What's your opinion of something like this

[Thunderbolt]

http://www.jcwhitney.com/tiregard-tpms-wireless-tire-monitor/p2021694.jcwx

Rode with a friend today that has these on his Goldwing.  When the valve stems that turn colors etc. came out, it concerned me that you are releasing the valve core and allowing the cap to hold the tire pressure.  This puts your safety on whatever is screwed onto the valve stem.  These have what is termed as an anti theft ring that you put on ahead of the cap with the sensor in it and tighten an allen screw to keep it attached.
These have instantaneous reading of tire pressure and temperature.  The sensors supposedly sense centrifugal force and turn off when the bike stops.

[Thunderbolt]

I have seen them as low as $149 at other sites.

[Thunderbolt]

I have metal 90 degree stems from Patchboy on mine, but the rubber OEM stems would probably tend to leak or fail with the extra few ounces of weight.

[Valkpilot]

I have metal 90 degree stems from Patchboy on mine, but the rubber OEM stems would probably tend to leak or fail with the extra few ounces of weight.

I just bought one from e-bay for quite a bit less than that price.  Works as advertised.  The caps don't weigh "ounces", but I would only use them with all metal stems such as Patchboys.

[Disco]

I don't have experience with the Show Chrome TPMS, but I've always been satisfied with their other goodies (much more so than kuryakyn).  

I do have several years and about 30,000 miles of experience with the Doran 360 TPMS.  I love it.  Its sensors can go either outside the tire OR inside the tire on the included metal valve stems.  They look just like patchboys valve stems but are threaded on both ends.  

Whichever way you choose to go, it's a REALLY nice feeling to be able to reach up, press a button, and see what pressure your tires are...  

[TJ]

  They work great Terry.. Had them on the Rainbow Dragon & the wing...
Never any leaks with metal stems...

[The Anvil]

I know quite a few guys who have mounted a similar system on their aircraft. Metal stems are no problem. Personally I think you'd probably be fine with rubber stems too. But you wanna balance the assembly with them installed whenever possible.

[Patrick]

Hummm, I was going to stay out of this, but, you asked for an opinion, and, I have one.. I've seen these critters, but, didn't know the cost.. Anyway, I have no problems with checking air pressure in tires[ tricycle, aircraft, trailer, etc] or any such thing as even a water system pressure tank with a good old hand held pressure gauge.. I kinda getting close and personal with such stuff cuz it allows you a close look at other things too.. Besides, I think you needed an opposing opinion..

[Valkpilot]

I know quite a few guys who have mounted a similar system on their aircraft. Metal stems are no problem. Personally I think you'd probably be fine with rubber stems too. But you wanna balance the assembly with them installed whenever possible.

The OEM stems that are a combination of metal but with rubber going through the rim are subect to cracking if flexed much or too often.  That's the primary purpose of the little plastic stand that hooks to the stem and the wheel -- to limit flexing.  The bad news is that when the rubber part that goes through the rim cracks, it can come apart suddenly causing rapid deflation of the tire.  This is sometimes a catastrophic failure when it happens at highway speeds.

Many here have switched to an all-metal 90° stem such as the Patchboy models.

Even though the additional weight of the the sensors is minimal, I would hesitate to use them on anything but all metal stems.

And as far as an up-close-and-personal check of things while airing up the tires, I'm all for that.  But I'm also all for knowing what my pressure is as I ride so that I can monitor changes that might alert me to a problem before it becomes a handling issue or cause a crash.  That's the main reason I bought one of these systems.

[Rocketman]

I've been having a discussion with some folks local to me regarding tire pressure vs. temperature (and thus riding speed/time, since that changes the temperature). 
Can anyone who has this system comment?  How much does the pressure increase from cold after, say, 1/2 hour of highway speeds?

[Thunderbolt]

Not sure I am accurate on the numbers, but seem like we stopped for gas after running interstate speed and got gas and some gatorade.  From when we stopped to just before we left the station, I think he said it had dropped several degrees and 5 or so pounds.  Hopefully someone who actually owns one will comment as you requested.