Causes of Vibration and Solutions

[Lee Welbanks]

Have you checked your driveshaft u joints? I've had a truck u joint go bad and it will act just like you have stated that yours feels like, starts vibrating around 50 and gets worse the faster you go.

[Gerald Farris]

Mike,
When it comes to a vibration issue, you should always follow the KISS (keep it simple stupid) method that I used for many years as a mechanic. Since 95% of the vibration issues that you described on a coach are either a tire problem (out of round or separated) or a wheel balance problem, you should start there in trying to correct the issue. If the tires check out to not be out of round, and you are certain they are properly balanced, and the vibration continues, then you can start looking for the problem that will be much harder to find and much more expensive.

Gerald

[Mike Groves]

I am having a maintenance service done and I'll have the U joints looked over.  I am having the "counteract" put in the front tires on Monday a week from tomorrow.  Can Les Schwab tell me if a tire is out of round without taking it off.  If they have to take the tires off, how do they tell if they are out of round?  Obviously I'll have the front tires off to have the counteract placed inside. 

Mike

[Gerald Farris]

Mike,
The tires have to be mounted to check for an out of round condition, because there has to be a center axle to gauge the tire roundness from. You just jack up the suspension until the tire leaves the ground, and rotate the tire a complete 360 degrees with a dial indicator against the thread. This will tell you how much variation there is in the tire as it rotates (out of round). Remember, you can balance a square box, but it will never roll smoothly.

Gerald   

[Mike Groves]

Ok, so they could check the two outside tires on the rear and they'll have the fronts ones off to put in the counteract, plus I'll have them properly torque to remove that issue as a possibility.

Thanks Gerald.

Mike