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Unread 12-08-2012, 08:40 AM   #1
jpin321
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Suspension "upgrade?"

So when i got my tj I slapped on a BB from skyjacker and some hydro shocks. I later installed a 1.25 jks bl and mm lift. Now my skyjacker shocks are rusted really bad and skyjacker doesn't care. My jeep is also a little "spongy" feeling to me now, shocks are showing their age i think.

Here is what I'm thinking.... I'm thinking about adding some OME 2 or 2.5" springs and some bilstein shocks (5100's?). Would this be an improvement or should I just leave the spacers and change out my shocks?

Keep in mind I like the 2" - 2.5" lift I think the jeep stays more stable at that height and I can go anywhere (excluding huge rocks, or deep water/mud) that other guys go with 3"+ lifts. Also my jeep doesn't see as much trail time as I would like so keep that in mind in your comments.

Thanks for your help forum....

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Unread 12-08-2012, 08:58 AM   #2
Gary2
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Springs and shocks would be an improvement . May be an issue locating a 5100 for that short of a lift . I can't remember how short they have them , you had better check with Bilstein before you commit
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Unread 12-08-2012, 09:07 AM   #3
jpin321
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Springs and shocks would be an improvement . May be an issue locating a 5100 for that short of a lift . I can't remember how short they have them , you had better check with Bilstein before you commit

They have them on Quadratec for 0-2" of lift. the also have them for 3" lift I'm guessing if I go with 2.5" springs I would just grab the 3" shocks. With the correct bump stops I don't think i would bottom them out.

http://www.quadratec.com/products/16070_229.htm
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Unread 12-08-2012, 09:16 AM   #4
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My understanding is that the shortest Bilstein 5100s for TJs require about 0.75" of rear bumpstop extension. Placing that 0.75" bumpstop extension on both front and rear might be sufficient for 2" lift springs? Those Bilstein shocks, for 0-2" of lift, have a decent amount of downtravel, so I'm guessing you won't be disappointed with 2" lift springs.

Also consider Rancho 7000 monotubes, which I've had a good experience with. Using the minimal lift version of the 7000 monotubes will give you good downtravel, but could require ballpark 1.5-2.0" of bumpstop extension, so, if you go that route, you might want 2.5+" of lift?
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Unread 12-08-2012, 09:49 AM   #5
Gary2
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Originally Posted by jpin321 View Post
They have them on Quadratec for 0-2" of lift. the also have them for 3" lift I'm guessing if I go with 2.5" springs I would just grab the 3" shocks. With the correct bump stops I don't think i would bottom them out.

http://www.quadratec.com/products/16070_229.htm
looks like you are almost set . Figure out your bump stops and you should be pretty well on your way .
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Unread 12-08-2012, 10:09 AM   #6
jpin321
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Thanks for the input guys. I'm guessing I'm looking in the right direction. I currently have 1" bump stop extensions, soups I keep them out get longer ones? I'm not sure the"rule of thumb".
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Unread 12-08-2012, 10:29 AM   #7
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What I typically see people use is bumpstop extension that's close to half of the spring lift that's being used. So 3" spring lift needs close to 1.5" bumpstop extension, and 2" spring lift needs close to 1" bumpstop extension. I think the actual amount of bumpstop extension needed to prevent coil bind is less than half, but coming up with the exact amount requires taking measurements.

We often see people using slightly longer bumpstop extension than is required to prevent coil bind, because the specifics of many suspension set-ups (e.g., trackbars, etc.) can result in components coming into contact with each other, or binding, at full compression. That's why the pros recommend cycling your suspension with the shocks/springs removed, to ensure than no components are binding.

My rule of thumb about using half as much bumpstop extension as spring lift just happens to work out well with most set-ups. Even though you don't need that much bumpstop extension to prevent coil bind, you might need that much bumpstop extension to prevent other components from binding.
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Unread 12-08-2012, 11:15 AM   #8
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Quote:
Originally Posted by Pine_Cat View Post
What I typically see people use is bumpstop extension that's close to half of the spring lift that's being used. So 3" spring lift needs close to 1.5" bumpstop extension, and 2" spring lift needs close to 1" bumpstop extension. I think the actual amount of bumpstop extension needed to prevent coil bind is less than half, but coming up with the exact amount requires taking measurements.

We often see people using slightly longer bumpstop extension than is required to prevent coil bind, because the specifics of many suspension set-ups (e.g., trackbars, etc.) can result in components coming into contact with each other, or binding, at full compression. That's why the pros recommend cycling your suspension with the shocks/springs removed, to ensure than no components are binding.

