1997 K2500 Front Camber Spec?

[slovcan]

Thanks guys. I'm going to go to my trusted mechanic and get him to remove the other 3 knockouts marking the concentric bolt positions first. Then I'll go back to the alignment place with the specs I want. I'll ask if the alignment guy can include the SAI numbers on the printout.

The truck has been babied and regularly maintained and inspected, really, so I don't expect bent components. Not saying there couldn't be, mind you.

Cheers,
Glenn

 

[Hipster]

when I was the "alignment guy" was to favor the camber by about .2 degrees (higher on the left) and the caster by .2 to .5 (lower on the left).
.

I believe that's about a lost art these days.

If camber is the same on both sides, the only thing that could cause one side to have more SAI than the other is bent components, correct? I had bent knuckles on my Camaro from some moderate contact and the car pulled badly. Once I replaced them, it tracked straight again. Perfect example.

Yes, a difference in SAI indicates bent components or bent frame or bent chassis in a unibody situation. Included angle is more indicative of a bent knuckle or strut. Valuable numbers for diagnosing issues and a lot of guys delete the info from printing out even at the dealership level. You can have a tweaked LCA and adjust the upper to get caster, camber, and toe within specs, but unless you have a setback number you'd never know.

Bouncing one off a curb can do more damage then just what's readily visible and if dealing with a vehicle of unknown history there's that.

Habeeb's use tires and $29 alignments is just not where you want to go. lol

 

[CKVortec]

Habeeb's use tires and $29 alignments is just not where you want to go. lol

Not according to Habeeb...

 

[Supercharged111]

Not according to Habeeb...

Here it's more Pedro's used tires and no alignment. But I'm OK with that.

 

[Erik the Awful]

A few years back a guy turned in front of me and I drove my Mustang through a shallow ditch. I took it to an alignment shop the next day. Everything looked fine and the alignment was still good, but over the next couple years it chewed up the insides of the front tires. I finally bought new control arms, even though the old arms looked great. No more tire chewing.

 

[slovcan]

Your specs are correct and Hipster is correct.
on top of what he previously stated, your alignment specs can be perfect, even adjusted to slightly fight road crown and your tires can cause a pull even with no visible tire wear. A "radial pull" can be caused by one of the "radials" in the tire being larger than the others.
when you remove the knockouts on a GM truck don't do just one, don't do just one side, remove them all so that you have full adjustment of camber and caster on both sides.
what your "alignment guy" did by removing one knockout and adjusting your caster with such a big difference from left to right is that he gave you a guaranteed pull to the right.
A vehicle will normally pull to the side with the higher camber and/or lower caster, so to fight road crown my strategy (when I was the "alignment guy" was to favor the camber by about .2 degrees (higher on the left) and the caster by .2 to .5 (lower on the left).
if the vehicle still pulls try crossing the front tires (if they are directional they obviously can't stay like that).
Things to keep in mind:
#1 no alignment can be "locked in" with loose parts.
#2 no alignment will be correct if the tire pressures are not even.
#3 Caster isn't a wear angle, so you can adjust it to whatever you need to get the truck going straight.
#4 all bets are off if the frame or other parts are bent.
#5 save the long detailed description and just post the alignment printout.

Thanks CKVortec. Much appreciated. Yeah, I sometimes tend to write a lot to get all the details out there. There are not supposed to be any "loose" bits in my steering linkage. I specifically asked my guy to look for that at my safety "pre-inspection" so I could change anything that showed any visible wear. That said, I fully expect worn rubber bushings to some degree. The tires are new, 50 psi front & 80 psi rear, rear airbags both at 0 for the alignment. I would be shocked if anything was bent given the history of the truck - babied by the original owner and me.

So, I take it you're saying the 0.0-1.0 degree camber spec is Positive and correct? They didn't just forget the " - "? If so, I guess your favoring the camber by about 0.2 degrees higher on the left would look something like +0.2 left and 0.0 on the right? Considering that, and considering that not all my roads are crowned the same - or even the same way - I think I should ask for 0.0 camber on both sides.

I understand what you are saying about the caster. My factory set caster seems to be 2.3 degrees left and 2.2 right. I'm sure they were gunning for even and that is what the knockouts gave them. Given that, I think I should aim for 2.3 left and 2.5-2.8 on the right.

So, with the historical 0.5L, 0.1R camber and 2.3L, 2.2R caster it always pulled a bit to the right - couldn't let go the wheel for more than a couple of seconds.

What do you think of my plan?

Thank you,
Glenn

 

[CKVortec]

Thanks CKVortec. Much appreciated. Yeah, I sometimes tend to write a lot to get all the details out there. There are not supposed to be any "loose" bits in my steering linkage. I specifically asked my guy to look for that at my safety "pre-inspection" so I could change anything that showed any visible wear. That said, I fully expect worn rubber bushings to some degree. The tires are new, 50 psi front & 80 psi rear, rear airbags both at 0 for the alignment. I would be shocked if anything was bent given the history of the truck - babied by the original owner and me.

So, I take it you're saying the 0.0-1.0 degree camber spec is Positive and correct? They didn't just forget the " - "? If so, I guess your favoring the camber by about 0.2 degrees higher on the left would look something like +0.2 left and 0.0 on the right? Considering that, and considering that not all my roads are crowned the same - or even the same way - I think I should ask for 0.0 camber on both sides.

I understand what you are saying about the caster. My factory set caster seems to be 2.3 degrees left and 2.2 right. I'm sure they were gunning for even and that is what the knockouts gave them. Given that, I think I should aim for 2.3 left and 2.5-2.8 on the right.

