[调查] 各位，你们平时骑行用到的最大齿片是多少齿的？

mauricze

我的KA-062（083）每天要经过一座桥20度出头，用21T或者26T过去
其实18T就可以了，只是路面不是非常平整，我不想用大力蹬踏（牙盘52T的，可能会变形），所以就用到最大21T，顶风的时候用26T

大家来说说你们在什么路况下，用到最大多少齿？还有牙盘是多少齿的，也请说明一下

mauricze

通常自行车的齿比（gear ratio）是如下表示的，等我有空了来翻译一下

Gear inches
From Wikipedia, the free encyclopedia

Gear inches is a system that assigns numerical measurements to bicycle gear ratios, to indicate how low or high a gear is.

With old-fashioned "penny-farthing" bicycles, the crankarms were directly attached to the large drive wheel. One turn of the pedals moved the bicycle a distance equal to the circumference of the wheel. The larger the wheel, the farther the bicycle went for each turn of the pedals. The gear-inch system is a holdover from the days of the boneshakers, when wheel diameter determined the bike's "gearing" and was the key measurement on the bike.

Riding in a high gear on a modern bicycle is mechanically equivalent to riding a high-wheeler with a large wheel.

Gear inches express gear ratios in terms of the diameter of an equivalent directly-driven wheel, and are calculated as follows:

Diameter of drive wheel in inches × number of teeth in front chainring / number of teeth in rear cog.

For example, suppose the drive wheel is actually 26 inches in diameter. If the front chainring and rear cog have equal numbers of teeth, one turn of the pedals produces exactly one turn of the drive wheel, just as if the pedals were directly driving the drive wheel. That combination of gears and wheel is said to be "26 gear inches." If the front chainring has 48 teeth and the rear cog has 24 teeth, then each turn of the pedals produces two turns of the rear wheel. This is equivalent to doubling the size of the drive wheel; that is, it is like a directly-driven bicycle with a 52-inch wheel. That gear is said to be "52 gear inches."

A bicycle with a 26-inch wheel, a 48-tooth chainring, and a cassette with gears ranging from 11 to 34 teeth has a lowest gear of 26 × 48 / 34 = 36.7 gear inches and a highest gear of 26 × 48 / 11 = 113 gear inches.

One could also calculate "gear centimeters," but in practice this is not done. An equivalent system customarily used by European cyclists is "meters of development," and measures the distance travelled with each turn of the crank. That is, meters of development is calculated as:

Circumference of drive wheel in meters × number of teeth in front chainring / number of teeth in rear cog.

Thus gear inches and development differ by a factor of π, and english/metric conversion. Some bicycles incorporate internally geared hubs, or other components that change the gear ratio and must be taken into account when calcuting gearing.

Both "gear inches" and "meters of development" are concerned with the distance travelled per turn of the pedals. That means that neither of them take into account the length of the crankarm itself. The crankarm is a lever arm. If two bicycles have different crank lengths but are otherwise identical, a longer lever arm gives a greater mechanical advantage, and the bicycle with the longer crank length in some ways can be considered to be in a lower gear. To take this into account, Sheldon Brown has proposed a gear measurement system called "gain ratio," which is calculated by the distance travelled by the bike divided by the distance travelled by the pedals during one turn of the crank. He argues that it also has the advantage of being a pure number (with no units of measure); the calculation gives the same value whether it is carried out in inches or meters.

babywu

用上自锁以后一般都在28和26之间。

mauricze

你练习踏频啊？那也不用这样

帮我标题上加【调查】两个字，好吗？谢谢！我不能编辑了

babywu

今天骑了一圈佘山，全程28T，AVS21。
陪LP骑，只能用这个速度了。

non

我陪我LP只能用16AVS啊!

mauricze

引用第4楼babywu于2006-04-08 13:33发表的“”:
今天骑了一圈佘山，全程28T，AVS21。
陪LP骑，只能用这个速度了。

你是骑sp8去的吗？
照着53/28的齿比，你得达到>120的踏频才能保持avs21啊！！
incredible