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I know there is already a discussion about suspension lefty forks. However, that post completely avoids mentioning of their rigid counterparts which also can be found in the wild.

Below is a couple of photos of rental bikes commonly used in Singapore.

lefty rigid fork

lefty rigid fork alternative view

[While looking closely at the second picture, I have realized that there is also just one rear dropout!]

Searching through the net gives other examples of rigid leftys:

another lefty

cannondale slate

EDIT Added more examples.

Vintage 1910's bike:

vintage

Somewhat's newer one:

one more

So, what's the deal with them? What are advantages, and there must be some disadvantages (like less compatibility with fenders, hubs, rim brakes etc.)?

Grigory Rechistov
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    Those Mobikes have lots of interesting features. They have a single fork and "chain"stay. They're shaft-drive. The drive-train is on the left. They have solid tyres. The mudguards don't cover enough of the wheels or the right parts of them. And, Jesus H. Christ, they're heavy. I mean, really heavy. I'm surprised they don't collapse into a neutron star when three of them are parked next to each other. – David Richerby Jul 12 '18 at 09:22
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    I suspect that, in the case of Mobikes, the extreme incompatibility with every other bike part on the planet may be a design goal: if you're going to put thousands of bikes out on the streets, you don't want people using them as a source of parts for their own bikes. – David Richerby Jul 12 '18 at 09:26
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    @DavidRicherby in both Bristol and Cardiff the hire bikes use fairly standard components. The former are dockless so easily stolen (even the tyres are marathon plus so not cheap; luckily I'm honest as I could do with a dynamo hub) – Chris H Jul 12 '18 at 15:50
  • I'd be much more concerned with the single chainstay. The frame must flex pretty horribly up a decent hill, even if it is made of scaffolding pole as @DavidRicherby's comment implies – Chris H Jul 12 '18 at 15:52
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    There's a big difference between the lefty on a uber-cheap rental bike and that on a cannodale race bike. Even using a thicker diameter stanchion there's only one leg so it will be lighter (the cannodale suspension lefty is stiffer than comparable dual leg forks). You can also fix a flat without removing the wheel which I see as a minor advantage – markd Jul 12 '18 at 17:21
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    Using rim brakes on a rental bike isn't a great idea; you want something basic and simple that people can't screw up (so usually some brake at the hub like a roller brake or coaster brake that people can't mess with and doesn't need adjustment). For multiple gears you want an igh rather than a derailleur, etc. With that bike it looks like there's little some joe could mess up – Batman Jul 14 '18 at 01:10
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    It advertises that you're "available": "Righty-tighty, lefty-loosie." – Daniel R Hicks Jul 20 '18 at 21:01
  • (There is a very slight advantage for chain-driven bikes, in that the chain is not wrapped through the chain stay and hence can be removed/replaced without "breaking".) – Daniel R Hicks Jul 20 '18 at 21:04

1 Answers1

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One obvious advantage for most lefty bikes is

  1. You’re able to change the tire and tube without taking the wheel off the bike. So wheel adjustments and repair can be made without interfering with the disk brake rotor. This is especially useful on rear wheels as you also don’t have to take off the chain.

In the case of these rental bikes, I suspect that the real reasons are:

  1. Most everything on these rentals that can be made non-standard is — from the head tube diameter to the axle width. This slightly lessens the risk that the bikes will be stolen to be stripped down for parts.

  2. Branding and theft reduction: The bikes are highly visible and recognizable even if they are repainted

RoboKaren
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