Van's Air Force
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RV-12 Shimming Main Gear Axles
- Thread starter Geico266
- Start date
Geico266
Well Known Member
After a few hard landings, then check them ! ! ! ! ! !
I never have hard landings....... just "stress tests".
Any of you other RV model builders? Mel? How much deviation is permissible? Is it noticeable during taxi? Tire wear? Better to wait and check it after you hang the engine?
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MartySantic
Well Known Member
Are these shims what you are looking for??
http://www.vansaircraft.com/cgi-bin...90-320-144&browse=airframe&product=axle-shims
http://www.vansaircraft.com/cgi-bin...90-320-144&browse=airframe&product=axle-shims
Geico266
Well Known Member
Yep! I just wonder how much or little we need to shim.
steve wyman
Well Known Member
Larry- If you have a little bit (say 1/2 degree) of toe in, you probably won't have any handling issue. What you REALLY DON'T WANT is toe out- (front of wheels wider than aft)- this will result in a truely ugly handling airplane! Steve
Geico266
Well Known Member
I would say it about 1/2 degree toe in. I guess I'll leave it alone and see how it handles on taxi and landings.
Thanks Steve!
Steve, Larry...
How did you get those big long cotter pins in the end of the axles after you screwed the covers on?
Okay John....what's a "sweeping" bend....and did you do from the top down? I also turned my nut till the bearings wouldn't move....is that what you did...sure sounds draggy.
Geico266
Well Known Member
Corrected: The keys should be vertical in the -12.
I think what John is saying is you have to bend the cotter keys just a little (in the middle ) to get them to go in.
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Geico266
Well Known Member
Any other RV I've seen has the hole horizonal, but John is right. It is vertical in the -12.
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Wheel bearing nut
Wheel bearing nuts should only be tightened finger tight (while rotating the wheel), then backed off slightly. That draggy sound means that the bearings are being subjected to excessive forces and will quickly wear out and fail. It is better to have the bearing nut too lose rather than too tight.
Joe
Pete,
Wheel bearing nuts should only be tightened finger tight (while rotating the wheel), then backed off slightly. That draggy sound means that the bearings are being subjected to excessive forces and will quickly wear out and fail. It is better to have the bearing nut too lose rather than too tight.
Joe
Correct
Finger tight, then back off to the first slot. The wheel will feel slightly loose, but will be fine if you pack the bearings. I would not fill the wheel full of grease. Just pack the bearings and a little extra, and that should be good for years. ( unless they get under water, then you would want to check them soon a possible ).
John Bender
Finger tight, then back off to the first slot. The wheel will feel slightly loose, but will be fine if you pack the bearings. I would not fill the wheel full of grease. Just pack the bearings and a little extra, and that should be good for years. ( unless they get under water, then you would want to check them soon a possible ).
John Bender
??????
Joe, John,
hmmmmm....now i'm confused. I called Matco before I saw your notes and they said to tighten enough that the bearings do NOT move while the wheel is moving. Can you do that by hand tightening? I will certainly be calling them back tomorrow. Thanks for the input. I am also assuming they "lean" at an angle because there is no engine or wing weight yet.
Joe, John,
hmmmmm....now i'm confused. I called Matco before I saw your notes and they said to tighten enough that the bearings do NOT move while the wheel is moving. Can you do that by hand tightening? I will certainly be calling them back tomorrow. Thanks for the input. I am also assuming they "lean" at an angle because there is no engine or wing weight yet.
Thats my story - - - -
That has always been the correct way to do bearings. If you tighten the nut until it is tight, even with fingers, you can cause future damage to the bearings in some cases. Slightly loose bearings never seem to fail if they have lube. Again, thats my story.
John Bender
That has always been the correct way to do bearings. If you tighten the nut until it is tight, even with fingers, you can cause future damage to the bearings in some cases. Slightly loose bearings never seem to fail if they have lube. Again, thats my story.
John Bender
John,
I've always done it the way you do when I had cleveland brakes etc...then I got to reading the Matco manual that came with our kit and it said their system is to tighten, then tighten more and that there should be a "draggy" sensation. Thats why I called 'em. I'll let you know what they say when I call em back tomorrow. Thanks.
I've always done it the way you do when I had cleveland brakes etc...then I got to reading the Matco manual that came with our kit and it said their system is to tighten, then tighten more and that there should be a "draggy" sensation. Thats why I called 'em. I'll let you know what they say when I call em back tomorrow. Thanks.
Matco Info
Pete,
I went to Matco's website http://matco.veracart.com/pdf/GeneralizedTechR2.pdf? and found the following:
"The axle nut should be tightened until all play is out of the assembly. Rotate the wheel back and forth while tightening the nut to help seat the bearing. When all play is out of the assembly, and the wheel rotates freely, tighten to the next castle slot and insert the cotter pin. The rubber seal on the tapered roller bearings will remain stationary while the wheel rotates around it. If the seal is spinning on the axle, the nut should be tightened further until the seal stops spinning with the wheel."
