Aluminum Link Deflection

[matth_85]

Measurements are as follows:

Front:
Uppers-40" eye to eye
Lowers-33" eye to eye
4" of separation at cab
8" of separation at axle

Rear:
Uppers-32" eye to eye
Lowers-35" eye to eye
5" separation at cab
9" separation at axle

The separation #'s are approximate as I was measuring by myself and just eyeballed it.

Front springs are as follows:
14" 125 over a 16" 250 shocks are 14" travel

Pics to follow.

Belly height is 22.5"

 

[matth_85]

I'm the most concerned with the front. I have thought all along the rear issue was coming from the front. But like I said the anti rock "fixed" that.

Forgot to measure belly height at ride height. Maybe I'll muster the energy to go measure it. Feeling kinda lazy...

 

[payne97]

The way your front is set up your pinion will roll up alot of builder will do that so it help drive shift angle
Aluminum links will fix thats why ever body talked about TC front axle moving
Looks like your rear link is bend if so I would guess u have 6061 links
just my 2 cents

 

[Neal3000]

7075 bends too

 

[al1tonyota]

7075 bends too

X2

 

[FlatlandFSJ]

Leafspring kid here to learn **** :****:

"Uppers-40" eye to eye
Lowers-33" eye to eye"

This is the issue right? Arent most lowers ~ 25% longer then the upper? The longer upper is causing the extra roll up? Ive seen this in a few other builds, do they do it just to help drive shaft angle at full droop or is there something I'm missing?

I just recently started really looking into 4 links, most exp Ive had with one is linking a mini truck...

 

[redneckengineered]

Measurements are as follows:

Front:
Uppers-40" eye to eye
Lowers-33" eye to eye
4" of separation at cab
8" of separation at axle

Rear:
Uppers-32" eye to eye
Lowers-35" eye to eye
5" separation at cab
9" separation at axle

The separation #'s are approximate as I was measuring by myself and just eyeballed it.

Front springs are as follows:
14" 125 over a 16" 250 shocks are 14" travel

Pics to follow.

Belly height is 22.5"

I know you and I have already talked but based on your numbers and looking at your pics here's my .02.

Front: Uppers are too long. Lowers are way to steep at ride height but I would concentrate on fixing the uppers as priority #1. I can also almost guarantee that your lower springs are too soft. Personally I think it's better to go softer than what you think you need then get your ride height with some additional preload on the shocks. I talked to a good friend last night that has done a lot of 4-links with a HP front axle like you have and he said he'd bet anything your issue happens when the driver side is completely compressed and the passenger side is completely flexed out. Set your caster at about 10 which should nose the pinion down just slightly and go from there.

 

[CHASMAN9]

Currently has a 250 lower and a 125 upper. I'll have to measure lengths. That's much heavier on the lower than what I ran on my previous buggy which I never weight but should have been a touch heavier.


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To run 250 lowers and a 125 upper seems like quite a bit of difference to me as you mentioned break-over point. Those uppers seem to soft to run such stiffer lowers creating body roll in my opinion. I had this problem badly on another buggy and felt like it was doing to roll on flat ground. Changing these rates might take out some of that roll and remove the leverage being created thus eliminating some frame flex. Also, running a anti sway might take some of that body roll out. Just my opinion which ain't worth much.

 

[matth_85]

Thanks for the input. I think the plan is going to be shorten the uppers and put a new truss on it that will allow them to be shorter.

In order to flatten the lowers I'd have to lower the mounting point on the frame or raise it on the axle. Raising it on the axle will kill my separation. And theres no where to go on the chassis side.

If I can just get it better, which what you said should work perfect, I will be happy.

Like I said, the buggy works extremely well. Just when I finally got comfortable with it I have been quite hard on it and it's started showing some imperfections. Nothing that can't be fixed.

Guess I will get to work and report back. I have a call in to the builder. I will also let you guys know his reasoning behind the design if I find out. I am curious myself...

 

[matth_85]

Currently has a 250 lower and a 125 upper. I'll have to measure lengths. That's much heavier on the lower than what I ran on my previous buggy which I never weight but should have been a touch heavier.






To run 250 lowers and a 125 upper seems like quite a bit of difference to me as you mentioned break-over point. Those uppers seem to soft to run such stiffer lowers creating body roll in my opinion. I had this problem badly on another buggy and felt like it was doing to roll on flat ground. Changing these rates might take out some of that roll and remove the leverage being created thus eliminating some frame flex. Also, running a anti sway might take some of that body roll out. Just my opinion which ain't worth much.

Oh I know the springs are wack. I did it as a "quick fix" It had a 175 upper of the same length and I swapped them just to try it. It's not right but it is better than it was. It doesn't really have body roll anymore since the rear anti rock. In fact it's quite stable and handles well. I was running 60 ish around the main trails in Harlan this weekend and it felt like a Sunday drive.

The reason I changed it was because with the 175 I couldn't even get the spanners tight to the spring and it would come unseated at flex.

I am going to order new springs, put limit straps on it, and turn the pinion down a touch first thing and see what that does at the local park. If that doesn't fix it I will shorten the uppers and change the truss.

 

[redneckengineered]

Oh I know the springs are wack. I did it as a "quick fix" It had a 175 upper of the same length and I swapped them just to try it. It's not right but it is better than it was. It doesn't really have body roll anymore since the rear anti rock. In fact it's quite stable and handles well. I was running 60 ish around the main trails in Harlan this weekend and it felt like a Sunday drive.

The reason I changed it was because with the 175 I couldn't even get the spanners tight to the spring and it would come unseated at flex.

I am going to order new springs, put limit straps on it, and turn the pinion down a touch first thing and see what that does at the local park. If that doesn't fix it I will shorten the uppers and change the truss.

Sounds like a plan. I like taking things one step at a time then checking to see the changes. If step 1 doesn't make a big difference go to step 2 and on down the line. If you change everything at once it's hard to quantify what all is making the difference for you. When you turn that pinion down (which I think needs to be done) be sure it doesn't bind at full drop out. My eyeballs are telling me that's a 1350 yoke, might want to go to a 1410. It will probably handle better with a little more caster too. I have a HP60 front just like yours with a double tri 4-link and mine is set at 10.

If you want to check clearance before you leave the shop you could really just pull the shock and bumpstop from the driver side and leave the passenger side intact then flex it out. That'll save some time.

 

[Neal3000]

When you re-do your uppers if i was you i would totally redo the brackets, there's really no need to have that much triangulation, i'm not sure how close they come to your oilpan at full stuff but you can probably pick up some uptravel if you make them fit around it

 

[redneckengineered]

When you re-do your uppers if i was you i would totally redo the brackets, there's really no need to have that much triangulation, i'm not sure how close they come to your oilpan at full stuff but you can probably pick up some uptravel if you make them fit around it

Yes. Great point.

 

[CHASMAN9]

My eyeballs are telling me that's a 1350 yoke, might want to go to a 1410. It will probably handle better with a little more caster too. I have a HP60 front just like yours with a double tri 4-link and mine is set at 10.



Good call, but I would still leave the transfer case yolk 1350 for the "weak link" to break before shafts and gears.

 

[matth_85]

All 1350 stuff and it has offset joints in it. It's really nowhere close to even needing that currently.

Also, I would spread the uppers out some if I were doing it. I don't know what I am doing really, but just basing off of what I have had and done in the past. It gets nowhere near the oil pan though. From that aspect it's a good design...lol

 

[Neal3000]

It doesn't gt near the pan probably because of where your bumpstops are set at

 

[payne97]

Longer lower links would help n alot of way