Any alignment pro's? I want more Caster!

FirstAscent · August 6, 2020

Hey everyone,

I've been frustrated with my alignment for a couple months now, I feel like it is VERY sensitive and reacts to everything in the road, wanders a lot, tracks to every line in the road. I don't like it! At first I thought I'd give it time, maybe it was just an adjustment I wasn't used to, then I did a road trip from OR to UT and back and got to really get some time in the seat and focus on how it reacted. It's even more of a concern that I'm experiencing this without hauling anything, and I have a fifth wheel on the way so want to get this dialed in before then. I didn't mention any of my feelings on it to my girlfriend and she drove it and she told me "it feels wiggly". Not really the feeling you should get on an $80k truck

No it isn't fully stock, I have a leveling kit with 22" wheels and 325/50R22 Nitto Ridge Grapplers. BUT, I've had these same size tires on my old 2019 Silverado 1500, I had 37x13.5 mud tires on my last Tundra, and they both drove straight and stable. I know tires etc can affect things, but I know it can be fixed with a good alignment.

Now I know I'm not an alignment tech, but do have a general understanding on what each setting does, and everything points to potentially being solved with increased Caster.

I took it back to the 4x4 shop who originally did my leveling kit and alignment (they did all my other trucks in the past too successfully), and they re-aligned it today for me. I specifically asked for more Caster and explained what I was experiencing. I just got home from picking it up and they didn't change Caster one bit, not even 0.1*. Their reasoning was "these are the best settings for these trucks and they don't want to make it unsafe".

What I asked for is STILL in spec, so it shouldn't be "unsafe". Driving home it felt the same as before, but that's not surprising given that all they changed was Toe slightly.

Right now the Caster is set at 2.4 / 2.6 (L/R), I thought it was funny when I just checked and from the factory it was set at 3.3 / 3.2! So me asking for more shouldn't be an issue. (acceptable range is +2 to +4 degrees).

Soooo, am I crazy for wanting more Caster? I know they will re-adjust it for free but it's still frustrating. I don't want to waste their time/money either. I'm going to give it a couple/few days and at least get 50 hwy miles in to make sure, but my short 5 mile drive home it didn't feel any different. So I'll now be taking it back again making sure they friggin add Caster! What do you guys think?

Full alignment sheet attached.

redwngr · August 7, 2020

Sometimes steering issues are caused by the tires/road rather than the alignment/road.

FirstAscent · August 7, 2020

17 minutes ago, redwngr said:

Sometimes steering issues are caused by the tires/road rather than the alignment/road.

Very true, and I know it has more of an effect with larger/wider tires. But I had no issues with these same tires on my 2019 Silverado 1500 with a 6" lift. And I drove it across 3 states and back, so many different types of roads, and always experienced the same issues.

I'm not saying there is absolutely no chance it could be tires, just very unlikely in this situation, I believe.

Adding Caster can fix these exact types of issues, so adding in Caster when I still have +1.5 degrees to play with seems like an easy "trial"

Grumpy Bear · August 7, 2020

Some observations on the alignment.

There should never be more than a quarter degree difference in castor between sides nor camber between sides.

Drivers side castor and camber track well if 1/4 degree more positive that the passenger side. Caster is flipped on this sheet. This helps neutralize the crown in the road wanting to pull the vehicle up the crown.

Spec for everything is no where near centered. 3 degrees castor IS mid spec. A half degree is huge. Explain later.

Toe setting should never ever differ from side to side with thrust angles zero or at least under 0.1 degrees thrust.

You have a quarter degree thrust angle. Dog tracking and the toe trying to equalize. Twitchy.

I have never seen an alignment spec where the ranges we identical left/right. Odd. Then again I haven't seen it all I'm sure. Okay on some race cars we use to stagger the wheel base a bit and run even numbers.

You have a lift and a wider tire. There is a thing called scrub radius. A line from the upper ball joint through the lower ball joint should intersect the ground at the middle of the tires contact patch when she is sitting on the ground. The lift and I would expect different wheel off set has moved this point. That alone will make them twitchy.

Okay when you get a load and the truck squats the caster will increase by exactly the change in frame angle. This will pull the camber more negative and increase the positive toe. Toe is near the limit now that is why we center our specs.

Okay. Listen up. If you think I'm full of crap just ignore me and put the torch away. Have a safe trip. Hope it works out for you.

