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Unread 12-18-2012, 07:12 AM   #286
Unlimited04
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Quote:
Originally Posted by andrewf09 View Post
I've been reading through the threads and I'm still a little confused.

My setup
33's, AEV 3" Springs, Rancho rs9000xl, 1.25BL, 1"MML

Rancho rs9000xl shocks
F Compressed: 16.110 Extended: 25.970
R Compressed: 15.290 Extended: 24.150

F 16.110 - 13.50 = 2.61 - 1.25 BL = 1.36 BS?
R 15.290 - 12.50 = 2.79 - 1.25 BL = 1.54 BS?
the body lift has absolutely nothing to do with it.

You're at ~3+" bumpstop extensions front and rear based on those shocks. No uptravel gain over stock. You need shorter shocks, IMHO. Unless you plan on cutting the mounts off and relocating them like mudb8's other thread, those shocks would be good for 5-6" lift.

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Unread 12-18-2012, 07:48 AM   #287
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Quote:
Originally Posted by Unlimited04 View Post
the body lift has absolutely nothing to do with it.

You're at ~3+" bumpstop extensions front and rear based on those shocks. No uptravel gain over stock. You need shorter shocks, IMHO. Unless you plan on cutting the mounts off and relocating them like mudb8's other thread, those shocks would be good for 5-6" lift.
I thought I read that the BL had something to do with the BS amount.

I definitely don't wont to start cutting things off.

Would this be better?
F RS999239: 14.640 / 23.090 / 8.450
R RS999241: 13.690 / 20.950 / 7.260
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Unread 12-18-2012, 08:53 AM   #288
Thomas302
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I'm running 33's with a 4" (well probably sagging to 3") in the rear. I'm just installed the jks extensions to keep my shocks out of the perches. I just installed the bilstein 5100 14.5 compressed and 23 extended. They are to long for my bump stops with the extensions. If i take out the shock extensions the shocks will hit and be a little short on the down travel. If i take out my 2" bump stop and add in a 4" that should keep me off my shocks. Will that limit my down travel? Not sure what to do.
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Unread 12-18-2012, 10:15 AM   #289
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Quote:
Originally Posted by andrewf09 View Post
Would this be better?
F RS999239: 14.640 / 23.090 / 8.450
R RS999241: 13.690 / 20.950 / 7.260
you do the math and tell me.
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Unread 12-18-2012, 10:36 AM   #290
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Originally Posted by Unlimited04 View Post
you do the math and tell me.
I really don't know. As far as the math goes, you need less of a BS. Would I still need a 2" BS?

14.640 - 13.50 = 1.14
13.690 - 12.50 = 1.19

Looking at the Mudb8's chart. it seems like the rear shock might be to short?

Sorry for the stupid questions, i'm just having a hard time wrapping my head around this.
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Unread 12-18-2012, 11:11 AM   #291
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Originally Posted by andrewf09 View Post
I really don't know. As far as the math goes, you need less of a BS. Would I still need a 2" BS?

14.640 - 13.50 = 1.14
13.690 - 12.50 = 1.19

Looking at the Mudb8's chart. it seems like the rear shock might be to short?

Sorry for the stupid questions, i'm just having a hard time wrapping my head around this.
they're not stupid questions at all. and yes, the math looks fine. I'd round up to the nearest 0.5" for good measure.

Therefore, you know you'll need around 1.5" bumpstop extension. Well, you can put together 1.25" or 1.5" from one of the expensive fancy bumpstop extension kits out there, or you can just make your own for a whole lot cheaper.

For example, you can buy 2" tall body lift pucks from Performance Accessories and cut them down to 1.5" (or whatever you need). "Mini" blocks fit in the rear, and "Big" blocks fit on the front spring pad, and they run really cheap on ebay/amazon/direct, etc.

Another example is buying some raw bar stock...like aluminum, delrin or UHMWPE. 2" diameter is what fits in the rear, and 3" diameter fits on the spring pad in front. Cut it to fit, drill a hole through the middle and bolt it up.

