Bike Build Log 2022 - Challenges / 2022初組車紀錄 - 挑戰

Bike Build Log 2022 - Challenges

  Problem encounteres and the solutions.

  The internet is in no shortage of bike build tutorial (#dreambuild). It’s shiny, sexy, relatively easy to follow when things progress as it should, until it is not. To troubleshot, the situation get hairy right away, for every build has its own unique context with caveats within caveats… and that, is with the subject technician capable of acknowledging them. 

  Unless one has a dedicated technical consultation source he/she can turn to, try to crack the diagnosis with resource online can be frustrating for the reason mentioned above. 

  I reckon it is more valuable to share my share of troubleshooting throughout my building process.

Undersized Headset Cap

Symptom

The headset cap came with the The One Pro handlebar was was too narrow to fit through the steerer tube. The cap was 0.2mm too narrow via the vernier scale reading. 

Cause

Probably QC issue. The cap looked like 3D printed.

Solution

As the (online)seller of the item was not being helpful, I ended up sanding the excessive material off with a fine sandpaper. It worked.

Hydraulic Brake Hose Fitting Compatibility

Symptom

Bleeding was unsuccessful. The braking feedback was inconsistent, reluctant on one side, totally not able to create a brake fluid path on the other side.

Cause

The fittings (barb and olive) I purchased online was the wrong ones. 

Solution

Fitted the compatible sets on.

Pressfit Installation Tool

Symptom

I was not able to keep the tool radially aligned with the bottom bracket cups, therefore not able to apply even force during the pressing/installation of the bottom bracket. This caused angular misalignment/the cups was slanted and theoretically squashed in a degree throughout the pressing. The bottom bracket shell was pressed onto an undesired spot and cracked.

Cause

The installation tool I purchased did not have the guiding sleeve for DUB BB86 29mm spindle.

Solution

Purchased a new bottom bracket and the correct pressfit tool.

Insufficient Head Tube Steerer Trimming

Symptom

The play presented even with the compression plug and top cap torqued up correctly.

Cause

An experienced technician pointed out that there was protrusion at the top of the compression plug, though minute, was enough to prevent the top cap to preload the steerer. It was proven by the wear mark found at the bottom of the top cap. 

Solutions

Added a headset spacer beneath to raise the stem, created space needed by the top cap.

Derailleur Hanger Incompatibility

Symptom

Rear derailleur’s range of operation was about 2 full cogs off from the cassette, which was beyond the adjustment with app.

Cause

The derailleur hanger was brand specific. The one came with the frameset was meant for Shimano groupsets (top).

Solution

Swapped the one for Sram (bottom) on.

Bottom Bracket Cup Detaching

Symptom

Chain rub was observed. It turned out the being cup of the bottom bracket was detaching, shifted the the whole crank towards the non-drive sides.

Cause

I believed it was a manifestation of the issue below.

Solution

Pushed the cups back in place.

Overlengthed Crank Shaft

Symptom

Chain rubbed on the front derailleur cage again. 

Cause

Excessive length space was found along the crank shaft. Measured ~3mm, but it could be 3.5mm if I retrieved the preload adjuster screw. This matches the info from an article online stating 90mm being one of the factory shaft length. That is, frame width 86.5mm + excessive 3.5mm.

Solution

Place a 2mm spacer came with the bottom bracket not eh drive side; closed up the rest of the slack with the preload adjuster screw at the non-drive side to achieve a balanced load distribution. 

// End //

中文：
挑戰 - 當事情發展不如預期時
Dreambuild視頻網上從來不缺。一切進行順利的時候情況只有一類 - 順利；但一旦遭遇問題，情況就會立刻變得極其複雜。除非有御用技術顧問，不然在網上撈資源診斷難度嘗試過的都懂。
此理，將分享此次組車過程中遇到的問題，照組裝過程排序。

頭碗過窄

表徵：一體式彎把配套來的頭碗塞不進上管。
排查：游標尺確認 - 窄了0.2mm。與賣家溝通，對方也沒能幫上什麼忙。
原因：品控問題吧。
解方：自己用細砂紙摩掉那多餘的，看來像3D打印的材質。問題即決。

液壓剎車管接頭

表徵：液壓管在安裝後一邊通不了液，一邊手變反應遲緩且剎車力道不穩定。
排查：經車店技師診斷，是用錯液壓管接頭了。
原因：讓網購產品頁面騙了，買了Avid規格接頭。
解方：還上了正確的接頭。

中軸壓入工具選擇

表徵：中軸軸承被斜著壓入，中軸外殼被壓裂。
排查：工具在壓入作業時沒能保持與中軸的中心對齊，以致受力不均。
原因：工具沒有對應 DUB BB86 29mm口徑的固定構造。
解方：新的中軸 + 選購個中軸鑄有對齊，固定29mm內徑的壓器。問題解決。

上管剪裁不足

表徵：上蓋鎖緊了的情況下，前叉還是有些許鬆動。
排查：另一名車店技師點撥，上蓋底部與有摩擦痕跡。
原因：前叉上管裁剪時沒納入膨脹鎖芯上緣的厚度，雖然很細微但已導致整體過長進而頂到上蓋，所以不可能鎖緊。
解方：龍頭底下塞個墊圈，問題解決。

尾鉤規格


表徵：後變速器的運動範圍與飛輪有著整兩個齒輪位的偏差。
排查：送店。
原因：尾鉤是對應原來車架搭載的Shimano(上半圖)套件，規格不通。
解方：換個Sram用尾鉤(下半圖)。問題解決。

中軸脫出

表徵：前變速器刮鏈
排查：以為校準偏了或變速器鬆脫移位，但其實是非驅動側的軸承整個從五通向外脫出。
原因：相信是下面的問題導致的其中一個現象。
解方：用工具壓其歸位。

但...不久後刮鏈條問題重現：下面繼續。

曲軸長度

表徵：（續上）前變速器又刮鏈。
排查：之前中軸脫出的空位被曲軸取代。測量～3mm。它一直都在，只是由於曲柄安裝時都是把非驅動側打進去所以那3mm一直隱與驅動側。
原因：不肯定。可能是曲柄設計想兼容不同車架的五通寬度？
網上扒文看到有90mm軸長是其中一基本規格。在測量時如果把預載環歸零的話可能就得到3.5mm，加上車架五通寬 86.5mm = 90mm。所以手上的可能就是這款。因沒置入墊圈，在騎乘中整個曲柄漸漸非驅動側移位，導致前變校準跑偏加中軸脫出。
解方：在驅動側植入2mm墊圈 + 非驅動側調節預載環不上那～1mm，儘量求左右平衡。 至今還沒再出問題。

// 完 //