big tires and props

mvivion · Post by **mvivion** » Sat Jan 15, 2005 5:15 am

Karl,

What brand are your 8.50's? My experience is that Goodyear 8.50's are pretty much the same diameter as the Goodyear 26, but McCreary's are all over the place in diameter.

This was reinforced by our chief of maintenance recently, when we were going to put 8.50's on one of our airplanes, and I already had one that was a McCreary. His comment was, who knows what diameter that actually is, I'll send you a set of Goodyears.

Mike V

Karl · Post by **Karl** » Sat Jan 15, 2005 5:46 am

they are mcrearys. they are at 21-22". and half bald.so there taller on one side. karl m.

zero.one.victor · Post by **zero.one.victor** » Sat Jan 15, 2005 7:11 am

Is a field approval for big tires a hassle like other field approvals? The "Tundra Tire Field Test" article in aug/sep 2000 Northern Pilot magazine sez that the Anchorage FSDO put together an approval package for big tires, consisting of a "form 337,a work sheet for tundra tire installation,bulletin number HBAW 97-01A, advisory circular number 23.733-1, and a stamp for the airplane logbook". I believe criteria & procedure for flight testing with the big tires is part of this package.

Eric

zero.one.victor · Post by **zero.one.victor** » Sat Jan 15, 2005 7:14 am

Regarding big tailwheels, XPMods also sells a couple different models, a 10" & a 14" (500-5 tire?). Theirs are for the 3400 series 180/185 tailwheel but the fork can probably be fitted to a 3200 series. You're probably on your own regarding paperwork though.

Eric

N170BP · Post by **N170BP** » Sat Jan 15, 2005 8:09 am

I don't know Jack about flying in Alaska, but from what I've heard,
the feds up there frown upon "big tire" installations on "3-bolt"
Cleveland wheels. Is this true? If I have the story straight, there
have been some failures of the early (3-bolt) Cleveland 6.00 inch
wheels with large tires mounted (8:50s or larger).

Anyway, I have 850's on mine, but for lower 48 flying, I can honestly
say there was only one time I actually needed them (Idaho back-country).
The strip we went into was in very poor shape, and had those diagonal
drain gutter things spaced every couple of hundred feet (felt like it
knocked the !@#$ out of the airplane while landing....). Should have
went in there with 15 or so lbs in the mains instead of the 24 or whatever
I had in there.

N2830C · Post by **N2830C** » Sat Jan 15, 2005 6:53 pm

Im in Alaska, in Eagle River, near Anchorage. I tied to get a field approval for 8.50s on my 54 170B last summer. My mechanic met with the FAA to disucuss it and they wanted me to put in steel axels and double puck brakes. This sounds like they were using the basis for the Gar Aero 8.50s to allow me install mine. I was going to install goodyears. I decided to just run the 8.00s as I didnt want to spend the money on the the other adders.

So anyway in my experience, even in alaska, getting a field approval for larger tires is a hassle. On the other hand maybe my mechanic didnt push it hard enough. Thats my 2Cents.

I think this would be a good item to add to the list of "pre-approved" field approvals I heard the FAA was working on.

I would be interested if anybody else has had better luck.

N3243A · Post by **N3243A** » Sat Jan 15, 2005 7:38 pm

N170BP wrote:I don't know Jack about flying in Alaska, but from what I've heard,
the feds up there frown upon "big tire" installations on "3-bolt"
Cleveland wheels. Is this true? If I have the story straight, there
have been some failures of the early (3-bolt) Cleveland 6.00 inch
wheels with large tires mounted (8:50s or larger).

Bela,

I don't know what the official "Feds" position is on this, but most every C-206 or C-185 you see working day in and day out on Gar Aeros that fly part 135 up here use the stronger 6 bolt wheels. Hard use will "wallow" out the holes on a 3 bolt wheel and set them up for wheel halve to wheel halve movement, then ultimately failure if you don't catch in time according to my mech. For a 170 flying part 91, 3 bolt wheels work Okay but in general the 6 bolt wheels are preferred. The 40-75D wheel is overkill for an airplane like a 170 according to my mech. anyway.

This would be a good question to ask the folks at AK Bushwheel for installation of their expensive rubber donuts. Don't know the details of what is in their STC for installation on a 170 yet.

Bruce

zero.one.victor · Post by **zero.one.victor** » Sun Jan 16, 2005 4:24 am

My ragwing has the 40-75D wheels with double-pucks, the wheels have 3 bolts.