Ok, so here's how I think about it. Stock is roughly ~4" uptravel/~4" downtravel in front. Anything over that is an improvement.

So take lift height (3"), divide by two (1.5"), and use that as a starting point for bumpstops and choosing shocks. 2" lift, 1" extension, 4" lift / 2" extension, etc. Now, try to pick a shock that gives you a 50/50 to 60/40 travel ratio around that. So you know 1.5" bumpstop extension with a 3" lift gain over stock gives you 1.5" additional uptravel over stock...so call it ~5.5" uptravel total. That means you want a shock around 10" travel, for ~5" up and ~5" down. You also know the stock compressed shock length ~13.50" or so, 13.50" + 1.5" = 15". So the max compressed shock length you can run with 1.5" bumpstop extension is 15". So look for a shock length at 15" or slightly under, with ~10" travel. And that's what you've done...14.6" compressed length is appropriate.

You can apply the same logic to the rear, but things get funky really quick. Pinion angle rotation changes things a bunch, and the bumpstops don't line up right...so you can end up needing different extension than your math might suggest. No big deal, just buy plenty extra and adjust it on the rig as you install everything and check full bump for clearance issues.

All of this is just theoretical starting points, and of course there are tire size clearance issues and suspension interference issues to consider as well. The above just describes addressing the shocks...you still need to figure out the rest...which may add additional bumpstop extension requirements.
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Unread 12-18-2012, 06:14 PM   #292
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Quote:
Originally Posted by Unlimited04 View Post
they're not stupid questions at all. and yes, the math looks fine. I'd round up to the nearest 0.5" for good measure.

Therefore, you know you'll need around 1.5" bumpstop extension. Well, you can put together 1.25" or 1.5" from one of the expensive fancy bumpstop extension kits out there, or you can just make your own for a whole lot cheaper.

For example, you can buy 2" tall body lift pucks from Performance Accessories and cut them down to 1.5" (or whatever you need). "Mini" blocks fit in the rear, and "Big" blocks fit on the front spring pad, and they run really cheap on ebay/amazon/direct, etc.

Another example is buying some raw bar stock...like aluminum, delrin or UHMWPE. 2" diameter is what fits in the rear, and 3" diameter fits on the spring pad in front. Cut it to fit, drill a hole through the middle and bolt it up.

Ok, so here's how I think about it. Stock is roughly ~4" uptravel/~4" downtravel in front. Anything over that is an improvement.

So take lift height (3"), divide by two (1.5"), and use that as a starting point for bumpstops and choosing shocks. 2" lift, 1" extension, 4" lift / 2" extension, etc. Now, try to pick a shock that gives you a 50/50 to 60/40 travel ratio around that. So you know 1.5" bumpstop extension with a 3" lift gain over stock gives you 1.5" additional uptravel over stock...so call it ~5.5" uptravel total. That means you want a shock around 10" travel, for ~5" up and ~5" down. You also know the stock compressed shock length ~13.50" or so, 13.50" + 1.5" = 15". So the max compressed shock length you can run with 1.5" bumpstop extension is 15". So look for a shock length at 15" or slightly under, with ~10" travel. And that's what you've done...14.6" compressed length is appropriate.

You can apply the same logic to the rear, but things get funky really quick. Pinion angle rotation changes things a bunch, and the bumpstops don't line up right...so you can end up needing different extension than your math might suggest. No big deal, just buy plenty extra and adjust it on the rig as you install everything and check full bump for clearance issues.

All of this is just theoretical starting points, and of course there are tire size clearance issues and suspension interference issues to consider as well. The above just describes addressing the shocks...you still need to figure out the rest...which may add additional bumpstop extension requirements.
This is great. I definitely have a better understanding.

i'm going to order the lift pucks from Performance Accessories. ~$5 is great.

