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Introduction: Bicycle Design
Why Upright Bikes?
Why Recumbents Cost More
Types of Recumbents
Seat Height
Handlebars
How Much To Spend?
The Importance of Wheels
Types of Wheels
The Importance of Weight
Frame Materials
Frame Alignment
Parts, Derailleurs etc
Brakes
Suspension
Are Recumbents Invisible?
Acclimatizing to a Recumbent
Hills on a Recumbent
Clip-On Pedals
Racks & Mudguards
Bicycle Trailers
Trikes
How to Ride a Tandem
Credit Card Touring
Information Sources
Vancouver, British Columbia
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Types of Recumbent Wheels

The common upright wheel sizes are 26-inch for mountain bikes and 700c for road bikes. Those sizes are optimized for large off-road tires and the crossing of European cobblestones, respectively. The 700c wheel was originally designed to bridge the gap between paving blocks (or bricks or stones) on rural cart tracks. Recumbents are mainly used on roads and modern roads tend to be smooth.

Recumbents can take advantage of the smaller 20-inch wheel which offers performance advantages on a recumbent. 20-inch wheels are inherently strong. The 20-inch wheel is smaller and lighter so it has less rotational inertia than the 26-inch or 700c wheel. The 20-inch wheel can accelerate more quickly. A recumbent with two 20-inch wheels accelerates like it is rocket-powered. Indeed, one recumbent model with the dual 20-inch configuration is named the “Rocket” by its manufacturer.

Theoretically, the 20-inch wheel should have a higher coefficient of rolling resistance than a wheel with a larger diameter carrying the same weight. In practice, the 20-inch wheel seems to offer the same speeds as the larger wheels.

Rolling resistance is affected by tire pressure, tire material and tire construction. A more supple tire will have less rolling resistance and many modern clincher tires have very low rolling resistance. A type of tire deformation leads to higher rolling resistance and tires with more air in them deform less.

Keep in mind that wind resistance on a bicycle makes up a far larger proportion of total resistance than rolling resistance. Although wind resistance on bicycle wheels is not going to matter very much for most cyclists, the 20-inch wheel has a smaller wind profile which will cause less aerodynamic drag, especially at high speeds.

Theoretically, 20-inch wheels should have their shorter (circumference) braking surfaces wear out more quickly than a larger wheel. That may well be the case for some cyclists but the wheel can simply be rebuilt, and probably should be at that point anyway. The 20-inch wheel has a smaller thermal mass than the larger wheels and should therefore be more subject to overheating. In real-life riding, the overheating of 20-inch wheels does not usually pose a more noticeable nuisance than that of larger wheels.

Most recumbents use two different sized wheels. Some former upright cyclists have objected to carrying two sizes of spares. However, 20-inch spare tubes (and tires) are not as heavy or bulky as large wheel spares.

The present industry standard common “20-inch” wheel size is 406mm.

26-inch and 700c wheels are sometimes used on the rear of recumbents to simplify drivetrain choices. Those wheels can use the same drivetrain combinations as upright bikes. Smaller wheels require a larger chainring to reach the same top speed as a larger wheel. The larger rear wheels may also offer a very slightly more comfortable ride (for a tandem stoker or single bike rider) over coarse pavement or fire roads. For example, coarse pavement would include newly applied sealcoat with large-sized gravel. Any noticeable smoothness will result from the longer contact patch of larger diameter tires, which can bridge gaps in the road surface.

Course road surfaces are also handled better by very supple tires which tend to conform to the surface and absorb some of the annoying zing of a rough surface. Silk tubular tires, used by some bike racers, offer a magical ride and some clincher tires come close to silk tubulars in ride quality. Surface smoothness will not be an issue for most cyclists because most areas do not sport roads with horribly coarse surfaces. Fire roads and trails are not an issue for most cyclists either. Most cycling is done on pavement. Even most people who own mountain bikes rarely, if ever, ride them off-pavement.

A larger 26-inch or 700c front wheel on a long-wheelbase recumbent does not really make any difference to comfort because the front wheel is far away from the rider and road forks provide a bit of suspension.