Tyre temps..........

[Donal]

While checking out the local weather forecast on TV I came across some F1 footage of qualifying in Japan. I was absolutely fascinated by the IR shots of tyre temps and how they cycled so rapidly during the race.

I had always imagined that when a tyre got up to 'working temperature' then you were in good shape.

Have a look at this clip https://www.reddit.com/r/videos/comments/1lvgss/thermal_camera_footage_showing_heat_distribution/ (sorry, don't know how to embed video).

 

[mcatrophy]

While checking out the local weather forecast on TV I came across some F1 footage of qualifying in Japan. I was absolutely fascinated by the IR shots of tyre temps and how they cycled so rapidly during the race.
I had always imagined that when a tyre got up to 'working temperature' then you were in good shape.

Have a look at this clip https://www.reddit.com/r/videos/comments/1lvgss/thermal_camera_footage_showing_heat_distribution/ (sorry, don't know how to embed video).

Help:



Remember they use false colours to indicate the temperature, but nowhere do we get to see the range of temperatures they are showing.

Where I worked before retirement, I was part of the design team of test equipment that used radiation pyrometry to show the temperatures of turbine blades in rotating aero-engines. Beside every resulting image we put a colour calibration chart. Have a look at the image below, taken from the published sales bumf.

Of course, it's not quite that simple, the radiation depends on the surface properties (emissivity) as well as the temperature, so precise temperature calibration is almost impossible.

But it does make for impressive viewing. They often show these shots on F1 broadcasts now.

 

[Donal]

Thanks for the assist.........

Taken form the blurb below the video "Paul Hembery (Pirelli Director of Motorsport) said the purple was 170°C and the orange was 300°C"

 

[mcatrophy]

...Taken form the blurb below the video "Paul Hembery (Pirelli Director of Motorsport) said the purple was 170°C and the orange was 300°C"

Missed that!

That's well hot for a tyre. Hope mine never get anywhere like that.

 

[ionbeam]

The tire temps of a racing tire is amazing! But, with that heat comes the down side of low tire life and the up side of crazy adhesion.

A general rule of thumb is: Tire pressure changes 1 psi for every 10° of temperature change.

The bike I'm riding right now has a tire pressure monitor system. When the bike is cold (~50°) it reads 40/41. At normal road temperature it reads 41/42 and when the porky bike is flogged through very curvy roads, very hard, with ambient temps in the mid eighties the tire pressure read 43/44. This is a temperature range that indicates the tires are inflated correctly for the load and use. Any higher temp rise indicates the tires are under inflated for the load and use.

Racing specific tires -- that's a whole different story. My street tires are designed so they have a life expectancy between 6k to 12k miles. A racing tire only needs to complete a small number of laps because the tire compound runs near the melting point for the very best adhesion possible. All serious races begin with bringing the tires up to temperature. Bike track rats even have tire heaters that get wrapped around the tires to get/keep the tires at temperature.

Street/Tour tires = low heat, long mileage. Racing tires = blistering hot for very best adhesion and only needs to make a very short distance.

 

[RossKean]

A general rule of thumb is: Tire pressure changes 1 psi for every 10° of temperature change.

Although I doubt that this applies to the temperatures indicated in the video (as I'm sure you know). The big excursions are brief moments of extreme tire surface temperature fluctuation. The temperature of the air (or N2) inside the tire is what affects the pressure and I would think it would hit a more-or-less steady state after several minutes. I wonder what is typical for tire internal temperatures? In a race, it is interesting to see the drivers deliberately weaving back and forth to keep the tires hot when there is a caution flag out.

 

[Twigg]

The softer tire on F1 cars are so soft that they can only deliver an ultimate lap time for 1, or possibly 2 laps. That means they are past their best in 2 to 6 miles, and rarely stay on the car at race-pace for more than 25 to 40 miles. They can hold a car on the track at acceleration and braking forces of up to about 6g.

They cost, I believe, about $2000 each.