Tire Problem?

[PerfTech]

... We mount, true & balance, and machine for bearing upgrades several aircraft tires and wheels daily and perhaps we can shed some light on this subject. Most front tire flats on RVs with the small tire are tube issues rather than punctures. Always have a good look at the tubes to determine the type and cause of failures if possible. Always use tire talc and don't use it sparingly. While tire if off the wheel, blend a small radius on the stem hole inside to remove sharp edge. Always keep the tire inflated to 50 PSI. This helps keep the tire from crawling on the rims bead and helps protect the tubes. The 50 PSI also maintains a smaller contact patch on the tire vastly reducing strain on the nose gear leg for some added safety. Another useful addition is to add about six or more (minimum three on each side) small screws through the wheel lip, into the tire bead. This stops the tire from slipping on the wheel when initial contact is made with the runway (primarily if tire pressure drops). This movement will kill the tube and usually shows up as a hole in the sidewall of the tube with no evidence on the tire. The screws also keep the tire from flopping away from the wheel beads in the event of a flat from a puncture. When this happens it can damage the wheel pant, wheel, tire and tube as well. As for a quality tube, there are several available from other sources than aviation suppliers. Contrary to popular beliefs, aviation tires and tubes for this nose wheel application are not magic or manufactured to some high standards better than other applications. There are several manufacturers offering tires and tubes in this size category that are very inexpensive and far superior in quality and durability. One supplier is "Northern Tool" who offers specialty tires for various equipment like large commercial lawn mowers, tractors, trailers and various other equipment. We have several customers that use these very thick, high quality tubes exclusively and swear by them and their results. We hope this will help clarify some of the questions, and if we can be of service or you have a question we may be able to answer, please feel free to give us a call. Thanks, Allan...

[pierre smith]

50 psi creates a smaller contact patch.

Best,

[Mike S]

Originally Posted by PerfTech

... The 50 PSI also maintains a larger contact patch on the tire vastly reducing strain on the nose gear leg for some added safety.

Larger contact patch???????

[PerfTech]

Originally Posted by Mike S

Larger contact patch???????

Originally Posted by pierre smith

50 psi creates a smaller contact patch.

Best,

OK !!! I was just testing you guys to see if you were paying attention! Thanks, Allan...
.
You have passed the test!!!!

[rvbuilder2002]

Yes, too low of pressure is bad for a number of reasons, but running a higher pressure than necessary greatly increases the likely hood of experiencing nose wheel shimmy.
This is because the pivoting friction of the tire on the ground is greatly reduced.
I have seen severe cases cause some serious damage.

[PerfTech]

Originally Posted by rvbuilder2002

Yes, too low of pressure is bad for a number of reasons, but running a higher pressure than necessary greatly increases the likely hood of experiencing nose wheel shimmy.
This is because the pivoting friction of the tire on the ground is greatly reduced.
I have seen severe cases cause some serious damage.

... Fifty psi. is pretty much middle of the road tire pressure for most manufacturers of tires of this size. Aero Classic max is 95 psi, Cheng Sheng is 75 psi, Goodyear is 110 psi and so on. Most recommend 60% for suggested tire pressures. If the nose gear is installed correctly aligned, the break away pressures are correct, the tire and wheel assembly are balanced and running anywhere near true, there will be no nose wheel shimmy. Nose wheel shimmy is an indicator that one or more of these conditions aren't met. Thanks, Allan...

[rvbuilder2002]

Originally Posted by PerfTech

If the nose gear is installed correctly aligned, the break away pressures are correct, the tire and wheel assembly are balanced and running anywhere near true, there will be no nose wheel shimmy. Nose wheel shimmy is an indicator that one or more of these conditions aren't met. Thanks, Allan...

I totally disagree.
Nose tire pressure is also one of the factors that has to be considered.

[RVbySDI]

Just a data point, I have been running 50 psi on my nose wheel tire since day one of installation. I have 4 years and 300+ hours with no indication of shimmy to date.

Oh yeah, I forgot to mention that my plane has always lived on a grass runway, so at least half of my landings/takeoffs have been on grass for these past 4 years. It works for me!

[Dave11]

I fairly new to the list and have found this information very beneficial as a new RV owner. I poked around the forums and from the posts I found gathered that about 40-45 psi was an average nose pressure for a 7A (for those who increased the pressure over Vans suggested). I found that 45 with the antisplat improvements worked well for me.

Since this subject comes up frequently and there are so many different suggestions on what pressures to run up front, would it be useful to take a poll of "A" owners on what PSI they really run on the nose?

For example:??
Under 30
30-40
40-50
50+

Dave

[rvbuilder2002]

I should have been more specific....

The reason you can't 100% generalize with nose tire pressure is it is dependent on what the weight on the nose wheel is. Different amount of weight... different amount of compression of the tire (and different amount of contact foot print area on the ground).
We know that this can vary widely depending on the engine/prop combination and other build details.
50 PSI might work for a large portion of the "A" models, but a guy with an O-320 and a fixed pitch prop on an RV-6A (lightest nose wheel weight case).