Go Back   Infamous Nissan - Hardbody / Frontier Forums > Tech Area > Suspension

Reply
 
Thread Tools Display Modes
Old 08-06-2017, 03:54 PM   #11
dvdswan
Super Moderator
 
dvdswan's Avatar
 
Join Date: Mar 2009
Location: Port Orchard, WA
Posts: 4,240
Vehicle: 96 HB
Thanks: 148
Thanked 549 Times in 485 Posts
Default

they work pretty decent from what I've read. you will need a track bar or panhard bar to keep the axle centered. I've seen it on desert racers and crawlers, not sure of any advantage or how street legal it is. IMO though I would go with a 3 or 4-link system. here are some images...

https://www.google.com/search?q=half...w=1366&bih=618
__________________
Dave
96 HB XE
SAS'd D44 3-link on 35s
http://www.cardomain.com/ride/2618002
dvdswan is offline   Reply With Quote
Old 08-06-2017, 04:15 PM   #12
Granitex
 
Join Date: May 2014
Location: Columbus OH.
Posts: 56
Vehicle: 1997 d21 4X4, 2004 xterrra
Thanks: 0
Thanked 7 Times in 7 Posts
Default

What you were describing was almost a 1/4 eliptial set up.
Granitex is offline   Reply With Quote
Old 08-07-2017, 04:23 PM   #13
street_rulerr
 
Join Date: Nov 2015
Location: West Coast
Posts: 1,290
Vehicle: 1996 4x4 5spd
Thanks: 0
Thanked 90 Times in 88 Posts
Default

Quote:
Originally Posted by fatleon View Post
Thanks for all your comments. I think I'll go with plain old leaf springs.
The reason I didn't want to use them is they seem to ride pretty hard, but I think that's cause I've only ever driven old trucks with stiff springs. With the right springs and shocks I should be able to keep a nice smooth ride.
Does anyone know a formula for choosing spring rate based on vehicle weight and wheel travel?

this is a BIG question. you need to understand how a leaf spring is made and calculated. they start life as a triangle shape and then are sliced from tip to base making "rectangular profiles" that are then stacked on one another. its playing with the WIDTH of the spring AND the number that affect its rate.

secondly theres the issue of number of springs.

thirdly theres how linear they arent. I dont think that with the design of them changing lengths in the stack that they are linear rates at all but i could be wrong. Ive never done the calc for that.


I assume that since you are doing a sas swap, you are wheeling it and want articulation so youd want a soft spring that has a TON of travel.
street_rulerr is offline   Reply With Quote
Old 08-07-2017, 04:25 PM   #14
street_rulerr
 
Join Date: Nov 2015
Location: West Coast
Posts: 1,290
Vehicle: 1996 4x4 5spd
Thanks: 0
Thanked 90 Times in 88 Posts
Default

Quote:
Originally Posted by Granitex View Post
What you were describing was almost a 1/4 eliptial set up.
the only use of a 1/4 ellipse ive ever seen is on a wagon buggy for the chest/trunk carrier. is there another use for them?
street_rulerr is offline   Reply With Quote
Old 08-10-2017, 04:52 AM   #15
fatleon
 
Join Date: Jul 2017
Location: Albuquerque
Posts: 19
Vehicle: 87 hardbody
Thanks: 1
Thanked 1 Time in 1 Post
Default

I think I'm going to go with a standard leaf spring design. I seem to have a new idea for how to do it everyday. I need to take careful measurements of the truck and axle and make some drawings to visualize this stuff.
I don't want any more lift than I need for axle clearance since I use the truck to haul stuff pretty frequently, and loading in and out of a tall truck gets annoying. I'm shooting for 3 or 4 inches to the bump stop at ride hight. And hopeful that much droop too.
If I can get away with using Xterra leafs in the rear and my rear leafs up front that would be nice.
__________________
fatleon is offline   Reply With Quote
Old 08-10-2017, 05:02 AM   #16
synbiotic12
 
synbiotic12's Avatar
 
Join Date: Dec 2013
Location: Newfoundland
Posts: 2,021
Vehicle: 2004 Frontier 2WD (sold), 1993 D21 4x4
Thanks: 87
Thanked 272 Times in 231 Posts
Default

Quote:
Originally Posted by fatleon View Post
I think I'm going to go with a standard leaf spring design. I seem to have a new idea for how to do it everyday. I need to take careful measurements of the truck and axle and make some drawings to visualize this stuff.
I don't want any more lift than I need for axle clearance since I use the truck to haul stuff pretty frequently, and loading in and out of a tall truck gets annoying. I'm shooting for 3 or 4 inches to the bump stop at ride hight. And hopeful that much droop too.
If I can get away with using Xterra leafs in the rear and my rear leafs up front that would be nice.
Might I suggest something here from someone who's done this.
Xterra leaves are known to crack, Honestly Nissan should've been forced to recall them. The factory nissan leaf springs don't flex very well at all and don't really stand up to the test of time in my personal opinion.

