Hi all,
I appreciate your previous information, on other topics.
This pertains to my 1951 A model 170, N1361D, which lives in Princeton NJ, at 39N.
The left tire is wearing on its outer edge, suggestion too much (positive?) camber.
The wheel assembly has several tapered shims in it to correct maybe toe-inn, I think.
Can I add shims to correct camber also?
Where do I get them?
Directions for use?
Is there another better solution to correct camber problems?
Jim
Wheel camber
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
Shims may be purchased from Cessna distributors ( http://www.cessnaparts.com is a good source) and from Aircraft Spruce (http://www.aircraftspruce.com is a good aftermarket source), salvage yards (but they may not have an accurate accounting of which shims of which values in inventory) .
But be aware that shims may also be rotated upon the axle/gearleg such that they can influence both camber and toe-in.
Also be aware that the airplane's wheel alignment is relative to an average weight of 2,000 lbs. If you are operating lighter than that, you will likely experience such outside tire wear. (As aircraft weight increases the gearlegs will spread and change the camber towards a negative camber-degree/number.) A simple fix is also to rotate your tires upon their own wheels or to the opposite wheel with the same rolling direction as previously experienced by that tire, in order to spread the wear out over the life of the tire.
It takes a bit of math and a bit of trial-and-error to get the wheel alignment perfect, but it can be done. I actually have one shim on my parts shelf, but I've not measured it to determine it's part number. I'll try to do that next weekend and post the results.
But be aware that shims may also be rotated upon the axle/gearleg such that they can influence both camber and toe-in.
Also be aware that the airplane's wheel alignment is relative to an average weight of 2,000 lbs. If you are operating lighter than that, you will likely experience such outside tire wear. (As aircraft weight increases the gearlegs will spread and change the camber towards a negative camber-degree/number.) A simple fix is also to rotate your tires upon their own wheels or to the opposite wheel with the same rolling direction as previously experienced by that tire, in order to spread the wear out over the life of the tire.
It takes a bit of math and a bit of trial-and-error to get the wheel alignment perfect, but it can be done. I actually have one shim on my parts shelf, but I've not measured it to determine it's part number. I'll try to do that next weekend and post the results.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
George,
You say you have an axle shim but you haven't measured it to determine the part number. Is there a method of determining the part number by measuring the shim? The Cessna manual advises the resulting change by installation of certain shims by part number. However, the part number was ink stamped on the shims when new, and used shims can seldom be
identified since the inked on part number is long gone. I have gone through a bag full of used shims measuring the corner thicknesses with a micrometer and marking the thickness of each corner, but it's kind of a losing proposition and you wind up with a sort of "cut and try" method. This is a very time consuming process, not to mention frustrating.
If there is a method of part number ibentification it would be a godsend.
You say you have an axle shim but you haven't measured it to determine the part number. Is there a method of determining the part number by measuring the shim? The Cessna manual advises the resulting change by installation of certain shims by part number. However, the part number was ink stamped on the shims when new, and used shims can seldom be
identified since the inked on part number is long gone. I have gone through a bag full of used shims measuring the corner thicknesses with a micrometer and marking the thickness of each corner, but it's kind of a losing proposition and you wind up with a sort of "cut and try" method. This is a very time consuming process, not to mention frustrating.
If there is a method of part number ibentification it would be a godsend.
BL
Well, on pg. 50 of the B-model IPC are the specs on the shims. Those specs are given in degrees/minutes of angle and not certain what that is in parenthesis. I seem to recall somewhere the actual thickness being specified, but I'll have to look when I get home next. I planned to mic it and compare to the specs.
The three shims are:
PN 0541111-2 priced at Spruce: $126.95, and Cessna: $123.00
PN 0441139-5 priced at Spruce: $ ??.??, and Cessna: $ 70.00
PN 0441139-6 priced at Spruce: $ 32.60, and Cessna: $ 31.80
(Add'l 10% discount for TIC170A members thru Cessna Dist. Hill Aircraft.)
The three shims are:
PN 0541111-2 priced at Spruce: $126.95, and Cessna: $123.00
PN 0441139-5 priced at Spruce: $ ??.??, and Cessna: $ 70.00
PN 0441139-6 priced at Spruce: $ 32.60, and Cessna: $ 31.80
(Add'l 10% discount for TIC170A members thru Cessna Dist. Hill Aircraft.)
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
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Jr.CubBuilder
- Posts: 517
- Joined: Thu Aug 12, 2004 10:33 pm
I've got the same problem on my right gear leg. Last annual it didn't seem worth messing with, but I think this time around I probably will if we don't find any other expensive issues.
Flipping the tire around was the solution last year and it works just fine, but it looks funny and just generally bugs me to the point that I'll be fixing it sometime in the near future. Also if you are contemplating the installation of those ridiculously big/expensive Bushwheels getting the alignment just right can make a huge difference in the tire life.
Flipping the tire around was the solution last year and it works just fine, but it looks funny and just generally bugs me to the point that I'll be fixing it sometime in the near future. Also if you are contemplating the installation of those ridiculously big/expensive Bushwheels getting the alignment just right can make a huge difference in the tire life.
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dentistpilot
- Posts: 18
- Joined: Thu Dec 15, 2005 9:49 pm