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Recomended bump stop length

Dragonlich1961

NAXJA Forum User
Location
Ohio
I'm wanting to purchase new bump stops for my rig but i'm unsure of what lenght i need. i have a RC 3" lift with 30 x 9.5 tire on factory rims. i know it's usually one inch more bumpstop for one more inch of suspension. problem is my factory bumpstops are non- existent, so i don't even have a starting lenght to go by.

Any sugestiong on what i should do to get proper stops again, would be helpful Recomended lengths and brands would be helpful.

This is my first jeep and first time having to replace these on any vehicle where the originals were gone. ( my 61 still had it's stops)

Thanks
Chris
 
Just get the factory length stops...30in tire will clear with a factory stop Crown makes decent ones and you can buy them from Amazon
 
I would start with some 4 ring prothane coil inserts with some kind of hard insert so that they do not get stuck on your bump towers.
 
So factory ones would be fine even with the increased height and tire?
What do you mean by 4 ring coil inserts ( could you please post a link or picture)? I'm new to jeeps and still amazed at all the little do-dads people sell.
 
Google prothane or go to jegs, amazon, etc.
 
The UpCountry optioned XJ's have rear bumpstop that are 4.1 inches long and the stock bumps are about 3 inches long. I just bought some on Amazon. For the front, glue a hockey puck to the bumpstop pad on the top of the axle.
 
I have extended prothane front stops. Theyre really hard, youll know when you hit bump. Next time I have the spring out im putting a stock bumps and some spacers at the coil base.
 
I have extended prothane front stops. Theyre really hard, youll know when you hit bump. Next time I have the spring out im putting a stock bumps and some spacers at the coil base.

That does not really make any sense to me. The point of Prothanes are to soften up the bump stop. Mine are like clouds.
 
I have extended prothane front stops. Theyre really hard, youll know when you hit bump. Next time I have the spring out im putting a stock bumps and some spacers at the coil base.


Extended prothane bumps or Prothane coil sprint inserts?

If they don't look like this, you didn't buy the product people are usually talking about.

pr191703rd_lg.jpg


198508d1371578224t-coil-spring-inserts-bumper-prothane-2ring-dsc02487.jpg
 
Nope, I was thinking of the wrong thing sorry. I was thinking of the actual bumpstop
 
Yeah the extended bumpstops are rock hard. The coil spring inserts are flipping magic.
 
So, if I go with stock bumpstops and the coil inserts, what size would I need for a 4.5" lift ?

And what keeps the normal bumpstop from getting stuck in the center of the inserts ?
 
You have to build a plate, and either replace the upper bumpstop with it, or weld some 1.5" tube to it (3-4" of it) and insert it downward into the bumpstop.

100_0233.jpg
 
Not sure I get it......

So you mean I use the inserts and put a plate where the stock bumpstop is now...I assume so the insert has something to 'stop' against,

Or put some tube inside it ?

second part I don't get


I see the plate in your first pic, but I also see a stock bumpstop too......


or just maybe...you meant the plate....with the tube on it.....goes in the insert to hold the plate in place ??
 
On my jeep we plated the upper and tap'd it, and bolt the plate there.


IMG_20140119_114601591_HDR_zpstaa6wqse.jpg


IMG_20150419_123924211_zpscxqutntn.jpg


That plate hits the top of the insert as a contact point (sorry, no good photos).

2013-01-26_14-56-00_778.jpg


2013-01-12_13-53-33_269.jpg



We cut a piece of 1.5" OD delrin rod to the 'exact' hard bumpstop height and put it inside of the insert. You come down on the prothane, it DRASTICALLY softens any impact (from feet in the air even) and then hard stops when it gets down to the delrin.

standard.jpg



Sorry that every picture is from a different iteration of build, or in the case of the last one, randomly stolen from google image search. I didnt really have a photo set of just this process. We used to kinda keep how we did it a secret, but most of the guys we compete against have worked it out by now, so its moot.
 
Last edited:
Not sure I get it......

So you mean I use the inserts and put a plate where the stock bumpstop is now...I assume so the insert has something to 'stop' against,

Or put some tube inside it ?

second part I don't get


I see the plate in your first pic, but I also see a stock bumpstop too......


or just maybe...you meant the plate....with the tube on it.....goes in the insert to hold the plate in place ??

I was looking for photos. I have over 2,000 photos of my jeep build, and still not a complete set of this setup. ;)

The other option is to build a plate like pictured a few posts up, weld a section of 1.5" OD tube to it at the length you would need for a 'hard' bumpstop, and pound that down into the prothane.

So your factory upper bump would come down, hit the plate, which at a certain compression point would hit the coil bucket and stop it from compressing further.


The latter way is easier, the way I posted one post up is better for a few reasons, though. You can get a more accurate hard bump point (arent calculating the OEM bumpstop compressing), the delrin will hit softer than 1.5" steel tube, and you get to play with not older a welder, but a drill and tap as well.

If you have a renix jeep, the upper stop is threaded on, you just unscrew it and screw a plate on, way easy.
 
Ok....how did you figure the hard bumpstop height ?? compressed spring height + ??


I ask cuz I was about to put the hard bumpstop in, but now am rethinking things, as this route may even be cheaper as well as softer


IO see yuou were typing when I was

Why not use delrin for the tube, but bolt it to the plate then put it in the insert ?

kinda best of both worlds ??
 
Jack the jeep up.

Remove the coils.

Bolt shocks back up.

Lower it down until you don't want it to go ANY further.

Measure between hard points.
1) If you're doing the plate and tap the upper method, measure from the bottom of the plate (not teh bolt head) to the bottom of the coil bucket. Cut a section of delrin rod that length and insert it inside your prothane.

2) If you're doing the plate welded to a steel tube inserted method, measure from the coil bucket to the metal at the bottom fo teh upper mount, and just assume that all of the rubber in the OEM bumpstop will 100% compress (it will). Subtract the thickness of the steel plate that you cut out, weld it together, install.


You can see why the 2nd method is harder to be accurate.

On my jeep, we cut the delrin rod to a length where it will hit with 3/8" shock shaft showing. The delrin is good for about one season (it chips) and has to be replaced. I keep a dozen of so pieces sitting around pre-cut, and swapping them out is part of our race prep. On the lift it takes me about 3 minutes.

It happens that I work for one of the biggest plastic distributors in the country, so replacing the delrin 3 times a year costs me less than buying a bit of steel tube.
 
Ok....how did you figure the hard bumpstop height ?? compressed spring height + ??


I ask cuz I was about to put the hard bumpstop in, but now am rethinking things, as this route may even be cheaper as well as softer


IO see yuou were typing when I was

Why not use delrin for the tube, but bolt it to the plate then put it in the insert ?

kinda best of both worlds ??

I don't think the delrin would hold up to being threaded. It chips off pretty quick as a solid chunk. If you drive like we do, you'd be replacing those plates every time you went out.
 
I ask cuz I was about to put the hard bumpstop in, but now am rethinking things, as this route may even be cheaper as well as softer

This route will probably not be cheaper. Id' expect to spend at least $100 before its done.

But its worth every cent. Most guys will compare the prothane's performance to air bumps.
 
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