I'd suggest using 4wd chevy leaf springs from a half ton chevy truck from 1988-2010. they measure 63" long, flex great, they sell kits to install them, and have a higher load cap. than your factory nissan leafs or X leafs. Plus they won't net you a huge lift, and can be found just about anywhere if you happen to need spares. it's a really well documented swap on toyota trucks.

Otherwise yes, definitely use your rears up front.
__________________
1993 D21 SE-V6, 4x4, X-cab
syn's 4x4 project build
2004 Frontier 4cyl, 2wd, X-cab (Sold)
2007 Subaru Impreza wagon 2.5i
synbiotic12 is offline   Reply With Quote
Thanked by:
fatleon (08-10-2017)
Old 08-10-2017, 05:31 AM   #17
fatleon
 
Join Date: Jul 2017
Location: Albuquerque
Posts: 19
Vehicle: 87 hardbody
Thanks: 1
Thanked 1 Time in 1 Post
Default

Good to know about the Xterra springs. Too bad cause it looked like they would bolt into the stock spring hangers.
I've heard about the 63s, I actually saw 2 Tacoma's with them today. I'll read up on them.
__________________
fatleon is offline   Reply With Quote
Old 08-12-2017, 01:23 AM   #18
fatleon
 
Join Date: Jul 2017
Location: Albuquerque
Posts: 19
Vehicle: 87 hardbody
Thanks: 1
Thanked 1 Time in 1 Post
Default

I did a bunch of measuring last night and made some very out-of-scale drawings of the frame, oil pan, steering box, and axle. At full compression the Dana 44 should tuck up to where the front diff is now, and that would be at the current ride height.
So adding 1" of bump stop and 3.5" of up travel it looks like using the rear springs up front will work nicely. But, they will be nearly flat at ride height, meaning any up travel will result in negative arch. They will go negative a little in the rear now, but not as much.
How bad is that? How much can these springs take?
Also, does my full compression estimate seem right to you other SAS guys?
__________________
fatleon is offline   Reply With Quote
Old 08-12-2017, 03:17 AM   #19
synbiotic12
 
synbiotic12's Avatar
 
Join Date: Dec 2013
Location: Newfoundland
Posts: 2,021
Vehicle: 2004 Frontier 2WD (sold), 1993 D21 4x4
Thanks: 87
Thanked 272 Times in 231 Posts
Default

I never used my rears up front, so for me to compare your springs to mine and my build to yours would be inaccurate.
First, are you planning to run your shackle through the frame or under it? Are you buying a kit or doing everything from scratch?
If you're doing it all from scratch do yourself a favor and move the centerline of the front axle forward 2-4" from stock, you'll thank me later.

I have read thousands of times not to negative arch your springs, I do it all the time. I also replace a broken rear leaf usually once every 6-8 months, but never a main leaf (just aftermarket leaves i've added in). I'd run it
If you're worried, you can look into a slightly longer leaf to mount up front (such as 84-01 jeep XJ rears), or something with a bigger arch (like rancho rs44044 springs).
Either option is a good one
__________________
1993 D21 SE-V6, 4x4, X-cab
syn's 4x4 project build
2004 Frontier 4cyl, 2wd, X-cab (Sold)
2007 Subaru Impreza wagon 2.5i
synbiotic12 is offline   Reply With Quote
Old 08-12-2017, 04:13 AM   #20
fatleon
 
Join Date: Jul 2017
Location: Albuquerque
Posts: 19
Vehicle: 87 hardbody
Thanks: 1
Thanked 1 Time in 1 Post
Default

I was planning to run the shackle through the frame, that way I can have a decent shackle length without gaining more lift than I need. As for kit vs scratch, I havn't decided yet. If I found a kit at the right price I'd go for it, but I usually prefer to build stuff.

Is moving the axle forward to avoid tire-firewall issues at full stuff?

I thought about using a spring with more arch, but I dont see a good way to raise the spring hangers to account for the taller spring. I could use a taller spring and go spring-under-axle, then I wouldn't have to move the spring perches on the axle. And it would make my steering linkage easier. Spring under has so many downsides though, harsher ride, less ground clearance, why-would-you-hang-the-spring-from-the-ubolts-when-gravity-will-do-the-work-for-you. Did I miss any?
__________________
fatleon is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 11:55 AM.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.