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2003 1200LT
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337 Posts
Discussion Starter #1
I was just setting up my tpms on my front Met 888 and read Shinko 777HD and I realized neither tire apparently has a temp rating on it. I went to find something and am not easily finding a temp xref to H rating and pressure.

The default on this tpms is 150 degrees. I thought at first I would check my car's specs since its tires are H rated and A rated for temp. Then I found on Tirerack that even though H means sustained lab speeds of 130mph, A temp rating only means tires can exceed 118mph in the lab. Neither of which gives me a good number to baseline as what should set off my tpms for excessive temperature.

I think I am going to just leave it at 150 and see if the tire temps even get close to that as it gets warmer. I wonder why these tires have no temp rating, or are they exempt like certain other tires? I do know my Michelin Road GT 4s got up to 130+ on a hot summer trip once on my RT. Now that I think of it, not really sure what pressure to use as "high" since I guess pressure would be correspondingly high to some point as temp rises?
 

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Wrencher Extraordinaire
2005 K1200LT
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14,257 Posts
I have run a smartire system for many years now and it only alerts at 176 F. I have seen my Bridgestone rear reach 160 in the summer with a full load. The old ME 880 would run a few degrees cooler for the same load.

Depends on the system. Does it temperature compensate the pressure? The BMW factor ones do (K1300GT it always read 42 rear cold and hot). My smartire system give me three parameters. Actual pressure, delta P (difference from cold; compensated) and temperature. So as long as I see delta P + - 1 or zero the tire has not lost air. It will alert if delta P goes above or below 5 psi. Going down the road with a cold setting of 47, I have seen actual pressure at 58 and temp at 160 but delta P was zero.
 
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Registered
2003 1200LT
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337 Posts
Discussion Starter #3
Thanks for the response, John. Mine is not that fancy, one of those RUPSE models but it does a good job of staying within about a pound of what my higher dollar air gauge says is in the tire. It measures temp through the metal valve stem I assume so doubt it is super accurate but it checks often and I have let out pressure before in the garage and it is pretty quick to signal.

Guess I'll leave it at 150 and carry a laser thermometer with and see how close the temps are when it gets warmer, I can toggle pressure or temp.
 
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