I made some rear bump stops. what do you think?

[4runnerguy512]

nice color

 

[Black798]

[MENTION=146407]Plastics guy[/MENTION], I went out and took a second look at the bumps and decided to back my truck up on the "flex ramp" in my driveway. I crawled under there and here is what I'm seeing. I also took your advice and "ponied up" the 1200 dollars for a set of king coilovers :naughty:

<a data-flickr-embed="true" href="https://www.flickr.com/photos/147275993@N05/42942965952/in/album-72157697093590395/" title="IMAG0185"><img src="https://farm2.staticflickr.com/1831/42942965952_7b72bec999_b.jpg" width="768" height="1024" alt="IMAG0185"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
<a data-flickr-embed="true" href="https://www.flickr.com/photos/147275993@N05/42091026675/in/album-72157697093590395/" title="IMAG0190"><img src="https://farm2.staticflickr.com/1838/42091026675_d5455e29c8_b.jpg" width="1024" height="768" alt="IMAG0190"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>

Because of that overhang, there is a perfect line for the bumpstop to just fold over. Granted yes I and [MENTION=143526]theesotericone[/MENTION] were exceeding the limit of both these bump stops and the stock ones up front but there is still 25% of the base that's unsupported. That, in turn, is why when that bolt contacted the frame it caused a catastrophic failure rather than just a hard hit into the control arm. Regardless of that bolt hitting it's creating a major stress point that I think would inevitably cause a failure over time. The bolt contacting just exponentially sped up the process.


Now as far as a solution, If you want to send me another set that would be fantastic, I'll cover shipping and we can work the details out over PM. But when they get here, since I'll have my control arms out any way to install new bushings, what I'll do is weld on a small steel pad to the edge of the lower control arm to extend it and support the whole base and also use a lower profile bolt head. I'm thinking of using a Panhead with an Allen drive if I can find one in an M12 size. That way the base will have an even support to prevent that high load point and there will be a little more clearance inside the bump stop for those harder hits. That way it's more like the rears where the entire mounting surface is supported, I checked those and there weren't any issues to be seen

I honestly think the rubber material you used is more than up to the task of what I was doing, seeing as it didn't completely tear even after the base had cracked and even now I cant get the bumpstop to fully tear apart. The weak point is really the base because of that high load area. Let me know your thoughts on that idea

 

[Plastics guy]

[MENTION=146407]Plastics guy[/MENTION], I went out and took a second look at the bumps and decided to back my truck up on the "flex ramp" in my driveway. I crawled under there and here is what I'm seeing. I also took your advice and "ponied up" the 1200 dollars for a set of king coilovers :naughty:

<a data-flickr-embed="true" href="https://www.flickr.com/photos/147275993@N05/42942965952/in/album-72157697093590395/" title="IMAG0185"><img src="https://farm2.staticflickr.com/1831/42942965952_7b72bec999_b.jpg" width="768" height="1024" alt="IMAG0185"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>
<a data-flickr-embed="true" href="https://www.flickr.com/photos/147275993@N05/42091026675/in/album-72157697093590395/" title="IMAG0190"><img src="https://farm2.staticflickr.com/1838/42091026675_d5455e29c8_b.jpg" width="1024" height="768" alt="IMAG0190"></a><script async src="//embedr.flickr.com/assets/client-code.js" charset="utf-8"></script>

Because of that overhang, there is a perfect line for the bumpstop to just fold over. Granted yes I and [MENTION=143526]theesotericone[/MENTION] were exceeding the limit of both these bump stops and the stock ones up front but there is still 25% of the base that's unsupported. That, in turn, is why when that bolt contacted the frame it caused a catastrophic failure rather than just a hard hit into the control arm. Regardless of that bolt hitting it's creating a major stress point that I think would inevitably cause a failure over time. The bolt contacting just exponentially sped up the process.


Now as far as a solution, If you want to send me another set that would be fantastic, I'll cover shipping and we can work the details out over PM. But when they get here, since I'll have my control arms out any way to install new bushings, what I'll do is weld on a small steel pad to the edge of the lower control arm to extend it and support the whole base and also use a lower profile bolt head. I'm thinking of using a Panhead with an Allen drive if I can find one in an M12 size. That way the base will have an even support to prevent that high load point and there will be a little more clearance inside the bump stop for those harder hits. That way it's more like the rears where the entire mounting surface is supported, I checked those and there weren't any issues to be seen

I honestly think the rubber material you used is more than up to the task of what I was doing, seeing as it didn't completely tear even after the base had cracked and even now I cant get the bumpstop to fully tear apart. The weak point is really the base because of that high load area. Let me know your thoughts on that idea

No need to weld a base. I have a better, easier solution. I'm not giving up on you, just need a minute to figure out how to make the improvements.

Glad I could nudge you into those KINGS!!!:lol:

PM In bound!!

