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Questions about stretching the frame on a TJ

Stevemack

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Just for clarification. Maybe I’m reading into it too much. Are we referring to a “wheelbase stretch” or are you really referring to cutting and stretching a frame?

***EDIT*** just re-read your first post. Yes you are talking about a frame stretch. Too keep it in laymen’s term, because that’s what I am, that seems like a lot of work, tedious work, and expensive if not doing it yourself.

And, as you can tell, there is a heavy Savvy bias here. Not saying that’s a bad thing, but there are other suspensions out there that work.

Many people on this side of the country, and all over really, run Clayton suspensions and are very happy with the quality, geometry and operation.
 
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mrblaine

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Just for clarification. Maybe I’m reading into it too much. Are we referring to a “wheelbase stretch” or are you really referring to cutting and stretching a frame?

And, as you can tell, there is a heavy Savvy bias here. Not saying that’s a bad thing, but there are other suspensions out there that work.

Many people on this side of the country, and all over really, run Clayton suspensions and are very happy with the quality, geometry and operation.
You make it sound like there is no Clayton out here.

1576254305396.png


Clayton has the same issues most long arm kits do, the geometry has been compromised to fit the arm length under the rig. There is no way to achieve even close to excellent rear geometry with the cargo step in the way which necessitates a compromise of the vertical separation at the front of the rear arms. That and the only reasons to run a radius arm front is because you like a company, don't know any better, and you want arms that are too long to get away from them. Clayton didn't solve the problems RE has, they are just packaged with a different shape arm.
 

someguysjeep

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i'm curious of this formula of wheelbase to belly ratio.

i plan on 35's on JK Rubi 44's.
i would love to entertain the idea of 37's, but so many suggest the C's and /or Bj's won't last, and i don't plan on babying it.

front is pretty much built, i'm not moving it. so the rear is my shot to open up the wheelbase.
4 link mid arm, a back 1/2 kit and fuel cell.

so whats the formula for 35's? i'm projecting the frame to be close to 22" that'd give me 20"ish under the belly.
my plan was to try and push the rear axle back 9-10" if able. and not opposed to a couple more if can go further and it's beneficial.

so that would have my #'s at 35" wheels / 102-103" WB / and 20" belly height. how does this jive against this formula?
 

someguysjeep

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Typically the backhalf kit is a solution if running coil overs.

IIRC, you can likely pull off that wheelbase with a stretch tank if staying 1/2 ton. Or use Curries.


yah i took up in an odd direction, and ended up with ORI's for the front end and will likely do the same in the rear, they'll require towers or hoops.
i considered the Alien 11gl tank GR offers, but the cost is steep. and i was able to make my own cell.
 

mrblaine

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i'm curious of this formula of wheelbase to belly ratio.

i plan on 35's on JK Rubi 44's.
i would love to entertain the idea of 37's, but so many suggest the C's and /or Bj's won't last, and i don't plan on babying it.

front is pretty much built, i'm not moving it. so the rear is my shot to open up the wheelbase.
4 link mid arm, a back 1/2 kit and fuel cell.

so whats the formula for 35's? i'm projecting the frame to be close to 22" that'd give me 20"ish under the belly.
my plan was to try and push the rear axle back 9-10" if able. and not opposed to a couple more if can go further and it's beneficial.

so that would have my #'s at 35" wheels / 102-103" WB / and 20" belly height. how does this jive against this formula?
For our area and the wheeling we do which is predominately Johnson Valley/Parker type stuff, you would be a bit low for 35's. That WB is very doable in a TJ without hacking up the tub. We like 104 and 22-23" frame height for 37's. The belly is only about 1.5" lower than the frame at the middle.
 

someguysjeep

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For our area and the wheeling we do which is predominately Johnson Valley/Parker type stuff, you would be a bit low for 35's. That WB is very doable in a TJ without hacking up the tub. We like 104 and 22-23" frame height for 37's. The belly is only about 1.5" lower than the frame at the middle.

whats your opinion of the JK Dana 44 front axle and it's ability to perform well with 37" wheel.
and 104 sounds great. i'll put the axle to the bumper if it's beneficial. but i gather i don't want to out stretch the 35's if that truly is my limit.
 

mrblaine

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whats your opinion of the JK Dana 44 front axle and it's ability to perform well with 37" wheel.
and 104 sounds great. i'll put the axle to the bumper if it's beneficial. but i gather i don't want to out stretch the 35's if that truly is my limit.
I built a TJ on 37's at about 102ish with beefed up JK Rubi 44's. The owner is not clueless, and drives it to a lot of places to wheel. He wheeled it a fair bit.
This was during the front axle build.
1576288259073.png

Finished product.
1576288332974.png

Fairly light weight rig for what it is. All aluminum armor, bumper and skids. Light winch. Aluminum bead locks.
To date-
3 sets of alloy rear axles due to bending.
1 factory JK locker replaced with a 35 spline ARB
Both rear brake rotors due to wobbling axle wearing them oddly.
Rear brake pads due to being worn at an angle from wobbling axle.
1 35 spline shaft is wobbling.
1 set stock ball joints
1 set Synergy ball joints
1 set Dynatrac ball joints
1 rebuild kit for upper Dynatrac ball joints.
1 set Superior JK front axles
1 set alloy large u-joint high strength front axles.
Finally went to RCV and they are now clunking badly.
Steering takes a beating due to the design and the what the knuckles dictate it has to be. As such, the cylinder is mounted to the tie rod and gets hammered. But, it needs to be highway friendly so not much else to do.

