The Cessna 120-140 Association Forum

Can I legally put 8.00 X 6.00 tires on my 6.00 wheels without
STC filing etc?

Is the ground handling experience much different? I plan to fly
to a lot of grass and back county locations and would like the
extra diameter for rougher fields.

Disclaimer: My opinion is worth what you paid for it.

8.00-6 4-ply tires are on the type certificate for the Goodyear wheels. If you’ve had Cleveland’s installed by STC, that STC specifies a specific tire size, and that’s what you’re legal to run. I’ve asked this question of a couple A&P IAs and their suggestion was to log the 8.00s as a minor alteration. I haven’t done it yet to my plane. Talk to your mechanic, as it will be up to him or her to certify your airplane.

-Lance

The (same) tires are listed separate from the wheels on the 140a TC, so, I'd install them with a log entry and be done with it. No use in stirring up a hornet's nest.

If it's listed on the TCDS then it doesn't even rise to the level of a minor modification.

I put these tires on my plane about a year ago. My Mechanic didn’t even make a note of it, other that a W&B adjustment, as they are on the original type. I lost about 4 mph, as best as I can figure, on cruise. However, I will never go back. They make a huge difference on rough strips.

I found the STC for 140 on the website here. 8.00 x 6.00 were OK on the original Goodyear wheels so
I guess on the Clevelands it would not be out of the question.

meloosifah wrote: ↑Fri Sep 27, 2024 9:22 pm I put these tires on my plane about a year ago. My Mechanic didn’t even make a note of it, other that a W&B adjustment, as they are on the original type. I lost about 4 mph, as best as I can figure, on cruise. However, I will never go back. They make a huge difference on rough strips.

What engine do you have?

meloosifah wrote: ↑Fri Sep 27, 2024 9:22 pm I put these tires on my plane about a year ago. My Mechanic didn’t even make a note of it, other that a W&B adjustment, as they are on the original type. I lost about 4 mph, as best as I can figure, on cruise. However, I will never go back. They make a huge difference on rough strips.

Fascinating.............. we went to 7:00 X 6's on the airplane back in the 70's because it helped with "rough grass fields" here in Michigan and elsewhere. It also makes the airplane sit up a little better than the 6:00 X 6's.
I fly such long distances ......irregularly............ 1000 miles one way about once a year & 200 miles monthly........I thought.......I'll go back to the 6:00 X 6's and save a little weight and gain a little speed. Yeah.... 3 pounds and 2mph. When these dudes wear out, I'm going back to the 7:00 X 6's and NEVER go back to the 6:00 X 6's......... The ride is worth the little bit I "saved".

vinceo wrote: ↑Sat Sep 28, 2024 8:44 am 8.00 x 6.00 were OK on the original Goodyear wheels so
I guess on the Clevelands it would not be out of the question.

The tires are approved on the Goodyear wheels and the Clevelands are approved on the plane by STC. It is up to the IA to determine that one modification is compatible with the other...