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TJ Bumpstops
 

Bumpstops.....we use them on our suspension systems to limit the spring travel.  This is done for two reasons.....the first is to prevent the spring from over compressing.  Over compressing a spring can result in spring fatigue and/or failure.  The spring can take a set and not return to its normal length after the load is removed.  The second reason is to keep tires from rubbing, usually the inside fender well area.  This normally occurs when we increase the tire size by a fair amount.  Some folks simply cut away the sheet metal while others prefer to keep the body as it was and limit the upward wheel travel.
 

In the above photo, a couple of bump stops are in use.  A 1" Teraflex aluminum extension has been installed where the factory bump stop cup is located.  This increases the factory bump stop length by an inch.  The problem with this method shows up if you try to go much longer.  It causes the spring to rub on the bump stop.  As the spring expands and the axle droops downward, the axle moves rearward a small amount.  This causes the longer spring to no longer stay centered on the upper spring perch and so the bump stop rubs the spring.  On the bottom spring perch, a 2" tall RE extension has been installed.  This method works very nicely because the extension down here does not interfere with the spring like the one at the top spring perch sometimes does.  You may be wondering why so much extension?  The spring shown in the above pic is a 4" Procomp coil.  With most 4" lifts, you add a 2" bump stop (that takes care of the lower 2" RE bump stop).  You will also note that there is a 1 3/4" coil spacer at the top of the spring.  I added the 1" Teraflex bump stop extension to help offset this spacer.  So....I have 6" of lift and 3" of bump sop extension to compensate for it.  This prevented my springs from being over compressed AND it allowed the front tires to come within about a 1/4" of rubbing the fenders.  Can't ask for much more than that. 

 

This is my current front spring (as of my writing these comments).  It is an 8" Skyjacker spring.  The bumpstop is extended at the top by more than 3".  It is a one piece unit and I am no longer running the aluminum extension that was shown in the previous photo.  The extension is tapered (an improvement over what I had) and so is not nearly as likely to tangle with the spring like the previous setup.   I still have the 2" RE extension at the bottom.  Given that the spring are taller and their spring rate is not overly soft, I can just barely get the bumpstops to touch under heavy compression.
 

This setup is from my buddy's TJ.  He is running 4" TeraFlex springs with a 1" coil spacer.  On the lower perch, you can see a 2" aluminum block (from the original Teraflex installation).  When we added the coil spacer at the top of the spring, we didn't want to cause an over compression situation.  A 1" thick hockey puck was RTVed on top of the aluminum spacer.  They work great.  Same 3" diameter as the existing spacer so it lines up just fine.  A pair of them were purchased at a used sporting goods store for a dollar each.  You can't beat the price and they do the job very well.
 

 

 

 

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