When 29-inch mountain bike wheels started to move into the mainstream, wheel manufacturers struggled to make the new, larger wheels as durable as the more stout 26-inch platforms they'd been perfecting for decades without creating enormously heavy hoops. The 29-inch wheel was, for a while, limited to lightweight riders and light-duty conditions. Naturally, then, the only tires available for a time were fairly narrow, cross-country-specific treads -- but boy, have things changed. Not only are 29-inch mountain bike wheels and frames at least as tough as their 27. 5-inch and 26-inch counterparts, but the tire selection available to them is, too. Witness the Geax Goma TNT 29-inch tire to see how far things have come. The Goma's tread pulls out all the stops for an all-mountain tire. A super sticky compound is formed into large, aggressive knobs that are siped and stepped for excellent mud-shedding and true high-speed tracking over both mild and highly technical terrain. Cornering is superb and progressive. Rolling resistance is low. Braking is right now. But what makes this tire so special is Geax's amazing TNT sidewall technology. TNT (for Tube-No-Tube) sidewalls maintain the durability of UST sidewalls while keeping weight in check (around 100g lighter than an equivalent UST tire), and the casing maintains the flexibility of a standard clincher, so ride quality is delectable. Also, speed can be kept higher over technical terrain because the tread can deflect around obstacles rather than bouncing over them and altering the course of the wheels' momentum. It weighs only 800 grams (2. 25in version), but the Goma is easily burly enough for cased or off-camber landings, too -- it'll take hit after hit and keep coming back. The Geax Goma TNT 29in mountain bike tire comes with black sidewalls and in 2. 25in and 2. 4in sizes.