Balancing the main tires weight?

[togaflyer]

So recently landed and had a significant shimmy. Checked everything and all was good so I’m rebalancing my tires. The one main tossed it’s weights, which I believe was about 1/2 oz when I changed them out 20 months ago. No issues until the one landing recently (and it was a decent landing The one main is requiring over 2 ounces of weight to get it somewhat trued. I’m thinking something went South with that tire. Question, what’s been your average weight required to get the tires balanced. Thanks…….

 

[Roadjunkie1]

Balancing tires

So recently landed and had a significant shimmy. Checked everything and all was good so I’m rebalancing my tires. The one main tossed it’s weights, which I believe was about 1/2 oz when I changed them out 20 months ago. No issues until the one landing recently (and it was a decent landing The one main is requiring over 2 ounces of weight to get it somewhat trued. I’m thinking something went South with that tire. Question, what’s been your average weight required to get the tires balanced. Thanks…….

I think it's pretty variable, depending on what tires you are using and how well they were balanced coming from the factory. I'm running Wilkerson retreads (great company to work with, by the way!) and I use the HF motorcycle wheel balancing machine, which does an excellent job for static balancing. It takes me quite a while to balance them because I am OCD and want them as balanced as they will get. Which means I wind up putting weights on and taking them off multiple times, trial and error, until I'm happy with the results.

Left: after much trial and error, I was happy. I use the 1/2 oz weights from HF as the 1/4 oz weights didn't seem to be enough. It took 4 spread out, two on each side of the stem, to make me happy. I put the wights in the vice and, with some other hammer work, got them bent to match the curve of the wheel. (Did I mention OCD?). Then found the stickum that comes on them was grossly inadequate. Good for the trial-and-error work but not for The Big Time. Mine are JB Welded in place. I experimented and they will come off when I want them to but are STUCK in place while the airplane is moving. I don't want to have what happen to you happen to me. Right: about to be pulled and done (on The List).

Be persistent. And a little OCD helps. YMMV..........

 

[Bill.Peyton]

I rotated my tires the other day, and it went from having 1 ounce to almost 2 ounces on each one of the wheels

 

[lr172]

I have not attempted to balance my tires. I have been through 3 or 4 sets of retreads on the 6 and still on the first retread on the 10. Never had a shimmy on either plane, though the 6 nose gear leg does all sorts of back and forth movement during take off (can't feel it but can be seen by onlookers). Not saying it is not a great idea to balance the tires, but have to question if out of balance tires is the reason that some folks get a shimmy. I speculate it is a different cause. I can't imagine that I lucked out and got 4 or 5 sets of tires that were perfectly balanced with my wheels. I have some experience in this area helping my son restore an old jeep. The ones with the big tires have something called the death wobble. You hit a bump at a certain speed and the front tires go into some type of harmonic and it feels like the front end is about to rip off the vehicle. Step on the brakes for about 3 seconds and it all stops. Did a lot of research and it is never tire balance. Always something related to front end geometry or looseness in wheel connecting parts or steering parts. Those that have used wheels that extend the width of the tire center line seem to have it much worse as there is more leverage in play. Bump steer due to poor geometry is also a significant contributor. A common theme is that the factory equipped vehicles NEVER have the problem. But lift it and put on big tires without carefull attention to geometry in all up and down movement of the axle and steering attach gear and you get problems.

I have done some work on a couple planes that had the hole for the cotter pin drilled such that the bearing was WAY too tight. Can't help but wonder if asymmetric drag from bearings or brakes may be creating a harmonic at some speeds; We are dealing with a spring steel leg here.

Larry

 

[togaflyer]

My plan is to pull both tires, split the rims and inspect everything. If nothing looks out of the ordinary, then I will rotate and balance them. Already replaced the brakes and packed the bearings and all is good there. It took 2 1/4 ounces to get the left main balanced. Sounds like that’s not too far out of left field. But I figure if I pull the tires and tubes and start from scratch it will resolve the issue. Thanks."……….

 

[tom_AZ]

Balancing and Shimmy

My plan is to pull both tires, split the rims and inspect everything. If nothing looks out of the ordinary, then I will rotate and balance them. Already replaced the brakes and packed the bearings and all is good there. It took 2 1/4 ounces to get the left main balanced. Sounds like that’s not too far out of left field. But I figure if I pull the tires and tubes and start from scratch it will resolve the issue. Thanks."……….

I do balance my tires, but agree with Larry that there's often more to than tires contributing to shimmy.

