I'll consider the Gates Drive when it gets a Hebie Chainglider of its own

[Andre Jute]

I have just been on this forum long enough to recognize that a certain other user has made the Chainglider his idée fixe. Seemingly every bicycle forum has its resident oddball like that.

You must be talking about Danneaux, who has written to Hebie several times to request that they make a Chainglider in his preferred 36-tooth size to match the half-step installations on his derailleur bikes for which decades of experience has given him a firm preference. I might add that in my opinion Dan is a superb judge of cost-benefit in bicycle components.

You can't be talking about me because it is well known that the minute a rationally better choice to the Chainglider becomes available, I'll be all over it, g'bye Hebie, thanks for your service, hello better component! But the Gates Drive (and the splittable alternative mentioned above) offers absolutely nothing that a Chainglider does not, and at about 14% of the price of a Gates installation.

You're welcome to try to prove otherwise, but you won't get far with snideries like these:

I have nothing against casual riders who feel the Chainglider works for them, I just think that experience with the wider cycling community on more varied routes would put paid to any hyperbole that it’s a miracle technology and its users a chosen people.

In case you're not an anglophone, or are terminally insensitive, the offensive phrases, all in a single sentence from you, are:
"casual riders"
"experience with the wider cycling community"
"more varied routes"
"put paid to any hyperbole"
"a miracle technology"
"its users a chosen people"

Good luck with your crusade for the Gates Belt Drive. A man should have a hobby.

[Andre Jute]

speculate it might be a 2-speed alternative for single-speed urban bikes? Maybe it auto-shifts at speed?

There used to be a two speed bottom bracket gearbox, designed for MUNI (mountain unicycle) needs, invented and made by Florian Schlumpf who IIRC sold the rights a decade or so ago.There were two choices for bicycles, from memory a fast touring ratio and a stump puller for cycling up mountains. The speeds were shifted by a knob sticking through the pedal axle centre, operated by the cyclist's heel. I looked into it as an alternative to a Rohloff, to be used with an electrified bike and the excellent controllers for the motor that had just then arrived on the market; mine had 9 pseudo "gears". I went for the more flexible Rohloff mainly because I didn't know how much gearbox I would need to get the exercise I required. (The answer with much more experience is that the top five or seven gears of the Rohloff should be enough for most people and most riding situations but the full complement of 14 gears are actually occasionally in use and I would miss them if I didn't have the luxury.)

I'm impressed by the cleverness of the conception of a "growing" sprocket but wonder about its complication.

Technically, the simple, proven CVT of the NuVinci seems to me a better idea, and it is available with an optional automatic control. I'm surprised the NuVinci Continuously Variable Transmission isn't much more popular: why, it even fits right in with the bicycling beau ideal of a constant cadence and changing gears to suit the rider's output to the terrain, which is after all the idea behind the derailleur.

[Andre Jute]

Which £6 chain was that, John? Do you have an estimate of its mileage?

KMC Z1 Narrow. It had done about 2000 miles. I decided, since I had a good stock of of those chains, that it was less hassle to replace it than to clean it. The new chain will probably have the same fate next spring but will have accumulated more miles.

Thanks, John. 2000 miles is still double what I used to get in the days when I ran Shimano's smart but soft Nexus groups including the chains inside big old plastic Dutch plastic chain cases that committed suicide every time I jumped a pavement or a fallen branch.

[JohnR]

This advert https://www.sjscycles.co.uk/bikes/vello-rohloff-folding-bike/ highlights another potential problem with the Gates belt drive - the minimum rear sprocket size. The bike on sale has gearing good for going up mountains (provided the rider can keep their balance) despite the 60T front sprocket, although I wonder why the bike has 22T on the back when Gates sell a 19T Rohloff sprocket. A purchaser could fit the smaller sprocket but this would also require buying a new belt.

[PH]

I'm belt curious in a way that I've never been interested in a Chainglider. All those who've used one have talked about the belt offering a different experience, in ways the chainglider doesn't.
Last weekend, at the York Rally, I saw the tandem used for the recent Round the World Record, with a Gates belt between cranks and a chain to the derailleur, they used two belts in rotation to even the wear on the rings, belts were fine, rings were worn out, that's in 18,000 miles.
https://www.cyclist.co.uk/in-depth/round-the-world-tandem-record

Belts are well established technology, the disadvantage for bikes is the same as that for any form of internal gearing, efficiency. How much of that is measurable or perceived is debatable.  Either way, that disadvantage disappears in a scenario where that's unimportant. That's why internal gearing and belt drive is such a good match for E-bikes. It is becoming mainstream, I see more belts on E-bikes than on non assisted bikes, not yet on the majority, but the percentage difference is huge.  It's easy to forget on a cycling forum that most riders are not interested in bikes!  Something you can wash off with a hosepipe and take to the dealer, at less frequent intervals, for everything else wins over more complex options however mechanically superior.   Cost is of course a factor in everything, but I think those people spending three grand plus on an E-bike, then replacing a lot of car miles with it, are not going to quibble if the annual service is £200.
Although belts are nothing new, their development for bikes is ongoing, including one from Schlumpf which can be run at lower tension.
https://www.cyclingabout.com/promising-new-bicycle-belt-drivetrains-from-eurobike/