3.5" Poly Rear Bumpstops (DIY thread)

[crazyjim]

So... after much deliberation, I finally came up with a way to bump the rear of my Jeep without air bumps. I just wanted something that would work, since I'd be tearing it all back apart soon anyway to do a shock hoop and rear air bumps. This is what I came up with:

Here is the drawing I came up with, to house the bump stop which is about 4.5" long and 2" wide.
http://i251.photobucket.com/albums/gg319/digitalc0nvict/Rear%20Bumps/IMG_0027.jpg

And here are the pieces all cut up and what not. Time to get to work!
http://i251.photobucket.com/albums/gg319/digitalc0nvict/Rear%20Bumps/IMG_0031.jpg
http://i251.photobucket.com/albums/gg319/digitalc0nvict/Rear%20Bumps/IMG_0033.jpg
http://i251.photobucket.com/albums/gg319/digitalc0nvict/Rear%20Bumps/IMG_0035.jpg
http://i251.photobucket.com/albums/gg319/digitalc0nvict/Rear%20Bumps/IMG_0038.jpg

Some of the beautiful TIG welds my buddy does
http://i251.photobucket.com/albums/gg319/digitalc0nvict/Rear%20Bumps/IMG_0046.jpg

And this is what happens when you bump into the rod while he's welding haha. Stupid me! :doh:
http://i251.photobucket.com/albums/gg319/digitalc0nvict/Rear%20Bumps/IMG_0048.jpg

So here are some mock up pictures.
http://i251.photobucket.com/albums/gg319/digitalc0nvict/Rear%20Bumps/IMG_0054.jpg
http://i251.photobucket.com/albums/gg319/digitalc0nvict/Rear%20Bumps/IMG_0058.jpg

Now... WARNING!! WARNING!!! Notice here the small gap between the corner of the bump and the shock. I looked at this probably 50 times, and thought to myself... damn that's close... but thought it would probably be fine, and the shocks don't travel towards the axle. I was wrong... I took it out for a quick romp after getting them setup, and it hit the shock. You can see the picture of the shock below
http://i251.photobucket.com/albums/gg319/digitalc0nvict/Rear%20Bumps/IMG_0060.jpg
http://i251.photobucket.com/albums/gg319/digitalc0nvict/Rear%20Bumps/IMG_0064.jpg

So what I ended up doing was shaving the side of both rear bumps off, just the corner that was hitting and that seemed to do the trick.
http://i251.photobucket.com/albums/gg319/digitalc0nvict/Rear%20Bumps/IMG_0062.jpg
http://i251.photobucket.com/albums/gg319/digitalc0nvict/Rear%20Bumps/IMG_0063.jpg



Now... my thoughts on these bumps. I fabbed and installed these the weekend before New Years... the NIGHT before we left for Ocotillo. I just wanted something that was going to work, because I knew I was going to be airing out my XJ. Well... aside from hitting the shock and gouging a section of it, they worked FLAWLESSLY. These things IMPRESSED THE HELL out of me that weekend, and every trip since. If you'll notice I kept my stock upper bump, and used that to fine tune the bump stop length, I measured it to get it close, then used the upper to fine tune. I cut it to where on a HARD hit I still have about 1/4" of shaft showing. I would recommend this setup for ANYBODY that's on a budget and wants a well performing rear bump setup. I would however recommend changing the design a bit, to keep from hitting the shock. Otherwise, JEEP ON!

[bluejeepkid]

i like this set up alot, if i was going jeepspeed thats what id do

[XJEEPER]

Point of drilling holes in the stock upper bump is to allow them to flex more?

[buzzbombxj]

I would watch out for starting to compress the frame at the stock bumpstop, but that looks real nice, tight to have somthing "temporary" tig welded for you

[crazyjim]

i like this set up alot, if i was going jeepspeed thats what id do

Thanks! You mean WHEN you go jeepspeed :D We'll get you over to the dark side soon enough.

Point of drilling holes in the stock upper bump is to allow them to flex more?

