How's my numbers?

[Treefrog]

i got spring rates i can figure oure mounting location but what is sliderstop?

The dual rate stop. Its the part that stops the slider that goes between the springs. If you don't have one, just put it at the full up travel.

 

[chaplinfj60]

The dual rate stop. Its the part that stops the slider that goes between the springs. If you don't have one, just put it at the full up travel.

funny story,,,,,, i had no idea what that piece was till last weekend, so i did nothing with mine, now the back is a 150 over 150 so a mute issue if i understand how they work but the front is 175 over 150 still the stop is all the ways to the top of the shock and does nothing. hahahha

 

[Treefrog]

funny story,,,,,, i had no idea what that piece was till last weekend, so i did nothing with mine, now the back is a 150 over 150 so a mute issue if i understand how they work but the front is 175 over 150 still the stop is all the ways to the top of the shock and does nothing. hahahha

The effective rate of two springs in series is (S1*S1)/(S1+S2). So the rate in the rear would double when it hits the stop. The front would go from 81 to 150.

 

[chaplinfj60]

The effective rate of two springs in series is (S1*S1)/(S1+S2). So the rate in the rear would double when it hits the stop. The front would go from 81 to 150.

so i dont think i understand but i think i might. so should i move my slider stop down on the rear, if so how much and more important how do i figure that part out. is it trial and error, is it flex it out. is there a math formula. and maybe i have heard these terms before but i had no idea how to apply them to me.

 

[chaplinfj60]

i just did a quick search its pretty easy now that i know what to look for. ty again bud. again love this site

 

[Treefrog]

so i dont think i understand but i think i might. so should i move my slider stop down on the rear, if so how much and more important how do i figure that part out. is it trial and error, is it flex it out. is there a math formula. and maybe i have heard these terms before but i had no idea how to apply them to me.

Up to you if you want to move it. Trial and error mostly. The closer to the stop it is, the more it will help absorb larger drops, but it will be stiffer in the rough, will resist roll more, and resist upward articulation.

 

[chaplinfj60]

Up to you if you want to move it. Trial and error mostly. The closer to the stop it is, the more it will help absorb larger drops, but it will be stiffer in the rough, will resist roll more, and resist upward articulation.

that was my next question and you answered it perfectly. i would like my rear to come in a little bit especially when bouncing around with some speed, but not much at all.

 

[Treefrog]

that was my next question and you answered it perfectly. i would like my rear to come in a little bit especially when bouncing around with some speed, but not much at all.

Just remember that the shock portion of the coilovers may need adjusting too

 

[chaplinfj60]

a local buddy here showed me some out of the box thinking, at least it opened my eyes and helped me not get stuck. my front upper link was kicking my ass when i had the frame end link mount on the frame, just could not get numbers to do what i wanted but more important i could not get anything to line up unless i went taller. so he showed me his and i adopted that idea. my upp frame end link mount is outside my frame under my rock slider. that helped so much

thats all for friday late day thoughts :^)

 

[YeeP]

Front:

Rear:

I am ready to start building the front, so that is my main concern right now, but I would like some "balance" so feel free to comment on either.

Thoughts on front:
1) Front Lower axle side, Y Dimension: I have not determined my font axle width, which will at least partially be determined by steering clearance at full bump, so I may be able to go farther outward with the lowers, but I have mimicked a rig that has similar steering amount and overall width to where I would like to end up.
2) I like the "strength" of a batwing style triangulated bracket on the lower frame side, but this would lock me in on the Y dimension there as well. Thoughts on triangulation there and stuff would be helpful.
3) I don't like having this much pinion movement.
4) I don't see anything showing me what me roll axis angle at ride height would be. Just kinda curious.
5) Anything I'm not thinking of/can improve on?

 

[Treefrog]

Front:

Rear:

I am ready to start building the front, so that is my main concern right now, but I would like some "balance" so feel free to comment on either.

Thoughts on front:
1) Front Lower axle side, Y Dimension: I have not determined my font axle width, which will at least partially be determined by steering clearance at full bump, so I may be able to go farther outward with the lowers, but I have mimicked a rig that has similar steering amount and overall width to where I would like to end up.
2) I like the "strength" of a batwing style triangulated bracket on the lower frame side, but this would lock me in on the Y dimension there as well. Thoughts on triangulation there and stuff would be helpful.
3) I don't like having this much pinion movement.
4) I don't see anything showing me what me roll axis angle at ride height would be. Just kinda curious.
5) Anything I'm not thinking of/can improve on?

1,2: The recommended minimum convergence angle is 40, you are at 77, so you have a bit of room in the front to work with there.
3) Try playing around with the lengths of the links relative to each other.
4) The red Xs along the travel = 0 line are the ride values. For the ends it is called roll slope, for the vehicle it is called roll axis. Roll slopes are ploted, axis is reported just above the center column of graphs
5) keep in mind that the rod ends have height to them, so a 16.5" mounting height may be more like 15" of clearance.

