大轮山地车（29寸）优劣谈
本帖最后由 lilang 于 2010-10-6 10:19 编辑一下文字翻译自英文网站，想给各位朋友提供一点关于大轮山地车的信息。29寸山地车在美国最近比较流行，关于它和传统26寸的轮子的优劣一直是一个热点话题。
---------------------下面是翻译的内容-----------------------------
29ers or two-niners are mountain bikes that are built to use 700c or ISO 622 mm wheels. 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".
29寸山地车的车轮使用的是700cc或者国际标准622毫米轮子。普通山地车使用的是国际标准559毫米轮子，也就是大家通常所说的26寸山地车。ISO 622mm轮子通常用于公路自行车，公路越野，旅行车，或者混合车。在大部分国家，尤其是欧洲国家，ISO 622毫米通常被称为28寸轮子。
起源
29er rims have a diameter of approximately 24.5" (622 mm) and the average 29" mountain bike tire has an outside diameter of about 28.5" (724 mm), though tires exist with diameters of over 29.15" (740mm). The typical 26" rim has a diameter of 22.0" (559 mm) and an outside tire diameter of about 26.2" (665 mm).
29寸轮子的直径大概有622毫米。平均下来29寸山地车的外围直径大概有724mm，加上轮胎直径大概有740mm。通常26寸轮子直径是559mm，加上轮胎直径有665mm
29寸轮子和26寸轮子的比较
In the early 1980s, the size of the wheels for the emerging mountain bikes was undecided. So when English off-road cycling pioneer Geoff Apps contacted Gary Fisher and Charlie Kelly with news that he had built a prototype off-road bicycle that used 700c Nokia snow tires from Finland, they where intrigued. In December 2006, Gary Fisher, speaking about the growing popularity of 29ers, gives his perspective: “We got some tires from Geoff Apps really early on and we said ‘Holy Toledo!’” But the poor supply situation of the larger diameter tires meant the fledging MTB industry stuck with the smaller wheel size." The first Geoff Apps designed 700c off-road bicycle was made in 1981 and was marketed as the Aventura by Apps' own company, Cleland Cycles Ltd , between 1982 and 1984. However production bikes used the more readily available Nokia 650b tires.
在80年代早起，山地车的轮子的尺寸还缺乏一个公认标准。当英国的越野自行车运动先驱Geoff Apps告知Gary Fisher 和Charlie Kelly说他打造了一个使用700cc芬兰诺基亚雪胎的原型自行车，Gary Fisher和Charlie Kelly都觉得这个主意不错。2006年12月，Gary Fisher在一次访谈中谈到了大轮山地车的流行趋势。他说“我们从一开始就在Geoff Apps哪里拿到了一些29寸轮胎，我们认为他这个主意非常不错”。但是这种大尺寸轮胎的生产制造无法和常见的26寸轮胎相媲美。第一个Geoff Apps设计的700cc越野轮胎制造与1981年。当时Apps自己的公司 Cleland Cycles ltd. 给它的牌子是"Aventura"。这种轮胎从1982年到1984年有销售。但是，由于供应链问题，大部分成品车还是使用的诺基亚650b轮胎
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. The US division of Bianchi Bicycles offered a line of 29" wheeled off-road 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. The original company Klein produced a small quantity of a 29" wheeled version of their successful "Attitude" MTB racer, and named it the Adept. It failed to find a market and was discontinued. In the mid 1990’s, Diamondback Bicycles made their Overdrive bike, and Specialized made their Crossroads bike with 700c wheels, but they were actually 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.
很多人声称“29er”这个名词的发明者，但是目前比较可信的是来的美国科罗拉多州Crested Btte的 Wes Williams首先提出了"29er"的概念。1991年Bianchi自行车美国分部提供了29寸大轮山地车的产品线，名称是“Project Bikes”。在1992年的产品目录中，Bianchi宣传了大轮山地车的优势，并同时推出了三款车“Project 3，5，7”.另外一个公司Klein生产了少量的他们热卖山地车“Attitude”的大轮版本，他们给这款大轮山地车起名“Adept”。但是这款山地车的市场很不好，早早的就停产了。90年代中期，Diamonback生产了他们的大轮山地车。Specilized使用700cc的轮胎生产了他们的公路越野车，但是这款是实际上是一款混合车，车架和前叉都为大轮做好了准备。但是由于种种原因，所有的这些车卖的都不好，这其中主要的原因还是缺少大轮越野车胎以及可以容纳大轮的前叉。
A key product release, the first true 29" tire, was produced by an early supporter of the 29" movement Wilderness Trail Bikes. The company introduced the first true 29" tire, the Nanoraptor, in 1999. At about the same time, White Brothers produced the first commercially available 29" suspension forks. Before then suspension forks used were forks designed for trekking bikes or hybrids. For many years 29" frames and bikes were usually only available from small little-known manufactures like Niner Bikes. Surly Bikes introduced their 29" 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 29" bikes. Their lines never sold well until the introduction of single-speed 29" bike the Rig, in 2004. Today most bicycle manufacturers in the US market offer at least one 29" bicycle or frame. Even companies that openly dismissed 29" as a bad idea or passing trend, Specialized and Turner, are bringing 29" wheels to market.