Well lol, yea kinda. That's what I tried at first, then realized it didn't help. That was from a previous bump setup I had off the spring perch, and it just hit way too hard with stock bumps. So I tried to soften them, only to realize there's a metal plate inside them to keep them stiff.

I would watch out for starting to compress the frame at the stock bumpstop, but that looks real nice, tight to have somthing "temporary" tig welded for you

You think that'd be a problem? I wouldn't imagine the frame bending or tweaking right there, I figured hell it's one of the only BOXED portions of our "frames" it's gotta be stronger. I'll check it out, but I won't have much more offroading on this bump setup, got something else in the works soon!

And yea, he's an awesome welder and a badass friend. He's slowly but surely teaching me how to weld, I just don't want to weld on my own stuff cause it's gotta look perty :D

[bluejeepkid]

Thanks! You mean WHEN you go jeepspeed :D We'll get you over to the dark side soon enough.



haha i was actually thinking about it but i like crawling a little more...altho i do go fast once in a while

[xcm]

looks good.
but your bearing cap is loose!

[crazyjim]

haha i was actually thinking about it but i like crawling a little more...altho i do go fast once in a while

Go dual purpose!! A jeepspeed setup rig will crawl a lot better than a crawl rig can jeepspeed (to a point)

looks good.
but your bearing cap is loose!


Yea, I've since fixed it :D

[XJLI]

im glad someone got these and posted up. i've been eyeing the poly ones bc the solid rubber 4 inchers do NOT flex. i'll be picking up a set of these to replace my uppers since i have the sweetzor DPG plates.

[vortex]

Stupid question here...What is jeep speed?

-PJ-

[MDR88MJ]

go to jeepspeed.com and go to you tueb and type in jeep speed , youl see =]

[crazyjim]

Stupid question here...What is jeep speed?

-PJ-
Jeepspeed is a race class for offroad racing. Basically cherokees and other jeeps built to go fast!

[slcpunk74]

Looks good thanks for the writeup. How do the polys feel? I just would think they would be hard but lets hear your side of how they are when you bottom. Did you have those on when you hit shell reef?

[crazyjim]

Looks good thanks for the writeup. How do the polys feel? I just would think they would be hard but lets hear your side of how they are when you bottom. Did you have those on when you hit shell reef?
So nice dude... Honestly, like the poor man's air bump. And yea, that's what I had on when I hit the shell reef, and you can see from the video I bottomed out HARD cause I caught the edge of the lip. Didn't bounce me back uncontrollably, or any at all actually, it just soaked it up. These bumps work great!

[slcpunk74]

sweet well I guess I know what Im doin to mine now thanks

[tcm glx]

Looking good jim!

[Ryno XJ]

Nice write up Jim, they look good and apparently they work. Good job.

[karstic]

Nice writeup Jim.
Where did you source the poly bumpstops?

[Starboard M]

How much do they compress?

What size did you get?

[slcpunk74]

http://www.tellico4x4.com/product_info.php/cPath/91_3052/products_id/29935

http://www.polyperformance.com/shop/Competition-Style-Studded-p-166.html

I would bet something like these

[crazyjim]

These are similar to what I got, but I got the energy suspensions ones but red :D


http://www.4wheelparts.com/Lift-Kits-Suspensions-Shocks/Bump-Stops.aspx?t_c=1&t_s=20&t_pt=4479&t_pl=1805&t_pn=EXP69081

[crazyjim]

Nice writeup Jim.
Where did you source the poly bumpstops?
A buddy of mine works at a shop in town that had some laying around. He had 5" or 3.5" I chose the smaller ones, as the 5" would just be too long. Plus they were bigger and would have rebound more. I think I made the right choice for being on the cusp of a breakdown for fear of not being able to go to ocotillo :D

[slcpunk74]

just ordered my polys so hopefully they get here soon

[slcpunk74]

just got a call from fourwheel parts and the pro comp 3.5" bump is no longer available. I went with a different one that was a 2.5" or 3" tall. so well see how that plays out

[crazyjim]

just got a call from fourwheel parts and the pro comp 3.5" bump is no longer available. I went with a different one that was a 2.5" or 3" tall. so well see how that plays out
What a bummer!!!

