not certainly in MM as a diameter x width. These can be mixed as 650x2.1 where 650 is mm nominal diameter and 2.1" is tire width. Yours might be a 559x1.9 (eg) or similar. Whatever it is make note and check local stores, and if they don't have them google on the size and see what pops up. Tires last 2000-4000mi depending on how ridden so this is not a big deal. Gearing and handling are a non issue. 90% of people riding bikes never change the speed. Sounds like a good choice. Tubes available same way, FWIW I toss a tube only if it has a cut too big to patch or a leaking valve. You need at least one spare tube just in case but tubes last 3-5 tires at least.
Steve