Hello, I am looking to replace main tires on a PA-39. I currently have 8-ply flight custom III on now but while looking thru service manual I noticed that 6-ply flight custom II were spec out. Not sure how long the III's have been on plane, I looked thru logs and cant see anything else used. Is any paperwork required to change ply's and what whould be the better tires to use? I did check some older post and they were mainly talking about, which tubes were better like the Leakguard.
Thanks
Mike

Mike,

I noticed this is your first post. Welcome to the Forum.

I also have a 39 and use 6x600 which is what is approved under the Type Certificate for the aircraft. As tires have changed size while having that same 6x600 spec, there have been issues with the nose tire rubbing the gear doors.

While I'm no expert I do know a similar thread of postings happened in the past and the conclusion was 6x600 was what the FAA expects to be on the aircraft.

Perhaps another party can suggest a path to get something else approved.

Look at the TC data sheet. However you can have and STC that approves a smaller tire on the nose. Zach Grant ran into a ramp check that grounded his airplane because it had the wrong ply tire on it. In 1993, I imported a 260B back into the USA from Canada and had a problem with the Milwaukee FSDO as the nose tire was of the improper spec.

Good luck!

Jim Covington