Front Alignment/Caster

2nd gen lifted 6 lug Tacomas with larger than stock tires.
Autozone lists stock caster at 0.30 and preferred at 0.67.

I've read a lot of people suggesting 3-4 with 3 being the minimum. From what I've read additional caster helps Tacomas clear front cab mounts. Is that the only reason for the additional caster?

From what I understand caster determines how straight the vehicle wants to go (with everything else set correctly) on a flat road. On a crowned road the more the caster the more effort required to keep the vehicle going straight. Corrections in my statements are appreciated.

I'm confused why people recommend so much more caster than stock.

 

autozone is wrong there. Spec is around 2.1* +- .75* for a 4x4

here is the spec sheet.

 

having the front weight over the front axle is used more for local commuter type vehicles that need slow speed maneuverability with a direct steering feel and response in terms of weight shifting... that's low caster. having the weight behind the front axle in high caster is used more for highway type stable higher speed applications when you are trying to stabilize weight shifting and not amplify like with low caster. race cars, high end German performance sedans, and highway cruisers all use high caster.

there is more to it because the package matters, and tires, pressures, etc all add up and contribute. but generally the feel is somewhat heavier, more self-centering, and more stable as speed increases with higher caster. it is generally more urgent, quickly responding, and relying on front tire response more with a low caster setup.

if you have higher caster on one side like the old school method of aligning in a caster split to accommodate road crowning, for example, then steering into the high caster side will feel heavier, slower to respond, and a bit stubborn relative to the other side, all things kept the same.

on this site you will see most mentions of caster referring to fitment and tire positioning in the well. more positive caster moves the front axle forward and helps clear the cab mount at the back of the tire.

 

Remember the only thing autozone is good for is borrowing tools. Most of us will say have caster between 3-4 degrees. I’ll have mine set at 4.

 

I have found a happy medium around the mid to high 2*s (2.5-3*) With a smidge (.3-4*) of more caster on the passenger side for road crown (so say 2.5 driver and 2.9 passenger)

Much higher than that (closer to 4* of caster) for my setup (2in lift all around - 265/75R16's) i found that pull due to road crown became excessive with no increase in straight line stability.

 

Road crown can be accounted for with camber as well if you go equal caster left and right. However, if both are dead nuts equal then you constantly be fighting a pull against the crown.

 

I thought autozone's numbers seemed really odd but since I've never done my own front end alignment... thank you.

Idk why but I've never been able to open any pdf file from this forum so I'm glad you took the time to write it for me. Thanks again.

 

You're awesome, thank you.

 

It was the top result in my Google search. I've bought maybe 5 parts from autozone in 4 decades. I typically go to my local privately owned parts house because they'll bend over backwards trying to find me anything I want so I try to use them no matter what part I'm looking for. The typical exception is when they don't have a part in stock and they can't get it the same day when I need it the same day.

 

You answered my next question without me asking it, thank you.

 

Wouldn't camber adversely affect front tire wear?

 

That's hilarious.

 

Yes, which is why most places adjust using caster. If you have a harder compound tire rotating every 5K it would be minimal since it is only 1-1.5* on one tire not both.

It is give and take. I moved my body mounts so i have room, but others may not. Just providing options.

I bought the lifetime alignment at Firestone for the cost of two alignments ($180). I have had them align my truck at least 12 times now. Just a thought as well as not all Firestone’s are equal to one another.

 

man am I glad I found this post! I went to VIP for an Inspection only on my 2019 offroad...but also needed an alignment after they checked...and oil change...so I called toyota directly and they said go ahead and do it there. When all was said and done, VIP: "couldn't adjust the right front caster"...so I was a bit concerned. After checking this post my left is also at 2.4 and Right is at 2.9....apparently the sweet spot with my 265/70 r16's...unbeknownst to me. I also live in Maine and the road I drive on has a crazy crown...not sure if this adjustment helps with that or not. My only real concern is that the tech "Could Not Adjust" but im also happy he couldnt I guess.