JBA Offroad Upper Control Arms And Suspension MEGA Thread BS thread

All good. Hopefully this stays true for the Tacoma as well .

Edit: Do you mind asking him what material the arms are? 4130 or higher? If higher the weld can be very tricky... if lower the weld is stonger but the metal is weaker... If something else than who knows lol. It'd be nice to know.

That's one thing I noticed when I looked at his arms. He has lots of good descriptors but things like his angles, materials, etc that other vendors post are missing. Those would be a good add to his site rather than just the verbiage he currently uses. Just an idea of course.

 

Thanks! As usual you seem to know these arms well. It'll be interesting to see what he comes up with for bushings. I like the poly because, if greased properly, they never seem to be a structural problem. Maybe it'd be too much to ask but if he offered a couple of options that would be pretty unique.

Here's a quick comparison I pulled off a website I keep around to help me understand steel because I'm no metalurgist.



They are very close in cost and weight except it appears that the A 36 steel appears to have significantly lower tensile strength. Before that causes any arguments keep in mind that if Marlin uses more steel in his arms that can make up the difference easily and leave him with a product that should have easier/stronger welds. Maybe, if you get a chance, could you get him to weigh his arms versus those TC arms with the joints and bushings popped out? Just food for thought. If he says his arms are stronger than his competition, and TC is who he compares too, it'd be good to know his argument .

 

If they are heavier than that makes sense. Basically what that would mean is that martins arms exchange a little extra weight for easier welds. There is nothing wrong with that sense it would give the arms the strength they need while making it easier to weld. If you really pushed the arms they still might be easier to snap... but then you should really of bought his HD product anyway.

Thanks again for the info. I'm serious, if I end up having too many issues with my Allpro's I'll try his HD version arms.

 

No. My answer wasn't meant to be secretive or cryptic. Just didn't want to speak for him. But I can elaborate some.

Marlins arms are made from A36 steel which is different from some other aftermarket manufacturers who may use chromoly steel.

Many of the chromoly arms are expensive and have gussets. The chromoly steel material is expensive, and the gussets may be necessary when fabricating with that metal. But the gussets are NOT necessary for A36 steel. The A36 will have some flex in it, where the chromoly is more rigid and will not.

Marlin asked me if I had ever seen a Toyota factory a-arm break at the welds. It's folded sheet metal mind you. I told him in seven years watching this from I've not seen it.

I asked Marlin to comment on why he thought the SPC "Built right" arms were breaking in the past. This should be obvious to anyone, but there were defects in how they were fabricated, and he explained to me why.

 

A36 Steel and Chromoly have the same elastic modulus, meaning the tensile elasticity, or the tendency of an object to deform along an axis when opposing forces are applied along that axis; it is defined as the ratio of tensile stress to tensile strain is the same. This means both will yield about the same amount when a force is applied.

However, in fact, A36 is more likely to snap than Chromoly. Check out the Tensile strength compared between the two:



A36 does have lower yield strength which means it will deform easier/further but at that point it stays bent and your UCA's are toast. Even the Tensile Strength of A36 is lower which means it's more likely to break when stress is applied which contradicts what Marlin is saying about the steel itself.

Now, like I said above, if Marlin uses significantly (roughly 30-40%) more steel in his UCA than he can compensate for some of the qualities of the steel he is using. However, that doesn't make his arms superior. It means they have different characteristics that may be superior to some and inferior to others depending on the applications. What I'm gathering is that he does use more steel which leads to a fairly strong arm that is easier to weld, since it's commonly known that 4130 is harder to weld, which gives his arms the characteristics he wants. However that doesn't make them stronger than a TC UCA and, given the material properties, I'd guess in a bench stress test his arm will bend or break before a quality chromoly part. That's not necessarily bad, since he does make an HD version that would probably hold up to the TC arm's steel better, but it is something people should be aware of.

