Adding spring spacers to existing lift

Hey all,

As discussed in my build page, I made a mistake with my lift. I have a ‘21 JLUR with a 2.5” AEV lift and my new 37” STT Pros/KMC machetes rub at full flex. I plan on chopping the fenders and ultimately getting a taller and better lift but I think that I need better rock sliders first. I’m hoping I can get by in the meantime with spring spacers.

Would there be a problem if I were to add a 1” spring spacer to the front and maybe a 1.5” on the back? What additional adjustments would I need to make? Would it still be safe at speed on the highway?

Thanks for the help!
 

CalSgt

Hooked
If all you are worried about is the rubbing you may just want to add a little more bump stop, probably easier and cheaper than spacers.

What is the backspacing on your wheels? If its greater than 4.75" a wheel spacer or different BS wheel might fix it too.

If you want the additional ride height you may need to add more bump stop anyway as the spacers may allow you to compress your AEV springs beyond what they are intended for.

Make sure your shocks are capable of the additional droop

Other than that adjustable arms or geometry correction brackets for the front might be required to go from 2.5 to 3.5 inches of lift. I ran 2" on my JL with the stock arms but added adjustable lowers to allow for a little caster correction when jumping up to 3.5" springs.

Last thing would be to make sure all wires and hoses going to the axles have enough slack freed up to accommodate the additional droop. This part is free and just requires loosening some wire retaining clips or re-routing stuff to get more slack.

Should be highway safe so long as alignment is good.
 

BlueRubicon

Caught the Bug
I would change wheels. Are you using Stock rims? The stock rim back spacing will cause rubbing with 37's with that lift. Also are you using 12.5 or 13.5 tires? Wheels I bought have 6.0mm back spacing and I only get very slight rubbing in front with MAX flex. Been running like this for 2 years.
 
If all you are worried about is the rubbing you may just want to add a little more bump stop, probably easier and cheaper than spacers.

What is the backspacing on your wheels? If its greater than 4.75" a wheel spacer or different BS wheel might fix it too.

If you want the additional ride height you may need to add more bump stop anyway as the spacers may allow you to compress your AEV springs beyond what they are intended for.

Make sure your shocks are capable of the additional droop

Other than that adjustable arms or geometry correction brackets for the front might be required to go from 2.5 to 3.5 inches of lift. I ran 2" on my JL with the stock arms but added adjustable lowers to allow for a little caster correction when jumping up to 3.5" springs.

Last thing would be to make sure all wires and hoses going to the axles have enough slack freed up to accommodate the additional droop. This part is free and just requires loosening some wire retaining clips or re-routing stuff to get more slack.

Should be highway safe so long as alignment is good.
Thanks for the help! Wow, way more things to consider than I was anticipating. Wheel BS is 3.5”.

I want all of the above, more ride hight, more clearance Clarence and no rubbing. So by the time I’ve done all mentioned above I might as well get a more robust lift with adjustable arms and such. I think I’ll trim the fenders now to alleviate the rubbing then get my rock sliders and then save up for a better lift.

I would change wheels. Are you using Stock rims? The stock rim back spacing will cause rubbing with 37's with that lift. Also are you using 12.5 or 13.5 tires? Wheels I bought have 6.0mm back spacing and I only get very slight rubbing in front with MAX flex. Been running like this for 2 years.
Thanks Blue. Wheels are brand new KMC machetes w/ 3.5” BS and the tires are new STT pros 37x12.5r17. Had Borahs and “37” KO2s on there before.
 
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