Ask Rancho about the bump stop requirements and how to determine them. Also ask if your body lift and tire size has any effect on the required bump stop extension.
Rancho RS5000X Shocks
- Thread starter JMT
- Start date
Ask Rancho about the bump stop requirements and how to determine them. Also ask if your body lift and tire size has any effect on the required bump stop extension.
The preferred way to extend the bumps is to add a spacer above the cup or to add a spacer to the axle pad.
Again, the soft jounce is not and should not be used as the limiter of travel. It's entire purpose is to slow the impact of hard bump when the cup hits the pad. It is a cushion. Depending on your intentions when you jump off of a building, would you prefer to land on a mattress or directly onto a concrete sidewalk?
Those jounce extensions can work, but they still need to be cut to the optimal length for your setup. The issue is that they are still soft enough to not provide a hard limit. At the same time, they are not soft enough to slow the suspension travel just before the impact of hard bump. The point is that the jounces have one job and they cannot do both jobs at the same time.
Thank you for explaining... Things are starting to make more sense for me. So something like these: https://www.amazon.com/gp/product/B002P8XQD8/?tag=wranglerorg-20, but for front and rear and the right length based on what Rancho advises when I call them back?
Btw, i spoke with them a little while ago and they said for a 2" spacer lift that the shortest ones would definitely be too short and to definitely go with the Rancho RS55239 & RS55241 for 2.5" lifts.
Btw, i spoke with them a little while ago and they said for a 2" spacer lift that the shortest ones would definitely be too short and to definitely go with the Rancho RS55239 & RS55241 for 2.5" lifts.
Just spoke with Rancho again - they're advising me to add 1.5" or 2" bump stop spacers in the rear and nothing in the front. So basically I'm now confused again... Any thoughts on that advice? Really appreciate everybody's help on here!
Since you need to remove the springs to add the spacers, just check for proper bump stops. It only takes a few minutes and is easy and at the same time you can measure for shocks.
I know that would be the best way to do it but I've got physical limitations stopping me from doing the work myself so I'm having the work done at a shop, so need to have parts there all at once (don't want to pay them to take it apart, take measurements and put it back together while i order parts and then take it apart again when the parts come in). Because of all that trying to get best guess on the right parts to order in advance from people's experience on here and manufacturer recommendations. Those bump stop spacers are cheap enough that I'm just going to order them and if i don't end up needing them it's not a big deal (maybe i can use them in the future or return, sell, etc.). That said, i don't want to order parts that are almost certainly not needed - Anybody think there's a decent chance I'll need them in front too, even though Rancho says i shouldn't? Don't want to order 2 sets if there's almost no way I'd need them... Plus the Prothane ones I linked to above (1.5" tall) say they're only for rear - every set I'm seeing that say they can fit front or rear look like they're going to be too long. Not sure why these say rear only??
I don't like doing it this way, but if I had to pre-plan for 33s and a 1.25" body lift and 2" coil spacers...
Rancho RS55239 (Front)
14.43" compressed
9.41" travel
1.75" bump stop extension
Bumps are extended to keep 33s out of steel fenders at full flex. Compressed shocks are selected to fit within the shock mounts at bump.
Rancho RS55128 (Rear)
13.05" compressed
7.98" travel
1" bump stop extension
Bumps are extended to prevent over-compression of the shock.
Hopefully someone can double check what I came up with. If there is doubt, add a bit of length to the bump stop extensions. A lot of this is based on how I set up my previous shocks while paying very close attention to the bump stops and compressed shock lengths. Then I added a small amount of extra bump stop extension. And I tried to account for the Rubicon's thicker front axle pad. If I'm correct, this should still be on the conservative side of safety.
Rancho RS55239 (Front)
14.43" compressed
9.41" travel
1.75" bump stop extension
Bumps are extended to keep 33s out of steel fenders at full flex. Compressed shocks are selected to fit within the shock mounts at bump.
Rancho RS55128 (Rear)
13.05" compressed
7.98" travel
1" bump stop extension
Bumps are extended to prevent over-compression of the shock.
Hopefully someone can double check what I came up with. If there is doubt, add a bit of length to the bump stop extensions. A lot of this is based on how I set up my previous shocks while paying very close attention to the bump stops and compressed shock lengths. Then I added a small amount of extra bump stop extension. And I tried to account for the Rubicon's thicker front axle pad. If I'm correct, this should still be on the conservative side of safety.
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Very intentional. The 55241 is ~5/8" longer compressed but only offers .02" additional travel at the expense of a sizable shift in the travel bias towards down travel because of the additional required extension. It may make more sense with more lift height than you have. My recommendation favors a bit more up travel.
Make sure the shocks have the correct mounts for the front and rear. I haven't looked closely enough, but I do know that the 55128 is available for both ends.
I have a spread sheet of shocks and sizes that I have assembled over several years.
Wow, that seems to make a lot of sense to me. I've gotten recommendations from a could folks to get both of the shorter ones and from a few folks (and Rancho) to get both of the longer ones, but you're thinking outside the box with the combo suggestion. Thanks!
This seems like a dumb question but i keep missing stuff so feel like i should ask - is there definitely no issue with "mixing and matching" the front and rear shocks instead of getting both sets to match the same stated lift height fitment? It seems like a very logical suggestion to me but i just want to be careful because nobody else has mentioned this as a possibility...
