Why does lift height regulate shock and bumpstop length?
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JK Enthusiast
Joined: Apr 2008
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From: hawaii
When I think about bump stop leangth should only increase when tire diameter increases and to me the bump stops should increase In a 1-2 ratio. Add two inches of tire add 1 inch of bump stop, and now that you've added 1 inch of bpstop you can afford an extra inch of shock body.....
JK Jedi Master
Joined: Jan 2008
Posts: 11,463
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From: Austin <--> Colorado Springs
Q: Do I need to install bump stop extensions?
A: Yes. Bump stop extensions are designed to prevent the over compression of your coils and are absolutely necessary. Bump stop extensions can also help prevent the rubbing of fender flares at a full stuff as well as the bottoming out of shocks.
Q: What size bump stop extensions should I install with my lift?
A: Typically, you'll want bump stop extensions that are approximately as tall as the lift you just installed on your Jeep. In other words, if you lift your jeep 2", you'll want bump stop extensions that are about 2" tall. Now, I do say 'typically' as this is just a guide to follow and not necessarily a rule. Depending on the actual height of the coil, thickness of the wire used and the amount of winds it has, the rules can change.
A: Yes. Bump stop extensions are designed to prevent the over compression of your coils and are absolutely necessary. Bump stop extensions can also help prevent the rubbing of fender flares at a full stuff as well as the bottoming out of shocks.
Q: What size bump stop extensions should I install with my lift?
A: Typically, you'll want bump stop extensions that are approximately as tall as the lift you just installed on your Jeep. In other words, if you lift your jeep 2", you'll want bump stop extensions that are about 2" tall. Now, I do say 'typically' as this is just a guide to follow and not necessarily a rule. Depending on the actual height of the coil, thickness of the wire used and the amount of winds it has, the rules can change.
Last edited by nthinuf; Nov 29, 2009 at 12:18 PM.
JK Freak
Joined: Jan 2009
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From: Carlsbad, CA
Umm, I disagree. I want the extra articulation, there are clips and guides that make it perfectly fine for your spring to leave it's perch momentarily and using the tire size as a benchmark would dictate bumpstop and shock body length and prevent over compressing and ruining the shock.
JK Freak
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From: Carlsbad, CA
Thread Starter
JK Enthusiast
Joined: Apr 2008
Posts: 382
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From: hawaii
Thread Starter
JK Enthusiast
Joined: Apr 2008
Posts: 382
Likes: 0
From: hawaii
Without spring retainers, what's to keep your springs from popping out at the worst possible time on the trail? Shocks (or mounting brackets) will fail if over extended or over compressed. Are you saying to let your tires hit the wheel well and act as the bump stops? This doesn't sound like a very well thought out theory. Let me know if I am missing something.
JK Jedi Master
Joined: Jan 2008
Posts: 11,463
Likes: 165
From: Austin <--> Colorado Springs
As I mentioned in my first post,
If you trim the fenders or go to flats, you negate the need for extra bumpstop to prevent rubbing from uptravel.
If your coils are designed to be able to stack without damage, you can get away with running less bumpstop. (assuming your shocks are not bottoming out, making them act as the bumpstop. And assuming you're comfortable with the metal to metal jarring you'll get on impacts instead of the milder compression from the rubber/poly bumpstops compressing)
My experience with bumpstops:
OME HD + spacer, appx 4" of lift. Disconnected, my 32" (actual height on vehicle) tires rubbed the fenders enough to rip them off, and the coil was fully stacked. Added 2" lower bumpstops - coil compresses to an acceptable level, and the tire/fender rubbing is very light. I will trim the fenders a bit instead of added more bumpstop. With 35" tires, there would be no choice but to add more bumpstop or go to flat flares. (which goes right back to 'lift height = bumpstop height'
If you trim the fenders or go to flats, you negate the need for extra bumpstop to prevent rubbing from uptravel.
If your coils are designed to be able to stack without damage, you can get away with running less bumpstop. (assuming your shocks are not bottoming out, making them act as the bumpstop. And assuming you're comfortable with the metal to metal jarring you'll get on impacts instead of the milder compression from the rubber/poly bumpstops compressing)
My experience with bumpstops:
OME HD + spacer, appx 4" of lift. Disconnected, my 32" (actual height on vehicle) tires rubbed the fenders enough to rip them off, and the coil was fully stacked. Added 2" lower bumpstops - coil compresses to an acceptable level, and the tire/fender rubbing is very light. I will trim the fenders a bit instead of added more bumpstop. With 35" tires, there would be no choice but to add more bumpstop or go to flat flares. (which goes right back to 'lift height = bumpstop height'
Last edited by nthinuf; Nov 29, 2009 at 01:28 PM.
Thread Starter
JK Enthusiast
Joined: Apr 2008
Posts: 382
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From: hawaii
As I mentioned in my first post,
If you trim the fenders or go to flats, you negate the need for extra bumpstop to prevent rubbing from uptravel.
If your coils are designed to be able to stack without damage, you can get away with running less bumpstop. (assuming your shocks are not bottoming out, making them act as the bumpstop. And assuming you're comfortable with the metal to metal jarring you'll get on impacts instead of the milder compression from the rubber/poly bumpstops compressing)
If you trim the fenders or go to flats, you negate the need for extra bumpstop to prevent rubbing from uptravel.
If your coils are designed to be able to stack without damage, you can get away with running less bumpstop. (assuming your shocks are not bottoming out, making them act as the bumpstop. And assuming you're comfortable with the metal to metal jarring you'll get on impacts instead of the milder compression from the rubber/poly bumpstops compressing)
Lets isolate a bit, my lift is a rock krawler 3.5 entry level lift and my intent will be to put 37's. I am still piecing together some support parts for the entry level kit and I currently have river raider fronts and hacked rears so there is plenty of space.
Why would I have metal on metal jarring? My factory bump stops dont have metal on metal jarring so why would an extended bump stop that just didn't fit the proptocol of one inch extension for 1 inch of lift cause metal on metal contact?