In short, if you plan to wheel it where 37's make a difference, be prepared to do a lot of high dollar maintenance. I believe only the rear locker has actually failed on trail. Everything else has just worn out or bent.
 

someguysjeep

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that's what i needed to see, thank you.

now i can quit dreaming, and be assured i didn't leave some tire size "on the table".

i've been draggin my feet with my tire purchase, himmin and hawwin over this, trying to convince my self the TJ is light enough, but really it's not.

the great news is the price diff between 35 and 37 means i got to call and order my new Savvy front bumper MON.
 
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mrblaine

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that's what i needed to see, thank you.

now i can quit dreaming, and be assured i didn't leave some tire size "on the table".

i've been draggin my feet with my tire purchase, himmin and hawwin over this, trying to convince my self the TJ is light enough, but really it's not.

the great news is the price diff between 35 and 37 means i got to call and order my new Savvy front bumper MON.
Be aware that folks tend to think they wheel hard no matter how hard they actually wheel. Every single time I have posted the above, there are 10 examples of folks wheeling "hard" on 37's and 40's that beg to differ. I tried to convince Cody Seler that his JK front wasn't going to cut it on his mid arm build. He has broken something every time out on 37's but he actually wheels hard.
 
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someguysjeep

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none of this stuff is cheap, and i'll accept the advice.
i love the build, but replacing components constantly is not desirable. i'd rather run a little shorter and a little stronger and try to minimize the carnage best i can.
 

rasband

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Here I am wondering how to pull in the rear of my LJ a bit - seems like we should mash up our rigs and see what baby (or monster) comes from it ;)
 

Fouledplugs

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Be aware that folks tend to think they wheel hard no matter how hard they actually wheel. Every single time I have posted the above, there are 10 examples of folks wheeling "hard" on 37's and 40's that beg to differ. I tried to convince Cody Seler that his JK front wasn't going to cut it on his mid arm build. He has broken something every time out on 37's but he actually wheels hard.
Ive been thinking about this and trying to not go to a 60 right off the bat in my mind. The only other axle I can think of that retains the somewhat equivalent axle housing size but increases in strength is a spider 9. But damn that’s a really expensive solution. It would be close to problem free considering the depth in which one can be built. Any other solutions, other than a 9 inch, for a rig on 37’s?

Not sure how much experience you have with the SpiderTrax axles, are they more or less ground clearance than the 44? 60?
 

mrblaine

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Ive been thinking about this and trying to not go to a 60 right off the bat in my mind. The only other axle I can think of that retains the somewhat equivalent axle housing size but increases in strength is a spider 9. But damn that’s a really expensive solution. It would be close to problem free considering the depth in which one can be built. Any other solutions, other than a 9 inch, for a rig on 37’s?

Not sure how much experience you have with the SpiderTrax axles, are they more or less ground clearance than the 44? 60?
It is going to be tough to beat a Currie HP RJ rear 60 with a set of the Super 60 gears in it. There again, depends on what you are going to be doing.
 

someguysjeep

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Carbon had what looked to be good deal on the 44/60 RJ combo, it's tempting.
but maybe the next build.
 

Stevemack

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You make it sound like there is no Clayton out here.



View attachment 129141

Clayton has the same issues most long arm kits do, the geometry has been compromised to fit the arm length under the rig. There is no way to achieve even close to excellent rear geometry with the cargo step in the way which necessitates a compromise of the vertical separation at the front of the rear arms. That and the only reasons to run a radius arm front is because you like a company, don't know any better, and you want arms that are too long to get away from them. Clayton didn't solve the problems RE has, they are just packaged with a different shape arm.

I know Clayton is “out there”. Just “in here”, sometimes the Savvy echo chamber is overwhelming...😁

I get it. You designed it and you’re probably the only suspension designer/builder that participates in forums. Your knowledge is deep. And we’re lucky you share it. But I would surmise that’s why the echo is so loud.

I lost you on the cargo step comment...

Vertical separation of rear arms, frame side: remember I’m not a suspension designer, keep it simple for me.

Savvy mid -arm, rear frame side brackets “look” exactly like mine. Based upon an image from Savvy website of their “TJ mid arm kit“. I get there might be minut differences in the arm angle because of the arm length, but vertical separation seems the same. They’re both a weld on combo, upper and lower bracket... My axle side brackets and bridge/truss seem to be at the same locations as Savvy also...

And even I know to compare apples to apples. I don’t expect the same performance between a radius arm and 3 link setup. I have a 3 link is sitting in the shop waiting to go in. Debating on whether it’s will be enough of a difference to go through the install. So far, following similar wb’s and equipped rigs in my group, my radius arm hasn’t been a factor in my being successful on the same trails/obstacles.