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Old 02-27-2013, 05:50 PM   #1
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Are my bumpstops too long?

I recently installed a 2" BB, Bumpstop extentions, and Bilstein 5100s and I'm a little worried that my bumpstops may be wrong. In the front I have about 2" of space between the bumpstop and the base and in the rear I have about 3". Here are some pictures.

Front

Rear

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Old 02-27-2013, 05:58 PM   #2
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looks to long to me... someone correct me if im wrong but i dont think you need bump stop extensions with a bb at all, those look like the stock springs

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Old 02-27-2013, 07:01 PM   #3
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looks to long to me... someone correct me if im wrong but i dont think you need bump stop extensions with a bb at all, those look like the stock springs
actually, that's normal for a budget boost.

you need the bumpstop extensions, especially the rear, to prevent coil damage.

here's some reading:
http://www.wranglerforum.com/f5/rear...ml#post3410789
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Old 02-27-2013, 07:03 PM   #4
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looks to long to me... someone correct me if im wrong but i dont think you need bump stop extensions with a bb at all, those look like the stock springs
You definitely need extended bump stops with a BB. Especially the rear. First, coil bind will be a huge issue. Second, the rear springs are held in by the bump stop cups. You have to extend them down to get them to fit with spring spacers. If you don't, the rear spring can fall out.
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Old 02-27-2013, 09:03 PM   #5
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So the front is supposed to be like that? I thought it would limit my flex but if it's correct I will leave it.
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Old 02-27-2013, 09:33 PM   #6
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Originally Posted by Jwolfer View Post
So the front is supposed to be like that? I thought it would limit my flex but if it's correct I will leave it.
well, it's the same travel as stock. a BB is mostly for looks anyway. if you want to improve your suspension behavior, you'll want good lift springs & proper length shocks, etc.

but to your point, yes it limits flex, but it also keeps your shocks from bottoming out.

if you want, you can reduce the front bumpstop extensions a little.

Here's how:
  • pull the springs out and compress the springs in a shop press until they reach coil bind. measure their compressed length and make sure you have enough space to accommodate that length.
  • while the springs are out, figure out the compressed length of the shocks...push the axle to full bump and measure the required amount of bumpstop extension.
  • also, while the springs are out, put a tire on each hub and cycle the axle through full flex to both sides. turn the wheels lock to lock and verify brake line length is correct too. figure out how much bumpstop extension you need to prevent the tires from rubbing.
  • Now, you should have bumpstop extension from three measurement metrics. take the largest requirement, and cut the bumpstop extension down to that amount - enough to prevent the shocks from bottoming out, prevent the coil bind, and prevent the tires from rubbing the steel of the fenders.
  • you'll probably gain about 1" uptravel doing that, assuming you're still on 31" tires.
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Old 02-27-2013, 11:01 PM   #7
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I just got the Bilstein 5100s so I'm not worried about them limiting flex. Would 2" springs help too?
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Old 02-27-2013, 11:06 PM   #8
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I just got the Bilstein 5100s so I'm not worried about them limiting flex.
ok, so, question - how does this "flex" relate to this discussion?

to ask this another way - what's the compressed and extended lengths of those shocks?

Quote:
Originally Posted by Jwolfer View Post
Would 2" springs help too?
if you want to improve uptravel, yes. maybe even 3" springs, or 2.5" springs, or just stiffer springs...depends what spring rate you need for whatever weight you have on the front end.

you'd remove the spacers, and modify the bumpstop extensions as necessary to accommodate the tire size & shock length as described above.
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Old 02-27-2013, 11:12 PM   #9
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Of course I didn't measure the lengths before I installed them. They are Bilstien 5100s for 0-2" of lift. I am slowly learning all of the aspects of proper suspension so please bear with me.
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Old 02-28-2013, 07:36 AM   #10
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Of course I didn't measure the lengths before I installed them. They are Bilstien 5100s for 0-2" of lift. I am slowly learning all of the aspects of proper suspension so please bear with me.
how about this - got part numbers of the shocks on the Jeep?
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Old 02-28-2013, 07:45 AM   #11
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Anyone interested in hockey puck lifts really should read this thread. Should be mandatory reading before you buy them.
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Old 02-28-2013, 10:09 AM   #12
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Here is what I found online for them

Front:
Collapsed Length (IN): 13.06
Extended Length (IN): 21.18
Travel Length (IN): 8.12

Rear:
Collapsed Length (IN): 12.81
Extended Length (IN): 20.08
Travel Length (IN): 7.27

Also, if it matters, I have the stock rubicon springs.
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Old 02-28-2013, 12:57 PM   #13
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Quote:
Originally Posted by Jwolfer View Post
Here is what I found online for them

Front:
Collapsed Length (IN): 13.06
Extended Length (IN): 21.18
Travel Length (IN): 8.12

Rear:
Collapsed Length (IN): 12.81
Extended Length (IN): 20.08
Travel Length (IN): 7.27

Also, if it matters, I have the stock rubicon springs.
nicely done.

