29er (bicycle)

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For the type of skiff, see 29er.

29ers or Two-niners are mountain bikes that are built to use 700c or ISO 622 mm wheels.^[1] Most mountain bicycles use ISO 559 mm wheels which are commonly called 26" wheels. The ISO 622 mm wheel is typically also used for road-racing, trekking, cyclo-cross, touring and hybrid bicycles. In some countries, mainly in Continental Europe, ISO 622 mm wheels are commonly called 28" wheels or "28 Incher".^[2]

1 Origins
2 Tires
3 Performance
- 3.1 Advantages
- 3.2 Drawbacks
4 96er or 69er Variations
5 References
6 External links

[edit] Origins

29" and 26" Mountain Bike wheels

The term 29er or two-niner is a little misleading. The rims have a diameter of approximately 24.5" (622 mm)^[3] and the average 29" mountain bike tire has an outside diameter of about 28.5" (724 mm), though tires exist with diameters of over 740mm. The typically 26er rim has a diameter of 22.0" (559 mm) and an outside tire diameter of about 26.2" (665 mm)

Various people claim to or are attributed to be the originator of the term 29er, the most plausible being Wes Williams of Crested Butte, CO.^[4] The US division of Bianchi Bicycles offered a line of off-road 29er bikes beginning in 1991 called the Project bikes. Their 1992 product catalog raved about the advantages of the larger wheels and showed three different bikes, the Project 3, 5 and 7. In the mid 1990’s, Diamondback Bicycles made their Overdrive bike, and Specialized made their Crossroads bike, almost 29ers but arguably more like hybrid bicycles with frame and fork clearance for larger tires. The Project and Overdrive bikes were not a success for many reasons, primarily a lack of proper off-road tires and suspension forks competitive with the 26" offerings of the time.

A key product release, the first true 29er tire, was produced by an early supporter of the 29er movement Wilderness Trail Bikes. The company introduced the first true 29er tire, the Nanoraptor, in 1999. At about the same time, White Brothers produced the first commercially available 29er suspension forks. Before then suspension forks used were forks designed for trekking bikes or hybrids. For many years 29er frames and bikes were usually only available from small little known manufactures like Niner Bikes. Surly Bikes introduced their 29er frameset, the Karate Monkey, in 2002. Gary Fisher Bicycles, a division of Trek Bicycles, became the first of the major manufactures to offer a line of 29er bikes. Their lines never sold well until the introduction of single-speed 29er bike the Rig, in 2004. Today nearly every large, medium and small bicycle manufacture in the US market offers at least one 29er bicycle or frame. Even companies that openly dismissed 29ers as a bad idea or passing trend, Specialized and Turner, are bringing 29ers to market.

[edit] Tires

A tire with a tread width of less than 2.0" (50 mm) is considered a Cyclo-cross tire by 29"er standards. This differs from the standards of cyclo-cross racing that consider any tire wider than 1.5" (38mm) as not a cyclocross tire. Although they are both used offroad and typically use a 622mm rim, cyclocross bikes and 29ers differ in many ways, specifically with regard to toptube length (most cyclocross bikes are about 2" shorter when built for a similarly sized rider), tire clearance, chainstay length, ability to run a suspension fork, bottom bracket height and brake setup, among others. Bikes exist that blur the distinction by combining attributes of both, however.

[edit] Performance

A debate over the advantages and disadvantages is currently raging in the mountain bike community. Those who believe the 29" wheel to be inferior often mention added weight, perceived sluggishness in handling, and problems with fit (specifically, front wheel/toe overlap and high standover height). 29" enthusiasts respond with comments about reduced rolling resistance, perceived increased stability without sacrificing quick handling, and an enhanced ability to roll over obstacles.

[edit] Advantages

Larger wheels roll over obstacles more easily due to decrease in approach angle
Larger wheels have a lower rolling resistance for the same width tire
29”er wheels are less prone to sinking in soft material such as sand and mud
Larger wheels are less prone to pinch flatting
The longer contact patch increases cornering and straight line traction
29"er bikes tend to offer taller riders a more "natural" frame geometry.

It is worth noting that most of these claims have yet to be objectively verified one way or the other. Small scale, unpublished studies (including one done by Pepperdine University, reportedly at the request of Gary Fisher) exist but both proponents and detractors of 29" wheels are generally unimpressed with their lack of scientific rigor. Long debates over how to conduct a "fair" test of the efficiency of 29" vs 26" mountain bikes have raged online, but no serious efforts have been made to conduct a large-scale, scientific study.

[edit] Drawbacks

Increased wheel weight and rotating mass - the spokes, rim, and tire are all larger.
Many types of tires, rims and forks do not come in 29"-compatible versions, though the expanding popularity of the size is reducing this problem.
Longer spokes and rim result in a more laterally flexible wheel.
Longer spokes and increased angle between hub flange and rim result in a weaker wheel.
Smaller riders (i.e. less than 5'5" tall) may not be able to find a 29" bike with a geometry suitable for them. Numerous examples exist of custom bikes built for very small riders with 29" wheels, but in many cases smaller riders face significant geometry tradeoffs in order to ride a 29er, especially with regard to toe overlap, handlebar height, and standover.

[edit] 96er or 69er Variations

One variation is to have a 29 inch front wheel and a 26 inch rear wheel. Using the smaller rear wheel allows shorter and quicker handling frames, more options for rear suspension designs and lighter bicycle weight. Another variation is to have a 26 inch front wheel with a 29 inch rear wheel. Both are commonly called 69ers or 96ers, depending on the manufacturer. For example, Trek Bicycle Corporation introduced a 69er in 2007 with a 29 inch front wheel and a 26 inch rear wheel.^[5] Carver Bicycles also has, what they call, a 96'er with a 29 inch front wheel and a 26 inch rear wheel.^[6]