Control Arm Length

[HOOP]

just wandering if ya'll can help a ol HOOP out,in process of install lift and was wandering what approximately should length on upper and lower arms be ,putting on 6 in. coils





thanks
HOOP

[GirlScout1]

Here you go...it's a good guide:
http://www.lunghd.com/Tech_Articles/Suspension_Steering_Axles_and_Brakes/Control_Arm_Chart.htm

[HOOP]

Thanks Gs1

Hoop

[Bounty Hunter]

I just installed RE 5.5" coils, LCA's were 17" and UCA's needed to be 16" for correct caster.

[Ramsey]

http://yuccaman.com/jeep/re_db.html#arms

[GirlScout1]

I just installed RE 5.5" coils, LCA's were 17" and UCA's needed to be 16" for correct caster.
Yeah thats about what I'm running except I have short arms. My lengths are about that thoug. I think My UCAs might only be 15 7/8" though.

[Bounty Hunter]

Yeah thats about what I'm running except I have short arms. My lengths are about that thoug. I think My UCAs might only be 15 7/8" though.
Mine are short arms too, no drop brackets either. Had I used the above chart I would have had way too much caster.

[Fergie]

At 6", your LCAs need to be adjusted out to 16 3/4" and your UCAs need to be set to correct your pinion angle.

Fergie

PS-Those charts are wrong.

[GirlScout1]

At 6", your LCAs need to be adjusted out to 16 3/4" and your UCAs need to be set to correct your pinion angle.

Fergie

PS-Those charts are wrong.
I agree Fergie but it is a good starting referance. Mine LCAs are set at about 17" and my uppers are about 16". I used a protractor after against the pinion output to get it about 94( can't remember exactly but I know my pinion is pointing at my TC out put yoke now)

[Yucca-Man]

PS-Those charts are wrong.Then feel free to priovide constructive numbers. I even say in the writeup that these are typical numbers that may vary on yours...if you have other numbers then feel free to let me know what they are instead of always claiming that these are wrong.

[Bounty Hunter]

At 6", your LCAs need to be adjusted out to 16 3/4" and your UCAs need to be set to correct your pinion angle.

Fergie

PS-Those charts are wrong.
I'd give a little more attention to caster when determining the length of the uppers.

I used ratchet staps on top of the C's on each end of the axle, to the rear of the jeep. Use these without the uppers installed to determine proper caster, then measure for UCA lenght.

[Fergie]

Then feel free to priovide constructive numbers. I even say in the writeup that these are typical numbers that may vary on yours...if you have other numbers then feel free to let me know what they are instead of always claiming that these are wrong.
Ummm...did you not see the numbers I DID provide?

It is real simple. You take 248.0625 and add the square of your lift height. Then you take the resulting number, and root it. This will give you the decimal value for your LCA length. Convert as needed.

For RE DBs, you use 232.5625 and subtract 3" from your lift height before squaring it.

As far as caster, I have no clue, and just set my pinion angle accordingly. I know there is a more accurate relationsip than that, but can't find it, or what the acster should be, but remember it being around 7*.

Here is something more....to find your lift height in the front, you measure from the top of the axle tube to the bottom of the frame rail. Stock measurement is 6.75"(7.75 for HD/Up Country).

For the rear, measure the same way, and it should be 6"(7") and both front and rear can vary by .5".

Good enough for you?

Fergie

[Gridikal]

Hmmm...

Copy/ Save

[Ramsey]

very interesting, where did those numbers come from

[Fergie]

very interesting, where did those numbers come from


The numbers I used were from the stock LCA length of 15.75", and from the RE site which states that the DBs move the stock location forward by .5" and down by 3", so the length would be 15.25". Square those and you get the number I used.

The stock height measurements I got from a post by Eagle from a while ago..."Measuring lift...the dirty way."

All the math is just a^2+b^2=c^2 and making sure to maintain stock geometry.

Fergie

[AZ DESERT RAT]

The numbers I used were from the stock LCA length of 15.75", and from the RE site which states that the DBs move the stock location forward by .5" and down by 3", so the length would be 15.25". Square those and you get the number I used.

The stock height measurements I got from a post by Eagle from a while ago..."Measuring lift...the dirty way."

All the math is just a^2+b^2=c^2 and making sure to maintain stock geometry.

Fergie


My brain hurts!!!!! LOL

[Ramsey]

wow, never would have thought of that