Bike Restoration 單車修復

Despite I’ve been living in the UK for a few years now and have adapted to most aspects of daily life, as someone who spent decades in Hong Kong, the winter temperatures here still feel quite daunting. Because of this, my outdoor cycling trips have significantly decreased over the past few years. That said, my passion for bikes remains strong – just shifted from riding to repairing and modifying them. My first actual attempt was probably a couple of years ago when I helped fix my son’s classmate’s bike.

So, my son had planned a cycling trip with his Russian classmate, but just before heading out, his classmate found that his bike chain had snapped. I quickly stepped in to reconnect the chain and adjust its length. While working on it, I noticed the bike had quite a few issues. However, not wanting to spoil their fun, I just focused on replacing the chain and giving the front and rear derailleurs a quick tune-up before going to Richmond Park with them.

雖然在英國住了幾年，衣食住行各方面大都適應了不少，但對於生活在香港幾十年的我，英國冬天那種溫度還是有點嚇人，所以過去幾年走到戶外踩單車的次數亦顯著減少了。話雖如此，我對單車仍有一番熱誠，只不過已由踩變作維修及改裝單車，而第一次全力投入的應該是前年幫兒子同學維修單車。

話說兒子打算和他的俄羅斯同學去踩單車，但同學仔出門前發覺家中單車的錬條已斷開，我便為他重新接駁及調整長度。修車時留意到這單車問題多多，不過因不想掃他們的慶，只盡快換了單車鍊及稍為調校好前、後變速器便與他們往 Richmond Park 出發。

After a quick ride around Richmond town centre, we started heading back along the River Thames. But thanks to the rough and uneven bike path, my son’s rather tall and solid classmate somehow snapped the hanger of his bike’s rear derailleur! In the end, he had no choice but to push his bike home. Seeing how disappointed he was, I volunteered to fix it for him.

His bike was a Carrera Vengeance, a hugely popular model in the UK. Bikes like this are the go-to choice for commuting, school runs, and everyday use. It might not be the flashiest ride, but it’s affordable, which means if it ever gets stolen, it’s not a massive loss. The Vengeance isn’t too bad in terms of components either – compared to my son’s Giant, it has slightly lower-tier components and a heavier frame, but the price is a solid 30 ~ 40% cheaper.

What’s funny about this particular bike, though, is that it seemed like a real mix-and-match project! The gear shifters were for an 8-speed setup, but the rear derailleur was actually a 6-speed model. To make things even stranger, the rear wheel was fitted with a 7-speed freewheel. I had already noticed these mismatch when replacing the chain earlier, but since we were short on time, I just did my best to tune it so at least a few gears were usable.

To top it all off, the bike was supposed to have 27.5-inch wheels, but in reality, it had two old 26-inch wheels fitted. Safe to say, this bike had quite a history before landing in his hands!

在 Richmond 市中心走了一圈便經泰晤士河畔回家，可能因路面崎嶇，這個高頭大碼同學仔竟把單車後變速器 (Rear Derailleur) 的 hanger 踩斷了，最後只好無奈地推車回家！見到他有點失落，我便自告奮勇地說會替他把車修理好。

同學仔那部單車是在英國非常流行的 Carrera Vengeance，這款式及其他相類似的單車，都是上班，上學及日常使用的首選。雖然款式較平凡，但最重要是價格相宜，即使被偷亦不算是大損失。而 Vengeance 用上的組件也不太差，與兒子的 Giant 比較，只是組件檔次稍低，車架重了一點，但價錢卻低約三、四成。

有趣的是這單車可算是「百鳥歸巢」之作，轉檔手制 (Gear Shifters) 是八速，但後變速器卻是個六速型號，更奇怪的是後輪又配上七速飛輪 (Freewheel)，當日更換鍊條時，我早已察覺到，但時間短促，那刻只能盡力去調整到有好幾個波段可以安全使用便是。

另外單車標示是配 27.5 inch 輪組 (Wheels and Tires)，但實際用上的卻是兩條 26 inch 的舊車輪。相信這部單車前半生都應該經歷過𣎴少故事！

Finding a compatible hanger for a Vengeance or similar everyday bikes isn’t too difficult. While taking the parts apart, I also noticed that the rear derailleur had likely been bent out of shape due to excessive force while pedalling. Since it needed replacing anyway, I might as well upgrade it to a proper 8-speed one!

為 Vengeance 這類日常用車找個相容的 hanger 不太困難，而在拆零件時亦發覺後變速器可能因過度用力踩踏而扭曲，既然需要更換，就當然要換個八速的。

After replacing the two components, the next step was to adjust the rear derailleur. Since the original freewheel only had six speeds, I had to limit the gear shifter to use only the first six positions. However, no matter how much I fine-tuned it, one or two gears still felt unstable.

