Suspension up travel, shocks, lift

OK, I have approx 6" lift, rear XJ44, RE1462 pack and 6* shim, sye, rusty's 6.5 coils up front and no vibes on 33" x 12.50 mt/r's on 4.75" BS wheels. Have a set of 12" travel bilstein 5100's. Without boring you with all the math, I end up with only 3.5" of up travel and about 8" droop. Distance between the coil spring pad and the bumpstop is approx 5" and when fully stuffed I rub just a bit. Getting 35's which should eat another inch of the possible uptravel. Now, I certainly can get 2 additional inches of bumpstop so I'll be right close with available shock and fender and make it work, or I can lift an additional inch, and add 1" bumpstop and have approx 4.5" uptravel and 7 droop... see how that works? Anyone understand what I'm getting at?

Now if I add the inch spacer up front, how do I add the same in the rear to keep the rig leveled? Don't want to stack a block and a shim, and don't know what the "taper" is on a tapered block, or what additional height I'm getting from the 6* shim.

Short term I'm gonna get the 2" bumpstop and live with 3.5 uptravel at current lift. No buring desire to go higher, just don't know where 3.5" uptravel fits within the grand scheme of things. FWIW I have almost 5" with my current shocks, but I can't say I've ever used it or if its even "available" given lift and the spring rate vs. weight of vehicle when compressed the far. Clear as mud? Any thoughts from y'all?

P

What was the question again?

3.5" of up travel isn't enough. If you want to take advantage of the extra handling that the 5100's will give you, meaning being able to go a little faster, 3.5" of up travel really isn't enough. I have 5.5" of up travel and bottom out regularly, both rock crawling and driving fast.

You could raise the bumpstops, defeating some of the extra performance given by the Bilsteins, or you could lower the shock mounts to handle the longer shocks....I'd lower the shock mounts. If you haven't bought the shocks yet, instead of using the 5100's, get the short body 7100's, where you get 12" of travel out of a normally 10" travel shock......the shorter length shock allowing more uptravel.

Thanks Goatman, I measure 21.75" eye to eye for the mounting location.
So, the 5150 (BF5-A197-H0 )would get me 6.24 droop and 5.25 uptravel, but the valving is 170/60 (don't know what that means really). The 7100 short body gets me 6.31 droop and 5.72 uptravel. Not much difference there. My question is I guess, other than trying to talk this out with ppl who probably know more than me, is at what point will the uptravel just not be used, regardless of tire size, say I had 30" tires, for example, would I ever be able to compress the spring to actually use the available uptravel?


Also, the 5100 valving is 255/70. Maybe you can help me understand that while we are at it. I know you have one # for rebound and one for compression? But can't qualify the real difference between 255/70 and 170/60.


All in all I guess the 5150 may be the best I can do? Thanks for your patience y'all.

P

xxxj-va said:

... the valving is 170/60 (don't know what that means really). Also, the 5100 valving is 255/70. Maybe you can help me understand that while we are at it. I know you have one # for rebound and one for compression? But can't qualify the real difference between 255/70 and 170/60.

Click to expand...

the designation 170/60 is rebound/compression in Newtons/10
so the actual rating is:
1700 N/ 600 N

To convert Newtons to pounds of force, divide be 4.448 or multiply by .2248
so:
1700 N/ 600 N = 382 lbf / 135 lbf

Bilstein shocks are rated at a velocity of .52 meter/second (1m = 39.37")

Without going into the conversion math, the 255/70 shock would be 50% stiffer in rebound and 17% stiffer in compression.

I'm at 5.5" of lift, removed the front pumpstops...am running 31" tires. The front RS9000s are set up with 5" up travel, and 5" down travel. with no bump stops and the 31"s i can use all of that 5" of up travel. I enjoy high speed dirt roads and washes. get a little air and the jeep wishes it had more than 5" up travel.

For crawling, i think a lot of people set theirs up for less up travel and more droop. like 60% droop.

in the end...if there is one for this jeep. I want 33"s , some nice pre-runner shocks with multistage damping...long travel up through the hood. i want to be able to launch the jeep safely...hehe

good luck

xxxj-va said:

Thanks Goatman, I measure 21.75" eye to eye for the mounting location.
So, the 5150 (BF5-A197-H0 )would get me 6.24 droop and 5.25 uptravel, but the valving is 170/60 (don't know what that means really). The 7100 short body gets me 6.31 droop and 5.72 uptravel. Not much difference there. My question is I guess, other than trying to talk this out with ppl who probably know more than me, is at what point will the uptravel just not be used, regardless of tire size, say I had 30" tires, for example, would I ever be able to compress the spring to actually use the available uptravel?


Also, the 5100 valving is 255/70. Maybe you can help me understand that while we are at it. I know you have one # for rebound and one for compression? But can't qualify the real difference between 255/70 and 170/60.


All in all I guess the 5150 may be the best I can do? Thanks for your patience y'all.

P

Click to expand...

While the travel of both of those shocks is nearly the same, the difference is in the overall length.....and what you have room for. The most important number is the compressed length, which is a finite amount for your situation, unless you're willing to change the location of the mounts. What you need is the longest travel shock that has a compressed length that will fit your rig. That number will be different for the front and the back. Look at the overall length, not just the travel, of the 5150's and the short body 7100's.

The 5150's come in two settings, 170/60 and 255/70, and you definitely need the stiffer one. You would probably be happier with a stiffer setting if you could get it. The 7100's come with more choices, and I'd get it stiffer than the 255/70. The one thing that helps the 5150's is that they are charged with 300 psi of nitrogen, while normally the shocks are charged to around 200 psi, so the 5150 at 255/70 will be a little more than the 7100 with the same setting (unless you also charged the 7100 with 300 psi).

Up travel is good, both rockcrawling where it adds stability, and for speed where it soaks up the big bumps. How much you can use depends on your tire clearance, but the spring will compress until the coils touch if enough weight or force is on them, like totally twisted up or hitting a big bump.