The Cessna 120-140 Association Forum

Anyone have a copy of their approved 337 to install 8.50 tires on a 140. Just wanted to see what the verbage used was.

So based on the lack of responses. I can assume that nobody has put 8.50x6 tires on a 120 or 140 using a 337?

Lemme check my records. Ours were field approved a while ago before I changed them out for 29” tires. That field approval for the 8.50 x 6 used to be pretty common here in AK......used to be.

While not exactly what you are looking for, but I thought I would put that picture I had on file. Could help other people as well. Good luck!

Here’s what I got.
If money is no concern I would look at the 26” Bushwheel airstreaks they are not that much bigger than 8.50x6 tires. I used those 8.50 tires for years off beaches and gravel bars and yeah if things get bad you can air them down but also risk tire slippage and shearing a valve stem. I just completely restored this plane and have a bit invested so after getting stuck bigger than sh$t on a beach last month I bit the bullet and got the 29” bushwheel and never looked back. Only lost 6-7 mph a tiny bit longer TO roll, but at 8 psi I can smoothly roll over 6” rocks and float over ankle deep sand. Just something to think about as we all use our planes differently. Bushwheel are STC’d for our planes as well. Less of a headache

The other attachment.

woow very neat. looks great with the big ones.
i see that there is single caliper for the brakes. if i remember some of those big tires required double ones.
would that be in relation with the GW for double to be required?

The tires require “heavy duty brakes” the FAA definition in one of their mx publications was the ability to hold the brakes at full power static runup and keep tires locked. Those single puck brakes are more than enough. 1/8 inch spacers to move out brake disk were required though to keep brake assembly from rubbing on tire at low pressures. Those tires provide quite a bit of shock absorption. When I had the gear straightened and inspected I had them bend the gear an hair more in so at gross weight the tires would not splay out. There was more than enough edge distance around the original axle bolt holes to enlarge them so a 180/185 steel axle could be used.

Thank you for the details. You said 'when you had the legs straightened'.
So a shop basically rebent the legs??? Didn't know that was possible. How do they proceed? Do they reheat the legs, shotpen again.??

Thanks for all the info. For the type of flying I do I think the 8.50s will be fine. Someday If I am lucky I may need some big tires like that