1.) Scared of steep, rocky terrain (Unfortunately, this is typically the reason people ride mountain bikes: for the adrenaline, for the freedom! I, however, usually don't enjoy the sensation of urine in my bike shorts. So I feel like I'm already at a disadvantage);
2.) Tires lock when I'm coming off of a steep hill, most likely due to my white-knuckling both brakes so hard, they touch the handlebars;
3.) Biking back up that steep, rocky terrain is THE WORST. Afraid there's no other cure to this besides getting out on the trails as much as possible. *Sigh*
But it occurs to me that a reason for these fears, aside from inexperience and a fear of breaking a limb, might have something to do with the wheel size.
(*Don't take my advice as the final word on the subject. The header of this blog is hopefully a clear indicator that all my advice comes strictly from my own blundering experience or the fury of someone else's forum responses. I'm just skimming the surface of basic points of fact. If you want a more impassioned opinion, talk to a bike mechanic. That's their job.)
Before Giant's release this year, an adult rider's only options were between a 26- or a 29-inch-wheel. The choice was originally no choice - the first mountain bikes were all 26ers. Now you find a war of the wheels in forums and in-shop bickering over which size is the Ultimate way to ride. Well, all that nonsense doesn't apply here. This is to give you basic understanding of which size works best in which situation, and then you can take these nuggets of knowledge and do more research on your own.
This is the largest of the now three wheel sizes offered for both mountain and road bikes. A bigger wheel is best for rolling over those rotted branches or rocks, and the larger tire has more tread because it makes more contact with the ground. There's something called an "attack angle," which equates to the ease of maneuvering the bike upward over obstacles. The larger the wheel, the higher the attack angle, or, the smoother the bike feels going over bumps. This creates a more comfortable ride for your arms and backside. A tall or normal- to heavier-set person might also see more merit in riding this because the height and geometry of a 29er frame is more accommodating to their stature.
The only real trade-off between a 29-er and one of its smaller counterparts is that the heavier weight limits a rider's ability to accelerate up hills - or so they say. If you're goal is to become a contender as a single track racer or to be more efficient on technical rides, then it will take more energy to carry that bike up a hill. BUT. Once the bike is efficiently moving, the larger size will sustain that momentum and help you make that climb.
While you don't see as many 26ers on the single track as much, "enduro" (down-hill racers) prefer this size. Because it's great for crashing down a hill at suicide speeds! But we'll talk specifically hills at a later time. The 26er is lightweight and agile. The perfect size for those who really want to "feel" the trail. The thing most people say about the 26 is that it is harder to handle on technical ascents (meaning climbs like this), and it takes a lot more strength to get perpetual momentum rolling. But the shorter frame takes weight off the front, making it easier to control the front wheel, and the dodging a lot more invigorating.
The 27.5 is Giant's compromise between the other two sizes. Their logic is that the 27.5 is lighter and gives you more flexibility than the 29. Yet the circumference is still larger enough for the propulsion of the wheel to carry you over obstacles easily. So you get the ease of acceleration from the larger wheel size, yet the nimbleness of a 26 in the lighter frame.
Now, I am not in the business of promoting one brand over another, but Giant was the only brand available to me in that size. And since this is the only thing I have tested so far, most of my perspective comes from how this bike affected my experiences. So a little attention paid to the Talon 27.5 is warranted here.
(Giant compares the weight, efficiency, and control of the 27.5 to that of the 26 and the 29 on their website if you want to get more charts. However if you want a less biased comparison, look no further than PinkBike's test runs.)
What I like most about the 27.5 is the traction it gives you without compromising agility. I feel I would have capsized a LOT more had I been riding a 26. (Twice, I can handle.) It had momentum when going up moderate technical hills, and it's "sticky" when turning sharp corners. A rider would still need to have really terrific balance on this size, though, just as you would need on a 29 since the wide tire makes crevices difficult to navigate around.
The point Giant seems to be making is that you can have your cake and eat it too. Er, or have your hills and eat dirt too....I guess?
So let's review: When choosing which wheel size is optimal for your situation, consider type of terrain, your height/weight, and in what capacity you will be riding (for leisure? Competitively?). Forget trends - go with what makes you feel comfortable. And definitely talk to your local bike shop. Or do as I have begun doing, and be a shop rat. It's amazing how much wisdom you can pick up by just hanging out in a shop for an hour and listening to the mechanics heckle each other in the background. Everyone needs a hobby - loitering can be yours!