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Old 07-24-2020, 10:04 AM
seagull seagull is online now
Join Date: Dec 2019
Location: Highland, CA
Posts: 644

How I balance mine;
I have a 24" axle, (steel rod), that I put horizontally in the shop vise. With the wheel on the axle I spin it up with a die grinder and a 2" rubber wheel. I watch the vibration through all speeds at it winds down. With the wheel 12" out on the axle small imbalances are very noticeable. I use 2" patches of duct tape stacked and stuck to the tread to balance it and remove the vibrations. When I find the right amount and spot I weigh the stack and multiple x 3. Then use that amount of stick on tire weight on the inside of the rim. I remove the original tire weight foam tape and replace it with Scotch 411 tape, the grey stuff, it does not come off easily.

To clarify, I put the weight on the "outside" of the wheel on the surface facing the axle. Centrifugal force works to make the weight stick better.

Last edited by seagull : 07-24-2020 at 10:58 AM.
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Old 07-24-2020, 04:43 PM
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dbhill916 dbhill916 is offline
Join Date: May 2013
Location: Westerville, OH
Posts: 190

Originally Posted by rvbuilder2002 View Post
I would caution other RV owners against using this technique to balance aircraft tires.

The reason we liberally coat the surface of the tube and the inside of the tire with talc is for it to act as a lubricant because the tube is always moving slightly from the flexing of the tire. The RV-12 is a light airplane. Because of that we run rather lower pressure in the nose tire compared to most airplanes so that can potentially make the situation even worse.

Even the smallest amount of movement of the tube against the sharp corners of the typical wheel weight is going to, at the very least, cause a major inconvenience at some point, and possibly worse.
Thanks for the input. Will definitely look at an alternative.
David B. Hill
RV-12 #0760
Dues paid through 6-2024
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Old 07-25-2020, 01:31 PM
Mike Howard Mike Howard is offline
Join Date: Jan 2006
Location: Omaha, NE.
Posts: 7

Follow up information on strange vibration.
I performed a test take off today with the stick full back. The nose lifted off very quickly with little or no nose wheel spin up. [b]No vibration, problem solved? maybe?[b]
This still doesn't explain why the vibration stops immediately after I reduce the throttle with a normal take off technique. Throttle position shouldn't have any impact on vibration caused by an unbalanced tire.
Also why did the vibration only start after I installed the new nose gear leg and fork? I didn't change the tire or wheel and it wasn't a problem before I installed the new pars.
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Old 07-25-2020, 01:41 PM
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Mike S Mike S is offline
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Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 16,849

Originally Posted by Mike Howard View Post
Also why did the vibration only start after I installed the new nose gear leg and fork? I didn't change the tire or wheel and it wasn't a problem before I installed the new pars.
This is a new "system" and probably has different vibration frequency.

Professor Horton could explain it most likely.
Mike Starkey
VAF 909

Rv-10, N210LM.

Flying as of 12/4/2010

Phase 1 done, 2/4/2011

Sold after 240+ wonderful hours of flight.

"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
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Old 07-25-2020, 08:48 PM
rk2436 rk2436 is offline
Join Date: Aug 2013
Location: chicago,ol
Posts: 66

I bit the bullet and bought some Michelin Pilot tires. I'm done with those cheap POS Aero Classics. No more vibrations and they make the nicest chirp too!!
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Old 07-25-2020, 10:25 PM
RFSchaller RFSchaller is offline
Join Date: Oct 2010
Location: Phoenix, AZ
Posts: 3,402

I bought a motorcycle tire balance rig from Harbor Freight. Itís a rod with two conical pieces that when pushed together clamp the wheel on either side at the bore for the axle. The rod then acts like an axle and rests on two bearings so the heavy spot rotates to the bottom, and you can add weights until the wheel doesnít rotate due to a heavy spot. Iíve found that you can balance really bad tires even on the aircraft axles and get a marked improvement.
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Old 07-26-2020, 10:32 AM
RickSolana RickSolana is offline
Join Date: Jul 2009
Location: Richmond, VA
Posts: 71

You might have mentioned this, but did you check the nose fork break out force?
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Old 09-05-2020, 10:27 AM
sblack sblack is offline
Join Date: Dec 2009
Location: Montreal
Posts: 1,606

Originally Posted by Mike Howard View Post
Follow up information on strange vibration.
Throttle position shouldn't have any impact on vibration caused by an unbalanced tire..
I have to disagree with this. Things resonate when they get vibrated at a specific frequency, or multiple of that frequency. It is possible that as you throttle back your engine goes through some specific rpm as it slows down that interacts with the fork.

If you have a wheel out of balance on your car it doesn’t necessarily get worse as you go faster. It will get bad at a certain speed and be fine above or below that speed.

Gear shimmy and resonance issues are very common and tricky to fix on many types of airplanes. Nosewheel shimmy on cessnas is common. It will break the engine mount. Tailwheel shimmy will damage structure as well. Lots of modern fighter aircraft have had nosewheel shimmy issues. In the airliner world they do exhaustive testing on the runway to identify any potential issues by hitting a shimmy plate at different speeds with nose and main gears, which is just a means of exciting vibration. It is a tricky thing. It would not surprise me at all to find that there is an interaction with the nosewheel fork and engine rpm. So not impossible at all.
Scott Black
Old school simple VFR RV 4, O-320, wood prop, MGL iEfis Lite
VAF dues 2021
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Old 09-06-2020, 01:43 AM
Hotscam Hotscam is offline
Join Date: Mar 2011
Location: Bosschenhoofd, Netherlands
Posts: 175
Default Vibration

I have the exact same problem since replacement of the nose leg.
The wheel is balanced and never had any vibration with the old leg.
It starts full throttle take off at about 2-300 feet @70 kts for 2-3 seconds.
Throttle back stops it immediately.

It seems related to a different stiffness of the leg.
Jack Netherlands


RV12 #120519 and #120790
Hobbs 700+ hours and 400+ hours
Dual SV1000 Skyview 15, Pocket FMS and Powerflarm 6.0 (ADSB)

RV10 PH-USN Hobbs 350 hours
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Old 09-09-2020, 04:47 PM
Slightlyabnormal Slightlyabnormal is offline
Join Date: Apr 2020
Location: Ohio
Posts: 25

Any further thoughts on the cause of this?
I have it too. Not every flight but on some of them a few seconds after lift off I get the vibration then it is gone as quickly. New nose gear.
Per the seller my break out force is lower than the instructions, I havenít checked it yet, unsure how much lower.
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