Brief Impressions: ThorUSA Dahon Mu XL Sport

ThorUSA loaned me their one-off belt drive Dahon Mu XL Sport to play around with for a couple of weeks. The Mu XL Sport is Dahon’s 20″ performance commuter. It’s a fun ride; nimble, fast — and with the Gates belt drive installed — smooth and silent.

You’ve heard me rave about belt drives before, and here we go again. There are gimmicks galore out there, and I’m as suspicious as anyone when it comes to the latest-and-greatest, but I’m a big fan of carbon belt drives. They’re tough, maintenance-free, clean, quiet and smooth. Of course, they’re limited in the fact that they can only be used on single speed or internal gear drivetrains, and on conventional bikes (not folders) they require a special frame that opens to allow installation of the one piece carbon belt. They also require precise alignment between the sprockets, and Gates only offers a limited range of sizes in both belts and sprockets at this time. Still, in cases where all of these requirements can be met without too much compromise, belt drives offer some real advantages over chains.

The belt drive conversion on this Dahon was done in-house at ThorUSA. The install is clean and it looks like a factory job. The only downside is that because of the limited range of sizes available in belts and sprockets, the gearing is quite low. The lowest 3 gears are going to be of only limited use to most people, essentially turning this 8-speed bike into a 4-5 speed. If you’re interested in having a belt drive Dahon built, be sure to talk to Thor about gearing before making a move.

Since I’m a Brompton devotee, it’s only natural to compare the Dahon to my regular ride. The Dahon is approximately 3 lbs. lighter (my scale shows 23 lbs.) and it rolls surprisingly fast on its Schwalbe Kojak tires. The construction is clean, though the lightweight Dahon is obviously not nearly as robust as the little tank-like Brommie. The fold isn’t as compact as the Brompton’s (none are), but the belt drive eliminates the exposed greasy chain issue which can be a bit of a problem with some Dahons.

The Mu XL Sport would be a great bike for anyone on a budget who wants a relatively lightweight, performance folder with an IGH. The addition of the belt drive makes it particularly appealing from the standpoint of cleanliness (something that’s always a consideration on folding bikes that are carried in street clothes and stored near other people in public places), though the impractically low gearing is an issue that will need to be resolved. Perhaps the upcoming 11-speed Shimano IGH will be the answer.


[Many thanks to Thor at ThorUSA for use of his belt drive Dahon. —Alan]

8 Responses to “Brief Impressions: ThorUSA Dahon Mu XL Sport”

  • JQFrederick says:

    How would a Rohloff hub work with this? It might address the gearing problem.
    I have to say I’m intrigued with the folding bike–belt drive combination. Currently we have two Bike Friday’s (Air Glides) with Rohloff hubs, which are great bikes. The real problem with them is that they are not “true” folders. They certainly (folded) get much smaller, and allowed us to ride the Katy Trail in Missouri this spring while traveling out there from the East Coast via VW Beetle, but to ride them around town and then folding them to carry up to our 3rd floor apartment is not really an option.
    Maybe we need some new bikes…

  • Tobias Linder says:

    Rohloff works fine with the gates belt drive. There are severeal brands that sell bikes with rohloff equiped belt drives here in Europe.

  • Alan says:


    “Rohloff works fine with the gates belt drive.”

    I’m not sure it would solve the low gear range with 20″ wheel issue though; either hub is still limited to the available sprockets and belt lengths from Gates.

  • Yvar says:

    Which front sprocket is on the Dahon? Is it the regular 55 tooth or the newer 60 tooth? I’v just converted my Trek District from single speed to Alfine 8speed myself and the belt/alfine combo is lovely.


  • Alan says:


    It’s the 55T. Apparently there’s not sufficient clearance for the 60T.


  • Garth says:

    This is splendid. I’d like to see more progress on maintenance free/maintenance easy bicycles. There’s little excuse left, really. The Pashley has become one of my favorite bikes, though I can’t justify the cost of such a bike when I’ve spent so much on my speedy Heron. Belt drives, drum/disc brakes and grease fittings, not to mention tapered bearings, now there you go!

  • Bob says:

    The Sturmey-Archer XRF-8, whose lowest gear is direct-drive, may be a possible solution to the gearing issue (if you can install a Gates cog on it).

  • EcoVelo » Blog Archive » Living with a Belt Drive: Two Months Out says:

    […] Civia Bryant is the 6th belt drive bike I’ve ridden. The others were a Norco Ceres, Dahon Mu XL Sport, Raleigh Alley Way, Trek Soho (test ride only), and a prototype Bryant back in 2009. I rode some of […]

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