Alignment help please!

[Cheech2017]

I have owned my 2017 1500 all terrain 6.2 since new, at 600 miles (1000km) I installed the following:

 

rancho quick lift all around 

rc top mount front strut spacers 

1.5” wheel spacers on factory 20” wheels 

305 55 20 Goodyear duratracs 

 

What specs would you recommend based on your experience with the same/similar set up? 

 

I cannot find a single alignment shop that can dial in my alignment. I’m getting really uneven outside wear on the front tires. I’ve had the truck aligned 4 times in 2 years it’s got 22,000 miles on it now (36,000km). 

 

Current specs:

caster L 2.2 

caster R 3.0

camber L -0.6

camber R -0.6

toe R 0.05

tor L 0.05

 

Previous specs:

caster R 3.6

caster L 3.7

camber R -0.1

camber L -0.1

toe R 0.10

toe L 0.10

 

It was my thought that if everything was returned to factory spec and add 2 degrees positive camber to put the front wheels more straight up and down rather than tilted into towards the truck is all that really needed to happen but I’m no expert and apparently neither are guys working on my truck. Please help! 

 

Thanks 

 

 

[1SLOW1500]

Factory specs. My lowering messed with mine. Shop said it was fine and it drove fine but I knew the tire wear would be bad so I called engineers and they sold me camber plates. Got it in GM spec no issues. 

I cant remember the factory specs but toe out and camber positive doesn't sound good at all. Camper negative a little at ride height and weight is better and too in drives straight with less dive. Caster is more of a bumps and feel thing, until you turn the wheels then it's a huge on tire edges. 

I had to go in and show their alignment pro what to do. One plate was backward and he was lost. 

[SirenRed16]

Factory specs. My lowering messed with mine. Shop said it was fine and it drove fine but I knew the tire wear would be bad so I called engineers and they sold me camber plates. Got it in GM spec no issues. 
I cant remember the factory specs but toe out and camber positive doesn't sound good at all. Camper negative a little at ride height and weight is better and too in drives straight with less dive. Caster is more of a bumps and feel thing, until you turn the wheels then it's a huge on tire edges. 
I had to go in and show their alignment pro what to do. One plate was backward and he was lost. 

You got camber plates at a dealer? I might need some.

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[1SLOW1500]

No from belltech. I got shims from dealer and for free. Part of the shake bulletin.

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[1SLOW1500]

Oh if you need more adjustment they sell offset bushings as well.
Normal the lower you go the more negative camber happens in the suspension. And it a good thing. Go up you get positive. Very good suspension from aftermarket manufacturers can stop most of this. But back to you. I would go factory or a little negative knowing that on downward travel there would be more negative. Again negative helps in handling on hard turns but caster can cause scrub this is where in or out side of tires as it rolls to the tires edge on turn. Again toe out helps on turn in as the tires want to turn but at straight high speeds make the car dart and too sensitive to input. Toe in helps with straight line stability. Both cause a amount tire wear.

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[Grumpy Bear]

13 hours ago, Cheech2017 said:

I cannot find a single alignment shop that can dial in my alignment. I’m getting really uneven outside wear on the front tires. I’ve had the truck aligned 4 times in 2 years it’s got 22,000 miles on it now (36,000km). 

 

Current specs:

caster L 2.2 

caster R 3.0

camber L -0.6

camber R -0.6

toe R 0.05

tor L 0.05

 

When you start using spacers and altering wheel offset you change the Ackermann. Weird stuff starts to happen. Add a ton of castor and it gets worse. Imagine a motorcycle with a really raked front end. At walking speed to turn the bike the tire has to lay over scrubbing the side of the tire silly. With two front wheels picture that event while both wheels are on completely different arcs. The more spacer you run the larger the difference in arc. A line from the knuckles center through the tie rod linkage center drawn rearward will intersect near the pumpkin. In front of, behind on centered. Factory linkage is set for the specific offset to assist in the designs under or over steer as the designer sees fit. Driven on the edge oversteer scares passengers. Understeer scares drivers. Under the limit and excess of either eats tires like candy at the country fair. You should never have more than a quarter degree left to right in either camber or castor with the greatest castor on the roads center and the least negative camber on same. The difference is in the design to keep the truck straight on a crowned road but as your set up it is fighting to climb the crown as much as if the truck were set up with large amounts of negative thrust angle. (dog tracking up the crown) 

 

While altering ride height does indeed change all three major specs, as 1SLOW1500 pointed out,  it does not change their target values. Messing with offset however does. 