 

[Unner]

Here's my 2 cents on the broken bump stops.

Put them on the front of the LCA instead of the rear. The front is wider than the rear giving more of support for the base of the bumpstop. I'm not surprised that they broke on your guy's rigs if they were installed on the rear of the LCA.

When I installed my Wheelers superbumps a few years back I initially put them on the rear of the LCA. I saw the huge amount overhanging and decided to put them on the front.

I've been running them on the front location of the LCA for nearly 100k miles now and they aren't broken. I've done the speeds [MENTION=121903]Black798[/MENTION] was going many many times, and even faster with the new Kings all around.

For the hardware portion of it the superbumps they have a socket cap bolt, that's kinda recessed when installed. Not sure how [MENTION=146407]Plastics guy[/MENTION] are, but maybe there is some sort of modification to be done that gets the head of the bolt lower? Or maybe it wouldn't have contacted if the base wouldn't have broken because there would have been enough resistance to keep the bolt from touching the frame.

Here's a couple pics showing the superbumps and the size difference in the front and rear of the LCA.

20180624_225123 by Unner Unner, on Flickr
20180624_225047 by Unner Unner, on Flickr
20180624_225109 by Unner Unner, on Flickr

 

[Tyler James Inc]

Interested to hear the solution to the overhang!
Also interested what it would take to break them.
I'll get my ass in gear and go hit some low freq speed bumps and see if that's all it would take

 

[89hatcher]

PM sent

 

[Plastics guy]

Interested to hear the solution to the overhang!
Also interested what it would take to break them.
I'll get my ass in gear and go hit some low freq speed bumps and see if that's all it would take

That would be great. I have tested these bump stops extensively up to 40 mph and haven't had any failures on my end.

These bump stops are designed for trails and light crawling. My bump stops are giving a false sense of security at higher speeds. In-turn the additional speed is adding much more compression than the bump stops were designed for and they blow up!

If I were going to try to make a rubber bump stop that was designed for 50+ mph it would not perform as well on lower speed hits. Its kind of a balancing act trying to find a middle road. This is the same balancing act in having your shocks valved. You cant expect shocks built for a crawler to perform well pre-running across the desert and alternately shocks valved for pre-runners are going to suck in the rocks.

Together with all of your guys help on this thread we will find a perfect balance. I have every intention on addressing any issues and looking into improvements that can be made. I wont leave [MENTION=121903]Black798[/MENTION] or [MENTION=143526]theesotericone[/MENTION] hanging without a solution. I am working directly with these guys to get the feedback I need to make the any improvements.

I specifically wanted to see the failure points of these bump stops. Its one thing to test in a lab with a load table, its a completely different beast when your in the real world. I dont do any high speeds over 45mph in the dirt, im an old man.... That's why I reached out to you crazies with big balls and a heavy foot for further testing. Looks like I've found the right guys!!!!

 

[theesotericone]

[MENTION=146407]I also took your advice and "ponied up" the 1200 dollars for a set of king coilovers :naughty:

Dude, don't overpay. Low Range still has them listed for $860. I'm so close to calling them. But dual cases will get me a lot further then better ride quality will. lol When your ready to get some we should time it for a group buy.


I've talked with [MENTION=146407]Plastics guy[/MENTION] about your complete failure and my partial. He's pretty damn serious about making these as bomb proof as you can expect. Hopefully you've had a chance to talk to him as well.

I gave my input which is that the compression load over the LCA is causing it. I think your idea of a plate is pretty spot on. That would spread the load more evenly. I also asked what load they failed at under compression during table testing. I don't want to give that number as it was a private conversation.

He did give me the figure and it's pretty damn high. I went and did the math and conversions to the best of my non-engineer ability. Using 55 MPH and a rig weight of 5000 lbs those bumps should have held. They have about another 20% before we reach the table breakage point according to my math. This goes back to them loading over the LCA. That compression force over an edge obviously acts as a multiplier.

The fact that you managed to break them and he reached out to a few of us almost instantly makes me look forward to his next version. It's been a fun process to watch and take part in and I'm sure it will continue to be. For low impact crawling the current version is so good. I hope he can find a new design and keep the same properties in the compound. I'm sure he will.

 

[Black798]

Dude, don't overpay. Low Range still has them listed for $860. I'm so close to calling them. But dual cases will get me a lot further then better ride quality will. lol When your ready to get some we should time it for a group buy.


I've talked with [MENTION=146407]Plastics guy[/MENTION] about your complete failure and my partial. He's pretty damn serious about making these as bomb proof as you can expect. Hopefully you've had a chance to talk to him as well.

I gave my input which is that the compression load over the LCA is causing it. I think your idea of a plate is pretty spot on. That would spread the load more evenly. I also asked what load they failed at under compression during table testing. I don't want to give that number as it was a private conversation.

