Street tire static and kinetic friction coefficients?

In summary, the conversation discusses finding data on normal street-tire friction coefficients on dry asphalt, including both static and kinetic coefficients. The conversation also mentions racing slicks on asphalt and possible sources for obtaining the data, such as calculating the static coefficient from breaking distance or using police forensics. The conversation concludes with the discovery of a website that may have the desired data.
  • #1
ektrules
35
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Anybody know where I can find data on normal street-tire friction coefficients on dry asphalt? I'd like both the static, and the kinetic coefficients. If not, can somebody give me a range of reasonable values?

While I'm at it... What about racing slicks on asphalt?

I found one source that said the static friction coefficient of a tire on concrete is about 1. But, it didn't say what kind of tire, didn't give me the kinetic coefficient, it's on concrete, and it seems too high.
 
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  • #2
You may calculate static coeff from breaking distance of cars using ABS. For most family cars breaking distance on dry asphalt from 100 km/h is 45-50 meters, thus (static) friction coefficient is 0.8-0.9.
Porsche 911 Carrera Turbo on rally tyres on standard German asfalt pavement claims breaking distance of 34.5m => f.coeff=1.1

Regarding kinetic coeff: police forensics use coeff=0.7 for dry and 0.55 for wet asphalt to compute speed from skid marks during collision investigation.
 
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  • #3
http://hpwizard.com/tire-friction-coefficient.html" [Broken]

https://www.youtube.com/watch?v=_rVprtWPsiw
 
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  • #4
Oh, cool. Before I started this thread, I got search results from that site, but the site was down at the time. I didn't know what was on that site. Thanks.
 
  • #5


I can provide some information regarding street tire static and kinetic friction coefficients. The friction coefficient for a tire on a dry asphalt surface can vary depending on factors such as tire material, tread design, and surface condition. However, a reasonable range for the static friction coefficient is between 0.7 to 0.9, while the kinetic friction coefficient is typically lower at around 0.5 to 0.7.

Unfortunately, I do not have specific data on normal street tire friction coefficients on dry asphalt. However, you may be able to find this information from tire manufacturers or through scientific research studies.

Regarding racing slicks on asphalt, the friction coefficients can be significantly higher due to their specialized design and materials. The static friction coefficient can range from 1.0 to 1.3, while the kinetic coefficient can be around 0.8 to 1.0.

It is important to note that these values are estimates and can vary depending on the specific conditions and variables involved. Therefore, it is always best to consult reliable sources or conduct experiments to determine the exact friction coefficients for a particular tire and surface combination.
 

1. What is the difference between static and kinetic friction coefficients?

Static friction coefficient refers to the force needed to overcome the initial resistance between surfaces at rest. Kinetic friction coefficient refers to the force needed to maintain movement between surfaces in motion.

2. How is the static friction coefficient determined for street tires?

The static friction coefficient for street tires is determined by conducting controlled experiments using a specialized machine that measures the force required to move a tire on different surfaces. The average of multiple trials is then calculated to determine the static friction coefficient.

3. What factors can affect the static and kinetic friction coefficients of street tires?

The main factors that can affect the friction coefficients of street tires include the composition and texture of the road surface, tire tread design, tire pressure, and the weight and speed of the vehicle.

4. How do the friction coefficients of street tires compare to other types of tires?

The friction coefficients of street tires are generally lower than those of off-road or racing tires, as they are designed for everyday driving and not high-performance situations. However, they are higher than those of winter tires, which are designed to have lower friction for better traction on snowy and icy roads.

5. Can the friction coefficients of street tires be improved?

Yes, the friction coefficients of street tires can be improved by using tires with a higher tread design, maintaining proper tire pressure, and adjusting driving techniques to reduce excessive speed or sudden braking. However, it is important to note that the friction coefficients are also limited by the road surface and external factors.

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