 

My truck has been lifted, leveled and now lowered and I have 85K on the current tires with this alignment but I do run stock rim offsets and no spacers. Get rid of a ton of the castor and get the left side over the right and that will help not only wear but ride. If you insist on altering offset then MAYBE you can compensate for a SOME of the outside scrub with maximum factory NEGITIVE camber and a hint of positive toe (positive toe is front of the tire closer than the rear) Opposite of camber. 

 

Do not kid yourself, you may burn down a few sets of tires before you nail it down and still you might not get it perfect. Mid 60's Corvettes has adjustable Ackerman. Silverado's do not. 

[1SLOW1500]

Yeah road crown is a issue for me as my steering wheel is a little turned to get truck straight. Wider and large tires seem to track the road more. Meaning want to roll true to the surface of the road.
You speak of Ackerman that is why I was saying custom shops rebuild all the suspension to get the angles right.

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[Cheech2017]

9 hours ago, Grumpy Bear said:

 

When you start using spacers and altering wheel offset you change the Ackermann. Weird stuff starts to happen. Add a ton of castor and it gets worse. Imagine a motorcycle with a really raked front end. At walking speed to turn the bike the tire has to lay over scrubbing the side of the tire silly. With two front wheels picture that event while both wheels are on completely different arcs. The more spacer you run the larger the difference in arc. A line from the knuckles center through the tie rod linkage center drawn rearward will intersect near the pumpkin. In front of, behind on centered. Factory linkage is set for the specific offset to assist in the designs under or over steer as the designer sees fit. Driven on the edge oversteer scares passengers. Understeer scares drivers. Under the limit and excess of either eats tires like candy at the country fair. You should never have more than a quarter degree left to right in either camber or castor with the greatest castor on the roads center and the least negative camber on same. The difference is in the design to keep the truck straight on a crowned road but as your set up it is fighting to climb the crown as much as if the truck were set up with large amounts of negative thrust angle. (dog tracking up the crown) 

 

While altering ride height does indeed change all three major specs, as 1SLOW1500 pointed out,  it does not change their target values. Messing with offset however does. 

 

My truck has been lifted, leveled and now lowered and I have 85K on the current tires with this alignment but I do run stock rim offsets and no spacers. Get rid of a ton of the castor and get the left side over the right and that will help not only wear but ride. If you insist on altering offset then MAYBE you can compensate for a SOME of the outside scrub with maximum factory NEGITIVE camber and a hint of positive toe (positive toe is front of the tire closer than the rear) Opposite of camber. 

 

Do not kid yourself, you may burn down a few sets of tires before you nail it down and still you might not get it perfect. Mid 60's Corvettes has adjustable Ackerman. Silverado's do not. 

 

So if I understand correctly I should get the camber to be adjusted to max factory negative threshold?  So -0.9 instead of -0.6 as an example, toe from 0.05 to 0.10? What about caster? 

 

With the spacers it’s lije running a small positive offset wheel a lot of guys go to zero some around +12ish which is about where mine would be give or take a couple mm. There’s got to be tire shops or alignment shops that have already figured this stuff out somewhere was my thought.

[Cheech2017]

19 hours ago, 1SLOW1500 said:

Oh if you need more adjustment they sell offset bushings as well.
Normal the lower you go the more negative camber happens in the suspension. And it a good thing. Go up you get positive. Very good suspension from aftermarket manufacturers can stop most of this. But back to you. I would go factory or a little negative knowing that on downward travel there would be more negative. Again negative helps in handling on hard turns but caster can cause scrub this is where in or out side of tires as it rolls to the tires edge on turn. Again toe out helps on turn in as the tires want to turn but at straight high speeds make the car dart and too sensitive to input. Toe in helps with straight line stability. Both cause a amount tire wear.

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I am finding the steering a tad stiff when turning out of the driveway or at times when turning from dead stop. Seems to be a tad stiffer turning left than right. Do you have any recommendations on the actual specs? 

