I think the TPMS monitor is a great idea if balance etc doesn't become a problem. Taking the wheel pants off to check tire pressure can be such a pain.
However, I think those minimum values you mentioned (22 / 25 psi) are way too low. I sold my 7A last year, but a few years ago I had some pretty significant wheel pant damage due to low tire pressure on the mains and those pressures were in the low 40s at the time of the problem. So I recommend something much higher. Just my $.02.
Matt McManus
The POH lists the "optimum" tire pressures at 22 front and 25 mains with 23 and 28 being the "maximum" respectively. I'd go with the POH.I don't have an answer to your actual question, but I am very curious about using tire pressure monitors on an RV. Do they work? Do they affect tire balance? If they work I think it would be a great addition because checking tire pressure is a pain, even with an access hole in the wheel pants.
Any info would be appreciated.
thanks
Ivan
Thanks. I'll order a TPMS today!I installed TPM’s on my RV-12 several years ago, but only on the main wheels. The fork on the nose wheel does not allow clearance for TPM to be installed. I used a ¼ ounce stick-on wheel weight to offset the TPM and balance is uneffected.
That said… I run the TPM app and place cell phone on pilot-side wing walk at beginning of preflight inspection. By the time I have fisnished my walk-around the TPM has registered for both wheels. I then log the readings to plot air loss over time. By setting phone on wing walk… it is almost impossible to forget phone before climbing into cockpit. Not impossible… but close to it.
I'm always wondering: does this cap sensor operate by pressing against the Schrader valve to gauge the pressure? If so, does this imply that the thread on the cap is the only thing maintaining the pressure?I installed TPM’s on my RV-12 several years ago, but only on the main wheels. The fork on the nose wheel does not allow clearance for TPM to be installed. I used a ¼ ounce stick-on wheel weight to offset the TPM and balance is uneffected.
That said… I run the TPM app and place cell phone on pilot-side wing walk at beginning of preflight inspection. By the time I have fisnished my walk-around the TPM has registered for both wheels. I then log the readings to plot air loss over time. By setting phone on wing walk… it is almost impossible to forget phone before climbing into cockpit. Not impossible… but close to it.
I believe that‘s exactly the case.I'm always wondering: does this cap sensor operate by pressing against the Schrader valve to gauge the pressure? If so, does this imply that the thread on the cap is the only thing maintaining the pressure?
I plan to the same and will maintain a log to more precisely monitor pressure loss over time.I installed TPM’s on my RV-12 several years ago, but only on the main wheels. The fork on the nose wheel does not allow clearance for TPM to be installed. I used a ¼ ounce stick-on wheel weight to offset the TPM and balance is uneffected.
That said… I run the TPM app and place cell phone on pilot-side wing walk at beginning of preflight inspection. By the time I have fisnished my walk-around the TPM has registered for both wheels. I then log the readings to plot air loss over time. By setting phone on wing walk… it is almost impossible to forget phone before climbing into cockpit. Not impossible… but close to it.
The TPM has a rubber diaphragm that presses against the schrader valve to hold it open. The rubber diaphragm seals against the end of the brass threaded valve stem. I use a thick silicone grease (dielectric grease) on the face of the diaphragm to maintain the seal.I'm always wondering: does this cap sensor operate by pressing against the Schrader valve to gauge the pressure? If so, does this imply that the thread on the cap is the only thing maintaining the pressure?
I bought a set but don’t need since I built access doors in my wheel pants. Will post in classifieds later today unless some wants them before I post. NIB $25 and shipping on me.
It’s just one thing less to get rid of later
Yes, I didn't feel that lucky to use this set-up. 25 psi seems very low. I use 40 psi min and air up to 60 psi. That is what Beringer recommends for the Michelin Aviator.I'm always wondering: does this cap sensor operate by pressing against the Schrader valve to gauge the pressure? If so, does this imply that the thread on the cap is the only thing maintaining the pressure?
It's an optimum (for some) in terms of shimmy reduction. It's far from optimum if you want long inner tube life and fewer wheelpant repairs.The POH lists the "optimum" tire pressures at 22 front and 25 mains with 23 and 28 being the "maximum" respectively. I'd go with the POH.
I think I remember reading that it has to do with dynamics of the landing gear – softens some the impact forces transferred into the airframe. There are a couple of SB’s to strengthen the landing gear carry-through channel...Any idea why Van’s recommends the lower pressures?
