Traction refers to the maximum frictional force that can be produced between surfaces without [1][2]
slipping. slipping.
The units of traction are those of force of force,, or if expressed as a coefficient of traction (as with coefficient of friction) friction) a ratio ratio..
Coefficient of traction The coefficient of traction is defined as the usable force for traction divided by the weight on the running gear (wheels, tracks etc.) etc. )
[4][5]
i.e.:
Usable Traction = coefficient of Traction x Weight As the coefficient of traction refers to two surfaces which are not slipping relative to one another it is the same as Coefficient of static friction, friction , also known as limiting friction. friction.
Go Kart Live Axle or Single Drive - DIY Go Karts www.diygokarts www.diy gokarts.com/ .com/kart kart-parts/ -parts/go go--kart kart-drive-axle.html -drive-axle.html
Go karts use a variety of rear r ear axle types. The most common for DIY types is the single wheel drive, but two wheel drive karts are also popular. The simplest of these is the live axle, and the more complicated use a differential. di fferential. A live axle means that the wheels are mounted directly to the axle, and the axle spins. A dead axle would be where the wheels spin freely and the axle does not turn.
Live Axles for Go karts use a variety of rear axle types. The most common for DIY types is the single wheel drive, but two wheel drive karts are also popular. The simplest of these is the live axle, and the more complicated use a differential. di fferential. A live axle means that the wheels are mounted directly to the axle, and the axle spins. A dead axle would be where the wheels spin freely and the axle does not turn.
Live Axles for Traction A live axle on a go kart means that the engine will power both rear wheels at the same speed and power. This is accomplished with a single sprocket mounted to the live axle. Since both wheels are locked in to the power all the time, off road go karts often use a live axle. When both wheels are turning at the same time, you'll have twice the traction. This is great for sand, loose dirt, etc, where a single wheel would often spin out. This is not to say that live axles don't have their drawbacks. Unfortunately for the onroad set, a live axle means that turning is difficult. This is because both rear whe els turn at the exact same speed. When making a turn, the outside wheel must be able to spin faster than the inside wheel. If they are forced to turn at the same rate by a live axle, then the outside wheel must slip on the driving surface in order to turn as fast as needed. That's easily accomplished on dirt and sand; the outside wheel can slip without problem. But on hard dirt and roads, the wheels have much more traction, and therefore it's harder for that wheel to slip.
Traction by the Numbers A more objective approach to the discussion of the traction chara cteristics of various surfaces is possible. . I have reproduced one chart of various Tracti on Coefficients below. None of the available information discusses differences among tire brands or tire compounds, only differences of the ground surface. Coef fi cient of Tr acti on Defi ned: The degree of traction between the tire and the ground is called the Coefficient of Traction. A spinning wheel does not deliver useful power to the ground. The two factors which keep a wheel from spinning are the mass it carries and the traction available from the ground conditions. Since there is never 100 percent adhesion, the coeffic ient is always less than 1.0. The result of multiplying the weight on the drive axle times the coeffi cient of traction represents the maximum force which can be transmitted before the tire spins. It is worth noting that in the all sources of information I found while researching this subject, the only variable considered was the ground surface. Tire type, construction, tread style, or rubber compound were not given any consideration. Probably the reason for this is that the variati ons in the ground surface overwhelm any variation of tires in this matter.
Coefficient of Traction for Rubber Tires on Various Surfaces Source: Forestry Handbook by Karl F. Wenger (1984) Concrete (dry) Asphalt (dry) Asphalt (wet) Gravel (packed, oiled, dry) Gravel (packed, oiled, wet) Dirt (packed, dry) Mud Snow (dry, on loose gravel) Ice (free of snow)
.70 .50 .45 .50 .40 .50 .15-.40 .25 .07
There seems to be general agreement among experienced Bonneville racers that the Coefficient of Traction for a best case prepared course at Bonneville is about .45 - .50 and can range downward to as low as .25 when the hard groomed surface breaks down into sandpit like conditions.
