Front caster post lift question
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JK Enthusiast
Joined: Oct 2008
Posts: 289
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From: USA
Front caster post lift question
Ok, so I installed my Teraflex 2.5" coil lift along with an adjustable track bar, adjustable front lower control arms and wheel spacers. Using an angle finder on the bottom of the steering knuckle pre lift both sides read 4*.
I set the lower control arms just shy of 23" and post lift the measurement at both knuckles is 6*. Am I correct in thinking that I have added more caster than stock or are there factors I'm not considering? My assumption is if I kept the measurement at 4* post lift I should maintain stock caster. Only had a chance to do a short drive last night as we have a big snow storm and icy roads today.
The lift gave me 3.25" front and 2" rear. Still running the stock tires for now with the wheel spacers installed.
I set the lower control arms just shy of 23" and post lift the measurement at both knuckles is 6*. Am I correct in thinking that I have added more caster than stock or are there factors I'm not considering? My assumption is if I kept the measurement at 4* post lift I should maintain stock caster. Only had a chance to do a short drive last night as we have a big snow storm and icy roads today.
The lift gave me 3.25" front and 2" rear. Still running the stock tires for now with the wheel spacers installed.
JK Jedi Master
Joined: Jan 2008
Posts: 11,463
Likes: 165
From: Austin <--> Colorado Springs
You have a lift, you don't want stock caster.
From the faq's up top there:
From the faq's up top there:
Q: What is Caster? How much do I need?
A: Caster is the angle upon which your front axle sits at in order to help keep your Jeep driving straight. Positive caster, which is what you want, will cause your axle to sit in a way that your pinion shaft will be dipping ever so slightly towards the ground. Too little or even negative caster angle can cause your Jeep to wander and feel 'flighty' or 'darty' as I've heard some people call it. From the factory, your JK will have +4.2° of caster and if you lift it and install larger tires, you will need to increase this amount to help compensate for the modifications. At 3"-4" of lift, I have found that +6°~8° of caster will do wonders to help improve the handling of your Jeep JK Wrangler.
A: Caster is the angle upon which your front axle sits at in order to help keep your Jeep driving straight. Positive caster, which is what you want, will cause your axle to sit in a way that your pinion shaft will be dipping ever so slightly towards the ground. Too little or even negative caster angle can cause your Jeep to wander and feel 'flighty' or 'darty' as I've heard some people call it. From the factory, your JK will have +4.2° of caster and if you lift it and install larger tires, you will need to increase this amount to help compensate for the modifications. At 3"-4" of lift, I have found that +6°~8° of caster will do wonders to help improve the handling of your Jeep JK Wrangler.
JK Newbie
Joined: Jun 2009
Posts: 93
Likes: 0
From: Monroe, LA
As was previously stated, you don't want stock caster numbers since you have a lift. Ideally, you want as much caster as possible without getting front driveshaft vibrations. You can get away with a bit more caster with aftermarket shafts too.
I will be doing the 2 1/2 Teraflex springs and shocks with 33"-35" tires.
JK Newbie
Joined: Jun 2009
Posts: 93
Likes: 0
From: Monroe, LA
Lowers give you the greatest range of adjustment so I would just go with lowers for now and if you want to add uppers later for better articulation then you can. A lot of people can't shorten the uppers enough to get enough caster out of them.
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JK Jedi Master
Joined: Jan 2008
Posts: 11,463
Likes: 165
From: Austin <--> Colorado Springs
Front uppers are less expensive, but are adjusted 'shorter' than stock.
Front lowers are a bit more expensive, and are set 'longer' than stock, which gives them a better range of adjustability.
Either will work, but lowers would be the better choice. If price is a concern, Currie uppers are known to adjust shorter than others and would be a good choice.
Also, with your 3+" lift height - If you find that you need a new rear driveshaft, you'll want to look at rear uppers as well to set the driveshaft angle.
Front lowers are a bit more expensive, and are set 'longer' than stock, which gives them a better range of adjustability.
Either will work, but lowers would be the better choice. If price is a concern, Currie uppers are known to adjust shorter than others and would be a good choice.
Also, with your 3+" lift height - If you find that you need a new rear driveshaft, you'll want to look at rear uppers as well to set the driveshaft angle.
Last edited by nthinuf; Dec 8, 2009 at 11:29 AM.