Alex Moulton -> Gravel tourer

[dimrub]

Some progress was made. It is around this point that I realized:
1. I don't have the special Ultegra tool for tightening this BR-60 bottom bracket
2. The original adjustable stem does not fit the new 31.8mm handlebar

So off to the shops first thing tomorrow morning. Then I think I can wrap it up in a day or two.

 

[Ming the Merciless]

It looks in great condition.

 

[dimrub]

More progress. In fact, most of the work is done. The only remaining issue is the awkward angle between the rear brake cable's housing and the noodle. I think I can solve this by either shortening the housing (so that the noodle is pointing forward) or by replacing the noodle. Once done, it's just gears/brakes adjustment, trial ride, handlebar tape and done. Well, easier said than done, there might still be last moment problems.

 

[dimrub]

Hubris, hubris and stupidity. Hubris, stupidity and excessive trust in AI. The bike is ready, but it's unridable. Well, I can ride on half the cassette, but at some point the derailleur becomes level with the ground, and then - well, lower than that. Too long a cage for 20" wheels. No 11-42 cassette for me. I think I can still salvage the situation somewhat (i.e., not giving up on 1x) by maybe finding a 11-36 11s cassette, and a shorter cage mech. But that will reduce the range by quite a bit.

 

[dimrub]

We regroup and continue. Alternative parts were ordered, the unfit once will go to FB market.

 

[dimrub]

Still practically unridable due to mech being level with the ground on low gears, but other than that is done, and here's the new looks.

 

[TheDoctor]

I begin to see why G Line Bromptons use a hub gear. Do you need a gear as high as 50/11? A smaller chainring would let you reduce the cassette spread and use a shorter cage rear mech. Apols if I'm into granny/egg territory here.

 

[dimrub]

I begin to see why G Line Bromptons use a hub gear. Do you need a gear as high as 50/11? A smaller chainring would let you reduce the cassette spread and use a shorter cage rear mech. Apols if I'm into granny/egg territory here.

On my Brompt-not, I easily spin out on 56/11, which is 81.5 gear inches. 50/11 on a 20 inch wheel is 90 gear inches, much better, but still not great. For comparison, on my full size gravel bike I'm on 101 gear inches (40t ring and 11t cog) - and yeah, I'm using that gear a lot.

But in general, yes, once your blanket is short, all you can do is decide whether it's your upper or lower half that is not fully covered.

 

[dimrub]

Oh and by the way, a hub gear is not a silver bullet. Apart from other considerations (e.g., weight, energy efficiency, ease of maintenance, cost), G-line's gear range is 29-88 gear inches, so pretty much similar - and even slighly smaller - to what I'll have with my new cassette (when it arrives).

 

[dimrub]

Speaking of weight - I managed to reduce it by almost exactly 1 kg. It's not a whole lot, but hey, I'll take it.

 

[Ming the Merciless]

Apols if I'm into granny/egg territory here.

If only you had said granny ring / egg…

 

[a.twiddler]

There's a reason for small wheelers being fitted with things like the Sram DD3 as a way of getting a reasonable gear range without a long arm derailleur or a huge chainring. I've experimented with 20" wheel folders with derailleurs, and you can get away with a certain amount with them to get manageably low gearing with a better range. Once the wheels get smaller it gets more tricky.

Things like Bromptons have the bonus of the folding related chain tensioner mechanism coincidentally taking up chain slack to the extent that I've been able to fit a 28T ring inside the 50T that was already there. It works by greasy finger power as I haven't got round to working out a FD to acommodate it yet. Not strictly relevant, but just an example.

Would your aversion to internal gears extend to something like a Schlumpf Mountain Drive? Assuming such a thing is practical with this. It would be a shame to have to compromise on gear range having got this far, though they are pricey. It would reduce the need for such a large cassette range, and a long arm derailleur on the rear.

Just thinking outside the box, is there any way to fit an additional chain tensioner to the chain run so that a shorter derailleur might work, or the longer one could work with less swing so that it doesn't contact the ground? I've used a Shimano one in the past which used a redundant mounting point on a recumbent trike frame, though it's possible to make up or adapt brackets.

I hope I'm not venturing into the territory of aged female relatives, education, suction and hen fruit. Just throwing out some random ideas.