Wilderness Tail Bikes生产了第一款真正的29寸轮胎“Nanoraptor”（名字翻译过来就是纳米猛禽）。1999年，White Brothers 生产了第一款商业化可以容纳29寸大轮的减震前叉。之前，没有专门的针对大轮的减震前叉。很长时间，大轮山地车只是有一些像Nine Bikes的小公司生产。Surly Bikes生产了他们的一款29寸车架，The Karate Monkey。2002年Gary Fisher（Trek的一个子公司）成为第一个生产大轮山地车的一线品牌。但是他们的大轮山地车销量不好，直到一款单速大轮山地车才使销量有所改观。现在，大部分美国市场自行车品牌都是提供了至少一块大轮型号或者车架。甚至有些公开反对大轮山地车的公司，比如Specialized和Turner，也有自己的大轮山地车型号。
Tires
A tire with a tread width of less than 2.0" (50 mm) is considered a Cyclocross tire by 29" enthusiasts, even though in cyclocross, any tire wider than 1.5" (38mm) is not a cyclocross tire. Although they are both used offroad and typically use a 622mm rim, cyclocross bikes and 29" wheeled MTBs also differ, from bikes basic handling geometry, to construction methods, durability and intended lifespan. Bikes exist that blur the distinction by combining attributes of both, however.
轮胎
大轮的爱好者认为宽度少于50毫米的轮胎是公路越野车。但是对于公路越野车选手来说，他们认为宽度大于38毫米的都不是公路越野车胎。尽管他们都可以越野，而且轮子大小都是622毫米，但是公路越野和山地车在尺寸，操纵上有很大的不同。有一些特殊的车子同时具有两种车子的特点，所以很难给出一个明确的定义。
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.
性能
目前关于大轮山地车的优劣是山地车业内一个很热的话题。有些人认为29寸轮子的性能会变差，因为重量增加，操纵上也不是那么灵活。同时由于尺寸问题，骑行者很难找到一个合适的尺寸（特别是前轮，脚踏和车轮重叠以及过高的座位高度）。但是29寸的爱好这认为轮子大可以减少滑动阻力，提高操作的稳定性以及由于轮子变大而提高的通过性。
Advantages
Larger wheels roll over obstacles more easily due to decrease in approach angle
29” wheels are less prone to sinking in soft material such as sand and mud
The longer contact patch increases cornering and straight line traction
The larger wheels tend to raise the allowable height of the bottom bracket, cranks and chain wheels improving ground clearance
29" bikes tend to offer taller riders a more "natural" frame geometry
Most of these claims have yet to be objectively investigated. 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 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.
优点
[*]大轮可以提高通过性因为接触角减小了
[*]大轮不容易陷在啥子和淤泥中
[*]增长的接触面积提高了过弯能力和直线上的抓地能力
[*]大轮可以让整车的中心提高，从而通过性提高
[*]大轮车可以让个高的人有更好的姿势
上述的这些优点大部分是主观，缺乏客观数据的支持。小规模，未公开的研究（Gary Fisher要求普渡大学做了相应的研究）未能从科学数据上证明大轮山地车的优劣。网上，关于怎样“公平”的测试29寸轮子和26寸轮子一直是一个很热门的话题，但是目前还没有大规模的科学研究。
Drawbacks
Increased wheel weight and rotating mass – the spokes, rim, and tire are all larger.
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.
Many types of bicycle tires, rims and forks do not come in 29"-compatible versions, though the expanding popularity of the size is reducing this problem.
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, especially with regard to toe overlap, handlebar height, and standover.
缺点
[*]重量增加
[*]过长的辐条和轮圈让车轮发软
[*]过长的辐条让轮子变的脆弱
[*]很多自行车胎，轮圈，前叉都没有相应29寸版本
[*]个矮的骑手（低于167厘米）很难找到一个合适的大轮山地车的尺寸。虽然有很多个矮的骑手都找到了合适的大轮山地车，但是大多是情况下，矮个的骑手还是面临很大的尺寸问题。
全文结束
翻译自维基百科 本帖最后由 lilang 于 2010-10-6 10:21 编辑
全文翻译结束
希望能对大家有所帮助 继续学习，等下一篇作品发表 喜欢这样的帖子！！帮顶一哈！！！ 长见识------------辛苦 阅
29的估计我还真骑不来 我就喜欢29的山地,目前探索者好像是700cc的嗖嗖的
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