I also think i'm going to switch to the OME shocks (N66L/N67). They seem to be a better fit for my setup.
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Unread 12-27-2012, 08:04 AM   #293
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This should definitely be a sticky. I've searched for it numerous times.
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Unread 12-27-2012, 12:19 PM   #294
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This should definitely be a sticky. I've searched for it numerous times.
I second that.
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Unread 03-22-2013, 09:35 AM   #295
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3" BDS with 1.25" BL, JKS front trackbar, and 33" Duras.

Front Bilstein 5100's- 14.8in collapsed, 24in extended.
Rear Bilstein 5100's- 14.6 collapsed, 23in extended.

The chart recommends 2" bumpstop extension up front and 1" in the rear. Without checking full bump yet, does this sound about right? I know I'll need 2" extension up front because of the JKS trackbar anyways.
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Unread 03-22-2013, 10:35 AM   #296
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Originally Posted by BamaJeepman21 View Post
3" BDS with 1.25" BL, JKS front trackbar, and 33" Duras.

Front Bilstein 5100's- 14.8in collapsed, 24in extended.
Rear Bilstein 5100's- 14.6 collapsed, 23in extended.

The chart recommends 2" bumpstop extension up front and 1" in the rear. Without checking full bump yet, does this sound about right? I know I'll need 2" extension up front because of the JKS trackbar anyways.
based on shocks alone you're looking at about 1.5" front, 2.5" rear.

in front you'll need to check full bump and see what happens with good caster. keep the stock diff cover, or get a barnett cover. a V8 ZJ tie-rod will also help clearance in front.

2" front and 2.5" rear would be safe until you check full bump front and rear and get a better look.
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Unread 03-23-2013, 03:23 PM   #297
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Originally Posted by Unlimited04 View Post
based on shocks alone you're looking at about 1.5" front, 2.5" rear.

in front you'll need to check full bump and see what happens with good caster. keep the stock diff cover, or get a barnett cover. a V8 ZJ tie-rod will also help clearance in front.

2" front and 2.5" rear would be safe until you check full bump front and rear and get a better look.
Thanks. How would I go about finding the travel of each shock? Extended - compressed?

Front: 24-14.8 = 9.2

Rear: 23-14.6 = 8.4

So does that mean the front is a 9" travel shock and the rear a 8"? Seems a bit short. I was talking to Imped and he recommended 5" up/down on stock mounts. Obviously I would need a 10" shock for that.
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Unread 03-23-2013, 03:31 PM   #298
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Originally Posted by BamaJeepman21 View Post
Thanks. How would I go about finding the travel of each shock? Extended - compressed?

Front: 24-14.8 = 9.2

Rear: 23-14.6 = 8.4

So does that mean the front is a 9" travel shock and the rear a 8"? Seems a bit short. I was talking to Imped and he recommended 5" up/down on stock mounts. Obviously I would need a 10" shock for that.
correct. Bilstein's run a bit on the short side. Old Man Emu usually has longer travel shocks.
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Unread 03-23-2013, 03:53 PM   #299
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correct. Bilstein's run a bit on the short side. Old Man Emu usually has longer travel shocks.
Here's a shot of the rear at ride height.



That's 4 3/4" of shaft showing. If I'm understanding up/down travel correctly, that leaves me with roughly 5" uptravel and 3" of downtravel in the rear?
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Unread 03-23-2013, 04:00 PM   #300
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so ... the remote reservoir 5160 seem to come out a bit shorter (because the floating piston is in the reservoir!):

front: TJ 3" lift Bilstein 5160 25-193114 / 14.5 - 24.7 / 10.2" travel
rear : TJ 3" lift Bilstein 5160 25-193145 / 13.5 - 22 / 8.5" travel
got them from Kolak here on JF!

I run them with about 1.5" bump stop extension (front and rear) and ~3" lift ... gives me nice ~5.5" up and ~4.5" down in the front ... In the rear plenty up as well...

prothane_rev2_front_passenger.jpg

prothane_rev2_rear_passenger_2.jpg

so far I like them ... and I came from the OME N66/N67 fraction.
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