RR8 Rolling Resistance

2010-05-18

We measured the rolling resistance of RR8 on a smooth and level floor inside the schools DT department. The test was done with the car including batteries and a driver. The car was pulled behind a model tank with a piece of string and two force meters in parallel (we didn't have one of the right amount and so used a 10N and 5N one). The motor was driven by the chain drive and we were using Schwalbe Durano tyres at 100PSI.

The all up weight was: 53Kg(Car) + 40Kg(Bats) + 48.6Kg(Driver)

The average force was: 8.5N. Cr is about: 0.006

With the rear tyres replaced with Schwalbe Kojak's at 100PSI:

The average force was: 10N. Cr is about: 0.007

With a greater all up weight and the Kojak tyres:

The all up weight was: 53Kg(Car) + 40Kg(Bats) + 79Kg(Driver)

The average force was 12N: Cr is about: 0.007

With the greater all up weight and the Kojak tyres at 110PSI:

The average force was 11N: Cr is about: 0.0065

Note: There was quite a variation in readings as it was difficult to keep the car moving at a steady pace. These were the average of about 8 runs in each direction.

Driver Weights