Certainly can’t speak for Van’s, but can’t help but notice how due to the camber of the main gear, that the higher the tire pressure, the more the tire rides on its outer edge. That, plus riding on a smaller area seems that it would accelerate tire wear. And the lighter the plane is loaded, the more pronounced it is. Might not be as bad if operating off grass, but on pavement it seems like it would cause earlier tire wear with higher inflation pressures.Any idea why Van’s recommends the lower pressures?
I think I remember reading that it has to do with dynamics of the landing gear – softens some the impact forces transferred into the airframe. There are a couple of SB’s to strengthen the landing gear carry-through channel...
I know landings are an important criterion but since I don't track these, I got 450 hrs. on my mains then changed and at 550 hrs. nose wheel has at least another 200 hrs. All pavement and my home base 3,500 ft with trees and power lines to contend with. RV-14A. Average about 45 mins per L&TO. Never a shimmy at 40 - 60 psi. Michelon tubeless tires. Did swap and flip the mains at 250 hrs. Solid tone on AOA point of contact with ground or at least goal.Certainly can’t speak for Van’s, but can’t help but notice how due to the camber of the main gear, that the higher the tire pressure, the more the tire rides on its outer edge. That, plus riding on a smaller area seems that it would accelerate tire wear. And the lighter the plane is loaded, the more pronounced it is. Might not be as bad if operating off grass, but on pavement it seems like it would cause earlier tire wear with higher inflation pressures.
My bad...I failed to note this thread is in the RV-12 forum. I have no idea why Vans specified the low pressure. However, compared to the 6-7-8-9, the 12's lower gross weight would not mash the tire so much during a sudden arrival.I think I remember reading that it has to do with dynamics of the landing gear – softens some the impact forces transferred into the airframe. There are a couple of SB’s to strengthen the landing gear carry-through channel...
I assume they have internal batteries in the sensor? How long before they turn off communication (saving battery mode) if they are not moving? This was an issue some time ago, the plane had to roll to initiate, and in a long flight they would time out and not read for landing.I installed TPM’s on my RV-12 several years ago, but only on the main wheels. The fork on the nose wheel does not allow clearance for TPM to be installed. I used a ¼ ounce stick-on wheel weight to offset the TPM and balance is uneffected.
That said… I run the TPM app and place cell phone on pilot-side wing walk at beginning of preflight inspection. By the time I have fisnished my walk-around the TPM has registered for both wheels. I then log the readings to plot air loss over time. By setting phone on wing walk… it is almost impossible to forget phone before climbing into cockpit. Not impossible… but close to it.
I just installed a set on my RV7 and want to say thanks to the original poster for giving me the idea. I used the FOBO Bike 2 version, $99 on Amazon. Installation and set up could not have been easier. Remove the front half of the wheel pant, remove the valve stem cap, screw on the TPMS sensor, activate via the app. As a previous poster said, it seals to the top of the valve stem with a rubber gasket. Each sensor weighs 7.6 grams (1/4 OZ). I put a compensating 1/4 OZ stick-on tire weight (also Amazon) opposite the valve stem. Rolled the airplane back and forth to confirm they did not hit anything. The only possible interference might be the cotter pin, if it stuck out unusually far. Mine had plenty of clearance.I assume they have internal batteries in the sensor? How long before they turn off communication (saving battery mode) if they are not moving? This was an issue some time ago, the plane had to roll to initiate, and in a long flight they would time out and not read for landing.
Thanks!!
Yes, tires wear on outside edge because camber angle is excessive when gear is lightly loaded as when wheels just touch on landing. Tires can be unmounted and flipped on wheels so inside surface can be used before carcass gets tossed.Certainly can’t speak for Van’s, but can’t help but notice how due to the camber of the main gear, that the higher the tire pressure, the more the tire rides on its outer edge. That, plus riding on a smaller area seems that it would accelerate tire wear. And the lighter the plane is loaded, the more pronounced it is. Might not be as bad if operating off grass, but on pavement it seems like it would cause earlier tire wear with higher inflation pressures.
I am looking for min/max. pressure values in order to setup the warning levels of my TPM BT sensors.
What values do you think are still acceptable before inflating is required.
My nominal value is 22psi for the nose wheel and 25psi for the mains.
Thanks a lot.
Chris
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