Again, without bench testing though who knows how much difference the tolerance between the two to abuse really would be.

I bent the fuck out of my stock arms on one impact. I'd rather not do that on a set of aftermarket arms. I hate comparing anything to the stock arms. It's like comparing yourself to the slow person at work lol.

Edited for attempt at clarity at a Science I am not an expert in lol.

 

BTW bent UCA's often go unnoticed unless the bend is enough to severely effect the alignment. I know the mechanic that put my drivers side front end back together thought the stock UCA was straight until he attempted to align it. He's an experienced mechanic, and without the arm failing or being bent horribly, he says it's almost impossible to visually tell something is wrong until you try to align the truck. That's also something people should be aware of .

 

Maybe I didn't explain myself well, or maybe you misunderstood. Nobody is saying that Marlins arms are stronger than the Chromoly alternate market versions. And in no way did I interpret anything I was told as such.

From the chart, chromoly steel has a higher yield strength, and higher tensile strength and a stronger weight to strength ratio. It is also a lot more expensive when it comes to materials purchase. Probably the main reason competitors products using 4130 cost so much more.

In my estimation, Marlins arms will work for 99% of folks out there.

You remarked you bent your stock a-arms from one impact. They are plenty strong for what they are. I think it's fair to say that when you abuse your truck and jump it, or hit things at speed, shit breaks.

 

That chart also lists average cost. Chromoly isn't a whole lot more money. It's all preference from the builder and what they are trying to do. The steel Marlin uses is easier to work with but a little weaker. It's similar to the discussions on here between DOM and HREW tubing except the cost difference is really on the time it takes to do it right rather than the material itself.

99% of trucks on here are pavement princesses, let's be honest lol.

I never said the arms won't work but it's great for people looking to understand the differences between his base arms, his HD arms, and the other options out there.

No jumps for me lol. I hate how on TW every time something like this comes out guys like you have to turn all white knight, for some silly immature reason, for a product you bought and try to save you damsel in distress product from the mean man making comments about it that are based on fact. I'm not here to call this product shit. I looked at buying it, and in the future may still purchase it if I'm not happy with what I did buy, and I think I've contributed more than 99% of people who are on this thread to figuring out exactly what this product is because Marlin does not list all the details.

If you must know my bend was one slip on a rock on a hill offroad. My truck was traveling roughly 5-10 mph when it happened. There was snow on the trail and I hit a hidden rock on a trail I hadn't run before. The truck went 90 degrees from going straight to going sideways and hit another rock I did know about and I was trying to avoid. It was the second rock and a blow straight on the center of the rim that slightly bent my spindle and UCA. I was able to drive the truck out. It wasn't a case of a torn apart front end from being an idiot. It wasn't abuse. Sure, I could of went slower, but I was doing exactly what I could to get down that hill and not use my brakes in slippery conditions. I was geared all the way down and what happened happened. It could happen to anyone here in the same situation that goes offroad. I was mid pack in a group of trucks and everyone on the trail agreed it could of happened to anyone. The only reason it happened to me was because I was the first LB truck to tackle that hill. I'd be willing to bet you abuse your truck more than I abuse mine given your signature, no offense .

Edited for grammar

 

Oh, and let's be realistic. Do you know how hard it would be for Marlin to add a little gusset on one side of the stock style arms he sells? Not hard, and there would be benefits. He likely won't though and anyone who does bend the arms going for the cheap version will probably receive some compensation from him to go up to the HD's because Marlin does honestly seem like a nice guy. Leaving that weak point is probably not a big deal, especially given the price, to most on these arms but it would be a concern to someone like me. It should be said ahead of time though that the weld on the bushing is a weak point, as is the material used, on these arms but the true amount of structural difference is likely fairly small for someone who sticks to gravel roads rather than rutted trails. Once you get into stuff like that the HD arms or something made of chromoly would be a better bet. Let's just leave it at that.