FirstAscent · August 7, 2020

28 minutes ago, Grumpy Bear said:

Some observations on the alignment.

There should never be more than a quarter degree difference in castor between sides nor camber between sides.

Drivers side castor and camber track well if 1/4 degree more positive that the passenger side. Caster is flipped on this sheet. This helps neutralize the crown in the road wanting to pull the vehicle up the crown.

Spec for everything is no where near centered. 3 degrees castor IS mid spec. A half degree is huge. Explain later.

Toe setting should never ever differ from side to side with thrust angles zero or at least under 0.1 degrees thrust.

You have a quarter degree thrust angle. Dog tracking and the toe trying to equalize. Twitchy.

I have never seen an alignment spec where the ranges we identical left/right. Odd. Then again I haven't seen it all I'm sure. Okay on some race cars we use to stagger the wheel base a bit and run even numbers.

You have a lift and a wider tire. There is a thing called scrub radius. A line from the upper ball joint through the lower ball joint should intersect the ground at the middle of the tires contact patch when she is sitting on the ground. The lift and I would expect different wheel off set has moved this point. That alone will make them twitchy.

Okay when you get a load and the truck squats the caster will increase by exactly the change in frame angle. This will pull the camber more negative and increase the positive toe. Toe is near the limit now that is why we center our specs.

Okay. Listen up. If you think I'm full of crap just ignore me and put the torch away. Have a safe trip. Hope it works out for you.

Yes, definitely full of crap. haha jk, no I really appreciate all your info. I know what I know and what I don't know, I only have a general understanding of what each setting is but when you get into troubleshooting and how much of a difference 0.1 or 1.0 degree makes I have no clue

Interesting note about wanting 1/4 degree more caster and camber on Driver side, yet mine is that way on the passenger side. I can ask them about that and their reasoning.

The lift, wider tire, and lower offset wheel I know all affects it and can make things more twitchy. Do you feel that adding caster could potentially help that though?

Thanks again for your input!

Grumpy Bear · August 7, 2020

8 hours ago, FirstAscent said:

Yes, definitely full of crap. haha jk, no I really appreciate all your info. I know what I know and what I don't know, I only have a general understanding of what each setting is but when you get into troubleshooting and how much of a difference 0.1 or 1.0 degree makes I have no clue

Interesting note about wanting 1/4 degree more caster and camber on Driver side, yet mine is that way on the passenger side. I can ask them about that and their reasoning.

The lift, wider tire, and lower offset wheel I know all affects it and can make things more twitchy. Do you feel that adding caster could potentially help that though?

Thanks again for your input!

I'm pulling the original set of Bridgestone HT's off my truck as soon as the replacements show up. This set has 125,000 miles on them with 25% of the useful tread left. She goes down the road with my hands off the wheel like auto pilot for what is an uncomfortable distance for my passengers. The truck is leveled by lowering. When I got the truck the factory alignment was awful. My castor was actually out of spec high. Notice the total toe is in spec but not centered? It had a mild pull toward the ditch and a twitch. Hit expansion joints like a jack hammer. A lot of castor will do that. Thrust angle was high. This drags the tire sideways as you go down the road. High wear. My rear axle was not square in the chassis. We corrected that too.

When were done. (printer wasn't working that day so photo on my phone). Centered. Thrust angle was 0.08*

This alignment calmed the pull and twitch, took some shock out of the hits and added almost 3 mpg to the averages.

I can't answer you last question in your case but I point you to a video that can help you understand it

Watch the interplay between scrub radius and castor and camber. Watch the second video too. It a real eye opener when it comes to changing one thing changes a bunch of things. Just sit tight and it will start in sequence.

Edited August 7, 2020 by Grumpy Bear

Grumpy Bear · August 7, 2020

Did it make you dizzy? :crackup: It isn't hopeless it just takes more thought that liking a picture in a catalog or a certain look.

For example you can use a wider rim but you have to adjust your offsets to maintain proper scrub and live with the idea that there is only so much room to work with.

One of the reasons I prefer ride height changes (lift or drop) with the knuckle is that it doesn't change wishbone angles and that preserves roll and pitch center.

When I lowered the tail 4 inches the castor and toe needed to be reset. We had to install extended range castor and camber eccentrics.

I hope all this rambling is helpful. I'll pause now.

gearheadesw · August 12, 2020

Good info, Grumpy, thanks.

