Update (11/2/2002): Matt Rule tells me of the Orange Sub 3, a small full-suspension bike. I haven't seen one myself yet, but it's available in frames down to 14", has a low bottom bracket and a design intended for quick steering and good handling, and looks quite nice.
Update (5/26/99): Heather Anita Rennalls informs me that some new small bikes are on the market!
The first bike I researched was by Trek. They have 2 new bikes under the "Women's Specific Design" (WSD), the 6500 and the 7000. These bikes have a shorter top tube, higher stem, brake levers with a short-reach and lighter wheels. Their specs also state that the Rock Judy C fork is customised for women riders.
I have not had a test-ride on one as yet but they do have a 13" (WXS) 17 and 19" frames. (I will no doubt be applying your parking lot tricks when I do get a chance to try one.) The March 1999 issue of "Bicycling Magazine" had a very good article on these bikes.
Another line of bikes is GT's "Anatomica" series. There are 4 bikes in these series ranging in price. The one I hope to test is the "Ricochet". They have 12.5", 15, and 17" frames.
An internet search found that Rocky Mountain has 3 bikes with 14.5" frames: "Blizzard", "Hammer Race" and "Cardiac". If you want, I can keep you posted on my search for a good small mountain bike. I would also appreciate any updates you have on this subject as well. Thanks.
Update (3/5/99): A 5'1" correspondant tells me that Titus makes very small aluminum frames in XS and XXS sizes. "I have the XXS and love it! But it aint cheap."
Update (5/21/96): I've added a section on some tricks I use during a parking lot test-ride to tell whether a bike fits.
Note: this is an html-ized copy of a mail message I sent to a specific person seeking a bike in the under-$700 range for his girlfriend, but it's probably applicable to anyone in the 5'0" to 5'4" range seeking a mountain bike. It's somewhat out of date (written in late '94) and could use being updated. If you know of a great small bike that I haven't mentioned, please tell me about it! I do want to update this and make it a fairly complete guide eventually.
Yep, as you've discovered, finding small mountain bikes is a big problem. Unfortunately, at 5'0", she really won't be able to find a 26" wheeled bike that's quite small enough for her; the limitations of 26" wheels plus the avoidance of toe/front wheel interference prevent it. But 24" wheels have disadvantages, too. I think if I were 5'0" (I'm actually 5'3"), I'd very strongly consider going with a 24" wheel, because having a frame that really fits is SO much better to me that it might even be worth the disadvantages of a 24" wheel. But it's borderline, so if she wants to stay with 26" wheels, I can understand that.
(BTW, if I were 5'0" and buying a 24" wheeled bike, I would probably either buy a Terry, or buy Cannondale's nifty little 24" wheeled frame and put better components on it.)
In 26" bikes, the problem is not standover clearance, it's top tube length. Before you buy anything, take a tape measure with you to bike stores, and measure the distance from the center of the handlebars to the center of the seat (imagine the seatpost sticking up through the seat), which tells you how far the reach will be with the stock stem; and also measure the distance from the stem binder bolt to the seat center, since stems can be changed and a short top tube bike with a long stem is better than the reverse.
Having said that, be especially sure to measure the Fisher, since you mentioned it as a candidate. Fishers, even the small ones, tend to have extremely long top tubes (at least, they did a few years ago), so the short seat-tube length is deceptive, and the bike really may not be that comfortable for a short person (unless it's a person with short legs and a long torso, more typical of short men than short women). The Kona is more likely to fit, I'd guess. But you absolutely should check out:
In a somewhat higher price range, two more good bikes are:
Here are a few more, recently contributed by Kevin Bailey (Bailey@cebaf.gov):
There are also several high-end (over $1000) manufacturers who have started making small bikes, so if she likes the sport and eventually wants to upgrade, things are looking better all the time. (Me, someday I'm going to have a custom frame built, but I think I'll be happy with my Cannondale for at least a few more years.)
Good luck! Feel free to ask if you have any questions on small-bike fit. I had so much trouble when I was getting into mountain biking that I want to do anything I can to help fellow small riders find something that fits them well.
Bike length affects two things: comfort, and balance. The comfort factor has to do with whether you're leaned forward too much, with your arms extended too much, so that after a long ride, you'll have a sore back or shoulders from the extended position. This is very hard to tell without riding for a few hours. If you have a bike now, even if it's a road bike, put in some time on it (road riding is fine, it doesn't have to be off-road) and get a feel for how far forward you can lean and remain comfortable. Then try to remember that when test-riding a new bike. Of course, if you can talk the shop into letting you borrow or rent a bike of similar size for a day, do it! That's the best possible test.
The balance factor has to do with the fact that mountain biking involves riding in situations of poor traction, where the rider has to shift weight constantly to keep the weight in the right place. If the bike is too long, then the rider won't be able to shift her weight enough, which means that technical trail rides get a lot harder (and of course nobody else on the ride understands why you're having so much trouble, because their bikes all fit properly). Again, off-road riding is the best way to test this, but since that's not usually possible, here are some things I used to test my current bike when I test rode it:
Note that if you do all of what I described, you'll be out in that parking lot for quite a while, maybe 20-30 minutes. That's good, since assuming you spent the whole time on the bike, it also helps you decide whether the basic seat/bar position is one which will be comfortable rather than fatiguing to you. A good bike shop should have no problem with letting you do this (they've always been very patient with me for my extended test-rides).