Recommended Tire PSI?

[dannyb]

My main gear tires looked a bit low last week, so I tended to inflate them... that's when the conundrum started.



I checked the manual for the recommended inflation pressures which is 23 PSI on the mains and 15 PSI on the nose (these seem low.) There are placards on the wheel pants that show 32 PSI on the mains and 40 PSI on the nose. I had to pull the wheel pants off of one of the mains (following a duffus move on my part) and saw the tire was an "Air Hawk 30842" which is a 5.00-5, 6 Ply tire. The specs on that tire recommend inflation to 50 PSI. The 4 Ply version of that tire recommends 31 PSI. (I did not check what tire was actually on the nose.)



So as far as the mains go, what should the inflation pressure be?



With the "Air Hawk 30842 , 5.00-5 6 Ply" on there now...

> The manual 23 PSI seems (and looks) way low.

> I inflated the tires to the placarded 32 PSI. The tires look "inflated enough" but not to the recommended PSI for that tire. Perhaps the placard is a remnant from a previous 4 Ply installation?

> The recommended spec is 50 PSI... should I inflate to that, or would I introduce some unwanted behavior?


BTW, the logs indicate that the main tires are 3 1/2 years old.


I plan on checking to see what actually is installed on the nose this weekend.



Thanks in advance for the input,

d.

[ronin5573]

It’s gonna be different from tire to tire. This aircraft is it using Beringer wheels or do you have the Matco wheels?
I use the Behringer wheels with Michelin tires 10 ply tubeless tires. I use 40 psi in the mains and 35 on the nose wheel.
The manufacturer would rather you use a lower tire pressure to absorb some of the shock of landing, however, lower tire pressure usually means twisted tubes in the tires. I even seen a guy rip his valve stem right out of the wheel from a bad landing and twisted up the tube in the wheel.

[dannyb]

The wheels are the Italian Marc Ingegno brand, likely the original wheel.

Thanks,
d.

[Glenn]

Be very careful about underinflation (wheel pant rubbing, tube rotation, valve stem cut, etc.) Certainly you can overinflate too but especially this time of the year in colder temperatures, underinflation is the bigger risk. Soft tires may help with smooth landings but soft tires cause other sometimes serious issues. Remember its not the tire assembly that actually supports the aircraft weight. The support comes from the inflation air pressure. The tire/tube and wheel just hold the air in its proper place. Recommended tire pressures are all over the place. I have removed my sleek, sexy wheel pants. I lost maybe 3 or 4 knots. But I can easily inspect my tires and check the inflation which I do every preflight. Tiny tires can loose air fairly quickly. 

My 2 cents.