He did give me the figure and it's pretty damn high. I went and did the math and conversions to the best of my non-engineer ability. Using 55 MPH and a rig weight of 5000 lbs those bumps should have held. They have about another 20% before we reach the table breakage point according to my math. This goes back to them loading over the LCA. That compression force over an edge obviously acts as a multiplier.

The fact that you managed to break them and he reached out to a few of us almost instantly makes me look forward to his next version. It's been a fun process to watch and take part in and I'm sure it will continue to be. For low impact crawling the current version is so good. I hope he can find a new design and keep the same properties in the compound. I'm sure he will.

I think the reason low range has the price so low is that they haven't updated their website. About a month ago king redid their entire catalog and in doing so raised all their prices. Every king dealer was also required to reflect those price changes. That may not be true but that's what I'm thinking is why low range has such a low price. Downsouth motorsports had the lower price listed for a while as well but it eventually went up to the 1200 mark. I ordered through filthy motorsports because I am having them tweak the valving a bit and install 650lb coils.

So onto the bumps. I have exchanged a few PMs with [MENTION=146407]Plastics guy[/MENTION] and am planning to talk with him over the phone sometime this evening. He mentioned he thinks he has a solution. I do admire that he is working with us to make these as strong as possible.

You are spot on with the theory of why they broke though. Im assuming in the lab the base of the bumpstop was on a flat surface with a linear compression force. That's how you would be able to get the absolute maximum strength value when testing. However, on the truck, there is almost 25% of the base that is unsupported. The line where the bumpstop overhangs the control arm also happens to fall directly in line with the cast in place washer that is inside the bumpstop.

Looking very closely at both of mine you can see that when the mounting bolt contacted the frame, the force was then transferred the washer and it then caused the fracture in the base because there wasn't a solid surface supporting the washer to transfer the load. By adding a plate under the bump it would have a solid surface and the lower profile bolt would give plety of room for aditional compression

Without knowing that lab test result number I cant do the fancy engineer math that I was taught last semester but I have to ask if you took into account the leverage effect of the control arm? These bump stops are really seeing roughly double the force that would be exerted at the wheel since they are further inboard. That's how we are able to run 4 inch travel coilovers but get 8 inches at the wheel.

 

[theesotericone]

I think the reason low range has the price so low is that they haven't updated their website. About a month ago king redid their entire catalog and in doing so raised all their prices. Every king dealer was also required to reflect those price changes. That may not be true but that's what I'm thinking is why low range has such a low price. Downsouth motorsports had the lower price listed for a while as well but it eventually went up to the 1200 mark. I ordered through filthy motorsports because I am having them tweak the valving a bit and install 650lb coils.


Without knowing that lab test result number I cant do the fancy engineer math that I was taught last semester but I have to ask if you took into account the leverage effect of the control arm? These bump stops are really seeing roughly double the force that would be exerted at the wheel since they are further inboard. That's how we are able to run 4 inch travel coilovers but get 8 inches at the wheel.

Holy hell, I thought you where joking about ordering them. Congrats man. I'm still at least 6 months out from them. In the meantime I keep expecting my Taco Billies to blow but they just keep on taking everything I throw at them. lol

I just used some math to convert force to psi. I did not take into account any leverage. I just figured the shock and spring are absorbing some of that force before the bumps actually make contact so the leverage might be close to a wash. I'd be curious to hear your thoughts on that for sure.

 

[Tyler James Inc]

These bump stops are designed for trails and light crawling. My bump stops are giving a false sense of security at higher speeds. In-turn the additional speed is adding much more compression than the bump stops were designed for and they blow up!

Really? You think they would have failed even if a shelf was welded on to fully support the base?

 

[Black798]

Holy hell, I thought you where joking about ordering them. Congrats man. I'm still at least 6 months out from them. In the meantime I keep expecting my Taco Billies to blow but they just keep on taking everything I throw at them. lol

I just used some math to convert force to psi. I did not take into account any leverage. I just figured the shock and spring are absorbing some of that force before the bumps actually make contact so the leverage might be close to a wash. I'd be curious to hear your thoughts on that for sure.

It wasn't really in the budget but since I'm replacing everything else from the rack forward it only made sense. My 5100s have 30 thousand miles on them and it shows. Im hoping they'll ship by the end of the week...

On the subject of the math... my truck weighs 4950 with me and a full tank of gas according to the steel recycler scale. On the night I broke the bumps I was probably in the neighborhood of 5500 with all my gear. Assuming an even distribution of weight, obviously not the case in the real world but Il use it for simplicity, that would equate to 1375 lbs a tire. Factor in your moving speed and what that does to your force, that 1375lbs turns into 33,275 lbs of moving mass. Now I dont know the calculations exactly for how to determine how much of that force and energy is being removed from the equation by the coilovers when I hit a bump, someone like [MENTION=57546]4-Ripcord[/MENTION] would probably know. But that 33,275 lbs gets doubled when the A-arm moves meaning the bumpstop sees around 66 thousand pounds of force. Over its surface area, roughly 3.14 inches, that means that bumpstop is seeing roughly 21,194 psi of force.