 

[YeeP]

1,2: The recommended minimum convergence angle is 40, you are at 77, so you have a bit of room in the front to work with there.
3) Try playing around with the lengths of the links relative to each other.
4) The red Xs along the travel = 0 line are the ride values. For the ends it is called roll slope, for the vehicle it is called roll axis. Roll slopes are ploted, axis is reported just above the center column of graphs
5) keep in mind that the rod ends have height to them, so a 16.5" mounting height may be more like 15" of clearance.

1:2) Good point.
5) Yeah That is going to be a guess as well. It will likely be higher, but I will have to determine that once I have the brackets.

Treefrog any idea why I lost the lines in the up/down graph?


On the convergence angle - Are the angles shown for Upper and Lower considered to be the angle between the two control arms?
If so, that would mean that when measured from a line that is perpendicular to the chassis (ie. axle or crossmember), The angle would be half of that. Is that a correct assumption?

 

[Treefrog]

1:2) Good point.
5) Yeah That is going to be a guess as well. It will likely be higher, but I will have to determine that once I have the brackets.

Treefrog any idea why I lost the lines in the up/down graph?


On the convergence angle - Are the angles shown for Upper and Lower considered to be the angle between the two control arms?
If so, that would mean that when measured from a line that is perpendicular to the chassis (ie. axle or crossmember), The angle would be half of that. Is that a correct assumption?

Which lines are missing? It doesn't appear that any are. You may have set "Highlight Travel" to 0.

Yes, your assumptions are correct. The angles shown are the angle between the links in a projected view. The angle of a link to a cross member would be half of that.

 

[YeeP]

Which lines are missing? It doesn't appear that any are. You may have set "Highlight Travel" to 0.

It wasn't but I didn't know that was the trigger for the lines. I cycled it on and off and they are back. Thank you.

 

[Treefrog]

It wasn't but I didn't know that was the trigger for the lines. I cycled it on and off and they are back. Thank you.

Yeah, they were not visible on my devolpment copy either, but updating the values fixed it for some reason.

 

[YeeP]

Only concerned with the front right now...

Treefrog I know "better" is pretty subjective here so I'll try not to frame it that way.

Concerns:
1) I'm used to "God of suspension" PBB days where I should be aiming for a higher anti-squat. Do the anti-dive and anti-lift seem too low?
2) Unsure what to think about my roll center good/bad?
3) Although the pinion stays relatively straight, I guess that is not a huge advantage. It would be great if it actually rolled up when the suspension cycled down but I think I would need upper control arms longer than lower. That is actually doable for me but I don't see any large advantages. This vehicle will sit pretty low and the driveshaft U-joints should be fine within the range I have defined.n Thoughts?

Flexibility of defined values:
LOWER
Lower Frame X: Could go up to 36.5 without having to raise drivetrain. If I need more I can do it but have to lift transmission higher
Lower Frame Y: anything between 13 to 4.5
Lower Frame Z: Attempting to keep this value

Lower Axle X: Can go down (farther from zero in the negative aka in the direction toward the rear axle)
Lower Axle Y: I can go inward easily, trying to not go wider to allow better steering angle/reasonable axle width
Lower Axle Z: IF the axle is 19.5" center truly, a 19" would put the bracket flush with the bottom of axle. It would be nice to keep but I can go down if needed.

UPPER:
Upper Frame X: Pretty accurate, cant go any longer but could make shorter
Upper Frame Y: Very close between frame rail and header, may have slight amount to go inward
Upper Frame Z: I have probably 3 inches in either direction available here

Upper Axle X: Keeping this here for now, expect more flexibility once I build the ram mount, but could change
Upper Axle Y: Can go up slightly, any amount less would bring me too close to engine block
Upper Axle Z: The value I have here is the absolute lowest I can go. I can go up without issue if needed (relative)


Thank you!

 

[Treefrog]

Concerns:
1) I'm used to "God of suspension" PBB days where I should be aiming for a higher anti-squat. Do the anti-dive and anti-lift seem too low?
2) Unsure what to think about my roll center good/bad?
3) Although the pinion stays relatively straight, I guess that is not a huge advantage. It would be great if it actually rolled up when the suspension cycled down but I think I would need upper control arms longer than lower. That is actually doable for me but I don't see any large advantages. This vehicle will sit pretty low and the driveshaft U-joints should be fine within the range I have defined.n Thoughts?

1) I remember that thread being an entertaining read. Anti-dive is generally preferred to be lower since it leaves the suspension freer to react to bumps during braking, but yeah, that might be a bit to low.

2) Looking at the values under sprung mass cog may provide some insight. But higher RC means less roll, but more jacking forces.

3) In the front, pinion angle change is also caster angle change. So having it add caster in bump/pitch forward may be good to keep it from going positive. The pitch page can help with this I believe. Generally to have good behavior in bump and droop you want the arms to be close in length and with an IC on the opposite end of the vehicle.

What is the use case of the rig?

 

[YeeP]

1) I remember that thread being an entertaining read. Anti-dive is generally preferred to be lower since it leaves the suspension freer to react to bumps during braking, but yeah, that might be a bit to low.

