TPMS questions for 2020 Unity with Alcoa wheels

mikescha

New member
We have the stock Continental tires on Alcoa wheels on our 2020 Unity MB. The valve stems appear to be metallic and not rubber, and there is an extension in the rear wheels to enable easily adding air to the inner tires. I would like to put a TPMS system on, probably either the TST 507 or EezTire.

1) How do I know what kind of metal the valve stems are? I read somewhere that if they are aluminum, then I need a different sensor.
2) Will the flow-through sensors fit on the shorter rear wheel valve stem (the one for the outside tire, which faces toward the interior of the RV)? The opening in the wheel to access the stem if fairly small so I would love to hear from somebody that has made this work.
3) If the flow-through won't fit, then will the cap sensors? Or do I need to get some kind of 90deg extension for the stem.

Thanks!
 

RangerDave

New member
We have the stock Continental tires on Alcoa wheels on our 2020 Unity MB. The valve stems appear to be metallic and not rubber, and there is an extension in the rear wheels to enable easily adding air to the inner tires. I would like to put a TPMS system on, probably either the TST 507 or EezTire.

1) How do I know what kind of metal the valve stems are? I read somewhere that if they are aluminum, then I need a different sensor.
2) Will the flow-through sensors fit on the shorter rear wheel valve stem (the one for the outside tire, which faces toward the interior of the RV)? The opening in the wheel to access the stem if fairly small so I would love to hear from somebody that has made this work.
3) If the flow-through won't fit, then will the cap sensors? Or do I need to get some kind of 90deg extension for the stem.

Thanks!
I also have a 2020 Unity MB and I added the EezTire monitoring system. I did not get the flow through sensors so can't comment on those, They install easily, I put the security caps on all but the outside duals as I figured that would add some frustration in removing those. I have had no movement of the metal valve stems, including the inside duals with the metal extenders. I enjoy the peace of mind that I will know if one of the duals is going flat. On my previous RV I had two flats on the outside duals and ruined the tire on one of them.
 
I have a 2019 Unity on the new chassis. I’ve added an Eeeztire system. A couple of comments.
1) I have no idea, and I have not heard this. What is the source of your information.
2) I used the cap sensors, not the flow through. I am sure there is enough room for flow through, there is an inch or two of space between the two tires. I think the flow through will be more difficult to install because of the length. The cap sensors are not too bad to thread on the outer duals.
4) :) You can’t install TPMS sensors on the end of the extensions LTV added to the inner duals. The extra weight causes the extensions to crack and fail. You can remove the extensions and install sensors on the short inner valves. This is fiddly to do, but works fine. Or you can have Borg stems installed, which is a stronger long one piece For the inner with a rubber support block. It will hold a TPMS without failing.
 

michaelh

2015 Unity TB
TireTraker TPMS says that if you have aluminum stems, you need to use a special lubricant to stop bi-metallic corrosion of the aluminum. It's a grease substance that just apparently stops the electrical flow between the aluminum and the brass of which the TireTraker is made. Not sure what those brands you mention are made of, but if brass, then you could get an insulating lubricant like that.
 

mikescha

New member
Thanks, all!

@Shadow5501 Do a web search using the terms, "brass vs. aluminum tpms" and you'll get a ton of results. Here are some:
 

Ben & Jenn

New member
I have a 2019 Unity on the new chassis. I’ve added an Eeeztire system. A couple of comments.
1) I have no idea, and I have not heard this. What is the source of your information.
2) I used the cap sensors, not the flow through. I am sure there is enough room for flow through, there is an inch or two of space between the two tires. I think the flow through will be more difficult to install because of the length. The cap sensors are not too bad to thread on the outer duals.
4) :) You can’t install TPMS sensors on the end of the extensions LTV added to the inner duals. The extra weight causes the extensions to crack and fail. You can remove the extensions and install sensors on the short inner valves. This is fiddly to do, but works fine. Or you can have Borg stems installed, which is a stronger long one piece For the inner with a rubber support block. It will hold a TPMS without failing.
Was there a trick to removing the extensions? We have the TPMS cap sensors from TST and it looks like I can reach between the dual tires to thread the sensor on to the stem with the extension removed.
 

Kosinar

2017 Unity TB Silver
Unscrew them. They are screwed on. I got the same tpms and after my rear inner tire extension cracked and caused flat i removed them. Now i screw sensor directly on valve without extension. I do it one time a year to adjust the tire pressure and replace batteries.
 

TwoClinks

2016 Unity TB
Those of you that are installing TPMS transmitters on the end of valve stem extensions will likely experience failure. The vibration and weight of the transmitters will cause failure between the OEM valve stem and the extension. You have a choice. Take the risk of a flat along side the road. Screw the transmitters directly on the valve stems and stand on your head to add / subtract air pressure or to fiddle with transmitters. Or have Borg one piece valve stems installed on the rear duals with rubber stabilizer boots. Do a search on this forum. This is a frequent topic.
 

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