Cessna 172 violent shimming.

James331 said:
Just say no to nose wheel
Click to expand...

broken-record.jpg
 
SixPapaCharlie said:
Maybe your tire was low and so you squirted some of this green tire goo into it.
I know a guy who did that once. What a terrible idea. The shimmy on landing was awful.
On takeoff it wasn't noticeable (To the guy I'm talking about) because the goo got distributed during taxi.
Click to expand...

The goo has it's place. I had to "goo up" a main once. It was the way to get Candy off of the active and over to the mx shop. The goo'ed tube was replaced and the inside of the tire cleaned up.

I don't think I'd fly a tire with that fix.
 
Our 172 had the violent nose wheel shimmy as well which usually occurred after landing and the correction was pulling back on the yoke. The fix was replacing the nose wheel tire. Ordered a new one from Aircraft Spruce and shimmy went away.
 
I’ve got the same thing going on with my Mooney. I tried inflation and deflation of the front tire to no avail. I suspect for good reason that it will need to be rebuilt.
 
Ive worked a plane where you could tighten the holy heck out of the axle through bolt, to the point it feels like it might strip or crack the wheel fairing, and the nose wheel still spins freely. Something in the stack up of parts was machined incorrectly and wouldn't allow the through bolt to properly preload the wheel bearings.
 
Severe shimmy on the 172 I rent. It's intermittent, but it's pretty bad when it happens.
Pulling on the yoke, pushing on the brakes, pushing on the rudder pedals slightly.. .nothing helps, until it slows down.
Tried to land as slow as I can, but still happens on occasion.
 
Last edited:
Well, here's my two cents worth:

The entire nose gear steering system including the bungees from the rudder pedals to the torque links needs to be in good condition; ie, no slop anywhere in the system. As Tom said, the shimmy damper needs to be properly serviced. Also, there should be no play in the wheel bearings and air pressure in the tire needs to be correct. There could also be play in the bearings inside the strut that are allowing excess side to side movement. Those bearings do not last forever and if very high time could be a factor.

Now; an observation from my flight school maintenance days. Were using Aero Trainer tires on the nose and they have a rounded motorcycle profile that does not provide a lot of surface contact with the runway.We purchased a 152 from a defunct flight school that hat a flat tread profile and never received a shimmy complaint about that plane. I switched our nose tires to that flat tread profile and the shimmy complaints suddenly disappeared.

You will be spending your own money finding the fix so take my advice for what you paid for it.
 
That thru bolt does not generally affect the bearing preload. That is determined by the spacer bushing/spools inside the wheel. The thru bolt holds the bushings in place and also serves as the attachment of the nose fairing.

When evaluating the nose gear steering damper linkage for backlash, you MUST have the nose gear in a PARTIALLY extended condition. Otherwise the auto centering locks the nosewheel straight ahead. It is an excellent system but poorly understood.

The easiest way I have found is to 1) vent the nose strut pressure, 2)tie/weight the tail down to lift the collapsed nosewheel, 3) bleed in enough atmospheric air to aloow the nose wheel to partially extend.

Then wiggle the nosewheel and note where the backlash is happening in the system. Cessna makes shims, but I don't know of anyone that makes oversize bushings for the shimmy damper pivot (or at least who will admit it)
 
Last edited:
Just went through this on a 172m

3 different shops all had thought they fixed it, from worn ends, bad tires and worn out holes.

Ended up being the nose tube assembly were the spacers and washer set the pre load on the nose wheel. Along with worn out bearing. So far after replacing this everything seems much better.
 
muddy00 said:
Just went through this on a 172m

3 different shops all had thought they fixed it, from worn ends, bad tires and worn out holes.

Ended up being the nose tube assembly were the spacers and washer set the pre load on the nose wheel. Along with worn out bearing. So far after replacing this everything seems much better.
Click to expand...

Even after I was in it. So, it must really be fixed... (where the heck is my sarcasm font...)


Sent from my iPhone using Tapatalk
 
You sissies, THIS is nose gear shimmy!


There's a video of a tail dragger with main gear shimmy as well.
 
Check the easy things first.
Low tire air pressure caused my Bo to shimmy on takeoff roll and landing roll.
 
If the OP hasn’t fixed it since November 12th, it probably isn’t getting fixed. :)
 
You must log in or register to reply here.
Back
Top