Tire pressure for the the 15x6.00x6 tires

I spoke to the manufacturer?s rep for Air Hawk tires today.

He mentioned that the recommended pressure for the 15x6.00x6 tires is 68 psi. He explained that it is a low squat tire and is designed for much higher pressures than a 6.00x6 tire (which is typically supposed to be at 42psi). I currently have 35 psi in them so I was pretty surprised by his comments.

He further said that all tubes by major manufacturers are the same now. Air Hawk was the last to switch away from natural rubber to butyl rubber (about 5 years ago). He said stories of people needing to put air in their tires monthly indicate a problem like a leaking valve.

I am wondering what pressure other people are using for the main gear tires on the RV10s (and other RVs for that matter).

BTW, can you tell I am doing the annual based on the number of maintenance related posts in the last few days?

One more data point

I just read the tire specification manual from GoodYear. It confirms 68 psi for that tire.

I was asking the same question at Osh. I had been running with 45 then someone told me 60 now 68 wow! I am replacing my tires this week so 68 it will be. Now what about the front one?

The Goodyear Tire Specification Book

Here is the resource I mentioned.

It says that the nose gear tire uses either 31 or 50 psi depending on whether it is 4 ply rated or 6 ply rated.

As stated before the 6 ply rated main gear tires for the RV-10 should be at 68psi.

Thanks. I have the front at 50.

Tire and WHEEL Pressure

You might want to check the documentation that came with your wheels. I think Cleveland recommends a maximum of 42 psi on the main wheels. The tire and wheel makers have different and conflicting design robustness and "keep our lawyers happy" requirements. They are not on the same page--maybe not even reading the same book! Cleveland's limits for the other RV models are even lower.

Maximum pressure is probably not the best choice

The best tire pressure for any particular application isn't necessairly the tire's maximum inflation pressure. While the maximum pressure is correct for the maximum allowable tire load, applications at lower than maximum load should use lower than maxiumum pressure. If the inflation pressure is too high, the tire's ground contact area will be smaller than optimum which can adversly afffect braking, not to mention that the tire will be stiffer than you would probably want.

For example, assusme you have 1600 pounds on the mains, or 800 pounds on each tire. At 68 psi, the ground contact area will be appriximately 800/68=11.8 sq.in., which is equivlaent to a 3.4 x 3.4 patch on the ground. If you reduce the pressure by half to 34 psi, the ground contact area will double.

The correct pressure for you aircraft should be chosen by experimenting, but I believe that most RVs are inftated closer to 34 psi than to 68 psi. Van's RV-7 wheel and tire assembly instructions say to inflate to 25 psi, although they did not say that 25 was the optimum operating pressure.

With about 65 flying hours on my plane I can tell you the tires hate 45psi. There is nothing left of the outer tread. I am going to 60 psi at a minimum. The RV-10 is completely different beast compared to the other RV's.

I called Parker (Cleveland) about this issue

Parker (Cleveland) tech support confirmed that they recommend a maximum of 42 psi.

He is going to go back to the engineers and point out that both Good Year and McCready recommend 68psi for the tire used on that rim. I am hoping for a call back within a day or so.

I clearly had the same problem with underinflation. The photos of under inflated tires shown in Good Year's tire manual might as well have been of my tires. The wear patterns were exactly the same.

As another poster suggested, I will experiment with different pressures to see what gives the best performance/feel etc. I will likely start at 50PSI.

Tire pressures

The tire pressures recommended by Vans take all of the above issues into account, including one other that hasn't been mentioned here yet. That is aircraft handling and gear leg excitement. If you run your tire pressures above what Vans recommends, then you may experience gear leg shimmy/vibration and other unknown handling issues. Lower tire pressures tend to dampen out the extra energy at the expense of some additional tire wear.

From what I heard most people were going to the higher pressure because of the shimmy.

So what is the tire pressure that Van's recommends?

I am not the builder so perhaps I am missing some document from Van's that gives such a recommendation.

thanks.

I was running my mains tire pressure (RV7A) at 31 and things were really happy (100 hours) till a friend told me that 65 PSI is the right pressure, so I bumped to 50 and don't like it as much. It is easier to push it back to the hanger but it does not feel right so I am going to reduce it to 35-40 and see how that goes.

Mehrdad
RV7A

Parker (Cleveland) called me back

I checked with Parker and they were suprised to hear the number 68. The guy checked with engineering and called their contact at Good Year. The Good Year guy said that the 68psi number is a maximum figure for that tire.

Anyway, it seems that the 42 figure is now "the" one to use (though I am unclear what Van's recommends).

Sorry for all the confusion on this topic. I never suspected that this was so hard.

MSFT-1 said:

I checked with Parker and they were suprised to hear the number 68. The guy checked with engineering and called their contact at Good Year. The Good Year guy said that the 68psi number is a maximum figure for that tire.

Anyway, it seems that the 42 figure is now "the" one to use (though I am unclear what Van's recommends).

Sorry for all the confusion on this topic. I never suspected that this was so hard.

Click to expand...

I am sticking with 60 psi. 42 psi destroyed the tire. I put 50 in the front tire along with the non-vans nose wheel axle system and my nose wheel shimmy went away.

I've run 50 PSI on all 3 tires, on both my RV-10 and my RV-7A for a number of years now, and it seems to work really well. Tires are balanced using a motorcycle weel balancer, and I have no shimmy.

vic

vic syracuse said:

I've run 50 PSI on all 3 tires, on both my RV-10 and my RV-7A for a number of years now, and it seems to work really well. Tires are balanced using a motorcycle weel balancer, and I have no shimmy.

vic

Click to expand...

Close to Vic’s numbers.
45 on nosewheel
55 on mains @ Goodyear Flight II (60 max)