Stock arms are 22-5/8″ long center of eye to center of eye and I always like to start at 23". Depending on how much lift you actually get, you will most likely find it necessary to REDUCE that amount a bit.
And that's for uppers and lowers ??
Sorry, that's just for the lowers and that should get you close to the caster you are wanting. If you have adjustable upper arms as well, you can actually set your lower arms a bit shorter and the uppers will just need to be set until you have your caster set correctly. If you stick with 23" eye to eye on the lowers, the uppers will need to be set close to factory length.
I have Clayton 3.5 lift, front uppers 18.75, lowers 23 and adjust for pinion
Ok, but I am still not clear on this subject.
If you set the front lowers to 23 and the front uppers to 18.75, what caster does that give you? And what pinion angle?
Stock caster on a JK is 4.1*. But I cannot find an solid spec for front pinion angle. I am running a Coast 1310 front shaft on my JKUR and my front pinion points up 2* which means my caster is 4*. (There is 6* of separation (angle difference) between balljoint centerline and pinion centerline on the factory Dana 44.)
I am pretty sure Eddie says pinion angle must take precedence over caster so running more than factory caster of 4* is presumably bad.
According to Metalcloak's website setting front lowers at 23 1/16 and front uppers at 18.75 (factory length) will give me caster of 5*. But this extra caster makes pinion angle worse (only up 1*) so it sounds like the front uppers need to be longer to reduce caster to 4*.
What do you guys think?
Thanks.
Ok, but I am still not clear on this subject.
If you set the front lowers to 23 and the front uppers to 18.75, what caster does that give you? And what pinion angle?
Stock caster on a JK is 4.1*. But I cannot find an solid spec for front pinion angle. I am running a Coast 1310 front shaft on my JKUR and my front pinion points up 2* which means my caster is 4*. (There is 6* of separation (angle difference) between balljoint centerline and pinion centerline on the factory Dana 44.)
I am pretty sure Eddie says pinion angle must take precedence over caster so running more than factory caster of 4* is presumably bad.
According to Metalcloak's website setting front lowers at 23 1/16 and front uppers at 18.75 (factory length) will give me caster of 5*. But this extra caster makes pinion angle worse (only up 1*) so it sounds like the front uppers need to be longer to reduce caster to 4*.
What do you guys think?
Thanks.
This is what too much positive caster can lead to...
Running 5.13 gears, your front drive shafts spin really really fast. For every one turn of your tire, it will spin 5.13 times and even the most balanced shafts will experience a slight vibration if your caster is set just a bit more than it should. But, however slight, it will eventually fatigue the metal of the transfer case housing and eventually lead to a break.
soo after seeing this i have a question. how much positive caster is to much positive caster? i ask since i have 5.13's and i dont want this to happen to me lol
If you were to have asked me this 5 years ago, I would have said +6° was about as high as you want to go. Today and after what I have seen, I wouldn't recommend anything more than a stock +4°.
ahh ok thanks eddie. so i assume being at 4.2-4.5ish degrees is perfectly fine and anything more than that you would consider to high?
If you were to have asked me this 5 years ago, I would have said +6° was about as high as you want to go. Today and after what I have seen, I wouldn't recommend anything more than a stock +4°. The more caster you have, the better your Jeep will feel especially at highway speeds but, it will lead to vibrations.
Does it matter if you are running a stock or aftermarket drive shaft? How much does the risk of running more caster change if running higher gears like 4.10's?
Yes. 4.10's will be ok with a bit more caster. Stock drive shafts use rzeppa joints and they will be fine as well. The problem with rzeppa joints is that the front shaft will get damaged on an 07-11 with an auto or on any 2012-up when running long enough shocks that allow for too much droop. EVEN IF you install a y-pipe or exhaust spacers, the CV boot will still fail prematurely - these are the reasons why you want to upgrade to a u-joint style double cardan shaft. You only really start to see vibration issues when running too much positive caster and/or 5.13 gears or higher.