National Aeronca Association Bulletin Board

I use 20 lbs grass or hard surface.

Gus,

Been running 15 psi in the 8.00x6, 4 plys on my Champ for the past 7 years with no problems. However, prior to 1999, had 6 ply tires at 20
psi and developed a crack in a wheel flange. A downside of higher pressures is increased stress in the root of the flanges, where they are prone to cracking. A good source of tech info is "Lee" at Specialty Tire
(McCreary).

Roger J.

Roger,

Thanks. I've about decided on 15psi as a good compromise.

What did you find different when you switched from the 6ply to 4ply?

Why did you switch?

Do you think your flanges would have cracked had you used 15psi instead of 20?

It appears to me that 6ply is just too heavy and stiff for 1220 lbs.

Gus,

Switched to 4 ply tires when I learned (from Lee at Specialty Tire) that the recommended pressure for 6 ply tires is 30+ psi and they are considerably stiffer than 4 plys. My grass strip is not world's smoothest;
taxi shock was noticeably less with the 4 plys at 15 psi.
Whether or not the higher pressure caused the crack is anyone's guess, but there is no question that flange loading will be greater. The 6 ply tires were on for 2 years following completion of rebuild in '97.

Roger

Roger,

Thanks. I was giving serious thought to changing to 4 ply and you have convinced me. My strip is just a mowed section of my pasture and also rough.

These tires are even larger than the 700s on my Stinson and it weighed twice as much??

I can never understand why people do these things, these tires must have been lying around the hangar when it was rebuilt in '03.

Gus,

Believe the rationale is something like: "If 4 plys are good then 6 must be even better." Happy flying with your Champ!

Roger

Does anyone know of a source for the 2 ply tires? I,ve done some looking and haven,t come across any yet.
Paul

Paul,

I didn't know 2 ply rated tires were even made? If they are I would think they would be ideal for 1220 lbs.

Gus,
The 2 ply tires were used on most of the light planes in the late 30s and thru the 40s. This was the reason for the low inflation presures as compared to the 4 or 6 ply tire.
I am looking for the tires to try and lose some excess weight from a project I,m working on.
Paul

Were these the 8:00x4 used on the J-3?

They were the 2ply 6.00x6. I believe U.S. Royal supplied them.
Paul