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nose wheel shimmy

In my experience so far....lower tire pressure and equal main gear pressures. Stick in your belly.
 
Be sure the breakout force is correct.

Also, wheel balance and roundness can play a part in shimmy issues.
 
Be sure the breakout force is correct.

What is the correct breakout force, and how do your measure it? Are talking just measuring torque on the castle nut? Does that apply if you have the Anti-Splat Aero bearing mod?
 
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What is the correct breakout force, and how do your measure it? Are talking just measuring torque on the castle nut? Does that apply if you have the Anti-Splat Aero bearing mod?

See drawing below. Make sure the nose wheel is off the ground. Wheel balance and tire pressure are also important some use lower tire pressure, I use 40-45PSI.
 

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Does that apply if you have the Anti-Splat Aero bearing mod?

Yes, the bearing mod just changes the hub from tapered bearings with lots of friction to very nice radial ball bearings with little friction. I have mine set above 25lbs of breakout force. (mine is a -7A but the forks/wheels should all be the same unless it's really old)
 
A general FYI suggestion, Amazon sells a cheap hand held digital hook scale, actually marketed for weighing luggage. Makes for a great and accurate (enough) way of measuring the breakout force. I do it at every CI now.
 
A general FYI suggestion, Amazon sells a cheap hand held digital hook scale, actually marketed for weighing luggage. Makes for a great and accurate (enough) way of measuring the breakout force. I do it at every CI now.

My plane has an Anti Splat nose mod. When I bought it home, the nose wheel tire pressure was set at 50 psi by previous owner. I did notice some shimmy, but it went away when I re-set the nose tire pressure to 30 psi.

I ask because I noted just this afternoon that the nose wheel was flat. I replaced the tube, but wasn't sure about the axle torque. It would have been a good time to measure breakout force, but I didn't know how.

So...I get the concept (presumably) of using a fish scale or similar to measure the amount of pressure it takes to rotate the nose gear, but.....how is that done, exactly? Where to you hook the fish scale?
 
So...I get the concept (presumably) of using a fish scale or similar to measure the amount of pressure it takes to rotate the nose gear, but.....how is that done, exactly? Where to you hook the fish scale?

Go back to post 5, the wire hook goes into the axle hole.
 
I got a piece of metal wire and bent it like a horseshoe so that I wouldn’t have to remove the wheel. Mine goes over the fork and not through the hole.
 
One More Thing

Have to admit, I've never worked on any RV nosegears, but did a lot of work on single engine Grummans with a similar nosegear. Along with breakout force on the steering bearing (very important) and wheel bearing preload, (almost as important) I used to check wheel and tire balance just by raising the nosewheel off the ground and loosening the wheel bearings until they spun as freely as possible. Then spin the wheel and watch where it stops. (you can add a chalk mark to help orientation) Repeat a few times. If it rocks back and forth and then stops, the balance is 'way off. I add stick-on weights from the auto parts store to at least get it closer. I was happy when the wheel stopped at random clock angles. Kind of rough, but it seemed to help. Then reset the bearing preload and fly. Actually, I do this on the main wheels of our RV-6, too. Seems like all the wheels on our RVs are at the end of long springs. Hope this helps!
 
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