Tony Petrone
Member
What is the tire pressure for a RV7?
What is the tire pressure for a RV7?
If you run 25 I suggest you carry a jack and spare.
I run 45 all around on my A model.
I can attest to that. Was experimenting trying to solve a vib issue and lost a tire in landing when it slipped on the rim. The tire was still good but it went flat with a leak at the stem junction.
I knew this thread would prompt all sorts of blanket statements and dire predictions, these tire pressure threads are very predictable. But maybe the original poster can see that optimum tire pressure may be dependent on his particular RV-7.
Walt, you have strongly stated your opinion about tire pressure in several threads over the years.
Please be advised that not everyone agrees with your opinion.
I recently added some Bluetooth tire pressure monitors that I found on Amazon $54. I put two on my RV7 and gave the other two to my hangar neighbor who also has an RV7. You screw them on to the air valve.
Just did a tire and tube change and started out at 37psi. The tire monitors connect to an APP on my iPhone. It reads both temperature and pressure. I compared the reading against my regular tire pressure gauge and it seems accurate.
I did a test flight with two full stop taxi backs. When I got back to the hangar I checked the APP and it showed 40psi and a temperature increase of about five degrees C.
To add air to my tires requires me to take half of the wheel pant off to access the air valve. So far these monitors are working great.
I recently added some Bluetooth tire pressure monitors that I found on Amazon $54. I put two on my RV7 and gave the other two to my hangar neighbor who also has an RV7. You screw them on to the air valve.
Just did a tire and tube change and started out at 37psi. The tire monitors connect to an APP on my iPhone. It reads both temperature and pressure. I compared the reading against my regular tire pressure gauge and it seems accurate.
I did a test flight with two full stop taxi backs. When I got back to the hangar I checked the APP and it showed 40psi and a temperature increase of about five degrees C.
To add air to my tires requires me to take half of the wheel pant off to access the air valve. So far these monitors are working great.
could lower tire pressure decrease the tendency to bounce on touchdown? especially taildraggers....
High tire pressure will wear out the tires in the middle. Around 25 psi will get you more even tire wear with no risk of spinning tires on rims and damaging valve stems. I am brutal on tires. I use the same tubes through several tire changes. Never had a flat. I can go through a set of tire in 100 hours but probably 1,000 full stop take-offs and landings.
High tire pressure will wear out the tires in the middle. Around 25 psi will get you more even tire wear with no risk of spinning tires on rims and damaging valve stems. I am brutal on tires. I use the same tubes through several tire changes. Never had a flat. I can go through a set of tire in 100 hours but probably 1,000 full stop take-offs and landings.
I don't have a shimmy problem. I do have a tire wear problem even with flipping the tire over halfway through.
Opinions vary, so let's move to fact.
Landing gears are generally designed for a 500 FPM arrival, which depending on leg design and other factors, is generally a bit over 3 G's. We want all the undercarriage components to meet this standard.
3-4-6-7-8-9's mount a 5.00-5 6-ply. Inflated diameter at 50 psi is about 14". The bead diameter beyond which the tire cannot possibly be compressed is 6.5", thus the max tire deflection available is 3.75", less the thickness of the tread carcass and the bead structure.
Given the above max arrival, the tire deflection at 36 psi is about 3.6". The tread carcass is smashed hard against the bead structure, with the sidewall in the immediate vicinity bent 180 degrees. Picture the effect on the tube.
For comparison, tire deflection at 50 psi is 2.75".
The above landing load spreads out the tire contact patch a lot. Consider what happens when the contact point is a square-edged pavement transition.
So (switching to opinion), given a pilot who produces consistently good landings, and a smoothly paved airport with no pavement height transitions, yep, low pressures will work. However, it won't take much to exceed the limits of tire deflection when using low pressures, and may not take more than one instance to result in a pinched tube.
Me? I set 50, and add at 45, but I have slab legs with no shimmy issue. One of many RV-8 advantages over lesser models
One of many RV-8 advantages over lesser models
I guess RVers who aren't running at least 45 in their tires just aren't living in the real world.....
That's a LDG/TO every 6 minutes, do you ever leave the pattern?
You obviously believe in being very frugal, std. practice is to install new tubes with new tires.
You've been pretty lucky IMO, maybe you should buy a lottery ticket.
Maybe a higher quality tire would help, of course if you're trying to use every available ounce of rubber before changing tires that could be a problem as most RV's don't wear tires evenly.
35psi is my lower limit, if you start at 45 it will likely be at 35 after 3-4 months (depends on what brand tube you use to some degree).