 

Yeah, I checked out his build thread after and it looks like he took them off. As for the white knight comment you know what I mean. If you try and talk about some products on here immediately people pick sides for some reason instead of talking things out. It's frustrating that, for whatever reason, those comments have to come out which seem more biased then fact based but whatever, it's a free forum.

BTW I was very lucky to be able to drive out. In all reality you are more likely to bend the spindle than the UCA. If you do anything to the UCA it'll probably move to far to be driven home, whether snapped or bent. Mine is bent so slightly it's still functional on the truck while I wait for coil overs .

If anything what I was hoping is that maybe Marlin would reinforce that weld. Feedback and all that, but I understand he has a method to his madness and he can do whatever he wants. It'll be interesting to see what the feedback is in a year or two after a few guys really push these arms on the Tacoma.

 

@Sterdog and @Crom thanks for the good discussion. I'll just add my uneducated interpretation of the differing designs.

The gussets used on UCAs that have them appear to primarily be protecting the *weld* as they extend only a short way along the UCA tube. You can still bend a UCA with a gusset further down the tube. To reduce bending under stress you need a stronger *tube*. As discussed that could be from stronger material or greater material thickness or tube diameter.

If I choose a stronger material for the tube but that material results in weaker welds or at least welds that are not as strong as the material then I better put on a gusset or there is no point to having used the stronger material. My (possibly wrong) interpretation is that those using 4130 need to use gussets to make the weld as strong as the rest of the arm. JBA using A36 is able to reliably produce a weld that is as strong as the rest of the arm without the need for gussets. The JBA arm could be weaker over all, but the point is the gusset wouldn't make it any stronger.

So to me the gussets question is totally separate from how strong a arm is or what its intended use is. You use a gusset if you need to protect the weld - i.e. if the weld is the weakest part of the design. If the weld is as strong as the tube itself then the gusset really doesn't add anything.

So my *guess* is the 4130 material and tube strength compared to the filler material and welding technology used on something like a TC would result in failed welds before bent tubes and so they put a gusset on. In the JBA case the tube would bend significantly before the weld ever failed. These statements say nothing about the overall comparative strength of the UCAs. They only address the issue of whether a gusset actually helps a particular design. Because of the different materials and designs it is quite possible one design very much needs a gusset and the other does not regardless of which one is stronger as a whole.

 

That could very well be possible. Like I said too, it's also more difficult to achieve a good weld on chromoly steel. All of those things likely factor into the design.

I do think though that either way it does suggest that if you offroad anything more than the odd logging road it might be a good idea to step up to the HD design from Marlin.

 

There seem to be a bunch of questions about JBA uca's concerning quality and design. Have the other companies that produce quality uca's disseminated detailed info concerning their manufacturing, design specs, quality control and failure rates. Not trying to bash anyone it's just that no one seems to break down the other manufacturers concerning their products like we are doing to JBA. They have had their issues but they have gone above and beyond to make people happy.

 

Exactly. Plus all the major existing UCA companies can answer any of those questions with a pretty exact answer without any guessing. I think it'd just be nice to see the same level of information and support from JBA.

 

mine are adamantium

 

Bitching.

 

Thread seemed to die once additional specs were requested...any update?

 

went for alignment today but did not have any success so sorry, can't supply numbers yet for my newly installed HD HC JBA UCA's



my front driver side cam tab is flattened out and cracked, so will have to take care of this first. sigh, it never ends. TC cam tabs next project

 

Yes. Easy to do. Do one at a time. No drama. Use wheel bearing grease.

 

Jack truck
Place jack stand under frame,
Remove wheel,
Mark alignment cams,
Unbolt shock from LCA,
Then loosen and remove one cam bolt,
Clean, grease, and put back.
Repeat for other bolt.
Reassemble.
Do otherside of truck.

Some guys have had success with straight up unbolting the camber bolt with a truck on its own weight and all. I tried that and I was not successful.