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PA12 Rims and Tires

E

etj763

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I am looking to install a set of tires and rims on my PA12. This PA12 has PA18 gear installed

My old PA12 (which I sold) had 8:00X6. Is there an STC for 8.50X6 for the PA12?

Also....Suggestions where to purchase both the tires and the rims w/brakes?

Who has STC if there is actually one out there?

THank you in advance. I am a bit of a novice on this so any and all suggestions would be helpful.
 
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Thank you! Looks like Atlee Dodge has the STC. Much appreciated. I also have the Borer Prop, so will look into this as well
 
it's a CAR 3 plane, you probably don't need an STC(even though people went and got STC's...).... just reference the section on tires.... strange things...
 
Thinkin' Mike has a good point! Unless the TCDS conflicts - - -


From CAR 3: http://www.ercoupeparts.com/CAR-PART3.pdf

Emphasis added.

§ 3.362 Tires. A landing gear wheel may be equipped with any make or type of tire, provided that the approved tire rating is not exceeded under the following conditions a) Load on main wheel tires equal to the airplane weight divided by the number of wheels,(b) Load on nose wheel tires (to be compared with the dynamic rating established for such tires) equal to the reaction obtained at the nose wheel, assuming the mass of the airplane concentrated at the center of gravity and exerting a force of 1.0g downward and 0.31g forward, the reactions being distributed to the nose and main wheels by the principle of statics with the drag reaction at the ground applied only at those wheels having brakes. When specially constructed tires are used to support an airplane,the wheels shall be plainly and conspicuously marked to that effect. Such marking shall include the make, size, number of plies, and identification marking of the proper tire.Note: Approved ratings are those assigned by the Tire and Rim Association or by the Administrator.
 
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Don't wanna look - - - -

Just joshing -

Sorry Bob, I haven't checked. But I'd suspect the TC would be the stumbling block.

I think (don't actually know) the CARs are for design and certification purposes, more than for mods.
 
Gordon Misch said:
I think (don't actually know) the CARs are for design and certification purposes, more than for mods.
Click to expand...
Mods are required to comply with the same CARs. The FAA can make a "finding" for deviations which can be with negotiations with the modifier.
 
mike mcs repair said:
it's a CAR 3 plane, you probably don't need an STC(even though people went and got STC's...).... just reference the section on tires.... strange things...
Click to expand...

I recently read a discussion about this same thing, as I'm in the process of putting some 26" GY's on my C180.
I think it's a little different when the TCDS / aircraft specification calls out specific tire specs.
The PA12 TCDS (aircraft specification A-780) does just that:

"Landing Gear and Floats
201. Two main wheel-brake assemblies, 8.00-4, Type III
(a) Goodrich model 841, with 8.00-4, 4-Ply rating tires and regular tubes +31 lbs. (+1)
Wheel Assembly #D-3-13
Brake Assembly #D-2-13 (modified per Piper Dwg. 31293)".

So IMHO, seems like anything other than 800x4 4 ply requires some sort of specific approval.

In my own case, the C180 TCDS (aircraft specification 5A6) did not call out specific sizes & plies.
However it has been revised a number of times and revision 34 includes
"two main wheel 6 ply rating tires ... 600-6... 800-6... or 700-6" under item 202.

 
I bet the type certs exist in the same legal space as STCs. For example, my Cub is legal for Polyfiber with any finish over silver, not just Poly Tone or Poly Thane. It stays that way until an AD hits it, and my next recover can be a major repair.

Similarly, I suspect whatever TC existed when your 180 rolled out of Wichita still governs. You do have options with newer versions - the 1950 Super Cubs can use the 8:00x6 from the later TC change.

I don't know any of that for a fact, but my PMI agrees with my interpretation of the STC changes.
 
I have a PA12 with PA18 3" extended gear. The PA18 TCDS has Cleveland 6" wheels and brakes on it with 8.00 tires. Cannot recall 8.5. This is the logic and justification A&P used for installation of Airframes Alaska PMA replacements.
 
If it is a major alteration, logic and justification won't cut it. I would probably go for the idea that 8:50s were a minor alteration, but Cleveland told me they did not recommend it. Something about brake discs. We ran 8:50s for hundreds of on-airport hours and thousands of landings with no problems.

If you file a 337, it must have approved data or an FAA stamp in block 3. I see bogus 337s every darn day (well,several times a year). The latest is on our most recent Cub - a J4. The IA's data was a J3 STC. Fortunately a friendly Fed is going to help make it legal for me. Been installed for a quarter century.
 
I will never tell you I operate on the conservative side of all this. I just maintain that a good IA ought to know the difference between major and minor, and if a 337 is to be filed, it ought to be done correctly. Fully half the alterations I see on 337s are improperly documented. Ditto the weight and balance documents.

I am loose enough that I consider the C-85-12F to be used legally even though it does not appear on the J3 TC. Just me.
 
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