I have been trying to track down the cause of vibration between 50-55mph. My next move was to have the tires rebalanced. However, when I took a closer look at the front tires, I noticed that the driver's side front tire had significant feathering on both the inside but more on the outside edge. The passenger side still looks ok, but did have some slight feathering. The upper control arms are of equal length, and the lowers have the passenger side set 1/8" longer as suggested for road crown. I did not change the toe at all with the lift and assumed this would not be a factor??

I only have 2000 miles on the tires and will have them burned up in no time if I don't find the cause. Any thoughts?

 

Can't see it through the computer, but it sounds like it may have too much toe in.

 

I'm going to take the tape measure to it tonight.

 

x's 2

I would take it to a reputable place to align the front. or you could do it yourself if you know how to. one way is to lift the front of the vehicle up using chalk or a tire marker spin the wheel to create a line all the way around on both sides drive it back then front a few feet as long as the wheel makes atleast two complete rotations using a tape measure the lines front and back of the wheels, on my vehicles I prefer at least 1/16" to no more than 3/16" toe in. with larger tires no more then 1/4" would be ok. Visual inspection can also be done as but nopt as accurate. Place one wheel parallel with the vehicle fenders and then look at the right side tire in comparison with the left to see if it is toed in to much or not. but as I said not as accurate. Hope this info helps some.

 

Since I didn't change this adjustment with the lift, is it just a function of the larger tires that may need the different toe adjustment? Does running at 28 psi vs say 32-35 psi create more drag and eccenuate the problem?

 

Yes due to the contact patch on the road being larger with less pressure For example with a ballon sitting on a table and no down pressure the contact patch is that less of a quarter the more pressure you force down on the ballon the contact patch will increase thus creating more friction or in the case of tires traction. That will increase the amount of tire on the road and will tend to pull one or both tires depending how bad the alignment is. Thae other poissible variable is that you may have an unserviceable Ball joint which causes the tire to move slightly back and forth causeing the tire to feather on the inside and outside of the tread. Good luck with your diagnosing..

 

After measuring several times and at several places, the toe was 1/4 more in the rear of the tire vs the front. I adjusted it to a 1/8 difference (toe in).

Question - could the 1/4 toe in create the feathering where the 1/8 now set will not contine the problem?

Question - would anyone suggest a rotation to pull these slightly feathered tires to the rear to burn them flat?

I am taking it in for an alignment this afternoon more to just get a good set of numbers and to officially have the toe set. More piece of mind (although a $70 piece of mind!).

 

as for a 1/4 of inch no it wouldn't cause that much of a problem thats what is being ran on larger tires in the Military. Larger I mean by 37" and larger. I would also check ball joints by lifting the tire off the ground grab the wheels and shake to see how much play is int themif you notice quite a bit several components could be goiing or are bad. idler arm could be bad, ball joints or what not have someone get in and turn the steering wheel while you are under it and the vehicle is on the ground not started and have them turn the wheel to the left or right. Look for exsecive play in any of the steering components. hopefully you find out whats causeing the feathering.

 

1/4" of toe is a ton. When I was doing alignments, I preferred measuring toe in degrees. It's more accurate and modern machines give the option for degrees, inches or milimeters. Generally, most vehicles start out at around 1/16" total toe in. Even that is excessive on some. Your best bet is to get into an alignment shop. Did you make your adjustments on turnplates? If not, then there's no guaranty that the tires iddn't "jack" out of shape. In other words, the wheels turned more than the tires due to the tires gripping the ground. It is nearly impossible because of this to get an accurate measurement on the ground.

 

Well, here's the numbers. Despite me thinking I had 1/8 inch toe in....

Left Front:

Camber -0.6 before and after (range is -0.6 to 0.1)
Caster +2.1 before and after (range is 3.7 to 4.7)
Toe -0.13 before +0.09 after (range 0.07 to 0.13)

Right Front:

Camber -0.7 before and after
Caster +1.9 before and after
Toe -0.12 before and +0.12 after

Observations:

From these numbers, it looks like I was actually toed out despite my measurements, and now it is toed in (probably the cause of the tire feathering).

Using the basic angle finder to set castor read 4.5 degrees on a relatively level driveway. This alignment is saying I am at 2 degrees! I will probably lengthen the lowers a little tomorrow to move more toward 4 or 5 (now that I have base numbers to start with)

The tech was really taking his time and spoke to me before making any adjustments, so I guess tape measures and basic angle finders are only so accurate!

Question:

The question I have is that I set my passenger (right side) control arm 3/16" longer than the driver's side. This would leave me to believe my passenger side should have a higher castor setting that the drivers side BUT according to these numbers, the driver's side has more castor. Does that mean these numbers could be off, or is there that much variation in the bracketry on the axle/frame to make a computerized alignment necessary to really dial these guys in?

I can't say whether the vibration between 50-55 mph has changed as it is really windy out and all I hear is gusting.