So, with the historical 0.5L, 0.1R camber and 2.3L, 2.2R caster it always pulled a bit to the right - couldn't let go the wheel for more than a couple of seconds.

What do you think of my plan?

Thank you,
Glenn

I would say your plan sounds solid, just because GM decided that 0.0 to 1.0 degrees was what they should have for a spec doesn't mean you HAVE to set it at positive .5 right in the middle of the range. Just that for some reason the way the short arm/long arm suspension works when hitting bumps or cornering and such influenced their recommendation.
Going with a negative will also work, but due to the heavy truck bodies and body roll in corners and such it might not be the best choice.
I don't have any empirical data for you, just my experience that 1 degree positive or negative doesn't seem to make a whole lot of difference as long as both sides are a close match.
If you are going to ask for camber to match on both sides you may need to increase the cross caster a bit to compensate for road crown or "drift".

Also, being able to let go of the steering wheel for a couple of seconds is not bad to start with, I classify that as a "drift" rather than a "pull" and could easily be caused by road crown or cross wind conditions, so find yourself the best piece of road you can and drive it on a calm day in BOTH directions and make sure before condemning the hack at the alignment shop.
As I stated before, you could also have a tire condition causing this, so if your alignment numbers don't reveal the reason for a pull make sure it isn't the tires by doing a side to side rotation (check tire pressures as well, 5 psi will make a big difference sometimes).

If the truck still drifts or pulls it will be really hard to nail down the cause, but some things I have seen in the past are:

rear drum brake adjusted improperly
one front disc brake dragging slightly more than it should
control arm bushings replaced on one side weren't tightened down at ride height
driver weighed 450#
rear spring replaced and tightened down while drooping, not at ride height.
power steering box applying some pressure/force one direction.

good luck, and remember, it's still a truck so it'll never drive like a caddy.

 

[Supercharged111]

I would say your plan sounds solid, just because GM decided that 0.0 to 1.0 degrees was what they should have for a spec doesn't mean you HAVE to set it at positive .5 right in the middle of the range. Just that for some reason the way the short arm/long arm suspension works when hitting bumps or cornering and such influenced their recommendation.
Going with a negative will also work, but due to the heavy truck bodies and body roll in corners and such it might not be the best choice.
I don't have any empirical data for you, just my experience that 1 degree positive or negative doesn't seem to make a whole lot of difference as long as both sides are a close match.
If you are going to ask for camber to match on both sides you may need to increase the cross caster a bit to compensate for road crown or "drift".

Also, being able to let go of the steering wheel for a couple of seconds is not bad to start with, I classify that as a "drift" rather than a "pull" and could easily be caused by road crown or cross wind conditions, so find yourself the best piece of road you can and drive it on a calm day in BOTH directions and make sure before condemning the hack at the alignment shop.
As I stated before, you could also have a tire condition causing this, so if your alignment numbers don't reveal the reason for a pull make sure it isn't the tires by doing a side to side rotation (check tire pressures as well, 5 psi will make a big difference sometimes).

If the truck still drifts or pulls it will be really hard to nail down the cause, but some things I have seen in the past are:

rear drum brake adjusted improperly
one front disc brake dragging slightly more than it should
control arm bushings replaced on one side weren't tightened down at ride height
driver weighed 450#
rear spring replaced and tightened down while drooping, not at ride height.
power steering box applying some pressure/force one direction.

good luck, and remember, it's still a truck so it'll never drive like a caddy.

SLA behaviour has nothing to do with their recommendations. The front of these trucks have poor geometry. Any time you take a corner they lose negative camber. Have you ever seen one with a wheel cranked in the parking lot? They lay over with tons of positive camber. This is a result of having way more KPI than caster. The KPI doesn't really begin to steal the camber though until the wheel is good and cranked. With more caster, you can gain negative camber initially, but since these trucks only run 2-4 degrees of caster they don't stand a chance. If you understand how suspension works, you'll realize GM's spec is retarded and seems aimed more at keeping the tire companies in business.

 

[slovcan]

Awesome CKVortec. Thank you. Yup, agreed, not a Caddy. I just want to get it as good as I can. And I will.

Yeah, the pull to the right - with a noticeable crown on a 2 lane road it is a pull, 2 seconds and we're heading for the ditch. On a flat road or straddling the center if there is a crown, letting go the wheel for a couple of seconds and it is a drift - heading toward the shoulder.

I think the 0.0 camber will be good (rarely ever carry a load in her anymore - 99% empty these days), so not much suspension compression. The caster I think I'll get the right side 0.2 more than the left. I will accept whatever result this gives. It will surely be better than what I've had for 11 years.

She is a daily driver now while my clutch leg heals, never was before until 4 years ago when she became the daily driver in winter.

Cheers,
Glenn

 

[CKVortec]

SLA behaviour has nothing to do with their recommendations. The front of these trucks have poor geometry. Any time you take a corner they lose negative camber. Have you ever seen one with a wheel cranked in the parking lot? They lay over with tons of positive camber. This is a result of having way more KPI than caster. The KPI doesn't really begin to steal the camber though until the wheel is good and cranked. With more caster, you can gain negative camber initially, but since these trucks only run 2-4 degrees of caster they don't stand a chance. If you understand how suspension works, you'll realize GM's spec is retarded and seems aimed more at keeping the tire companies in business.

Since I don't drive around in circles all the time I'm not too concerned about what happens in the parking lot.
I get plenty of tire life out of my 3 trucks, all wear even and for a long time. They are all aligned to spec.
Since the camber changes when the suspension compresses on SLA suspension it has a lot to do with drivability and tire wear, so if your torsion bars aren't adjusted evenly or are cranked up to add lift it will mess with everything.
Set yours to whatever you like, but I'll leave mine alone.