800 X 6 tire problem

[doug8082a]

I agree with Dave on the life span topic. The other reason I gave up the McCreary's is that they have a softer side wall and tend to flex more. This caused them to rub against the inside of my wheel pants. Of course, I'm running 600x6. I realize that "real men" don't run 600x6 and certainly don't wear panties, but hey, life's a little different here on the east coast.

[N2830C]

I Forgot to say in my last post that Im running goodyear 8.00. When looked at 8.50 I found out that there was not an STC available to run them(at least thats what my mchanic said).

I know that there are STCs available for larger tires like 26", 29" and 31". Look at http://www.akbushwheel.com. They have some picks of a 170. These are a little to large for my liking and exspensive.

[zero.one.victor]

Hey Eric yours might be cheaper but then the Goodyears on mine will last twice as long. At least. That's all I'll buy now.

My last set of McCreary Airtrac 800's lasted 641 hours,reversing them once on the wheels at about midtime for even wear. That's mostly local flights of an hour or less,sometimes lots less,and (unfortunately) almost all on paved airstrips. At the time,I added up the number of landings on the first set in my logbook and was impressed that they lasted that long. A couple friends run Goodyears & I haven't seen that they get much more hours/landings out of them. Think I'll stick with the McCreary's.

Eric

[zero.one.victor]

I Forgot to say in my last post that Im running goodyear 8.00. When looked at 8.50 I found out that there was not an STC available to run them(at least thats what my mchanic said).

I know that there are STCs available for larger tires like 26", 29" and 31". Look at http://www.akbushwheel.com. They have some picks of a 170. These are a little to large for my liking and exspensive.

The 850's are a 337/field approval show. Bela went thru thr process & could probably tell us what's involved,and how to word the 337. It no doubt helps to have an IA on good terms with the local FSDO &/or DAR!

Eric

[N170BP]

I don't think I can be of much help, as the 337 on file for my
850s just says "Verified previous installation of 8:50x6 tires
& tubes on Cleveland P/N 40-97A 6-inch wheels. See Canadian
logbook entry and sign-off dated June 10, 1987 by Canadian
Maintenance Technician #?????????" (number edited to protect
the guilty).

Since I had to go through a conformity inspection, all the mods
on the airplane had to be addressed (my IA had to submit 13
different 337s). This is why I tell myself I will never import another airplane from another country into the U.S.

It was the 1987 Canadian logbook entry stating 850s were installed
that prompted us to use that as "precedence".

Did the airplane have 850s on it when I bought it in 2002?
Um, yeah.... that's right. That's the ticket.... Yes, I'm sure
it did (I think it did anyway....).

Bela P. Havasreti
'54 C-170B N170BP

[km74]

While we are on the subject. Is there anything I should know about removing the tires and switching them over? What tools do I need? What torque specs should I use? Is it pretty straight forward? I havent looked at them that closely yet. Is there anything to be careful of? I made a jack to lift the fuselage between the gear legs using a quad lift. Thanks

Ken

[GAHorn]

I wrote two articles about repacking wheel bearings, brakes, and tire changes at:
http://globalair.com/discussions/george ... et+Article

http://globalair.com/discussions/george ... le#replies

[km74]

Both very good articles. Thanks George.

Ken

[Dave Clark]

Well I just sat in on a Cleveland brake seminar at my IA refresher today. I asked about the washers and the shim kit and the Cleveland factory service tech said he was aware of it, was not sure of the approval basis of the shim kit but that they had disks that took care of the problem also. I was really interested in his opinion on the washers as shims because I thought they might not be the best solution but he said it seemed ok to him (other than an approval basis). But then he was not an engineer. But he had a lot of real world experience.

One thing needs to be mentioned here for the owner/mechanic. For safety purposes ALWAYS deflate the tire before loosening the axel nut. If the wheel is cracked or one bolt broken you have a very dangerous bomb that has the axel not as a fuse holding it all together. Also mount the tire and secure the axel nut before inflating.

[N1478D]

Those are such GREAT articles George! Going to make myself get in the habit of visiting your other website to see more of those. Am sure that you have kept somebody from getting hurt, or maybe worse.