My rule of thumb about using half as much bumpstop extension as spring lift just happens to work out well with most set-ups. Even though you don't need that much bumpstop extension to prevent coil bind, you might need that much bumpstop extension to prevent other components from binding.
No need to estimate anything. Measure distance between spring pad and lip of bumpstop cup (not jounce bumper). Measure distance from tires to fenders. Measure distance from ride height to full shock compression. Add bumpstops so first measurement is equal to or less than other two measurements. Then cycle axles to check for other interference (e.g. trackbar and diff cover) and add additional extension as necessary to prevent that interference.

Additionally, don't buy shocks based on lift height labels that manufacturers put on them. That gets results that are all over the place. Find out what the compressed and extended lengths are that fit your setup and buy based on that.
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Unread 12-08-2012, 11:38 AM   #9
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Kolak can set you up with ome and bilstein.

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Unread 12-08-2012, 11:39 AM   #10
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Kolak can set you up with ome and bilstein.

'06 LJ
I'm not sure who/what that is.
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Unread 12-08-2012, 11:44 AM   #11
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I'm not sure who/what that is.
Vendor here. Have seen good prices from him on Bilstein stuff. For OME most people very happy with Dirk at DPG.
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Unread 01-06-2013, 10:22 AM   #12
jpin321
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Wanted to resurrect my thread for anyone still following and willing to help. I know its been a month and I'm still contemplating my next move. At this point I'm strongly considering the 2.5" springs. I'd like to stuff some 33's under my rig at some point I can do it now but flex is an issue. I already had some drive live vibes after the 2" spacer lift that I corrected with the above mentioned mml + bl combo. Will the added .5" cause these to return? Whats the best way of correcting it, I've read that adjustable ca's can correct it by adjusting the pinion angle. Should I buy uppers or lowers for this? Thanks again in advance.
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Unread 01-06-2013, 10:37 AM   #13
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SYE/DC shaft with rear upper and lower adjustable CA's is the real fix for driveline vibes. It's not cheap though. All those things can run close to $1,000 depending on quality/manufacturer.
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Unread 01-06-2013, 11:03 AM   #14
Pine_Cat
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Quote:
Originally Posted by jpin321 View Post
Wanted to resurrect my thread for anyone still following and willing to help. I know its been a month and I'm still contemplating my next move. At this point I'm strongly considering the 2.5" springs. I'd like to stuff some 33's under my rig at some point I can do it now but flex is an issue. I already had some drive live vibes after the 2" spacer lift that I corrected with the above mentioned mml + bl combo. Will the added .5" cause these to return? Whats the best way of correcting it, I've read that adjustable ca's can correct it by adjusting the pinion angle. Should I buy uppers or lowers for this? Thanks again in advance.
Uppers vs. lowers depends on which kind of driveshaft you want to run. For a conventional driveshaft, lowers will allow you to push your rear pinion angle back down into phase with your transfer case output angle. For a double cardan, cv, driveshaft, uppers are needed to rotate your rear pinion angle upward, to point almost directly at the transfer case output.

Most in the forum will recommend sye and cv driveshaft, because that allows you to install a higher lift and/or tummy tuck later on. The complication with using a cv driveshaft is that you might want to buy a rear trackbar bracket to accomodate the rear pinion rotation.

I've used a non-cv driveshaft, and it still works, at 2.5" of t-case lift (1.25" of tuck and 1.25" of suspension lift), but my driveshaft u-joint angles are maxed out to 14 degrees. Only a faint, borderline vibe when I'm going uphill, in overdrive, around 45-50, but I should probably do something about it. A little bit more tinkering with my adjustable lowers might get rid of the vibe, or I could install a low-profile transmission mount.

Here are some helpful links provided by another member. These links are a really great way of beginning the learning process.



Good reading:
http://www.wranglerforum.com/f5/how-...le-121998.html

Good reading:
http://www.jeepforum.com/forum/f9/wh...nt-one-854790/

You'll find confusing advice in the forum about axle wrap. At cruising speed, maybe a YJ's leaf-sprung axle wants to lift up the rear pinion, such that the older recommendation was to keep your rear pinion angle 1-2 degrees lower than your t-case output.

I think some have been finding the opposite to be true about the coil-sprung TJ. Applying minimal torque, at cruising speed, makes the rear axle want to get closer to the tub, which actually lowers rear pinion instead of raising it. As a result, the TJ's pinion seems to rotate under torque in the exact opposite of the direction that you would expect to occur from axle wrap. Some people here in the forum found that having the rear pinion about one degree higher than the t-case output (the exact opposite of the traditional recommendation!) seemed to provide better results. This slight elevation of rear pinion angle can yield a noticeable improvement over adjusting the rear pinion angle to an exact match for the t-case output angle.
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Unread 01-06-2013, 02:26 PM   #15
jpin321
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^^ Good info some of it I knew already some I didn't. I was hoping to not have to do a sye kit. But its starting to look like if I ever want rid of these stupid spacers I may have to start by installing one. But that will push me way above any current budget that I have. I was hoping I could adjust out the stock shaft with just 2.5" of lift and a mml lift.
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