Caster Question (Alignment) Again

[BFL13]

Been some posts about alignments for Cs the last couple years, which I wrote down what I was supposed to have for Caster according to those that know.

I finally got to use that info (I thought) when getting new front tires today that have aged out and were showing uneven wear.

So I asked about the recommended Caster numbers from those posts here, and was told they have a computer alignment set-up and could not tell me what the specs were for my 1991 Ford (In sig) so I said tell me what it says to do and then do these numbers I have if different.

Then he looked under the front and said I had tie-rods so the caster was not adjustable, but it must have been somewhat adjustable, since the report shows them different before and after.

So if anybody has a clue about all this, please explain what I have here now. 🙂

The "Alignment Report" I was given, has before and after for Camber, Toe, and Caster. Plus some "secondary angles". Anyway it badly needed alignment, which I knew from the tire wear. So here are the Caster numbers:

Initial Left 4.4, (Spec 2 - 8 ) Final 4.0
Initial Right 4.7 (Spec 2-8) Final 4.5 degrees.

I had these numbers from a previous post , that I should want 5.0 L and 5.5 R and NOT 3.0. So:

I have 4.0 L and 4.5 R, which is more than 3.0, and also the R is 0.5 more than than the L same as with 5 and 5.5 so I almost got there? Or am I still not where it should be? ( I can't change it, so it is what it is, but I would like to know where I am at in this whole deal wrt those posts about all this.)

(It does drive ok but still a bit light on its feet up front due to being overweight at the back I guess--can't be helped there)

Thanks.

[BFL13]

Funny that there are actual alignment guys on here, although rv.net does attract all sorts! 🙂

Big issue at my garage was if the Class C would even "fit". They were worried the back of its roof would hit their doorway when it was up on the hoist. It just fit inside.

With a longer rig, I don't know where I would go to get it done. Must be some places with longer bays, haven't checked into that.

[CapriRacer]

I'm with Time2Roll. The camber looks excessive, but the toe (THEE most important setting) looks good.

[BFL13]

I am not seeing post #5 from 1344 and post #7 from 1532, so can't reply unless they show up eventually. No idea why that happens. 😞

EDIT: got the posts finally! Yes, good to go! 🙂

[Grit_dog]

^The RIGHT way. You understand camber caster and toe and how each affects each other, not just turn the nut until the computer beeps...

[time2roll]

Were the tires wearing more on the outside edges? Perfect camber would be zero, right in the middle of the spec. Zero is perfectly vertical. Both at 1 degree would be leaning out that small amount. Each is pulling against each other so it still goes straight. Some tires may tolerate the camber better than others. Heavy vehicle may not be as forgiving.

Toe looks good. Slight in as shown is good. The idea is that when at speed the suspension is loaded a bit and wheels are pushed back just slightly and should dynamically be at zero and both be pointed straight and parallel forward.

And yes I was certified 35 years ago. Old school with levels and bubbles, no electronics.

[Grit_dog]

The ole twin I beam, in my experience yielded more positive camber when loaded down in back. Which sounds like your case maybe?
Your tires both wear more on the outside? If so I’d attribute that to too much + camber as well as your excessive toe in.
Bottom line, like you said, it’s an old rig and if it drives straight and relatively well, provided you’re not packing on mega miles, tires for the front are cheap. Drive it!

[BFL13]

Thanks all for the good explanations. I let the tires wear without getting an alignment as they were aging out and I waited till now to get the alignment with the new front tires.

It drove ok for our short trips, but I wanted to get it right after reading all those alignment posts for Cs. Seems like the Castor numbers are ok; it drives straight.

Old tires gone so no photo. They had tread wear mostly on one side that kept getting worse. Still had tread, so was able to wait till they aged out.

Here are the other numbers in case they mean anything to those who know.

Camber Left : initial 1.1 (spec 0.5 - 0.5) final 1.1 degree
Camber Right: initial 0.4 (spec 0.5-0.5) final 1.0

Toe Left: initial 5/16" (spec -1.32" min to 1/16" max) final 0"
Toe Right: initial 5/16" (spec -1/32 to 1/16" ) final 1/32"
Toe Total" initial 5/8" (spec -3/32" to 5/32" ) final 1/32"

They did centre the steering wheel too, which I asked for. It drove straight, no pulling, but the wheel was to the left- made me crazy. It is fixed now.

I have no idea why they list those specs but some final numbers are not to spec, but I believe from past experience that garage guy knows his stuff, so no worries.

Whatever it is now, that's what it will be while the old C runs out its clock. So far so good! 🙂

[time2roll]

Caster is the degrees angle to represent how far the top pivot point is behind the lower pivot point. Generally the more caster you have the more the vehicle will want to self straighten the wheels. A little extra on the right will help compensate for the crown of the road. Also more caster may transmit more road harshness into the vehicle. Bad caster may not cause any tire wear issue.

If the vehicle does not drift to one side the numbers look fine to me.

Generally camber and toe will be the adjustments needed to correct bad tire wear. Camber will also tend to push the steering toward the side it is leaning.

The tie rods only adjust the toe. Not all angles are adjustable on all suspensions. Some may need special equipment to bend parts. You may need to replace bent or worn parts. Or a body shop would need to square the frame if bent.

Can you post a picture of the worn tire? Or at least describe the issue.

[CA_Traveler]

BFL13 wrote:
Then he looked under the front and said I had tie-rods so the caster was not adjustable, but it must have been somewhat adjustable, since the report shows them different before and after.

I'm not a suspension guy but I thought tie rods were for tow in/out and steering wheel alignment. Caster and camber are different aspects of alignment AFAIK.

[DougE]

If your truck has twin I-beam suspension the caster is not adjustable and the lack of caster in the stock version often leads to the apparent front end lightness you reference. If you will google "ford I beam caster adjustment" you will find a number of references to a caster/camber bushing that can allow more caster to be dialed in to the front suspension. It may be a little difficult to find an alignment shop that will do an adjustment to non-stock settings though.