Yeah, I'm dizzy from all that information.

Dunn · August 20, 2020

On 8/6/2020 at 4:45 PM, FirstAscent said:

Hey everyone,

I've been frustrated with my alignment for a couple months now, I feel like it is VERY sensitive and reacts to everything in the road, wanders a lot, tracks to every line in the road. I don't like it! At first I thought I'd give it time, maybe it was just an adjustment I wasn't used to, then I did a road trip from OR to UT and back and got to really get some time in the seat and focus on how it reacted. It's even more of a concern that I'm experiencing this without hauling anything, and I have a fifth wheel on the way so want to get this dialed in before then. I didn't mention any of my feelings on it to my girlfriend and she drove it and she told me "it feels wiggly". Not really the feeling you should get on an $80k truck

No it isn't fully stock, I have a leveling kit with 22" wheels and 325/50R22 Nitto Ridge Grapplers. BUT, I've had these same size tires on my old 2019 Silverado 1500, I had 37x13.5 mud tires on my last Tundra, and they both drove straight and stable. I know tires etc can affect things, but I know it can be fixed with a good alignment.

Now I know I'm not an alignment tech, but do have a general understanding on what each setting does, and everything points to potentially being solved with increased Caster.

I took it back to the 4x4 shop who originally did my leveling kit and alignment (they did all my other trucks in the past too successfully), and they re-aligned it today for me. I specifically asked for more Caster and explained what I was experiencing. I just got home from picking it up and they didn't change Caster one bit, not even 0.1*. Their reasoning was "these are the best settings for these trucks and they don't want to make it unsafe".

What I asked for is STILL in spec, so it shouldn't be "unsafe". Driving home it felt the same as before, but that's not surprising given that all they changed was Toe slightly.

Right now the Caster is set at 2.4 / 2.6 (L/R), I thought it was funny when I just checked and from the factory it was set at 3.3 / 3.2! So me asking for more shouldn't be an issue. (acceptable range is +2 to +4 degrees).

Soooo, am I crazy for wanting more Caster? I know they will re-adjust it for free but it's still frustrating. I don't want to waste their time/money either. I'm going to give it a couple/few days and at least get 50 hwy miles in to make sure, but my short 5 mile drive home it didn't feel any different. So I'll now be taking it back again making sure they friggin add Caster! What do you guys think?

Full alignment sheet attached.

haha.....biggest thing i noticed between these and 1500 was steering and brakes.......it does wander quite a bit not near as tight as 1500.....i kinda think this is HD trait based on others who have said same thing

mine is 100% stock so i will probably take it in to just have it checked as i can totally see it not being correct from factory as grumpy said.....in fact i would almost expect it to be "out"

Edited August 20, 2020 by Dunn

FirstAscent · August 20, 2020

Did it make you dizzy? :crackup:It isn't hopeless it just takes more thought that liking a picture in a catalog or a certain look.

For example you can use a wider rim but you have to adjust your offsets to maintain proper scrub and live with the idea that there is only so much room to work with.

One of the reasons I prefer ride height changes (lift or drop) with the knuckle is that it doesn't change wishbone angles and that preserves roll and pitch center.

When I lowered the tail 4 inches the castor and toe needed to be reset. We had to install extended range castor and camber eccentrics.

I hope all this rambling is helpful. I'll pause now. [emoji4]

I never responded but thought I did, sorry. But thanks for the additional info and the vid links.

I have another appt I just set for the 28th, so we’ll see what happens.

Part of me also thinks that these trucks are different from previous gen and from what I’ve read the whole Chevy shake issues of the past gens are a non issue. So I feel like them not wanting to make a change because they don’t want to “make it unsafe” while still well within spec is just silly.

haha.....biggest thing i noticed between these and 1500 was steering and brakes.......it does wander quite a bit not near as tight as 1500.....i kinda think this is HD trait based on others who have said same thing

mine is 100% stock so i will probably take it in to just have it checked as i can totally see it not being correct from factory as grumpy said.....in fact i would almost expect it to be "out"

for sure, completely agree on that. Even bone stock it was a lighter steering than my 2019 1500. But now it’s even worse.

I can’t remember the post but I recall reading in here a few members who installed steering dampers they were pleased with. I might look into that as well but I want to get the alignment better first instead of trying to use a damper as a bandaid