4 link UCarms - strong enough?

rokker

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Originally I had planned on using 7/8" x 7/8" heims in 1.5 - .120 4130 w/ a 5/8" bolt then after welding the bungs in running both arms inside equal lengths of 1 3/4" .120 4130 to make the UPArms stronger - when mt heims came in, the heims were actually only 3/4" x 3/4" w/ a 5/8" bolt - question is - If I use 3/4 x 3/4 heims inside of 1 1/4 .120 4130 and than double up with 1 1/2 .120 4130 - will the 3/4" x 3/4" heims be strong enough?? Or should I really re-order the 7/8" x 7/8" heims? Recomendations please...

Thanks
 

rokker

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I have no idea about the loads, - I actually just got an answer from the guy who built like 93% of this truck and he said that the 3/4" x 3/4" would be fine - anyone disagree and why?

Thanks
 

FABRICATOR

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Without seeing exactly what you are up to, it's not logical that anyone tell someone else what size rod ends to use. What happened to your plan? You planned on 7/8 x 7/8, got 3/4 x 3/4, but the bolt size is 5/8? Most high quality rod ends are available with a bigger shank than the hole. Like 7/8 male thread x 3/4 eye hole. A high quality end this size has a high load rating. A full length 1.5 x .120 tube inside a full length 1.75 x .120, both 4130, is overkill for the UCA. There is no substitute for cubic inches and this goes for tubing too. If the UCA is straight with nothing else hooked to, binding, or hitting it, the 1.75 x .120 4130 by itself is very strong.
 

ntsqd

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WHOA, one more post to go & I turn over the eon mark. Didn't even know that.
 

rokker

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I should have worded my 2nd response differently... the individual that I spoke too actually engineered the whole truck and built 95% of it (Im just putting it together/finishing it up - making the UCArms and LCArms based on his mockups, making and mounting shock tabs etc...) he set up everything for the truck, motor mounts, transmission mount, designed the 4-link etc... he knows what engine, transmission, tires I am running and says that 3/4" x 3/4" heims are fine for the UCAs and thats what he uses on his kits. My bungs for the 3/4" x 3/4" heims fit 1 1/4 .120 tubing, he recommended that I run 1 1/2 .120 over the 1 1/4 .120 - if this is overkill thats fine - I would rather have my truck be too strong than too weak...
 

FABRICATOR

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Congratulations Thom! At least there was one thing on this thread that made some sense.
 

rokker

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Fabricator - Im not trying to start an argument here but what exactly doesnt make sense to you?

Thanks
 

toddz

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I think he's frustrated like the rest of us reading your posts. We don't know enough information about your 4 link application to give you a good answer to your questions.

Todd Z.
 

FABRICATOR

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That about sums it up. There is also contradiction from beginning to end and the whole thing looks like an argument waiting to happen. Questions and follow up comments like this make input from anyone, right or wrong/good or bad, a waste of time.
 

CRAIG_HALL

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So you use two tubes to get more strength but you still got the smaller heim???Get the bigger heims and bigger O.D. bungs to allow the use of 1-5/8" or 1-3/4" x.120 tube.
 

geoff

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you are correct that the 1 1/4 .120 wall is too weak, but not knowing your app who knows what you are doing?

We did a full analysis on the rear of a toyota that had 33s, we decided to use 1 1/2 .250 wall. sleeving tubes is just a ghetto way of doing this. The 3/4x3/4 heim had a factor of safety of 8
 

rokker

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my bad guys for speaking in riddles and not being clear in my questions - I appreciate everyone trying to help... let me try again

my application is a 98 ranger - completely gutted - 4130 caged front to back, Im going to be running 33s on it, it has a 351w - 500 hp, C6 transmission, I do not know my dynamic or static loads sorry, I am asking if 3/4" x 3/4" heims are rated strong enough for the UCarms on a 4 link for this type/size of vehicle - also factor of safety rating of 8, can you please explain how you came about with a rating of 8... Im a software engineer not a mechanical engineer so this is unfamiliar to me.

Thanks Again
 

CRAIG_HALL

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Sound like you got plenty of power-I'd hold out till you can get the larger heims.I'm using 3/4"x7/8" high misalign with a direct 3/4" bolt on the axle and a custom bung for 1-5/8" x .120 wall tube. 97 ex.cab ranger,stock explorer 5.0 and c-4.
 

V8Ranger

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I'm not sure if your asking what a factor of safety is or how he got it but the factor of safety is obtained by dividing the ultimate stress (max stress that the part can withstand before failure) of the by the working stress (the stress that the part actually sees). For example a part that can hold 100 psi but sees only 20 psi has a factor of safety of 5. He probably obtained the value from a bunch of analysis and calculations that can be very complicated and lengthy. I'm not sure if that helped you out but your rather simple question has a pretty complicated answer with tons of variables (mounting positions, locations, design, etc). If your unsure and don't want to spend the time to figure out the loadings I'd probably just step up to the bigger size.
 
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