Vibration

Paul Owner/Technician West Collingswood, New Jersey Posted   Latest   Edited  
Question
Chassis
2008 Ford F-450 Super Duty King Ranch 6.4L (R) 5-spd (5R110W)
Vibration

Hello 1st time here posting. We have used car dealer who brought the above listed F450 for vibration above 40 mph. It did have fifth wheel at 1 time​. ​He had new tire installed and balanced at another shop but vibration still. He also had driveshaft balanced​. We hook the PICO NVH 3 channel scope over 40 mph has T1 vibration. Above 50 mph the wave form is above the scale and 75 mph whole truck shacks​. ​So we drove the truck on the rack can see the tire shacking. We put a dial indicator on the hub it has 0.010" run out and then we put 1 wheel and did the run out close to the wheel edge​.​ It's has 0.042". We rotate the tire 180 and show 0.025" run out​.​ My question; is that's enough run out to cause the vibration or I should I be looking something else. I'm attaching video and waveform pic.​ 

Please let me know what your thoughts are​. 

Thank you

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Rusty Owner/Technician
Oakham, Massachusetts
Rusty
 

I'd remove all 4 rear tires and run it on the rack. If it's smooth, put em back on one at a time. I MO, small amounts of tire run-out are only felt with higher tire pressures and no payload

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Chris Technical Support Specialist
Commack, New York
Chris
 

if you have the ability to recheck the balance I would recommend it. If the vibration is matching with the tire speed suspect that wobbly rim. a lot of these trucks get the rims beaten to hell and back to remove. Most light duty shops do not have wheel pullers available. kienediesel​.​com/WHEEL-GRABBER… Just because someone balanced the wheels does not mean they are in balance…

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Chad Technician
Winter park, Florida
Chad
 

Balance the tires. IMO they look good Spinning. Those wheels have larger hubs that sometimes can be difficult to set up properly on the balancer. Balance all 6 tires

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David Technician
Colorado Springs, Colorado
David
 

Hi, we had the same situation with a 2016 F450 last year. He would experience a vibration at 70 - 75 mph whether it was loaded or unloaded. He had the driveshaft balanced, tires balanced multiple times and had several wheels that were distorted replaced. Two of the replaced wheels were slightly distorted again within a year or so after replacement. We inspected the wheel and tire run

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Darren Mechanic
West Allis, Wisconsin
Darren
 

Had an 05 f350 with a t1 vibration, found rear brake calipers locked up, fixed it. Still dont understand why to this day.....

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John Educator
Ogden, Utah
John
 

Hi Paul, You can balance a square tire and it will still cause a vibration. Yes, the excessive lateral and radial runout at the out edge of the outside tire can cause a vibration, especially at higher speeds. The vibration as indicated on the graph is a T1 (first order tire speed related vibration). This indicates one shake is being felt per revolution of the tire. I suspect you have an

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Eric Mechanic
Chapel Hill, North Carolina
Eric
 

You may need to use a road force balancer. A tire with side wall stiffness variation can be in balance but will shake on the road due to uneven flexing in the side wall.

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