Dog Tracking W24

[stearn]

Just wondering if anyone has encountered a dog tracking issue? I have an appointment on the 7th to have ours checked out. Had two different friends following me mention the tracking. Tires seem to be wearing the same.

[Ding-a-ling]

On our '05 38R Suncruiser the front tires were wearing on the edge. While in Washington state I had it looked into at Brazel's RV in Centralia. They did a "thrust angle" alignment on the rear axle.
I'm not sure most chassis places know of this..... Ask.

FJF

[Dadeaux]

Quote:

Originally Posted by stearn Just wondering if anyone has encountered a dog tracking issue? I have an appointment on the 7th to have ours checked out. Had two different friends following me mention the tracking. Tires seem to be wearing the same.

I had that same issue with my 40 ft. Phaeton, two or three people had told me it looked to be out-of-track. Freightliner in Mobile put the frame on their laser alignment equipment and it showed to be dead-on track.

In discussions with them they said in could be perception since the roads are crowned and technically you are climbing slightly to the left all the time, something that is not noticeable on a car or pickup but a long wheel base tends to exaggerate. If you think about it you usually are steering slightly left or your alignment settings are doing it for you otherwise you will drift to the right.

Another possibility is, and let us hope this not your case, there have been cases of motorhomes that were built with the box slightly offset on the chassis. This is not intentional and is the worst possibility since correcting would be monetarily prohibitive.

Good luck.

[Duner]

Del is right, on the longer chassis, they will track sideways because of the crown of the road.

My 40 ft Winnie was dog tracking from day one. I followed the factory delivery guy for 160 miles to take delivery out of state (CA) and the rear looked 4-6 inches to the right. Since my WH chassis is extended 20 inches by Winnebago, there was a lot of finger pointing as to who's warranty covers the fix. 3-T's in Lake Havasu is pretty reliable Winnie service and they said thrust angle was ok and box is straight on chassis.

WH service had a great suggestion ...... water down a the street, or parking lot where it is flat and drive thru perfectly straight out of the water and look at the tracks. I used the middle of my street where the crown breaks evenly left and right. The tracks of the rear duals were 4 inches off the the right of the fronts.

Long story short, it was the front that was toed out too much and was out of spec. Now when a friend is following me they say it looks straight traveling down the road.

From the drivers seat looking thru the mirrors, it still seems to track sideways .....even straddling the center line of a back highway. But I think that is an optical illusion from the angle of the mirrors. Then when you add the crown angle, or a side wind from the left, there will be some dog tracking.

Good luck,
Bill

[Mike Thomas]

All you have to do is measure from front to rear on both sides. Pick a point on the front wheel/axle, whatever, and a point on the back wheel/axle. Take that measurement and check the other side same way. Not uncommon for the right side to be slightly longer. This is the "thrust angle" they are talking about. By cocking the rear axle slightly the motorhome is constantly pushing uphill on the crown of the road, making the motorhome seem like it is tracking straight. A fellow named Mike Beckett of MD Alignment does seminars at truck conventions, written several books and is a consultant to major tire companies and truck companies. In my book, he is the "guru of tires and alignment". As he has often said "it only takes a piece of string, a tape measure, and the correct information, and you can line up anything."

[stearn]

Thanks for the great advice, now I have some things to ask the mechanics. My appointment is Wednesday. Will be interesting to see what they find.

[wa8yxm]

Two or Three suggestions.

First, if it really is dog tracking a good alignment shop is the place that 1: Diagnoses and 2: Repairs that condition.

However it may be just side winds or as someone suggested road crown..

There are devices called Pan-Hard bars or Track Bars. these "Lock" the body centered over the axle.. They stop the tail of the motor home from "Wagging" side to side.

Brazill's RV (A member here if I"ve not mangled his name) sells the Ultra Power model for Ford and Workhorse if I'm not mistaken.. You may wish to look into these.. There are two.. Front and rear, not all companies make the front one.

With these installed the body remains centered on the axle no side to side "Wag"

[stearn]

I am taking it to a place that specializes on truck and bus drive trains. I called for an alignment, and after answering their questions they recomended checking more than alignment. They've been in business many years, with a good reputation. With the info from here I will atleast have some questions after I am told what they did or did not find.

[Ding-a-ling]

Quote:

Originally Posted by stearn I am taking it to a place that specializes on truck and bus drive trains.

Stearn,
When you have the work done, ask if they can give you a printout of the specs. I long ago took our rig to a business that specializes in heavy truck F/E alignment. At the time, I didn't know to ask for a printout, nor did they give me one. At Brazel's the tech went over the printout specs with me, without asking.

FJF

[DriVer]

One of the true time-tested methods for checking tracking is ......... water down the street, or parking lot where it is flat and drive thru perfectly straight out of the water and look at the tracks. Duner used the middle of my street where the crown breaks evenly left and right. The tracks of the rear duals were 4 inches off the the right of the fronts.

The only thing invested was a little time and water.

[Mr_D]

Quote:

Originally Posted by Ding-a-ling On our '05 38R Suncruiser the front tires were wearing on the edge. While in Washington state I had it looked into at Brazel's RV in Centralia. They did a "thrust angle" alignment on the rear axle. I'm not sure most chassis places know of this..... Ask. FJF

Same thing they do on Honda's when you have a four wheel alignment.

[wa8yxm]

The Chassis places may or may not know "Thrust angle" (Which by the way will not cure dog tracking, it simply means the wheels all point the same way

Kind of like this

.. F F
R R

Now a full 4-wheel alingnment (even if the rears are duals) ends up with the wheels like this

F F
R R
as they should be

You will note that in the "Thrust" they tires were all pointed straight up.. Not like this

F F
R R

[Ding-a-ling]

Quote:

Originally Posted by wa8yxm The Chassis places may or may not know "Thrust angle" (Which by the way will not cure dog tracking, it simply means the wheels all point the same way Kind of like this .. F F R R Now a full 4-wheel alingnment (even if the rears are duals) ends up with the wheels like this F F R R as they should be You will note that in the "Thrust" they tires were all pointed straight up.. Not like this F F R R

I like your illustration!!!!
I don't know if I had a "dog tracking" issue, but the slight thrust angle adjustment corrected my front tire wear.

BTW, For those of you out there who know Chip Maddox of Rallys R Us - a few months before I had the RE alignment done he eyeballed my front tire wear and said, "Needs rear axle thrust angle alignment." Chip knows MH suspensions.....

FJF

[stearn]

Well I got the roadhouse back today. They found that the rearend was off by 1/2 inch. They replaced a clip that was broke and center pins, and also did a laser track, and adjustment. DW followed me to the barn and she said " we looked normal". I must admit I did not detect a problem while driving. Maybe now that it's right I will know if that kind of problem shows up again. Thanks again for all your advice!