So, I recently decided to research how to calculate traction, specifically the traction of a car, so that I could have a  mathematical rebuttal in conversations with people sayin that speed limits are just arbitrary, I ended up on engineeringtoolbox.com, where there was an entire page for car traction, which featured this formula  F = μt W. They give an example of a car that has a mass of 2000 kg, and calculate the traction of one wheel, on wet asphalt (cohesion = 0.5), the formula looking like this  0.5 ((2000 kg)  (9.81 m/s2) / 4)   = 2452 N

 But when I started to calculate the traction of one tyre, using the formula given on the page, with a car weighing in at 1515 kg, on  wet asphalt, the formula looking like this  0.5 x ((1515 kg) x (9.81 m/s2) / 4) = 18 224.71


Am I doing something wrong, or have I misinturpreted the the formula, and what it calculates. Picture attached shows how my formula is set up. 

Link to the page: https://www.engineeringtoolbox.com/tractive-effort-d_1783.html

SomeoneSomewhere  Jan 14, 2018

2+0 Answers


0.5 ((2000 kg)  (9.81 m/s2) / 4)   = 2452 N - This is accurate.


[0.5 x 1,515 x 9.81] /4 = ~1,858 N - What your calculation should be. Don't square 9.81!! That is just the force of gravity on Earth=9.81 meters per second per second!!.

Guest Jan 14, 2018

Thanks man. 

I want to say something like 'I was tired' or some other excuse, but I guess I am just a bit dumb. 

Thanks again though. 

SomeoneSomewhere  Jan 14, 2018

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