[Starboard M]

How much do they compress?

Anyone?

[98XJROKS]

just got a call from fourwheel parts and the pro comp 3.5" bump is no longer available. I went with a different one that was a 2.5" or 3" tall. so well see how that plays out


Very True, however 4wheel drive hardware has two in stock and they should have known that since they are affiliated...

[crazyjim]

Anyone?
I'd venture to say about 2" or so.

[slcpunk74]

Very True, however 4wheel drive hardware has two in stock and they should have known that since they are affiliated...


I called a couple of the limited places that I knew of and nobody had any so I just figured if I did in store pickup they would get here fast and with free shipping.
I think the smaller ones will work better because I plan to run the bump mounted to the spring plate like a t and j plate and then just cut down a stock bump up top.
So you guys were saying the stock bumps have metal in them so that if you drill ino them it wont make them softer?

[Gravesdiggerxj]

FYI that poly bump is an aftermarket replacement for the bumpstops on a superduty.
I've actually seen the Daystar ones at Autozone before.

Brad used to have a stack of them from when he worked at Ray's,

unfortunately they are all gone now

[slcpunk74]

FYI that poly bump is an aftermarket replacement for the bumpstops on a superduty.
I've actually seen the Daystar ones at Autozone before.

Brad used to have a stack of them from when he worked at Ray's,

unfortunately they are all gone now
Thats were I heard that from... I kept searching for f150 and such but I could'nt remember who told me that.

[buzzbombxj]

You think that'd be a problem? I wouldn't imagine the frame bending or tweaking right there, I figured hell it's one of the only BOXED portions of our "frames" it's gotta be stronger. I'll check it out, but I won't have much more offroading on this bump setup, got something else in the works soon!


http://www.freeimagehosting.net/uploads/e2a1259de6.jpg (http://www.freeimagehosting.net/)

Its hard to tell with a blurry pic of a dirty frame, but the bumpstops are pushing up on the frame, giving it a nice "crinkle", and now they arent stright up and down they are at an angle. After i noticed this and the fact that my bumpstop towers in the front go different directions I stopped jumping :(


for now... :gee:

[slcpunk74]

good thing I plan to plate mine because I am gonna run my straps right there

[jjvande]

Too bad these poly products are terrible colors... black would be nice.

[slcpunk74]

Too bad these poly products are terrible colors... black would be nice.
The energy ones I just got are black...

[jjvande]

source? for black ones?

Thanks

[slcpunk74]

called fourwheel parts looking for the pro comp3.5" and they said it was not avail so they could only find a 4.5" and a 2.5" so I went with the 2.5" for space reasons. They are made by energy suspension part# 9.9109g vato zone might be able to get them for you. http://www.energysuspension.com/pages/bsp2.html

[slcpunk74]

did a little digging and found these too just in case someone wants options.
http://www.pirate4x4.com/forum/showthread.php?t=347598&highlight=timbren

[slcpunk74]

I got my polys installed today.

http://i35.photobucket.com/albums/d158/troopdiggin87/DSC00981.jpg

http://i35.photobucket.com/albums/d158/troopdiggin87/DSC00980.jpg

http://i35.photobucket.com/albums/d158/troopdiggin87/DSC00978.jpg

[yourconfusedhaha]

http://www.freeimagehosting.net/uploads/e2a1259de6.jpg (http://www.freeimagehosting.net/)

Its hard to tell with a blurry pic of a dirty frame, but the bumpstops are pushing up on the frame, giving it a nice "crinkle", and now they arent stright up and down they are at an angle. After i noticed this and the fact that my bumpstop towers in the front go different directions I stopped jumping :(


for now... :gee:

same thing happened to me, but its even worse then that

[Starboard M]

did a little digging and found these too just in case someone wants options.
http://www.pirate4x4.com/forum/showthread.php?t=347598&highlight=timbren

Those are interesting.



They give load capacities on their bumps, which I assume is the max weight that will bottom out the bumpstop.

