Gear Leg Shimmy

[Sonex 772]

Hey All

I have the standard gear (taildragger) and I am having problems with gear leg shimmy on my.. Every thing is tight, my alinment is spot on, I repacked the wheel bearings and nothing seems to help.. No problems on take-off the shimmy just happens on landing.. When I touch down and start the roll out that is when is starts to shimmy. It did is so bad one time it cracked my wheel pant. Has any one else had this problem??

Thanks
Mike

[radfordc]

Bob Mika had shimmy problems on his plane. He stiffened the gear by taping a hardwood strip to the back of the leg. Seemed to cure his problem. Somewhere he has posted video of how he did it.

[MichaelFarley56]

I've had shimmy issues that were cured by making darn sure all bolts were snug (especially the upper gear leg bolt that goes through the engine mount) and making sure the alignment of the wheel halves kept the actual wheel turning straight. At first, when I assembled the wheels the wheel halves were at a slight angle which caused the wheel to spin untrue.

Have you balanced your wheels? That always helps a little. Also, where are you running your tire pressures?

[planeolbob]

Here is what I did:

1. video of problem
https://www.youtube.com/watch?v=_z8YL0ibwjU

2. Video of fix
https://www.youtube.com/watch?v=HAH-xGvLKfc

3. Stills of the fix
https://www.flickr.com/photos/53052604@ ... 125454107/

Bob MIka

[fastj22]

I used Dynabeads to balance my tires. I don't have a shimmy problem and can't prove these are the reason. But its cheap and makes sense.
I also used them on my sport bike.

http://www.innovativebalancing.com/index.php

[Sonex 772]

I've had shimmy issues that were cured by making darn sure all bolts were snug (especially the upper gear leg bolt that goes through the engine mount) and making sure the alignment of the wheel halves kept the actual wheel turning straight. At first, when I assembled the wheels the wheel halves were at a slight angle which caused the wheel to spin untrue.

Have you balanced your wheels? That always helps a little. Also, where are you running your tire pressures?

Hey Mike

All bolts are tight and alignment is good..

How do you balance the wheels??

I am running my tire pressures at 45 psi

Thanks
Mike

[DCASonex]

Make sure the seats for the Timken bearings are fully pressed into the wheel halves. They often are NOT as supplied. You will need to back up the wheel hub when doing this so as not to put stress on web of wheels. A proper sized socket makes a good push tool, use arbor press, or big threaded rod with heavy washers through the bore. Tighten the axle nuts enough to remove all play.

David A.

[tonyr]

I used Dynabeads to balance my tires. I don't have a shimmy problem and can't prove these are the reason. But its cheap and makes sense.
I also used them on my sport bike.

http://www.innovativebalancing.com/index.php

These are pretty intriguing... how much did use for each tire?
more importantly, what did you tell them you were using it in.. ?

Cheers

[fastj22]

I got a bag of them from another home builder. I put about an OZ in each wheel. They come with an applicator which is just a plastic bottle with a tube you screw on the valve stem. It looks like fine sand but I guess it isn't sand but tiny ceramic balls.
If you need to tell them what you are using them for, tell them a go-cart.
Here's some on Amazon.
http://www.amazon.com/Motorcycle-Tire-B ... =dynabeads

I've read that off roaders with those giant rock crawling jeeps use golf balls in their tires to do the same thing.

[floridasonex]

I on occasion was getting a shimmy like vibration when landing. One of the guys told me he saw it
right as I touched down and to check the brake on that side. That was it .. a slightly dragging
brake would pull the gear back and it would start back and forth.

RT