I may be way off on the theory behind that math but the numbers seem realistic to me. If someone knows better though please chime in, I dont want to just be giving out utter bullshit.

 

[4-Ripcord]

Usually safe to assume 2-3G's of force for a fairly significant bump stop activation input.

that's 2-3x the SPRUNG vehicle weight, so take away tire weight and most of the suspension.

If you are talking complete bottom out, it can get exponentially higher.

 

[Plastics guy]

Really? You think they would have failed even if a shelf was welded on to fully support the base?

Added support would absolutely help things out. I would prefer to adjust my design a bit to have all the support it needs built into the bump stop itself opposed to a weld on support. Easier and faster to install.

I am building a V2 currently. I have talked with [MENTION=121903]Black798[/MENTION] and [MENTION=143526]theesotericone[/MENTION] and they took the time to explain in detail exactly what they were doing at the time of the failures. After their input I am very confident that V2 base will not fail.

Dont know what to fix if you cant see the failure...

I have the materials I need ordered up for V2 and I'll have it by the end of this week.

To everyone that purchased a set of my original V1 front bump stops (with the hex shaped base):
If you break your V1 set I will replace them with a V2 set at my expense. No problems and no B.S. Other than Black798 and theesotericone, there have not been any failures at all. As both guys said they were hauling ass during the failures and its a safe bet that the higher speeds is what killed them.

V2 is built for the added abuse!!

 

[wrench.n.wheel]

Added support would absolutely help things out. I would prefer to adjust my design a bit to have all the support it needs built into the bump stop itself opposed to a weld on support. Easier and faster to install.

I am building a V2 currently. I have talked with [MENTION=121903]Black798[/MENTION] and [MENTION=143526]theesotericone[/MENTION] and they took the time to explain in detail exactly what they were doing at the time of the failures. After their input I am very confident that V2 base will not fail.

Dont know what to fix if you cant see the failure...

I have the materials I need ordered up for V2 and I'll have it by the end of this week.

To everyone that purchased a set of my original V1 front bump stops (with the hex shaped base):
If you break your V1 set I will replace them with a V2 set at my expense. No problems and no B.S. Other than Black798 and theesotericone, there have not been any failures at all. As both guys said they were hauling ass during the failures and its a safe bet that the higher speeds is what killed them.

V2 is built for the added abuse!!

Time to break these puppies then!:rockon:

 

[Plastics guy]

Here are some pics of my Prototype V2. Same rubber material as V1 and same overall size. V2 Changed the base to be round in shape and added a 3/16" steel plate to the bottom of the mounting base. That should more than be enough to take a beating. Looking forward to you guys testing these!!!:lookout:lane:
[MENTION=121903]Black798[/MENTION] [MENTION=143526]theesotericone[/MENTION]

V1 and V2 side by side. The notch in the casting of V2 is to face the wheel. just makes installation a little more fool proof.


This pic shows the clearance that I am getting between my bump stop and the frame of the truck. With my particular suspension setup I have about 1-1/2" of upstroke before my bump stop starts to make contact with the frame.


Front coilover pulled out. holding the static weight of the truck completly on the front OEM bump stop. in the left of the picture my bump stop can be seen compressed.


All the edges of V2 are now round as to prevent any potential wear issues from contacting the base under full compression.

 

[Black798]

I was very impressed by the V1 bumps I installed and then broke. V2 looks substantially more refined though, the notch in the base for mounting is a really great idea, it will make positioning way easier. I had to take a minute to make sure the slant was pointed the right way when I installed mine but looks like that won't be an issue now.

It also looks like next weekend I'll be making another trip out to the same area and down the road that broke the originals so well see if all these improvements fixed the issues. I have a good feeling about it though. Looking forward to trying to break these :bravo:

Unfortunately, though it looks like I won't be installing the kings for awhile and will be making my Colorado trip without them. I spoke to Ben at Filthy Motorsports today and was told that the coilovers aren't in stock and I'm looking at a 5 week lead time.

 

[theesotericone]

That was a super fast turn around for V2. I believe having that 3/16th plate in the casting will solve the issue. I really like the handling characteristics of V1. Thanks for keeping the same free height and compound. Looks like I have an excuse to go drive like a jack ass again.:lookout:

 

[Plastics guy]

Looks like I have an excuse to go drive like a jack ass again.:lookout:

No peer pressure! No peer Pressure!!:jk:

 

[octanejunkie]

No peer pressure! No peer Pressure!!:jk:

None

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