Assuming a normal built XJ weighs somewhere between 4200 and 5k, what weight rating should you get for the bumpstop?

If there is a 50-50 weight bias front and rear, do you get one that is between 2100 and 2500? Or will the force of a jump make that weight too light and require one that is heavier?

[slcpunk74]

Those are interesting.



They give load capacities on their bumps, which I assume is the max weight that will bottom out the bumpstop.

Assuming a normal built XJ weighs somewhere between 4200 and 5k, what weight rating should you get for the bumpstop?

If there is a 50-50 weight bias front and rear, do you get one that is between 2100 and 2500? Or will the force of a jump make that weight too light and require one that is heavier?

I have no idea on any of those questions but I just wanted to quote so someone who knows would not miss it after I posted.

I tried my front and rear polys yesterday and I really like the way they felt. Very soft and they still kept my tires and shocks happy:yelclap:

[dakineJ]

Those are interesting.



They give load capacities on their bumps, which I assume is the max weight that will bottom out the bumpstop.

Assuming a normal built XJ weighs somewhere between 4200 and 5k, what weight rating should you get for the bumpstop?

If there is a 50-50 weight bias front and rear, do you get one that is between 2100 and 2500? Or will the force of a jump make that weight too light and require one that is heavier?

Excellent question. Maybe a Tech at one of the shock manufacturers that makes air bumps would have info on compression forces.

[XJLI]

Assuming a normal built XJ weighs somewhere between 4200 and 5k, what weight rating should you get for the bumpstop?


holy crap i dont think so. mine was 3875 with some gear and me in it- weighed it right after i put the 33s on.

[srimes]

Those are interesting.



They give load capacities on their bumps, which I assume is the max weight that will bottom out the bumpstop.

Assuming a normal built XJ weighs somewhere between 4200 and 5k, what weight rating should you get for the bumpstop?

If there is a 50-50 weight bias front and rear, do you get one that is between 2100 and 2500? Or will the force of a jump make that weight too light and require one that is heavier?

I don't speak from experience, but from a physics standpoint it's pretty complicated. If it was just the bumpstop you could calculate it for a given jump height and jeep weight. But you also have the main springs, which you could account for if you know the spring rate and travel, but more importantly there's the shocks, which vary widely and their resistance depends on velocity.

How about this: take high-speed video of a big jump to measure downward velocity as the suspension bottoms out. We could then pick a good bumpstop size to use after fixing whatever broke. :D

v=at, d=.5at^2
a = 32 ft/s*s


I'll take a SWAG and say 2-3 g's at full compression. Stiffer with less travel, softer with more.

[JeepFreak21]

These are similar to what I got, but I got the energy suspensions ones but red :D


You don't have a part number on those do you? I contacted Energy Suspensions and they claim to not have a 3.5" tall bump in the style you have. (The guy was less than helpful).

I've got $40 in credit to use at VatoZone, so I was hoping to pick them up there :)

EDIT:
called fourwheel parts looking for the pro comp3.5" and they said it was not avail so they could only find a 4.5" and a 2.5" so I went with the 2.5" for space reasons. They are made by energy suspension part# 9.9109g vato zone might be able to get them for you. http://www.energysuspension.com/pages/bsp2.html

Have you tried out the 2.5" bumps yet? How do you like them?
Thanks,
Billy

[slcpunk74]

You don't have a part number on those do you? I contacted Energy Suspensions and they claim to not have a 3.5" tall bump in the style you have. (The guy was less than helpful).

I've got $40 in credit to use at VatoZone, so I was hoping to pick them up there :)
I would check out the ones that I am using if you want to go the vato zone way. I bet that you can get energy polys at the "zone".


Have you tried out the 2.5" bumps yet? How do you like them?
Thanks,
Billy

I love them. I hit some whoops yesterday goin about 50-55 pretty gnarly. I did pop off one of my back flares but I guess that just means I need to trim a bit more.

[XJLI]

got mine in today. welded some steel to them so I could mount them to the stock location since I already have DPG bumpstop plates. So far they work great on road lol.