So since we got our tandem Jackyll we've covered a fair bit of distance on it. Not too long ago I noticed that the front wheel was making a particularly rumbly sound, so I set out to try to grind the bearings. In short this hasn't really worked, although I didn't really expect it to last very long.
The rumbly bearing noise was tolerable for a while, however I was tightening the front wheel and I felt it give... the threading on the axle had given up and I was left with a loose front wheel a few days before the Dunwich Dynamo. I must had accidentally damaged the thread before when I was grinding the bearings before. The obvious solution was to replace the axle with a new one, however the only new ones available were rare and expensive because the manufacturer Maxi-Car went out of business decades ago.
Add to the fact that the bearing cups in the hub were damaged beyond repair, so it was not worth spending any more money or time on the existing front wheel. So to cut a story short the only choice was to build a new front wheel from scratch.
Choices, Choices, Choices...
There are few tandem bikes around generally, there are even fewer 650B wheeled tandems. These days most 650B rims are aimed towards MTB or French inspired randonneur bikes, so anything beyond 36 hole rims is uncommon as these are meant for a solo bikes. What drove my component choices was this: Firstly the frame requires a tandem specific rear hub due to the 140mm spacing, secondly I wanted a nice strong wheelset which would survive a fully loaded tandem.
Components:
Rims: Velocity Atlas 40h 650B/ISO584mm
Hub: Shimano HF-08 40h Large flange hub w/ wheels manufacturing Cromoly axle 110mm spacing
Spokes: DT Swiss Alpine III Triple butted spokes
The rims were a special order as there is very little demand for that drilling in that size apart from 650B tandems! The Velocity Atlas rims are a nice wide 25mm in a traditional triple box setup with single eyelets, the width should be good for the wide tyres needed to support the extra weight of a tandem and riders. The quality was not quite up to the same standard as the H+Son Archetype rims I used for Phil, there was still swarf (sharp metal remants) in the interior of the rim which had to be cleared, and the rim extrusion joint was pinned not welded which meant there was a visible seam. However the overall quality was fine and I'm confident they should be able to hold the weight of the bike for years to come.
The Shimano tandem front hub was the only real choice I had, because of the unusual 110mm spacing of the forks, its cup and cone construction meant I was able to swap in a slightly longer axle and spacers to fit properly. The quality of the hub is top notch, beautifully finished with dual labyrinth seals (very little dirt will be able to get in), silky smooth bearings and nice thick flanges for the extra weight of the tandem. I wasn't able to build the wheel before the Dunwich Dynamo, so I swapped in the front wheel of my partner's 650B road bike for it.
I could have gone with a 36h setup however I figured we might as well build a super strong wheelset now with tandem specific parts than risk a failure later down the track. Spokes used were DT Swiss Alpine III triple butted spokes, which are reinforced for tandems and heavily loaded bikes. My partner built the front wheel as her first wheel build, and it came out nice and straight quite easily.
Drum time
Next up is the replacement of the drum brake. I actually did this back in April however I realised that I never posted about it. The drum linings were replaced by a shop that normally does vintage motorcycles and cars, all they required was the inside diameter of the drum and to send them the shoes which they would returned with a new lining. The maker of the hub is still unknown however the size is about 90mm in diameter which is a similar size to the Sturmey Archer X-FDD drum hub I also have.
Recently I noticed that the rear hub was making a racket similar to the old front hub, it sounded distinctly like the bearings had failed. Also when the drum was engaged it tended to brake unevenly, like it was not centred properly on the axle which would sometimes cause a really loud shuddering when it was applied sometimes. After opening it up I found that the non-drive side bearing had failed, one of the balls had cracked and they were all discoloured a goldish brown colour... This must have happened when we engaged the drum a few too many times on longer descents.
This points to the bearing having been overheated at some point with the grease liquefying and burning. Also when I stripped it down originally, I knew that the axle being bent would inevitably lead to the failure of the bearings. Due to this, I decided to replace the rear axle with a chromoly axle along with new cones and bearings. This quietened the rear hub to normal levels, as well when the drum is engaged now, it seems a lot smoother and actually useful! Ultimately however, the condition of the cups in the hub is quite poor so it will need to be entirely replaced at some point. Part of the reason the bearings overheated is that the drum itself has very little heat capacity, unlike the typical Arai drum brake you typically see on tandems which is much larger and has cooling fins to cope with the heat. I'll need to find one of them as well as a tandem hub to suit in the future.
Thanks for reading.
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