This seems like a dumb question but i keep missing stuff so feel like i should ask - is there definitely no issue with "mixing and matching" the front and rear shocks instead of getting both sets to match the same stated lift height fitment? It seems like a very logical suggestion to me but i just want to be careful because nobody else has mentioned this as a possibility...
To the best of my knowledge, the valving is the same across the 5000x ranges of length. Our job is to find the best lengths that put the up and down travels where we think they are best utilized. Once you can understand the movements and variables, there is a clear method to figure it out. Unfortunately, the lift height has far less to do with that decision than most will ever realize.
As daunting as it may sound, moving the axles around with a floor jack is the simplest and clearest way to see what is needed. Doing so takes most of the math and guessing away.
Given my situation, what do you think about ordering the longer jounces that can be cut down to have on hand so that they can measure the proper length while putting everything on and that way at least having something that can be made the right length for now and then maybe getting spacers that are the right length and putting those on next time it's in the shop (with the standard length jounces i have now)? I know you said those long ones weren't ideal, but would that be better than having the right type of extension (spacers) that are the wrong length? Thanks again
Many of us use these and cut them to the length we need.
Zone Offroad Bulk 3" Tall x 2" Wide Body Lift Block https://www.amazon.com/dp/B0021I8NAI/?tag=wranglerorg-20
If the shop is willing and able, then that is great. If I guessed well, the lengths I suggested will hopefully be a bit less. With the tires and shocks installed and the soft yellow jounces and sway bars disconnected, they will need to move the axle to both full flex and full bump. The cup gets extended so that the cup and pad are always what touches before anything else interferes with the movements. The one exception I'll make is that a little bit of tire rub on the steel fender at full flex is fine.
If your Jeep doesn't have the factory yellow jounces, then get new ones from Crown.
Zone Offroad Bulk 3" Tall x 2" Wide Body Lift Block https://www.amazon.com/dp/B0021I8NAI/?tag=wranglerorg-20
If the shop is willing and able, then that is great. If I guessed well, the lengths I suggested will hopefully be a bit less. With the tires and shocks installed and the soft yellow jounces and sway bars disconnected, they will need to move the axle to both full flex and full bump. The cup gets extended so that the cup and pad are always what touches before anything else interferes with the movements. The one exception I'll make is that a little bit of tire rub on the steel fender at full flex is fine.
If your Jeep doesn't have the factory yellow jounces, then get new ones from Crown.
That's great, thank you for the link and instructions - saw those but didn't realize they could be used for this purpose - i wouldust use them as spacers under the cups once we cut them to the right length? I think the shop will be willing to measure it (might have to pay a little extra but that's fine if it's important, just didn't want to double my labor costs by making it a multi day job).
I don't think i have the yellow jounces - recently had these installed when i first got the Jeep - they have a couple hundred miles on them. Is it worth getting the yellow ones from crown to replace these or did you just mean if i had old ones?
I don't think i have the yellow jounces - recently had these installed when i first got the Jeep - they have a couple hundred miles on them. Is it worth getting the yellow ones from crown to replace these or did you just mean if i had old ones?
Correct. I'll post a pic of the finished job later, if someone else doesn't beat me to it.
Either way, the jounce inside the cup should be the factory yellow foam. Then the bump stop system will work as intended. Extend the cup to make it be what limits the up travel. Then just let the foam jounce be the cushion that it is meant to be.
Some examples of what the end result would look like.
With the axle raised as high as it will go, both by fully stuffing one tire...
...and raising both sides until something stops the upward movement...
...fill in this gap between the cup and axle pad...
...so that the cup and pad are always what touch before anything else interferes and stops the up ward travel.
With the axle raised as high as it will go, both by fully stuffing one tire...
...and raising both sides until something stops the upward movement...
...fill in this gap between the cup and axle pad...
...so that the cup and pad are always what touch before anything else interferes and stops the up ward travel.
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In the above examples, the front has been extended by attaching a 3" wide hard puck of the appropriate thickness to the axle pad.
Zone Offroad Bulk 3" Tall x 3" Wide Body Lift Block https://www.amazon.com/dp/B0021IAOQE/?tag=wranglerorg-20
The reason for this is that on the front, if the cup is extended too much, it can pluck the coil as the suspension moves. Raising the axle pad will prevent this, rather than extending the cup too much.
Regardless of how it is done, the goal is to reduce the space between the cup and the pad in order to create a safe limit to the up travel. The entire idea is to keep parts that were not designed to crash together from crashing together..
Zone Offroad Bulk 3" Tall x 3" Wide Body Lift Block https://www.amazon.com/dp/B0021IAOQE/?tag=wranglerorg-20
The reason for this is that on the front, if the cup is extended too much, it can pluck the coil as the suspension moves. Raising the axle pad will prevent this, rather than extending the cup too much.
Regardless of how it is done, the goal is to reduce the space between the cup and the pad in order to create a safe limit to the up travel. The entire idea is to keep parts that were not designed to crash together from crashing together..
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Pictures are worth a zillion words. This makes everything we've been discussing so much clearer. Thank you so much for all the help - I feel like I will now be able to discuss all of this with my mechanic at least half intelligently and make sure it's done the right way to protect everything.