now, what this means if your front shocks alone will fit at stock height, or without any bumpstop extension.
.......but don't get too excited, because you still have coil bind and tire clearance to consider. 1" of bumpstop extension in front will keep you covered. So you could cut 1" off the front bumpstop extensions (the 2" tall, 2" OD hockey puck looking thing between the bumpstop cup and the bumpstop tower). *This is assuming you use 31s, the stock track bar, and stock diff cover. If not, things change a whole bunch.

now, the rear shocks need about 3/4" bumpstop extension over stock.
......but again, don't get too excited because your main problem is coil bind in the rear due to the coil spacers. you need bumpstop extensions of the same height as the spacers to prevent problems. So you actually need 2" bumpstop extensions in the rear.
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Old 02-28-2013, 04:37 PM   #14
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Awesome, thanks so much for your help. Is there anything I can use instead of the spacers rather than cutting them down for the front?
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Old 02-28-2013, 06:47 PM   #15
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Quote:
Originally Posted by UnlimitedLJ04 View Post
well, it's the same travel as stock. a BB is mostly for looks anyway. if you want to improve your suspension behavior, you'll want good lift springs & proper length shocks, etc.

but to your point, yes it limits flex, but it also keeps your shocks from bottoming out.

if you want, you can reduce the front bumpstop extensions a little.

Here's how:
  • pull the springs out and compress the springs in a shop press until they reach coil bind. measure their compressed length and make sure you have enough space to accommodate that length.
  • while the springs are out, figure out the compressed length of the shocks...push the axle to full bump and measure the required amount of bumpstop extension.
  • also, while the springs are out, put a tire on each hub and cycle the axle through full flex to both sides. turn the wheels lock to lock and verify brake line length is correct too. figure out how much bumpstop extension you need to prevent the tires from rubbing.
  • Now, you should have bumpstop extension from three measurement metrics. take the largest requirement, and cut the bumpstop extension down to that amount - enough to prevent the shocks from bottoming out, prevent the coil bind, and prevent the tires from rubbing the steel of the fenders.
  • you'll probably gain about 1" uptravel doing that, assuming you're still on 31" tires.
This is the kind of knowledge sharing that makes this a great place to learn. Thanks for sharing in a way that is simple to understand. Great Job Unlimited.
Bob
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Old 02-28-2013, 07:03 PM   #16
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He is actually the reason I made this post. I knew he would chime in with help like always.
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Old 03-24-2013, 11:08 AM   #17
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Originally Posted by UnlimitedLJ04 View Post
nicely done.

now, what this means if your front shocks alone will fit at stock height, or without any bumpstop extension.
.......but don't get too excited, because you still have coil bind and tire clearance to consider. 1" of bumpstop extension in front will keep you covered. So you could cut 1" off the front bumpstop extensions (the 2" tall, 2" OD hockey puck looking thing between the bumpstop cup and the bumpstop tower). *This is assuming you use 31s, the stock track bar, and stock diff cover. If not, things change a whole bunch.

now, the rear shocks need about 3/4" bumpstop extension over stock.
......but again, don't get too excited because your main problem is coil bind in the rear due to the coil spacers. you need bumpstop extensions of the same height as the spacers to prevent problems. So you actually need 2" bumpstop extensions in the rear.
Well, sorry to bump an old thread but I moved up to 33's and added a 1.25" Body lift. Can I cut down these bumpstops some more?
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Old 03-24-2013, 11:25 AM   #18
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Well, sorry to bump an old thread but I moved up to 33's and added a 1.25" Body lift. Can I cut down these bumpstops some more?
You added 1" of tire radius, and 1.25" of body clearance. If you have your bump stops set to avoid coil bind and shock absorber bottoming, you should still be fine.
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Old 03-24-2013, 12:36 PM   #19
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Let me See if I can hijack this thread (just a little).

I recently changed out the stock Rubi springs on my 06 TJL with H&R progressive springs that are supposed to add 1.25" in the front and rear but in actuality the rears (LJ only) add about 2.25".....pics of springs attached. You can see in the pics that the front springs are about the same length (uncompressed) but add the 1.25" when installed......the rear springs also added the stated height but this could also be due to wear on the factory springs after ~80K miles. Also to be noted is that while it is difficult to see in the pics the thickness of the newer coils are a little bit heavier than stock.

I am also running the same Bilstein 5100's listed above and have made no bumpstop modifications. Has anyone done this mod and if so any feedback.

On a related note the front is now about 1" lower than the rear and looks just a little like I'm going downhill.....any thoughts on adding 1" spacers in front to level it out and any additional issues that this may cause??

Thanks guys
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Old 03-24-2013, 06:02 PM   #20
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I don't think adding spacers to level it out would be an issue. I'm not sure what the bumpstops should be though.
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Old 03-24-2013, 06:25 PM   #21
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get springs of the proper spring rate and length.
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Old 03-24-2013, 07:03 PM   #22
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Any change needed to mine?
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Old 03-24-2013, 07:10 PM   #23
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Any change needed to mine?
push your axle to full bump, full flex and full droop and find out for yourself.

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