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Shimmy/Vibration

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Our new to us MH has a shimmy at around 60 mph, but not all the time, about half the time. The steering wheel vibrates quickly moving back and forth and moves no more than a quarter of an inch. The tires are Michelin 315/80R22.5s, 18 months old, not over loaded and properly inflated. So...do I get an alignment check to include thrust alignment, it has a tag, or get the front wheels balanced? Can they be properly balance while mounted, or should they be removed to be balanced?

Comments appreciated, thanks.

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I would have the front tires check for out of round and balanced if OK. Most truck tire dealers have an off vehicle balance machine. If one of the Michelin is out of round it will be interesting to know how they handle the warranty.

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I would also have all the steering components checked out, King Pins or Ball Joints, Tie Rod ends, Drag Link and ever thing else. Also does it happen on rough roads only or on both rough and smooth alike? Have the tires inspected for possible tread separation. This can happen to best of tires.

Yes, you can have the tires balanced on the vehicle, but it is difficult finding a place to do it. If you have them taken off to balance have them check for run out. Sometimes it is a simple as having the bead reset on the rim.

Good luck and let us know what you find.

Herman

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I agree with Ray as to the place to start.

Call around and find a HD truck tire dealer who can check RUN-OUT and them balance the fronts ON THE COACH. These guys still exist! Let us know where you are located and perhaps we can point you in the right direction.

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Thanks for the comments...no Tryon, BTW.

After several calls and a half dozen selections from the verbal menu, I finally got a real live person on the Michelin 800 #. I don't think they want their people doing any talking, this guy was very hard to understand. Anyway, he found a local Michelin RV dealer and gave me a case number in the event I have a warranty issue. I went by and talked to them today. Sounds like the plan is to do on axle balancing and go from there. Going to take the MH there next week. I'll keep you posted.

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Thanks for the comments...no Tryon, BTW.

Sounds like the plan is to do on axle balancing and go from there.

Actually, I would want them to start by checking RUN-OUT. If over about .035" correct that. Then balance both front tires on the coach.

I would verify they can do both of these before driving over there.

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If over .035, what is the corrective action?

Several things:

Rotate tire on wheel

Loosen lug nuts and position high spot at top and retighten lug nuts.

True tires-- yes this IS still done and is the ultimate answer if the above don't work.

Of course, another option is to replace the tire.

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Brett. How does a ROLL-OUT help to determine if you have a high spot and the height of same? More than a little lost here!

Carl

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When you replace your tires most dealers don't have the capability of balancing the tires on the vehicle. They will put the tire on the balancing machine. That is a good time to check the run out. Then it there is a problem the tire may be rotated on the rim. And if that doesn't correct the problem then you can ask for a different tire be mounted.

I take a different approach to balancing, I have all 8 of my tires balance and watch as it is done. What may be close enough for the tech may not be for me.

A past experience for me. I needed tires on my vehicle I used to travel for work. 4 GoodYear Eagles. They were always considered the best in the past. Drove 450 miles had them rebalanced drove back and went back to have them re-rebalanced. The manager of Discount Tire had one of his tire gurus look at them, after he inspected them his exact quote was "I wouldn't put this set on a trailer". He had 4 or 5 defects marked on each one. My point is that no matter who is the manufacturer is there can always be a bad run or batch.

Herman

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Great, now I understand what they was doing, when I had my 8 replaced last year....wanted to ask, but they where "knee deep" in coaches from Redmond.

Thanks for the link! :)

Carl

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Vibration that comes & goes... My vote is Balance and /or run-out.

Do run out first as you can balance a cinder block.

Run out can be more than just the tire as pointed out. centering on hub is easy to mess up when re-mounting tire & wheel on the RV.

Once you know run out is OK then I vote for on-vehicle spin balance as hubs and brakes can be out of balance. While I don't recall ever seeing a rotor balance weight coming out (its a metal slug driven into the cooling vane of some rotors) it is always possible.

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Thanks for all the input. Went to an authorized Michelin RV tire dealer today. One tire was way out of balance...problem solved, no more shimmy at 60 or faster.

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When I went to Bear Alignment school many, many years ago one thing really stuck in my mind. If you have a shimmy in your vehicle where do you feel it? If you feel it in the Steering Wheel it is coming from the front tires. If you feel it in your Seat it is coming from the rear tires. Also any time a shimmy suddenly starts, check your tires for a bulge on the side wall. If you find a bulge replace the tire imminently.

40X glad you found and cured your problem.

Good luck,

Herman

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