So what are 29 inch wheels and why?
What they are is easy – 2 inch (or wider) tyres mounted on road/hybrid diameter rims. This makes for a wheel which is around 29 inches in diameter, as opposed to the standard 26” inches.
The single biggest reason for using this wheel-size is to make a proportionate fitting bike. 26” wheels only ever became the standard for mountain bikes because the beach cruisers of the mid-70’s, which when converted became the first mountain bikes, used this diameter of rim – they were the only tyres available with enough volume. These were bikes primarily designed for children, and it took over 20 years until someone said hey, these little wheels just feel too small for grown adults. Anyone over about 5’7” (170cm) will generally feel much more proportionate and balanced on a 29” wheeled bike.
In addition to fit, there are a number of other benefits of larger wheels. A bigger wheel makes anything in front of it seem relatively smaller, which means it’ll roll over the top of it more easily. Because they’re bigger, they maintain momentum better.
Of course, there are downsides. The primary ones are weight, and a somewhat limited selection of parts. The parts selection for 29”ers is rapidly growing, tyres, tubes, forks and rims are generally not a problem – we’ll sell you some, plus they are more and more available both online and in your local bike shop. Weight is another issue, this one a bit harder to get around. Of course, a bigger wheel is always going to be a little heavier. However, if lighter wheels were really the only goal we’d be riding super light 20” wheels wouldn’t we? A lot of riders are trading a little weight for better fit and riding performance.