Is there a clear technical definition for a recumbent? Is it the position of the knee in relation to the crank? The presence or absence of a back rest?

There seems to be a fine line between, for example, stretch cruisers and recumbents:



  • 3
    There's not an agreed upon definition I've ever seen. The term "semi-recumbent" is also around, used on bikes such as the Rans Fusion and Cruz. And then between those and a normal upright bike are the "crank forward" bikes, such as Electra. Jan 18, 2017 at 0:04
  • 4
    I'm not sure there's even agreement on the need for a definition, since none of them are used by the racing crowd who are the primary users of definitions. Once you step off the tiny island of UCI-compliant bikes into the big wide world of "wheels and pedals" questions like "is this a recumbent" pale compared to "does the bike work for you?" (and "where will I store it" or "does it fit through my doorway")
    – Móż
    Jan 18, 2017 at 0:32
  • 1
    I'd guess that if your back-side is on a saddle, its an upright bike. If you're seated on something that has a backrest, or could be describes as a chair, then its recumbent (or semi-) and if your shoulder blades or mid-spine is resting on a backrest then its fully recumbent. Comment because its opinion.
    – Criggie
    Jan 18, 2017 at 3:03
  • I don't think there is. Sheldon has some classification system for recumbents, but I don't think anyone else uses that system.
    – Batman
    Jan 18, 2017 at 3:14
  • @Batman do you mean the short vs long wheelbase, high vs low handlebar stuff? That is fairly standard, but commonly the handlebars are "above seat" and "under seat", with acronyms: SWB, LWB, ASS, USS. But those are almost exclusively bikes, because there are so few LWB or ASS trikes and quads. Unicycles tend not to be recumbent :)
    – Móż
    Jan 18, 2017 at 5:50

2 Answers 2


Short answer: whoever is describing it.

There are a bunch of dictionary definitions around that all centre on the "lying down" part, which doesn't help when there are recumbents with quite upright seating positions:

lwb recumbent with upright seating position

as well as (semi?) recumbents with quite small backrests and seats off upright bikes:

semi-recumbent with seat back behind upright seat

At the other extreme, of course, you have the virtually horizontal positions mostly used for racing:

very laid back recumbent

I am inclined to the view that anything with a laid back seating position and a backrest is probably a recumbent.

Note that the racing world has side-stepped the whole definitional question in favour of using "human powered" to describe what they care about. You get the "International Human Powered Vehicle Association" which sadly doesn't have a space vehicle category yet. They do have categories for number of riders, multitrack and single track, and age/sex ones. But no "recumbent vs prone vs upright" rider position ones.

  • 7
    I especially liked I am inclined to the view :-)
    – andy256
    Jan 18, 2017 at 11:35

A Recumbent is a bike with a SEAT, whereas other bikes are equipped with a SADDLE.

The difference here is that you can get out of a saddle while riding, for increased power or comfort or balance. You cannot get out of a seat while riding because its supporting all of your weight.

Horses have saddles because the rider can stand in the stirrups, whereas cars have seats because there's no way for the driver to effectively stand while driving. By that logic a motorbike seat should be called a saddle as well.

So a recumbent is any bike that has a seat instead of a saddle. The crossovers would be the semi-recumbent or crank-forward bikes which are a bit of both.

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