Upon closer inspection, I noticed a significant wobble in the rear wheel, which explained why some gears weren’t shifting smoothly.

The wobbling could have been caused by either a bent wheel axle or a warped freewheel. The former is relatively easier to fix – just replace the axle, and the job remains fairly straightforward.

更換好兩個組件後就先要調校後變速器，由於原本的飛輪只有六速，因此要限制轉檔手制只用頭六個波段， 但無論怎樣調整，六個波段中仍有一、兩個轉檔不太穩定。經仔細檢查後留意到後輪出現了大幅度的搖晃 (Wobblig)，這亦解釋了為何有些波段出現不穩定。

搖晃的原因可能是輪軸彎曲 (Bent Wheel Axle) 又或者是飛輪變形，前者比較容易解決，只需更換輪軸，工序尚算簡單。

To replace the wheel axle, the freewheel had to be removed first, which required a special freewheel removing tool.

Once I got the axle out, I confirmed that it was indeed slightly bent in the middle. So, I took the opportunity to upgrade it to a hollow axle with a quick-release skewer, making future maintenance a bit more convenient.

更換輪軸先要拆除飛輪，所需工具是專用的 Freewheel Removing Tool。取出的後輪軸確實在中央部分有些彎曲，那麼就借機會轉用快拆軸 (Hollow Axis and Quick Relase Skewer)。

With the upgrade completed, the wobbling issue on the rear wheel was somewhat reduced, and the shifting performance improved slightly. However, since I was still using the old freewheel, the instability issue wasn’t fully resolved.

如此這般的又完成了所需的升級，後輪的搖晃减少了一點，轉檔亦稍為改善了，不過因仍然用回舊的飛輪，不穩定的問題未能完全解決。

In general, a worn-out freewheel can cause the wheelset to wobble more easily. I believe the only way to fully resolve the issue would be to replace the freewheel with a new one or switch to a Cassette, but doing so would require replacing the entire wheelset! I’m leaning toward upgrading to a rear wheelset with an eight-speed cassette, but since the cost is quite high, I’ll consider looking for a second-hand wheelset online to keep expenses down.

一般情況下，有損耗的飛輪亦較容易引至輪組搖晃，相信要完全解決問題就要換新的飛輪或改用 Cassette，而後者就需更換輪組！我傾向換個配備八速 Cassette 的後輪組，不過因所需費用較高昂，我會考慮網上的易手輪組。

After a little over a month’s online search, I finally found a pair of 27.5-inch wheelsets with an eight-speed cassette on Facebook Marketplace. The tires were a bit worn, but those are just consumables, so I can easily replace them with new ones. It felt like a good deal!

個多月後終於在 Facebook Marketplace 找到一對含八速 Cassette 的 27.5 inch 輪組，雖然輪胎有點破舊，但這些 consumables，換過新的便可以。

After a series of replacements and upgrades, my son’s classmate’s bike is almost back to its original factory setup. The mismatched components have been sorted, and the shifting is now accurate and smooth. The only downside is that the front and rear rims are slightly deformed, causing some wobbling while riding. However, it’s not a major issue, and a Wheel Truing Exercise should easily fix it.

For wheel truing, you’d need a Wheel Truing Stand, but I didn’t have one, and of course, I wasn’t about to spend a few hundred pounds to buy one!

經過一連串的更換、升級後，同學仔的單車差不多已回復原廠配置，組件上的不協調亦消除了，轉檔也變得準確及暢順。唯一不足是前後輪圈有些變形，騎行中有點顛頗，不過問題不大，來個車輪修整 (Wheel Truing exercise) 相信便可解決。

Wheel Truing 要用到車輪修整台 (Wheel Truing Stand)，我沒有亦當然不會花數佰英鎊去買！

If only a simple adjustment is required, you can actually use a few plastic cable ties to serve a similar purpose. Carefully observe the distance between the tips of the cable ties and the rim, then use a Spoke Key Wrench to fine-tune the tension of the spokes so that the distance becomes uniform.

Just be sure to pick cable ties that aren’t the same colour as the frame!

如果只是簡單調校，利用數條 plastic cable ties 亦有類似作用。細心觀察 cable 前端與輪圈的距離，再利用車輪輻條扳手 (Spoke Key Wrench) 去微調輻條的張力 (spoke tension) 令距離變得平均即可。

不過切記要揀些與車架不是同色的 cables！

Of course, a test ride is a must before handing the bike back!

交車前當然要試車啦。

Just like my son, his classmate also attends the same Sixth Form school. And every now and then, when I see him riding that repaired bike to school, it brings a small sense of satisfaction to me.

與兒子一樣，同學仔亦就讀於同一 Sixth Form school，偶爾看到他騎著那部修理好的單車上學，我心裏也感到一絲的欣慰。