yeah, i still haven't really found a solid reason as to why its bad for the shocks to bottom out. i keep getting "someone told me that...", but i do understand the ripping the shock mounts off. if i came crashing down off a rock and the wheel ramed up into my fender, that could break the welds on the shock mount.

i wonder if cutting it close is bad? i mean so close that we are talking tenth's of an inch. my jeep is 75% on road (wish it was the otherway around), so the shocks bottoming out won't happen very often, if ever. and even off road, its not like i get fully flexed all the time. guess my question is, how bad would it be running shocks meant for a 3" lift on a 2.5" lift...?

 

I respectively disagree on the uptravel and stability issue.

The statement that up travel makes a roll more likely is flawed....as more rolls occur from one end being tipped too high, and the COG being shifted out of the contact patch shadow.

Ideally, a suspension allows the tires to go up and down, while the truck stays dead level.

On terrain like dunes, where there's not too much up, mostly down, and the ability to absorb landing impacts...which depend upon long down travel as a ride height, absorbing impact is the one area where the bias is to a high ride height....to leave ROOM for shocks to compress upwards...but, not past where he stock uptravel ended, etc.

This is because the droop length would be too short if the compressed length had to reach OEM starting points, etc.

On a slow rock crawl though...the tire that climbs a rock 2", then j=its a bumpstop, and therefore raises the trucks corner inch for inch going up that rock is going to possible tip the truck over due to a lack of uptravel.

A long uptravel adds stability when the truck would be tipped up on a corner...the tire goies up, the truck stays level.

I've seen first hand the rollovers that occurred when the truck was driving at a high ride height, to maximize droop, with tall bumpstops to prevent over compression....and was tipped up at the bumpstoped corner due to a lack of uptravel.

The confusion for some is when the truck is side hilled/off camber....and the down hill side can roll too far to the down hill, because the weight transfer shifted the COG to the down hill side of the contact patch shadow.

What is forgotten, is that the reason the downhill side was foreced over, was the ride height of the unweighted UPhill side of the truck, essentially PUSHING the truck over to the down hill side, exacerbating the problem....a double edge sword perhaps...

So - the RIGHT uptravel/down travel is more important than maximizing one or the other per se......

And valving of the shock's compression and rebound, and the spring rates of the coils, will all play a part in what that magic balance should be.

Example - as I compress the down hill side when I'm side hilling...I 'm compressing the down hill side coil...if its a progressive spring rate...and properly chosen, it should prevent the weight shift to the down hill side from tipping the jeep too far over...providing more and more resistance as the jeep's tilt approached a reasonable limit.

If too stiff a coil set is used, the UP hill side is tilting me over more than the DOWN hill side can stabilize....

Or - I am on the side of the hill/off camber, with my frame and axles dead parallel, and my roof line parallel to the slope, etc.

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Stability is all about keeping the COG withing the shadow of my contact patches.

To pick a COG point, lets say my OG is an imaginary point located about at my radio dial.

If the jeep tips in any direction, such that a line drawn straight down by gravity, from my dial, to the ground below, puts my radio dial's position outside the box formed by the 4 corners of my tire's contact patches...I can tip over towards the dial's spot on the ground outside the contact area box.

 

Here is a link to Quadratec referencing the preferred length of shocks of TF BB.
TF has even changed the shocks length on the 4" inch system because of the stock drive line and interference issues.

http://www.quadratec.com/sb/TeraFlex/JK_Lift_Kits.htm

http://www.teraflex.biz/pages/tech.php?article=27

The best way to ensure that the those shocks will work if the measurement are far from the recommended values is the following. Remove your springs and compress your axle to the hard into bump stops take measure and then do the same on the the extended length. You may have to install your springs to insure the it will not fall out under max extension.

My front shocks have an extended length of 29.50" and my front drive shaft was hitting hard on the front exhaust at that length.

 

You will have to address the sway bar links. The links will have to be longer to prevent them from folding the incorrect way at max droop and at normal ride height the sway bar(s) will not be at the preferred angle.

 

So if im wanting to go with a 3" teraflex lift for my 4door jk, And i also purchased a set of spring retainers..so the springs wouldnt fall out..what is the longest shock i can run. According to the chart, it says 26" front and 28" rear.

 

From Teraflex's Site

 

cant i put a longer shock on if i have a spring retainer...?? atleast an inch or two longer. im wanting to get the most drop possible out of the suspension. Im either thinking FT or Teraflex....not sure yet still i keep going back and forth

 

The spring length will not change your droop.

The axle droops from gravity, and cantilevered leverage...the tiny amount of remaining down force of a longer coil is all but unmeasurable at full droop.

TF's COME with a spring retainer...it just clips the top in place...so it doesn't limit droop, just keeps the coil seated in the upper bucket.



Also - TF NOW uses the SAME shock on the 4" lift as they do on the BB anyway, so its a moot point (Their site's chart is out of date)

 

ahhhh...did not know that. so how long are their shocks on the 3" lifts....same as the 4 and 2.5 BB im guessing

 

Yep.



Same shocks for 2- 4" SL's