TireTraker Tire Monitoring System – Review

[tractors1]

Originally Posted by sokhapkin

Stem screw on sensors can't provide accurate tire temperature reading by definition. Because they are not inside the tire.

I've never seen that definition published.

The air temp inside the main body of the tire is going to be very close to the air temp in the stem. It's well mixed - do the math and you'll find that a 30 inch diameter tire spins at 17.6 revolutions per second when traveling at 60 mph. The sensor samples that same air since it opens the stem valve.

Just the opinion of a retired engineer - and I trust my TPMS; I don't need to know the exact temperature of every tire - just the one of the four that reads differently.

[sokhapkin]

Stem temperature is closer to the ambient air temperature rather than to inside tire temperature, especially when the vehicle is moving.

[tractors1]

Originally Posted by sokhapkin

Stem temperature is closer to the ambient air temperature rather than to inside tire temperature, especially when the vehicle is moving.

How did you actually measure that difference? What instrumentation?

My stem sensors have run around 95 degrees when driving long hauls at 60 mph on a 70 degree day (with the trailer fully loaded.)

[sokhapkin]

No instrumentation involved, just a common sense. Steam on sensor can't sense a temperature inside the tire, the stem is cooled or heated by outside air or by the wheel. It measures outside the wheel temperature. 95 degrees could be induced by the brake drum or wheel rim heated by the drum.

Only inside the tire sensor could provide the accurate tire temperature.

[tractors1]

Originally Posted by sokhapkin

No instrumentation involved, just a common sense. Steam on sensor can't sense a temperature inside the tire, the stem is cooled or heated by outside air or by the wheel. It measures outside the wheel temperature. 95 degrees could be induced by the brake drum or wheel rim heated by the drum.

Only inside the tire sensor could provide the accurate tire temperature.

But the internal sensor isn't mounted on the tire. It's on the same rim as the stem.

It's not "common sense." It's basic physics and engineering in my opinion. Without instruments to refute mine I'll stay with that.

Common sense once had a lot of folks believing the world is flat and the sun revolved around the earth.

[sokhapkin]

Internal sensor is inside the tire. Screw on stem sensor is few inches outside the tire. That makes a big difference in the inside tire temperature sensing.

As for basic physics, any temperature sensor measures its own temperature. The temperature of inside tire sensor is much closer to inside tire temperature than temperature of screw on stem sensor.

[tractors1]

I'm ending the discussion with Sergey before a moderator jumps on me. Let the thread resume.........

[honda03842]

Originally Posted by sokhapkin

Internal sensor is inside the tire. Screw on stem sensor is few inches outside the tire. That makes a big difference in the inside tire temperature sensing.

As for basic physics, any temperature sensor measures its own temperature. The temperature of inside tire sensor is much closer to inside tire temperature than temperature of screw on stem sensor.

I would also question the 'absolute' accuracy of temperature and maybe even pressure.

Absolute accuracy isn't necessary to provide value. The reality is that you can see pressure and temperature changes. When one tire is 20 degrees hotter than another you can recognize a problem, when you see pressure dropping compared to another.....

We've seen both situations. As suggested we had a tow vehicle without pressure sensing and installed the two extra sensors on the tow vehicle.

Our new tow vehicle has sensors inside the tires but only reports a fault and does not monitor temperature, they're not as good as the stem sensors we had.

[sokhapkin]

I believe factory inside tire sensors transmit detailed pressure and temperature information to the vehicle. But the vehicle's computer is programmed to show alerts only.

It's like factory car dashboard is showing only a limited number of predefined parameters. Connect Scan gauge device to the OBD2 port - and you get a hundred more parameters on its display. When I towed with Mercury Grand Marquis I used Scan gauge to display transmission fluid temperature and MPG.