Front End Shake

[bill40]

Looking for advice. We have a 2000 National Tropi-Cal on Ford chassis with 54000 miles. On secondary roads at 40 mph it has developed a very noticeable shake in the steering wheel, run it past 40 and it stops. There appears to be no problem on interstates. The coach does have Air-Ride bags front and rear, I normally run 40psi in front. Thought it might be a ball joint or shock going bad but thought I would ask first. Thanks Bill40 ???

 

[fredethomas]

The Ford shaking is probably the air shock that is tied from the drivers side front wheel to the front axle.? There is a clamp that ties the shock to the axle which can loosen up.? I fixed two of them on the 1994 Ford chassis.
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[Gary RV_Wizard]

When somebody says front end shake I immediately think of tire balance and then front end alignment. The fact that it disappears above 40 mpg suggests tire balance, which changes with RPMs.  You may not notice it on interstates because you don't spend any time around 40 mph - you are either accelerating or decelerating through that speed rather quickly in most cases.

Could also be a front end component, either adjustment or wear. A front end alignment will take care of adjustment and should diagnose any wear problems as well.  Since you should have your tires balanced and front end aligned  periodically anyway, I would suggest doing those two things and see what happens.

 

[John From Detroit]

I agree with Roamer, I've had front end shake such as you describe in many vehicles, in many it was strongest at some speed, but disappeared at other speeds.  I have a theory (resonance) as to why this happens but beyond the word in prens, I don't wish to expound just now.

In my cases I found various causes, From simple tire imbalance to bad alignment to bad suspension components.

In any case, do get it fixed, some of those are SERIOUS problems if allowed to continue.

I have also heard of tires that were "out of round" causing such a problem, and I've had other tire problems do it (What happens when you have spent 40 years driving older cars, you get experience with problems)

I would guess some tread problems can cause it too

Suggestion is to follow this path.  Step 1, Have the tires checked and balanced by a good truck tire shop

If that fixes it.. Great, if not, have a good front end specialist look at it (note, most good tire shops have a front end specialist because front end problems cause tires to fail faster)

 

[bill40]

Thanks for all the thoughts, I do have a appointment for a front end alignment on the 14th, will up date after the job is complete.

 

[John From Detroit]

As part of the front ened alingment they should check the condition of your tires, they may not check balance or "Roundness" however as, well, those are special tests.  This may show up the problem right there, Tires do speak very clearly to an expert (i'm not expert enough to hear them clearly without help)

Oh,,,, From time to time I have heard of folks who had problems, usually with truck size tires, and vibration

Turns out the tire guy left his flashlight inside the tire

 

[Gary RV_Wizard]

I would try to get the tires get balanced either before the alignment or at the same time they do the alignment. 

Hope those two things resolve your problem - odds are good that they will.   

 

[bill40]

Well I finally got the coach back, and we just returned from a short trip. The tire service dealer had the unit for several days and checked the    complete front end for any problems.They even checked the transmission for torque converter shake.The major problem was the tire balance and the wheel alignment.
Thanks too all for their comments and suggestions . Bill

 

[Gary RV_Wizard]

Glad to hear you got it fixed, Bill. Now it's time to enjoy!  ;D