随笔与拾记。

(English version follows Chinese Part)

我的通勤自行车车是2007年买的普利司通27寸三挡变速车，至今使用已逾8年，初高中日日往返于家和学校间，里程不胜计数。大学期间在外地读书，车便久置，回家后无需专门恢复调校，车胎打足气便可继续上路，车况良好。

My commuter bike is a Bridgestone 27″ 3-gear-bike bought in 2007 for daily transportation during secondary school years. It is still function well today after 8 years and countless miles working. What’s more, when I went to university far from hometown, the bike left unused for years can still do its duty after aerating without rust or repairing.

唯独两个地方需要维护升级。一是支撑车的脚撑，年久生锈，折弯部应力集中而破坏，27寸自行车又体型高大，停车时总是重心不稳，自行车不时发生倒伏。二是变速线损坏，档位只能固定在最高速档，骑行起来实在有些费力与不变，尤其是起步时。这两个问题是高中毕业时出现的，当时考虑到马上离乡读书，车不常用，遂未考虑将之解决。如今终于下定决心，又拜神奇的X宝能够买到合适的配件，给通勤车恢复最佳车况。

But it also getting old. Two things have to be fixed. Firstly, the bike stand crash because of rust and stress concentration, and the 27″ bike frame has high center of gravity that will make it worse. Then, the shift cables lost part of it which is indispensable for gear changing. 

These problems were not fatal so I ignored them for years. Thanks to extremely rich kinds of  merchandise sold in Chinese web shops, I searched out the exact type of  spare parts fix my bike, and I made the decision to upgrade her.

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首先是更换脚撑。原配的脚撑是单边式，在损坏前还勉强支撑27寸大车不倒，如今在冲压件折弯处开裂，实在无法堪用。考虑到一劳永逸地解决泊车不稳的问题，网购了双梯式脚撑，这样架起车来便稳稳当当。图1便是换下的脚撑和泊车状态的双梯脚撑。

Waiting the spare part of gear-change, I replaced the bike stand at the first time. The original one was prop stand that is too weak for supporting 27″ bike, I bought a double kickstand instead. Retired stand and the new one shown in Fig.1.

图.1(Fig.1)

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第二个问题是变速器控制线损坏导致无法变速的问题。

The gear-change problem was solved the other day.

先解释下禧玛诺NEXUS变速器(维基百科链接)外部控制的原理。图2是外观，图3是原理图。如图3(a)是变速控制线释放状态，变速杆伸出，档位是1档，速度最慢。当手拨调高档位至2或3档到高速档时，控制线绷紧，杠杆将变速杆压入轴内，改变内变速传动比。注意图3中的钢珠，那个是控制线拉动杠杆的施力件，我的自行车的控制线钢珠脱落了，所以没法拉动杠杆变速。

It is SHIMANO NEXUS 3-speed-change system (Wikipedia Link) . You can see what’s it like in Fig.2 and how it woks in Fig.3. When control cable release at Gear-1 (Low), the pin was released, too (Fig.3(a)). After you turn the shift lever set by right hand, the cable tension and the pin is pressed into gear-box by pry bar that will change the gear ratio at Gear-2 or Gear-3 (High), as you can see from Fig.3(b).

图.2(Fig.2)

图.3(Fig.3)

坏掉的控制线末端如图4。

The tail of  broken cable as Fig.4.

图.4(Fig.4)

由于钢珠是直接包紧控制线末端的，我的工具条件没法自制维修。原打算是在钢丝末端打一个结来替代钢珠的作用，但是发现钢丝弹性太大，没法成型。所以只好更换整条控制线。如图5，网购的控制线到货了，左侧是变速器端，右侧是手拨端。

The iron ball was attach to the wire rigid that I can not fix by tools I have, and the plan that tight knot was failed. Then I have to replace the hole control cable. Luckily I found it in web shop. Look at the Fig.5, the left side iss the end at gear-box side and the right one should be attached to controller at the handle-bar.

图.5(Fig.5)

换好后的样子如图6(变速器端)和图7(手拨端)。

That is the appearance of gear-box side (Fig.6) and the hand-controller (Fig.7).

图.6(Fig.6)

图.7(Fig.7)