2) Looking at the values under sprung mass cog may provide some insight. But higher RC means less roll, but more jacking forces.

3) In the front, pinion angle change is also caster angle change. So having it add caster in bump/pitch forward may be good to keep it from going positive. The pitch page can help with this I believe. Generally to have good behavior in bump and droop you want the arms to be close in length and with an IC on the opposite end of the vehicle.

What is the use case of the rig?

Mostly technical crawling. I do like to play around on roads between trails, but that is secondary to ability to climb.

 

[Treefrog]

Mostly technical crawling. I do like to play around on roads between trails, but that is secondary to ability to climb.

A higher roll center may be better in your application. It will reduce the need for a sway bar and reduce the lean when off camber . But it will give less warning that its about to tip over. It will reduce how hard you can corner.

 

[YeeP]

A higher roll center may be better in your application. It will reduce the need for a sway bar and reduce the lean when off camber . But it will give less warning that its about to tip over. It will reduce how hard you can corner.

Yeah I have read that and heard it. I would like to avoid needing a sway bar for multiple reasons. Ill tell you though, I cannot seem to find a way to get it much higher than my current guestimate below.

Any ideas?

 

[Treefrog]

Yeah I have read that and heard it. I would like to avoid needing a sway bar for multiple reasons. Ill tell you though, I cannot seem to find a way to get it much higher than my current guestimate below.

Any ideas?

Lowers closer to parallel, uppers angled more is the general approach.

 

[Broncofntc]

I'm new here and looking to improve the handling of my Bronco. I had a chance to run it out at the bonneville salt flats and some high speed dirt roads. It was spooky at 75mph

My first move will be to widen the front uppers at the axle to 7-9". Anyone have any suggestions beyond that? Mostly used for crawling but some high speed desert.

 

[Treefrog]

I'm new here and looking to improve the handling of my Bronco. I had a chance to run it out at the bonneville salt flats and some high speed dirt roads. It was spooky at 75mph

My first move will be to widen the front uppers at the axle to 7-9". Anyone have any suggestions beyond that? Mostly used for crawling but some high speed desert.

Spook how? Guessing oversteer and body wanted to roll?

 

[mano002]

Spook how? Guessing oversteer and body wanted to roll?

The first version of the 4link on my FJ40 had too much roll oversteer. I realized what it was after driving it on the highway and a semi passed me on the left and the wind pushed the body (body roll) and the truck turned towards the semi that was passing me.

 

[Diezl]

I built my rear 4 link with V3 quite a few years ago and now im going to 4 link my front. I recently got V6.7 and i put the same numbers in from my old v3 file and one thing i noticed is in the new version my antisquat is about half of what i got in V3. I put my front numbers in both versions and kind of the same thing about half of V3. Thought i remember someone saying you could use v3 for the front just antisquat becomes antidive. Now im questioning my old numbers and what is correct, made sure all numbers were the same. Anyone had this, or am i doing something wrong?

 

[Treefrog]

I built my rear 4 link with V3 quite a few years ago and now im going to 4 link my front. I recently got V6.7 and i put the same numbers in from my old v3 file and one thing i noticed is in the new version my antisquat is about half of what i got in V3. I put my front numbers in both versions and kind of the same thing about half of V3. Thought i remember someone saying you could use v3 for the front just antisquat becomes antidive. Now im questioning my old numbers and what is correct, made sure all numbers were the same. Anyone had this, or am i doing something wrong?

Drive and brake bias. V3 is all power at the end of the vehicle being looked at. V4+ it is adjustable. The values were 50% drive and 60% brake in the most recent version when it was uploaded. They are in the center column of inputs, towards the top.

 

[Treefrog]

The first version of the 4link on my FJ40 had too much roll oversteer. I realized what it was after driving it on the highway and a semi passed me on the left and the wind pushed the body (body roll) and the truck turned towards the semi that was passing me.

I tend towards driving in a controlled circle in a parking lot. If it gets smaller as you increase speed, oversteer, larger means understeer.

 

[Broncofntc]

Spook how? Guessing oversteer and body wanted to roll?

Yes both. I move the horizontal separation of the front uppers to 7" and it tightens up but i need to get the roll center higher and settle the instant center through the travel cycle.

 

[Treefrog]

Yes both. I move the horizontal separation of the front uppers to 7" and it tightens up but i need to get the roll center higher and settle the instant center through the travel cycle.

Are you able to widen the front uppers at the axle any more? Lowering the rear upper axle mounts would make the front's roll center seem higher. Is it an issue with the instant centers moving or the pinion angle changing? I'm not really seeing how the ICs moving would make it spooky.

 

[Broncofntc]

Are you able to widen the front uppers at the axle any more? Lowering the rear upper axle mounts would make the front's roll center seem higher. Is it an issue with the instant centers moving or the pinion angle changing? I'm not really seeing how the ICs moving would make it spooky.

Yes I'm going to move the front uppers at the axle to 7-9" separation. I just want the roll center closer to the CG to help control body roll. As for the IC I thought having them more stable would make the rig more predictable throughout the suspension cycle?