Alignment and Wear question

[cubangt]

I have a 17 Silverado with 6" lift, everytime i take it in for alignment check, they say its within spec and dont charge me anything because there is nothing to do, But i am getting wear on the front tires. On the passenger side front tire, the outside of the tire is wearing and inside is full thread(normal wear).  The driver side front tire, the inside is wearing and the outside is full thread(normal wear).

 

And then i called around and trying to find alignment shops that will just do a 2 wheel alignment on the truck, is that correct, that a 4 wheel alignment on a truck is not needed? Or is that misstated online. 

 

I just checked the price of the tires and they have gone up to $450/each tire and right now only need 2, but when i do my rotation, im going to need all 4 sooner than later.

 

Is there anything i can check myself that would be causing the uneven wear on the front tires?

[TheRiver]

Brand of lift???

[Grumpy Bear]

1 hour ago, cubangt said:

they say its within spec and dont charge me anything because there is nothing to do

 

There is WITHIN SPEC and then there is ON SPEC. People don't like to work. They like you to hand them all your money. 

 

Did you get print out? INSIST on a printout. Give you an example: Look at the camber on this job. See those arrow in the middle where the arrows are? That is ON SPEC. You could have the left one at +0.7 and the right at -1.1 and be IN SPEC and have opposite edges of the tire wear. His job isn't to get in IN SPEC, it's to get it ON SPEC. If he doesn't see it that way find a shop that does. 

 

[cubangt]

58 minutes ago, TheRiver said:

Brand of lift???

Zone

[cubangt]

9 minutes ago, Grumpy Bear said:

 

There is WITHIN SPEC and then there is ON SPEC. People don't like to work. They like you to hand them all your money. 

 

Did you get print out? INSIST on a printout. Give you an example: Look at the camber on this job. See those arrow in the middle where the arrows are? That is ON SPEC. You could have the left one at +0.7 and the right at -1.1 and be IN SPEC and have opposite edges of the tire wear. His job isn't to get in IN SPEC, it's to get it ON SPEC. If he doesn't see it that way find a shop that does. 

 

thanks, not sure i know where the last print out is, but will ask the additional questions next shop i find. I def want to get it done before i spend money on another set of tires. 

[cubangt]

Finally getting around to getting new tires and going for an alignment right after.. So my question, when getting the alignment, so that i know when i ask the questions, does having the lift on the truck determine what is "On Spec" or is that regardless of lift?

 

Just want to go in there prepared.

[Grumpy Bear]

12 hours ago, cubangt said:

Finally getting around to getting new tires and going for an alignment right after.. So my question, when getting the alignment, so that i know when i ask the questions, does having the lift on the truck determine what is "On Spec" or is that regardless of lift?

 

Just want to go in there prepared.

 

Opinion time. You good with that?  

 

Tire wants to be stood up straight and not drug sideways a hundred feet per mile down the road. The OEM had a plan for geometry and when we lift or lower, we toss that plan out. We change roll, pitch and yaw centers, Ackerman and scrub radius, and we do this without thinking about the affect it has on tire wear, fuel economy or handling. It even matters HOW we move the ride height. Spindles? Moving shock centering? Blocks? I guess the good news is for a street vehicle most of our miles are pointed straight ahead. Better news is the factory alignment is wide and toggles each side of neutral for camber and toe but always positive caster. 

 

I set lowered truck up with a hint of negative camber. Like -0.1 to -0.2 which favors the wearing the inside of the tire and then a hint of positive toe favoring the outside of the tire. they cancel each other. Something like .02 to .05 and equal. Target zero steer ahead and zero trust angle. 2 degrees castor is a good compromise between impact harshness and stability in my experience. If I towed or hauled allot, I might go a bit shallower like 1.5 positive caster. (It will get more positive as the rear squats.) 

 

50 years ago, when roads had actual crown, I went a bit more positive on both camber and castor on the drives side but still negative camber to prevent crown climb. But since the Interstates became the main arteries of travel and have zero crown and primary highways lost their gutters and curbs, it doesn't matter much anymore. 

 

If in addition to the lift you've also moved the contact patch out, (wider track width) you have a recipe for shimmy. 

 

Draw a line from the upper ball joint through the lower to the ground. That line should land in the middle of the tires tread width plus or minus a smidgen. The difference between the two is the scrub radius. Watch some videos on it. 

 

 

[cubangt]

9 hours ago, Grumpy Bear said:

 

Opinion time. You good with that?  

 

Tire wants to be stood up straight and not drug sideways a hundred feet per mile down the road. The OEM had a plan for geometry and when we lift or lower, we toss that plan out. We change roll, pitch and yaw centers, Ackerman and scrub radius, and we do this without thinking about the affect it has on tire wear, fuel economy or handling. It even matters HOW we move the ride height. Spindles? Moving shock centering? Blocks? I guess the good news is for a street vehicle most of our miles are pointed straight ahead. Better news is the factory alignment is wide and toggles each side of neutral for camber and toe but always positive caster. 

 

I set lowered truck up with a hint of negative camber. Like -0.1 to -0.2 which favors the wearing the inside of the tire and then a hint of positive toe favoring the outside of the tire. they cancel each other. Something like .02 to .05 and equal. Target zero steer ahead and zero trust angle. 2 degrees castor is a good compromise between impact harshness and stability in my experience. If I towed or hauled allot, I might go a bit shallower like 1.5 positive caster. (It will get more positive as the rear squats.) 

 

50 years ago, when roads had actual crown, I went a bit more positive on both camber and castor on the drives side but still negative camber to prevent crown climb. But since the Interstates became the main arteries of travel and have zero crown and primary highways lost their gutters and curbs, it doesn't matter much anymore. 

 

If in addition to the lift you've also moved the contact patch out, (wider track width) you have a recipe for shimmy. 

 

Draw a line from the upper ball joint through the lower to the ground. That line should land in the middle of the tires tread width plus or minus a smidgen. The difference between the two is the scrub radius. Watch some videos on it. 

 

 

Thank you, i will watch a few videos and make sure to get everything ready before going to the shop to get the alignment. Just waiting on the tires to get delivered to the tire shop to get them installed.