[1SLOW1500]

I could.be wrong but I would look to get rid of caster. If you are at Zero then the tire when turning is doing so flat on the contact patch of the rubber. At max caster on the edge of the tire, that causes tire wear and bushings to wear. However more caster is a better ride and more stable vs suspension straight up and down like a Jack hammer.
Some will say more caster and they are 100% right but with wide tires and also tires farther out you are multiplying the issue of scrubbing. As the turn causes the truck to lift up on its toes( edge of tire) or roll over the rubber. These is very hard on your steering as at its max the tire is at its worst position.
My Bell Tire had the specs.

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[Grumpy Bear]

Minimize castor and continue to dial in negative camber within reason. .01-.05 toe is fine. Get the left over right differences on both on the correct side of the road. Rotate and balance often. 

 

What tire shop do you think has figured out the numbers for say 100 different combinations on one model of truck? 

 

The aftermarket doesn't care if it works, only that it fits and that about half the time. The few shops that have fabricated some off road set up have done so under the same constraints the factory had to. They are not infinite. Follow the instructions carefully OR hire an engineer who specializes. 

 

Past that your in no mans land.  

 

[1SLOW1500]

Exactly who I was waiting to post in here. In my experience grumpy is very knowledgeable on these things.

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[Cheech2017]

On 2019-01-15 at 6:20 PM, Grumpy Bear said:

Minimize castor and continue to dial in negative camber within reason. .01-.05 toe is fine. Get the left over right differences on both on the correct side of the road. Rotate and balance often. 

 

What tire shop do you think has figured out the numbers for say 100 different combinations on one model of truck? 

 

The aftermarket doesn't care if it works, only that it fits and that about half the time. The few shops that have fabricated some off road set up have done so under the same constraints the factory had to. They are not infinite. Follow the instructions carefully OR hire an engineer who specializes. 

 

Past that your in no mans land.  

 

Sorry, what’s the left over right differences suggestion referring too exactly? 

 

What I had meant earlier was that I’m sure this is a popular set up for this model truck so there may had been folks who already had  been through this and had some specs to recommend. 

 

So based on my current set up it should wear better than my previous set up correct? I don’t find that to be the case however.

 

thanks for the help btw! 

[Grumpy Bear]

1 hour ago, Cheech2017 said:

Sorry, what’s the left over right differences suggestion referring too exactly? 

 

What I had meant earlier was that I’m sure this is a popular set up for this model truck so there may had been folks who already had  been through this and had some specs to recommend. 

 

So based on my current set up it should wear better than my previous set up correct? I don’t find that to be the case however.

 

thanks for the help btw! 

In the USA we drive on the right. Two lane roads are crowned. A quarter degree more castor on the drivers side and a quarter degree more POSITIVE camber (less negative in an all negative setup) on the drivers side assist the car in going straight on a crowned road. 

 

Your second question is been asked and answered as well as it can be. Your not liking the answer. Sorry. Maybe someone else will give it a stab in the dark. 

 

You answer your own third question. 

 

 

[Cheech2017]

20 hours ago, Grumpy Bear said:

In the USA we drive on the right. Two lane roads are crowned. A quarter degree more castor on the drivers side and a quarter degree more POSITIVE camber (less negative in an all negative setup) on the drivers side assist the car in going straight on a crowned road. 

 

Your second question is been asked and answered as well as it can be. Your not liking the answer. Sorry. Maybe someone else will give it a stab in the dark. 

 

You answer your own third question. 

 

 

Ok thanks for clarifying the first question. 

 

Second question has nothing to do with me not liking how the question was answered previously just clarifying your question as to why I thought a shop may have specs. Actually I appreciate the help not trying to sound like I don’t.

 

third question confuses me bc your recommendation and that of others is to add negative camber and reduce caster. That was done as per the specs I posted. That should mean I would be seeing less wear now than previous,  I am seeing more wear. So I’m not sure how that answers my question bc if i were to go in the opposite direction and add more positive camber and caster then I would be going into a positive camber and more caster situation like the previous set up only more. That’s not the advice I am getting here so yeah that’s a tad confusing when you suggest I answered my own question. I’m trying to learn.