"IMPORTANT NOTE ABOUT AXLE NUT TORQUE ON WHEELS WITH TAPERED
ROLLER BEARINGS
Your MATCG mfg wheel is equipped with Timken tapered roller bearings with integrated grease seals on the bearing cone to ensure the longest possible life. The torqueing procedure for bearings with these type seals is different than for tapered roller bearings without them, A common torqueing technique for bearings without seals is to tighten the axle nut until the wheel stops spinning freely and then back off to the nearest locking feature. THIS TECHNEQUE WILL NOT WORK ON A BEARING WITH AN INTEGRATED SEAL. The reason for a different torqueing technique is that the grease seal produces some drag and makes the wheel feel somewhat stiff when rotated.
Reducing the axle nut torque until the wheel spins freely will allow the grease seal and the bearing cone to improperly rotate with the wheel (the cone must not rotate relative to the axle). The higher rolling drag is completely normal for this bearing and allows for longer bearing life since the seal will keep most contaminants out. Timken specification state, for example, that the two 1.25 inch tapered roller bearing used on the WE51 will produce between 18-26 inch pounds of torque (drag) when properly installed. Alight coating of grease on the seal will help reduce the drag on initial installation. "The drag will also reduce after the bearings have been installed and the seal relaxes in the bore. It is important that the axle nut torque be sufficient to keep the seal from rotating with the wheel."
Pete, it looks like you were right and I was wrong. Do not tell my wife that I made a mistake!
Pete,
I went to Matco's website http://matco.veracart.com/pdf/GeneralizedTechR2.pdf? and found the following:
"The axle nut should be tightened until all play is out of the assembly. Rotate the wheel back and forth while tightening the nut to help seat the bearing. When all play is out of the assembly, and the wheel rotates freely, tighten to the next castle slot and insert the cotter pin. The rubber seal on the tapered roller bearings will remain stationary while the wheel rotates around it. If the seal is spinning on the axle, the nut should be tightened further until the seal stops spinning with the wheel."
"IMPORTANT NOTE ABOUT AXLE NUT TORQUE ON WHEELS WITH TAPERED
ROLLER BEARINGS
Your MATCG mfg wheel is equipped with Timken tapered roller bearings with integrated grease seals on the bearing cone to ensure the longest possible life. The torqueing procedure for bearings with these type seals is different than for tapered roller bearings without them, A common torqueing technique for bearings without seals is to tighten the axle nut until the wheel stops spinning freely and then back off to the nearest locking feature. THIS TECHNEQUE WILL NOT WORK ON A BEARING WITH AN INTEGRATED SEAL. The reason for a different torqueing technique is that the grease seal produces some drag and makes the wheel feel somewhat stiff when rotated.
Reducing the axle nut torque until the wheel spins freely will allow the grease seal and the bearing cone to improperly rotate with the wheel (the cone must not rotate relative to the axle). The higher rolling drag is completely normal for this bearing and allows for longer bearing life since the seal will keep most contaminants out. Timken specification state, for example, that the two 1.25 inch tapered roller bearing used on the WE51 will produce between 18-26 inch pounds of torque (drag) when properly installed. Alight coating of grease on the seal will help reduce the drag on initial installation. "The drag will also reduce after the bearings have been installed and the seal relaxes in the bore. It is important that the axle nut torque be sufficient to keep the seal from rotating with the wheel."
Pete, it looks like you were right and I was wrong. Do not tell my wife that I made a mistake!
Joe,
I was as perplexed as you, that's why I called...I was really leary about draggy wheels and tightening the nut rather than backing off. I guess if my bearings are dust this time next year I will be telling your wife what a genius you are.
By the way, they (Matco) also said do NOT replace the Nordloc washers with 416L's as the plans say. According to them the 416's won't hold up and the Nordlocs will...they should...they cost 70 cents apiece!
I was as perplexed as you, that's why I called...I was really leary about draggy wheels and tightening the nut rather than backing off. I guess if my bearings are dust this time next year I will be telling your wife what a genius you are.
By the way, they (Matco) also said do NOT replace the Nordloc washers with 416L's as the plans say. According to them the 416's won't hold up and the Nordlocs will...they should...they cost 70 cents apiece!
I have noticed that my plane tends to steer left when taxiing. So I gently need the right brake to go straight. I am wondering if anyone of you with the same issue corrected that with the 0.5 or 1 deg. gear shims from Van‘s.
Would that help to minimize the behavior?
Would that help to minimize the behavior?
