Questions regarding tire flex

[Mikester86]

The picture is from Patches, the '02 TJ build thread. Hope he doesn’t mind.

The question is when the tires flex like that, what part(s) of the axle/shafts/suspension allow for it? And how much wear/damage is being done?

 

[Jerry Bransford]

Everything on the suspension is allowing that great flex... joints on the tie rod, drag link, track bars, control arms, shocks, etc. Wear of those parts in situations like above is not normally a concern. The chief concern is are you using flexible-enough joints/bushings where you should be? For example, that level of flex is fine when you have good flexible control arms that allow for a lot of misalignment but if you're using poorly designed aftermarket control arms with bushings at both ends, which limits how much the arms can move/flex/articulate, it stresses the control arm mounting brackets. Sometimes to the point the brackets can be torn away from where they are welded in place.

Generally speaking the flex being shown above is not usually anything but a good thing. Other than it looks like he needs taller bump stops.

 

[Mikester86]

Everything on the suspension is allowing that great flex... joints on the tie rod, drag link, track bars, control arms, shocks, etc. Wear of those parts in situations like above is not normally a concern. The chief concern is are you using flexible-enough joints/bushings where you should be? For example, that level of flex is fine when you have good flexible control arms that allow for a lot of misalignment but if you're using poorly designed aftermarket control arms with bushings at both ends, which limits how much the arms can move/flex/articulate, it stresses the control arm mounting brackets. Sometimes to the point the brackets can be torn away from where they are welded in place.

Generally speaking the flex being shown above is not usually anything but a good thing. Other than it looks like he needs taller bump stops.

Thanks for the detailed reply Jerry!

 

[TurboTJ]

I think this is on topic. I have Currie control arms but I did not install the upper front Johnny joints that require welding. Is it worth the trouble to add those for better flex?

 

[MaloStapalo]

I think this is on topic. I have Currie control arms but I did not install the upper front Johnny joints that require welding. Is it worth the trouble to add those for better flex?

I don't have those either, just the OEM upper mounts on axle end.

 

[TJDaveX]

I think this is on topic. I have Currie control arms but I did not install the upper front Johnny joints that require welding. Is it worth the trouble to add those for better flex?

I installed the Currie upper JJ conversion kit when I swapped out my cheaper "R" brand adjustable control arms for a full set of Savvy arms. I wanted to have all 16 Johnny Joints. The stock passenger bushing just fell out when I removed the old arm! Maybe from the added stress Jerry talked about above? The joint on the driver's/pumpkin side took a little more work. But, the Currie kit provides you with a little tool to help.
Worth it? I think so. Still silent and creak free after a few years. My friends are amazed at how tight and silent my Jeep is when they drive it.

 

[TurboTJ]

I installed the Currie upper JJ conversion kit when I swapped out my cheaper "R" brand adjustable control arms for a full set of Savvy arms. I wanted to have all 16 Johnny Joints. The stock passenger bushing just fell out when I removed the old arm! Maybe from the added stress Jerry talked about above? The joint on the driver's/pumpkin side took a little more work. But, the Currie kit provides you with a little tool to help.
Worth it? I think so. Still silent and creak free after a few years. My friends are amazed at how tight and silent my Jeep is when they drive it.

Did you have to disassemble the axle before welding the passenger side on? I am concerned about the heat generated and the oil that might be in the axle tube.

 

[TJDaveX]

Did you have to disassemble the axle before welding the passenger side on? I am concerned about the heat generated and the oil that might be in the axle tube.

I did not. Although, we did not weld the lower part all at once to allow some cooling.

 

[TurboTJ]

I did not. Although, we did not weld the lower part all at once to allow some cooling.

Thanks for your reply. How did you weld it? Mig? Tig? Stick?

 

[TJDaveX]

Thanks for your reply. How did you weld it? Mig? Tig? Stick?

My buddy did the welding. Mig. Now that I'm thinking about it, the gear oil was drained because we were working on the e-locker wires.

 

[Jankoid]

Other than it looks like he needs taller bump stops.

The bumps were set properly. Looks close but the tire did clear the fender.