Coil bumpers
#1
Junior Member
Thread Starter
Join Date: Sep 2017
Location: Auburn, WA
Posts: 59
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1999
Model: Cherokee
Engine: 4.0
Coil bumpers
I'm in the process of gathering all the parts needed to turn my '99 Sport into a factory UpCountry. Doing pretty good so far as I'm following the list of parts needed. (forgot who posted but huge thanks)
Shocks, coils, leafs, coil spacers, etc.
The one thing I didn't see or I might of missed it, is what size bumpers go inside the front coils?
I have one that is ready to fall off and the other one looks like a dog chew toy.
So, for a 1 1/2" UpCountry clone, what size bumpers are needed?
Shocks, coils, leafs, coil spacers, etc.
The one thing I didn't see or I might of missed it, is what size bumpers go inside the front coils?
I have one that is ready to fall off and the other one looks like a dog chew toy.
So, for a 1 1/2" UpCountry clone, what size bumpers are needed?
#2
CF Veteran
Join Date: Oct 2011
Location: SEMO
Posts: 1,394
Likes: 0
Received 7 Likes
on
7 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0 L6
The best way is to buy long ones and cut them to the proper length. The exact length you need will depend on the collapsed length of your shocks. Articulate, measure and cut: Doing it this way will also allow you to safely use shocks that are longer than stock for more travel as well.
These bump stops are much stiffer than the stock "jounce" bumpers, so you can be pretty accurate with your cut and not have to worry about a lot of extra compression of the bumper on hard hits. I cut mine so that they make hard contact with .5" travel left in the shock before bottoming (see zip tie). These are Bilstein 5100's specified for 2-3" of lift, and I sit right in the middle of up/down travel. You could use an even longer shock than this and lose some uptravel, but gain some down travel. My down travel is limited by the max extension of these shocks:
These bump stops are much stiffer than the stock "jounce" bumpers, so you can be pretty accurate with your cut and not have to worry about a lot of extra compression of the bumper on hard hits. I cut mine so that they make hard contact with .5" travel left in the shock before bottoming (see zip tie). These are Bilstein 5100's specified for 2-3" of lift, and I sit right in the middle of up/down travel. You could use an even longer shock than this and lose some uptravel, but gain some down travel. My down travel is limited by the max extension of these shocks:
Last edited by Tbone289; 11-03-2017 at 08:22 AM.
#3
Junior Member
Thread Starter
Join Date: Sep 2017
Location: Auburn, WA
Posts: 59
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1999
Model: Cherokee
Engine: 4.0
I think I get what your saying but just to make it crystal clear, here is what my shocks are:
Compressed Length 13.250 In.
Extended Length 21.125 In.
Travel Length 7.875 In.
(I'll also be using a .75" coil spacer)
The 'bumpers' per your Amazon link are
This confuses me a little. Are they standard @ 5" and extended an extra 2 inches?
Bottom line, what length should I cut the bumpers to?
Compressed Length 13.250 In.
Extended Length 21.125 In.
Travel Length 7.875 In.
(I'll also be using a .75" coil spacer)
The 'bumpers' per your Amazon link are
2" extended 5" tall
Bottom line, what length should I cut the bumpers to?
#4
CF Veteran
Join Date: Oct 2011
Location: SEMO
Posts: 1,394
Likes: 0
Received 7 Likes
on
7 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0 L6
I believe what they are saying is that they are 2" longer than OEM jounce bumpers, 5" long total. However, that doesn't really translate well because stock bumpers compress much more than these do. These are polyurethane, and the stock bumpers are dense foam.
I can take measurements of mine, compare my collapsed shock length to yours and get in the ballpark. IMO, "ballpark" isn't really good enough to ensure protection of your shocks, but I will do this for you if you ask me to.
If you mount your shocks, springs and spacers and put the full weight of the Jeep on them, you can measure the length of the exposed shock shaft. Take that measurement, add at least .5", and that is the distance you should have between the bottom of the bump stop and the flat part of the coil seat that the bump stop contacts. From there you can determine how much to cut off the bump stop.
I can take measurements of mine, compare my collapsed shock length to yours and get in the ballpark. IMO, "ballpark" isn't really good enough to ensure protection of your shocks, but I will do this for you if you ask me to.
If you mount your shocks, springs and spacers and put the full weight of the Jeep on them, you can measure the length of the exposed shock shaft. Take that measurement, add at least .5", and that is the distance you should have between the bottom of the bump stop and the flat part of the coil seat that the bump stop contacts. From there you can determine how much to cut off the bump stop.
#5
Junior Member
Thread Starter
Join Date: Sep 2017
Location: Auburn, WA
Posts: 59
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1999
Model: Cherokee
Engine: 4.0
If you mount your shocks, springs and spacers and put the full weight of the Jeep on them, you can measure the length of the exposed shock shaft. Take that measurement, add at least .5", and that is the distance you should have between the bottom of the bump stop and the flat part of the coil seat that the bump stop contacts. From there you can determine how much to cut off the bump stop.
Thanks
#6
CF Veteran
Join Date: Oct 2011
Location: SEMO
Posts: 1,394
Likes: 0
Received 7 Likes
on
7 Posts
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0 L6
The frustrating thing is that you have to put it all together before you know what length to cut the stop. I was able to cut the bumpstop using reciprocating saw between the coils to fine-tune the length of mine in the end though. I had to lift the frame to extend the spring just the right amount to get in-between the coils with the saw.
#7
Junior Member
Thread Starter
Join Date: Sep 2017
Location: Auburn, WA
Posts: 59
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1999
Model: Cherokee
Engine: 4.0
The frustrating thing is that you have to put it all together before you know what length to cut the stop. I was able to cut the bumpstop using reciprocating saw between the coils to fine-tune the length of mine in the end though. I had to lift the frame to extend the spring just the right amount to get in-between the coils with the saw.
Real scientific.