Ok, it's been a couple years since I originally installed the system on my 2004 Wing and 2009 CSC Escapade Elite trailer. All but one sensor is now dead. The batteries started going on them all about 6 months ago. So, effectively, I'm seeing what others are seeing - approx. 1 1/2 years battery life. I'm not sure how Doran is obtaining or even able to claim an expected battery life of 3-4 years, as I've yet to hear of anyone getting that much battery life out of them. Hence, I'm dropping my rating to 3 Stars. It's still a great and reliable system and provides excellent piece of mind, but keeping it operational is going to cost some coins. Per my original post, I mounted the original sensors "inside" the rims. I won't do that again with the replacements, as the tires are outlasing the sensor batteries. I'm now changing out the tires on the Wing a little earlier than really necessary, so I'll replace the 90 degree stems on the Wing with the straight stems, and mount the sensors outside the tires this time. Will do the same with the trailer sensors too when the last sensor dies. My customer service experience with Doran has been positive on both occassions that I've had to contact them. I too received one dead sensor when I first purchased these in 2009, and a simple call to them, and it was replaced free, although one other sensor had to be replaced at that time too, as it was "crushed" during the mounting process. I just called them today to order fresh replacement sensors. They were only $25.00 each, the same amount they were back in 2009. Maybe they have rolled back their price since recent posts are claiming the sensors cost them $50.00 each to replace.

I purchased the 360M4 for my wing and trailer and was hoping to finally find a TPMS solution that worked. Unfortunately like any other product this one has issues. The first issue I encountered is the sensor locking rings that come with the kit as pictured are fragile and are difficult to use with 90 deg valve stems. The second issue is two out of the four sensors are DOA. I can confirm that Doran have doubled the price for replacement sensors to 50$ each. Replace six sensors and you have paid for the kit again. I've contacted Doran about warranty claim for the two DOA sensors in a new kit but they have not responded yet, time will tell.

3 years ago I gave this 5 stars. Now I give 2 because of the cost of replacing the sensors have just DOUBLED. Doran claims 3 to 4 years of life. More like 1 1/2 to 2 years. I have a set in the box that I purchased with the set I am using. At the time I purchased these they did not have a system for trailers so I thought about putting a system on just for my trailer, mounting the display in the trunk and using the red light as a warning by the dash. I never installed the 2nd set. Sitting in the box they did not last 3 years. I went to use one of the sensors from the spare set, and it was dead. At $25.00 to replace the sensor I felt I could afford that cost every 2 years, but $50.00 per sensor?. Doran DOUBLED the cost of the sensors, so if you have a trailer your looking at $200.00 every 2 years just to keep the TPM working. I wrote Doran asking for a explanation why the sensors doubled in price, did they do some huge changes to them, do they now really last 4 years, or did they just double the price?. No answer in the past 2 weeks. This is still the best system I found, it has just become very expensive to maintain.

I've had these on my Wing and CSC Escapade Elite trailer for well over a year now. Excellent piece of mind. Accurate and consistent with other pressure guages +/- 1 PSI (assuming you are using quality guages). Readings will remind you to add air to the tires in cooler temps if it was warmer when air was last put in the tires. Takes a couple minutes or more sometimes for the sensors to provide pressure readout. As noted by another reviewer, when not pulling the trailer, you need to "de-program" the sensor numbers for the trailer tires or the device will assume there's a problem. Make sure you write down what sensor number is installed on what tire (especially if you install them inside the tire)!

Two major observations/concerns: 1) Had the sensors mounted "inside" of the tires to protect them from the elements and hopefully last longer. Your tire installer has to be VERY Careful and not "pinch" or "crush" the sensor that is installed on the bottom of the valve stem when they use a tire machine. It fits pretty tight up against the interior rim contour of the Goldwing's Rims. There's little room for error when you remove or mount a tire and there is a specific way it should be done to prevent damaging the sensor in the process. Had one pinched ever so slightly which made it inop when tire was installed. 2) Once installed, you might be amazed at how much "counter weight" needs to be added to the rim of the tire to off-set the weight of the sensor. Also, some folks don't bother balancing trailer tires, but if you install a sensor on your trailer tires, either inside or out, you might reconsider doing that.

Durabilty/Reliability: Notwithstanding the great care that needs to be exercised when installing the sensors inside the tire, which I believe was a good decision (both for cosmetics and enhanced protection of the sensors) I did have one on the trailer that seemed to work "intermittently". Duran sent me a replacement free of charge (but I had to pay for the "pinched" one).

As for battery life, so far, so good, but I agree with other reviewers that for the price of the sensors, they should have a way to replace the battery and from what I can tell, replacement sensors are only available directly through Duran. There are plenty of "water proof" devices with "O" rings that batteries can be replaced in.

Duran claims the sensor batteries should last 3-4 years, but since I go through a set of tires about every couple years, I think I'll simply "replace" all the sensors at that time, to ensure they all have fresh batteries along with a new set of tires. The cost of a new set of sensors vs the cost and effort in removing the tires in order to replace a sensor (assuming the tires don't need to be changed when the sensor dies), may be worth it.

Pros: Reliable as long as the sensors work in the first place and the batteries last.
Unit is waterproof and runs off the bike
Has remote warning light I mounted on dashboard

Cons: Sensors are huge and cannot replace the battery. Battery life is estimated to be 3 to 4 years. My rear one did not last 2 years. They are active as long as they are screwed on the valve stem. I had to add another one to the outside of the rear tire so I didn't have to have a sensor. Luckily I had Centramatic balancers.
The unit will go nuts if you don't have the trailer hooked up, because it will loose the sensors. so you have to unprogram them every time you leave the trailer.
My trailer sensors were weak and only intermittently worked when attached.
Doran has no plans to fix the battery issue because their engineers don't believe in having the capability to change the battery due to the o-ring. They also don't have plans to have G-force activation like cars do.

I have tried to get my trailer sensors replaced twice. While Doran was seemingly co-operative on the phone, they never sent out the replacement sensors they said they would. The info I have given for their plans came from these conversations.