[zero.one.victor]

Just for grins I cross-referenced my airplane & pilot logbooks to check how many landings on that first set of McCreary 800's (6 ply). Believe it or not I had 1,448 landings in 641.1 tach hours on them,almost 100% operating from paved airstrips. I'm plenty satisfied.
The current McCreary 800's (my second set) are the 4-ply version. I reversed them on the wheels at just under 300 hours,so I'm betting I'll get about the same service out of them.
Ken: as I recall,there's a placard on the Cleveland wheels with the tork spec on it? Changing tires is pretty straightforward. I don't quite understand what you've got going with jacking the plane up. Most of us use a kinda tapered channel that fits on the gear leg not too far above the axle area,which provides a point to use a floor or bottle type jack. The tapered configuration allows it to wedge itself into place on the gear leg. You need to use a rag or something to protect the gear leg finish. You can then jack up one side at a time.
As I recall a couple different guys here were fabricating & selling this sort of jack point. You really want to be careful not to drop the airplane off the jack when the wheels are off--that can be kinda hard on the axles.
A lot of these "easy" jobs aren't necesarily that easy the first time,especially if maybe you're not real mechanically inclined. Maybe pay your mechanic to do an "owner assisted" tire change the first time? Ditto for oil changes,mag timing,etc. No offense if you ARE mechanically inclined.

Eric

[GAHorn]

Eric, you're not supposed to count all those bounces as individual landings!
Everyone remember, jacking an airplane outside in the wind is a hazardous proposition. Do it in a hangar.
Also, be aware of your surroundings. Jacking/Lowering your airplane can endanger those others all around you.
And NEVER leave a jacked airplane unattended without secondary supports and roping it off, or placing barricades/warning signs around it to KEEP AWAY!
(I know, sounds like overkill, but a falling airplane gives the word a whole new definition!)

[zero.one.victor]

(George,if I counted all my bounces I'd have about 3 or 4 thousand landings on that set of tires!)
If you don't have a jack-point device for the gear leg,you can use a big C clamp as per the first of George's articles-- there's a good photo illustrating this. Slick trick!
Re: shim kit/washers versus new disc with more offset for tire clearance--I'm sure Cleveland would rather you buy the new disc's at anywhere from $80 to $130 bucks apiece. I'm sure I'd rather go with the shims!
George is right re: being very careful with jacking the airplane. A local guy had his Cherokee up on wing jacks monkeying around with his nosewheel assembly. After it was back on the plane (luckily!),he was doing something back where the tail was tied down to a weight--trying to take it loose or re-rig it somehow-- and managed to bounce the airplane right off the jacks! They poked a matching set of holes up into the bottom of each wing just as neat as you please! He was understandably unhappy.
I think he's still kicking himself over that one. A costly but unforgetable lesson.

Eric

[pdb]

I Forgot to say in my last post that Im running goodyear 8.00. When looked at 8.50 I found out that there was not an STC available to run them(at least thats what my mchanic said).

I know that there are STCs available for larger tires like 26", 29" and 31". Look at http://www.akbushwheel.com. They have some picks of a 170. These are a little to large for my liking and exspensive.

Boys:

If any of you need help getting a 337 for 8:50 x 6s, email me at pdb@gci.net. Every 170 in Alaska has them. AC 23.733-1 Tundra Tires, covers the installation process and there is a worksheet for Tundra Tire Installation produced by the ANC FSDO which must be filled out which says:

1) The aircraft has a current W&B and the new forward and aft CG for the new empty and gross weight has been determined.

2) the aircraft wing/tail/ and control surfaces have not been improperly altered and the aircraft is properly rigged.

3) The aircraft was flown IAW FAR 91.407. One flight was conducted at the worst case forward CG and one flight conducted at the worst case aft CG. The aircraft was flown at speed from 48 to 140 mph and no appreciable effects on the flight characteristcs were experienced. All tests were conducted at a safe altitude and outside controlled airspace. Airman must hold at least a private certificate.

Having both the AC and the FAA supplied worksheet will probably help with your local Forces Against Aviation.

IMHO, you really shouldn't be laning anywhere with your valuable vintage airplane if you really need tires larger than the 8:50s.

[Dave Clark]

What's next you say?

One other thing was mentioned by the Cleveland guy..... There might soon be a requirement to magnaflux the bolts prior to reassembly of the wheels. I guess if this happens we'll be buying new bolts with our tires unless we have a buddy nearby with the equipment.