Strain on valve stems with air pressure monitors

[RF_Burns]

So I installed air pressure monitors on my tires last year. TST unit with 6 monitors included for $199 which seemed to be a good deal. So far has
worked excellent.

Then I read the monitors should be installed on all steel valve stems. Mine are rubber with a metal sleeve which seem to be rated for our use up to
80psi (I believe). So I Googled a site with a centrifugal force calculator to measure this. The sensor weights 0.77 oz according to the TST site and
the distance from the center of the wheel to the center of the sensor is 6.5". So at 700rpm (approx for 65MPH on my LT225/75R16 tires) the calculator
indicates 4.4Lb-force.

That seems like alot! maybe I'm using the calculator wrong, but I then tried several others with the same result. It works out to be a 100 times
increase in weight force.

Has anyone had issues with the sensors causing issues? Have you changed to all metal valve stems?

Thanks,
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[RF_Burns]

JP,
Its the force on the valve stem that I am worried about. It didn't occur to me that o.77oz could become 4.4lbs at 700rpm. Not to mention that in the
linear direction, the circumference of the tire goes from Stop, accelerates to 120mph at the top of the rotation, then decelerates to zero mph again
when the rubber meets the road... 700 times per minute.
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

 

[john r. lebetski]

Are these the add on screw on type? Realize that those have the schraeder depressed so it can't do it's job and you are relying on the threads and
the seal there to retain air. Not a fan of add on's that can cause faults.
--
John Lebetski
Woodstock, IL
77 Eleganza II

 

[RJW]

> So I installed air pressure monitors on my tires last year. TST unit with 6 monitors included for $199 which seemed to be a good deal. So far
> has worked excellent.
>
> Then I read the monitors should be installed on all steel valve stems. Mine are rubber with a metal sleeve which seem to be rated for our use up
> to 80psi (I believe). So I Googled a site with a centrifugal force calculator to measure this. The sensor weights 0.77 oz according to the TST site
> and the distance from the center of the wheel to the center of the sensor is 6.5". So at 700rpm (approx for 65MPH on my LT225/75R16 tires) the
> calculator indicates 4.4Lb-force.
>
> That seems like alot! maybe I'm using the calculator wrong, but I then tried several others with the same result. It works out to be a 100 times
> increase in weight force.
>
> Has anyone had issues with the sensors causing issues? Have you changed to all metal valve stems?
>
> Thanks,

I have a TST TPMS with flow through monitors (sensors). I have Alcoa wheels and metal valve stems. The sensors are a fairly tight fit in the wheels
which probably help to keep them from moving around.

I installed them in July 2013. It's been over 40,000 miles and almost 6 years and the only issue I had was at random intervals, some of the sensors
would drop off and not display. The solution was to add a repeater. That fixed the problem and I have no issues.

The system works great. I would not want to be without TPMS.

--
Richard
76 Palm Beach
SE Michigan
www.PalmBeachGMC.com


Coop Roller Cam 455, Howell TBI + EBL, 3.42 FD, Quadra Bag, Macerator, Lenzi stuff, Manny Tranny etc.

 

[johnny]

Bruce, the tire doesn't start and stop each rotation - it rotates at a constant speed. The motion of any spot on the tire accelerates and decelerates
>relative to the ground