Bikes with 29 inch wheels are all the rage these days, so my guess is that if you ride cross country and if you haven't tried one yet, you'll probably try one sometime soon. Some of the qualities that have attracted riders to the world of 29ers are increased tire patch on the ground, faster rolling, lesser angle of attack when rolling over roots and rocks leading to a smoother ride. There are a lot of reasons why as a cross country rider a 29 inch wheel might appeal to you. But what if your inseam is 29 inches or less? Then what, you ride it like some sort of circus balancing act? You make sure you always stop beside a log or rock so that you don't topple over? Here was my dilemma. I wanted to try the 29er because many of my friends are singing their praises, but I struggle with the idea of finding a 29er that's small enough to fit my mini-legs that is not a hardtail. Luckily, I happen to live with a bike engineer which means a) you'll never know when you'll come home to find your bike in pieces, b) you get free repairs, and most importantly c) you get the opportunity to try some of the more rare bike set ups that are available (and an education in how it works).
Most mountain bikes either have 26 inch wheels or 29 inch wheels. But there is middle ground available, it's just not so common. 27.5 inch wheels, better known as 650b, are basically right in the middle providing all of the same effects of a 29er wheel, just on a slightly smaller scale, and still allowing me to stand over my top tube. I am 5'3" (with a 28.5" inseam) and I currently ride and extra small (15 ") Rocky Mountain Element MSL. With 26 inch wheels my bike is set up with 120 mm fox suspension front and rear. In order to change my wheel size to dual 650b on the front, it's pretty simple, there's enough clearance with a regular front fork to accommodate a 27.5 inch wheel, nothing really had to be done. On the rear, I had to switch my shock from 120 mm travel to 95 mm travel so when at the end of my travel the larger rear wheel doesn't touch the seat tube. Due to the unique design of the Element, the rear suspension can be changed by simply switching out the rear link to the shorter version from the Element RSL. With the shorter linkage and the 95 mm travel the wheel fits and works perfectly.
I've been out for two rides on the new set up and so far the my reviews are nothing but positive. It rolls faster on the descents, it rolls smoother over roots and rocks and the little bit (0.75 inches) of extra clearance in the BB means effortlessly cruising over larger obstacles. Riding some flowy traverses on the shore the wheels felt grippy and fast. Every rut felt a little smaller and the bike felt fast and nimble in the berms.
I'm not sure what the future is for 650b wheels, whether they will make a resurgence in the mountain biking world, or they will stay in relative obscurity. I know they will stay on my bike for a while and I'm looking forward to putting more miles on them and figuring out just what they're capable of. For all those smaller riders out there balking at the 29ers because you don't have quite enough leg to swing over one, I definitely suggest giving 650b a try.