I don't recall exactly, but think that the last time I balanced the mains (after swapping sides to try to even out wear), that it took something in the range of 2 oz. for each. I also agree with another poster that the double-sided foam adhesive isn't confidence-inspiring. I've opted to put tape over the weights, extending it an inch or so on each side. Belt and suspenders? I like to use speed tape, if I can talk a neighbor A&P into letting me have 6" or so from his roll. The adhesive on that stuff is fantastic, assuming of course that you cleaned the surface properly before applying it. I did use the similar looking stuff from the hardware store once, when speed tape wasn't handy, and it seemed to work OK. To apply, I place it first nearest the center of the wheel, then gradually smooth it out toward the edge of the rim following the contours of the weights, and CAREFULLY trim it flush with a razor blade.

 

[rongawer]

I recently balanced my tires, also with Wilkerson Retreads (I echo their value and customer service is great).

I'm including a photo of my balanced tire that I used 3x 1/2 ounce weights, I used 2x 1/2 and 1x 1/4oz weights on the other tire.

I use a Marc Parnes balancer for my BMW motorcycle wheels, but Marc offered that buying an extra universal cone would work well for GA airplane wheels. I can attest this works very well.

 

[cajunwings]

Wheel balance

I’m a big fan of balancing tire/wheel assemblies every time they come off the plane. I remove the double sided sticky tape from the weights and use silicone or pro-seal to bond them in place. Sometimes even with new tires it’s surprising how much weight is required to achieve balance.

Don Broussard
RV9 Rebuild in Progress
57 Pacer

 

[Lynnb]

This may be a dumb question, but did you check your nosewheel break out, when it gets low it gives a good shimmy feel, sometimes I find it hard to tell whats from the nose vs the mains. Just my 2 cents.

 

[togaflyer]

Yes checked the nose wheel. Everything on all three have been checked. This weekend I’m going for broke. Going to rotate and do all I can with the current tires. If it does not resolved it I have new tire and tube ready to go. The guy who I rent hanger space to had a similar issue with his plane (non Van). They went trough everything too. It turned out to be a tire issue. They replaced it and all was resolved. Maybe it’s contagious!

 

[Walt]

So recently landed and had a significant shimmy. Checked everything and all was good so I’m rebalancing my tires. The one main tossed it’s weights, which I believe was about 1/2 oz when I changed them out 20 months ago. No issues until the one landing recently (and it was a decent landing The one main is requiring over 2 ounces of weight to get it somewhat trued. I’m thinking something went South with that tire. Question, what’s been your average weight required to get the tires balanced. Thanks…….

Time for new tires.

 

[togaflyer]

So final results.

New tires and tubes installed on mains. The new tires were balanced well and did not require added weights. A shout out for Dresser. I explained my issues when I ordered New Flight custom III retreads and they comped me new tubes. I had been keeping the tire pressure at 44 psi, but I plan to keep them up at 49 psi to see if it prevents future issues.

I checked the break out force on the nose assembly. It was around 23 lbs. I increased the break out to 30 lbs, I had to drill a new cotter pin hole to lock that setting in.

Problems solved. Thank you for your assist!

 

[clarenceoveur]

I recently balanced my tires, also with Wilkerson Retreads (I echo their value and customer service is great).

I'm including a photo of my balanced tire that I used 3x 1/2 ounce weights, I used 2x 1/2 and 1x 1/4oz weights on the other tire.

I use a Marc Parnes balancer for my BMW motorcycle wheels, but Marc offered that buying an extra universal cone would work well for GA airplane wheels. I can attest this works very well.

Why do you need to buy a additional cone? Doesn't it work on aircraft tires as it comes with two cones. I was going to order one but wasn't sure if I needed to additional cone or not after reading your post.

 

[rongawer]

Why do you need to buy a additional cone? Doesn't it work on aircraft tires as it comes with two cones. I was going to order one but wasn't sure if I needed to additional cone or not after reading your post.

It was explaining that my setup was for my BMW motorcycle, which uses a different end cone on the rear wheel. The Universal cone setup that I linked from Marc works very well for GA aircraft wheels.

 

[kenpilot]

The Universal cone setup that I linked from Marc works very well for GA aircraft wheels.

For anyone else considering Marc Parnes balancer... It's awesome! Don't even bother with the Harbor Freight stand, because you don't really need a stand. Just grab some nearby buckets or boxes, and level it left-to-right, and it's ready for the Marc Parnes balancer on top.

But the "Universal" cones are too small for RV-6A axles (maybe all RVs?). Get the DU42 cones. The picture looks very similar to Universal, but the cones are actually larger diameter. I ordered Universal, and he contacted me to tell me it wouldn't work, and modify the order for me.
http://www.marcparnes.com/UNIV.JPG
http://www.marcparnes.com/du42.jpg