Front Upper Bump Stop Extension Ideas
- Thread starter BlackBeard1790
- Start date
To be fair, an engineer with experience can look at a problem and arrive at tolerable well founded assumptions as to their efficacy. In this case, there are a few things to take into account. Axle movement which is an arc, bump stop length, axle location fore and aft, and finally, what we want a bump stop to actually accomplish.
You are far too smart to say you don't know if hockey pucks will work when you damn well know they will. You are only saying that due to that answer being contrary to your position that tennis balls are perfect. The other side of that, if you can't tell they will work perfectly, then you had no business telling Jeep anything.
Since the axle moves in an arc, as it droops it moves rearward which pulls the spring with it. If all of the bump stop extension is done at the top, we get the problem of the spring coils getting caught and making noise, harmless but annoying.
The solution to that is to split the extension between the top and bottom, easy, simple, effective and adjustable.
The answer to what we want a bump stop to do is derived from cycling the suspension to define hard bump which is the point at which any further upward movement is undesirable and intolerable due to the possibility of damage. The second thing we want bump stops to do is progressively slow down the axle movement as we approach hard bump.
In this case, we have someone who has stated they are unwilling to employ any methods which require spring removal. That also means the post should have died after that was presented because there are NO answers which will solve his problem.
But, once they did continue, tennis balls only solve one side of the problem. No one knows how many will provide enough compressibility to define where hard bump is and whether or not they will remain in a state without failure if we find a way through experimentation to achieve hard bump.
The last thing is unless you apply a large and emphatic caveat to the beginning of a solution saying that while this has worked for you, it may not work for everyone and as such should be tested and defined by the end user, then it will be assumed it is being offered as an answer. It is very disingenuous to say that it worked for you and leave the rest to the vagaries of forum members only to plead innocent over your intentions. You meant it to be an answer to his problem, don't be shy about owning it. If you aren't going to own it, then don't post it as an answer.
One of the main points of the forum is to offer our knowledge to others. We should be trying to give the best advice we think.
I offered the solution he wanted (daystar bump stop) but then continued with what’s really better and why (bump stop extension on the axle pad). I’m giving advice on options (Currie vs hockey pucks) that I know and explaining the reasons for those options.
This gives him the knowledge and ability to choose depending on his need and now better understanding of the system and offerings.
To offer the advice that tennis balls are what he’s looking for is just incredibly short sighted. I don’t care how qualified you are professionally. You offered nothing that would actually help and you did it poorly on top of it. I actually thought you were joking at first when you said it. Since I started writing this everyone else has also explained this well but I already wrote this just didn’t send it.
The practice has been around for a while. Definitely a bandaid solution.
My google-fu pulled up this old thread on pirate. https://www.pirate4x4.com/threads/tennis-balls-in-coils.273902/
Select comments:
"yeah seen 'em ran too. works like bumpstops. every now and then you need to pull it apart and add a few, they escape outta there sometimes"
"FWIW, arena racers and tough trucks have been using different balls in the springs for years. It does make for an entertaining display when they hit a jump wrong, tear off the suspension, and puke a few dozen brightly colored balls onto the dirt."
Old Jeepin Cowboy
Member
what about oranges, do you put oranges inside your coil springs if you run out of tennis balls?
I actually like using a silicone "marital aid," even has a suction cup to avoid coming out like the tennis balls.
I can see how the addition of the suction cup would be a benefit.
Should I ask Wayne Gretzky? Did you ask John McEnroe when you did the tennis balls?
Old Jeepin Cowboy
Member
Hmmmm interesting, I could do that and have fresh squeezed OJ on the trail and make some Tequila Sunrise. Thanks for bringing that up.
What’s with the oranges?
. Bright side is if you did maybe you’d be able to get some OJ a little later in the day. Nothing like freshly squeezed OJ.
Now back to regular programming.
Since it’s mentioned sometimes splitting the extensions to the top and bottom for the front, I just want to know what is the max spacer thickness can go on the top of the jounce cup without getting caught in the springs during the bump? Can 3/4” or 1” spacer be added safely to the top?
That depends very much on lift height, shock travel and the axle position from the adjustable control arms.
4.0L Auto light weight all stock TJ (I.e. soft top, half doors, no winch or any other modifications or extra weight added anywhere) H&R - 52107 1” sports springs, netting 1.5” lift approx.
Bilstein B8 5100 - Shock Absorber
Part Number: BIL24-293099
Position: Front
Descriptor: For Front Lifted Height: 0-2"
Collapsed Length (IN): 13.06
Extended Length (IN): 21.18
Part Number: BIL24-293105
Position: Rear
Descriptor: For Rear Lifted Height: 0-2"
Collapsed Length (IN): 12.81
Extended Length (IN): 20.08
30X9.50 R15 tyres and all other suspension components are factory stock standard. I am considering adding bump stop spacers (20mm or 3/4”) mainly to avoid any chance of Bilstein 5100 bottoming out, although compressed length difference is not that much and may well be within the stock specs.
For comparison -
Stock shocks are....
Front
13" compressed
7.5" travel
20.5" extended
Rear
12.2" compressed
7" travel
19.2" extended
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I don't know. Usually I would say to cycle the axle without springs installed. But you need the springs installed to know.
Build and install something and run it. If the bump stop cup plucks the coil spring and it bothers you, then change it until it doesn't bother you.
Thanks, as per my post #54 above, I may not even need bump stop extensions but just trying to be a bit cautious and thinking of adding 20mm (3/4”) spacers front and rear to be on the safe side. My driving is mostly on the street and some light gravel roads. Idea is to avoid drilling holes on the axle pad if I can.
Mine has a hole drilled in the bottom with about a 2 1/2-3” spacer with the 1” spacer up top. 35” tire, 11” shock, 4” spring lift and 1 1/4” body lift with stock fenders
It didn't take too long into the threads life for someone to dig this up..
Lost me at "Zero-Defect environment"
Kinda the same, only different...
I like the tennis ball idea... cuz they are fuzzy.
What he said ^^^
Clearly I have nothing of real value to add to this thread. But I have always loved the word "efficacy".
I am going to go replace my seat cushion. Wait.. Can I use the old one as a bump stop extension?
