Are Big Bike Wheels Better
Examining the trend to 29-inch mountain bike wheels
Those big 29-inch wheels on mountain bikes - are they a flash in the pan or will we all be riding them in a year or two?
The 2006 trade show season and the unveiling of the 2007 ranges have highlighted two major trends. First, the onward march of carbon fibre, already dominant in competition road bikes and increasingly prevalent in high-end mountain bikes too.
The other major trend is the growing number of 29-inch wheel mountain bikes available. Gary Fisher was the first major manufacturer to include 29-ers in their range, in 2002; this year most makers have at least one or two.
The terminology is confusing, so let’s try and be clear. ‘29-inch’ refers to the approximate overall diameter of the wheel including tyre - necessarily approximate, because tyres vary. What doesn't vary is the diameter of the wheel rim, which is 622mm or about 24.5 inches - the same as the 700C size, which is all but universal on road bikes.
Hitherto, virtually all adult mountain bikes have had 26-inch wheels (again an approximate overall diameter). Anyway, however you crunch the numbers, 29 inch wheels are more than 10 percent larger than the traditional 26-incher.
The natural question is why change? What, if anything, are the advantages? Basically, bigger wheels roll better over bumps, making rough trails easier and rougher trails possible.
Against this, 29-inch wheels are heavier. The overall effect may be small, but because this is revolving weight it matters more. Big-wheel bikes are harder to accelerate. (On the other hand, once rolling they keep on rolling that bit better). And bigger wheels will collect that much more mud. This may not be an issue on the rocky trails of California or Utah, but it definitely is here in the UK, and many other parts of the world.
There are evangelists who avow that 29-ers are the future, and skeptics who maintain that they will never be more than a niche product. The truth probably lies somewhere in between. It depends where and how you ride and it also depends who you are. Bigger wheels make more sense for larger riders; it’s hard to shoehorn them into smaller bikes without compromising the fundamentals of frame geometry.
Whether you’re a 29-inch convert, or you’re sticking with 26, email me or have your say in the discussion forum.
