A arm hit

gren71 · **Posted:** Tue Apr 03, 2012 9:32 am

So I've read and been told that going to high with a lift can cause the a arms/ uca will "hit"

I'm curious at what point they hit? Full flex, or general use...
And what happens when the hit? Do they bend or break or just stop the movement of the wheel.

And wouldn't a larger bump stop mitigate this?

Thanks

tommudd · **Posted:** Tue Apr 03, 2012 9:53 am

Bumpstops help prevent the wheel/tire from going up into the fenderwell too much causing the shock to compress too far at times or the tire hitting the fender
The contact on the spring/UCA happens when you lift too high and/or also when you drop that front tire into a hole etc
You'll hear it ( the UCA) hit the spring as it passes past it going up and down
At what point? Well depends on lift/KJ/KK etc
I can say that on a KJ with the 4.5 arms and measuring over 23.5 from middle of wheel to bottom of flare it does, on a KK of course you all are not getting that same measurement so it will be different

gren71 · **Posted:** Tue Apr 03, 2012 10:03 am

I appreciate the fast an informative response!!

So When the jeep is over lifted it will cause the a arm to hit.
Realistically how much of a serious issue is this if our not off roading? And wen if you are..what can it do?

At The Helm · **Posted:** Tue Apr 03, 2012 10:09 am

For me it was just over 21.5" when contact starts. It kind of depends on how the spring is positioned though, if the space between the coil is in just the right place then the uca can get a little more travel.
On mine the contact point was the ball joint, so its something you don't want to happen.

isomswim · **Posted:** Tue Apr 03, 2012 10:14 am

gren71 wrote:

I appreciate the fast an informative response!!

So When the jeep is over lifted it will cause the a arm to hit.
Realistically how much of a serious issue is this if our not off roading? And wen if you are..what can it do?

Even for normal road driving it can cause issues if the roads around you are terrible with potholes. Plus if you decide to go offroad you can with out worrying. When the UCA rubs it will chip paint off the spring which will cause the spring to rust up, no bueno. Even my mall crawler FJ I wouldnt drive until I got UCAs because they were conacting the spring. Just my :2cents:

as having lifted other vehicles.

gren71 · **Posted:** Tue Apr 03, 2012 12:18 pm

Thank you both!

I'm sitting at 21 all around at the moment but I think I have an addiction...so back to saving and scheming for now.

See you all at the group meeting >_>

Scar0 · **Posted:** Tue Apr 03, 2012 11:52 pm

Something else to consider. Beyond the spring contact mentioned above, you may also experience the UCA hitting the bottom of the pocket as well, even with new A-arms. Unfortunately it seems the KK has less room to trim in this area than the KJ does.

A arm hit

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