has any one know the mathmatics for four link suspensions - Pirate4x4.Com : 4x4 and Off-Road Forum

nissanmini2000 · 12-02-2003, 11:10 PM

I have a custom nissan hard body almost every thing is shaved
. And I am geting ready to do an engin swap to a vg30et out of a 1984 300zx turbo car. And probally when the engine is out I want to four link the front and rear and put air bags on all four corners.
But I dont know the mathmatics and equasians to do it. Any info would be greatly apreciated.

bignissan · 12-03-2003, 01:16 AM

i don't know the "math", but if you search in the general section..it has been covered A LOT. not really many equations to it, just trial and error more than anything after you find a good basis to start from...good luck
greg

LoFrontier · 12-03-2003, 05:26 AM

so this is like a show quality 4x4 truck? When I think shaving and bags I think of my lo-lo's.

You might want to pick up a suspension design book for the technical ins and outs like instant center and all that fun stuff.

A rolling sleeve bag will give you a lot of lift and would be the best choice if you were going to mount the bags directly over the axles. They don't like a lot of misalignment between the upper and lower cups but they get a lot of lift and will give a nice ride. Double convoluted bags can stand more misalignment yet less lift. They'd be best used in a leverage setup, i.e. between the frame and a 4 link bar. This type of setup will give good lift and will mellow out the high spring rate of the double convoluted bag. Oh, and sleeve bags need to be strapped to limit their travel. If they over extend they will blow out.

www.airliftcompany.com has some tech specs on some Firestone bags like size, inflated height and deflated height.

I'd go with a triangulated 4 link that way you don't have to mess with panhard bars and the axle will always stay centered under the truck. A triangulated 4 link up front will probably require you to run hydraulic steering because the axle will want to move straight up and down and the steering link will want to move in an arc resulting in bump steer. Most parallel linkage front suspensions I've seen have the panhard bar and steering arm set up to be parallel to each other to reduce bump steer.

I'm just talking generalities here. My only 4 link experience comes in getting trucks to lay frame. I'm just throwing out some things that you're going to want to look at.

I can help you locate good compressors, valves, gauges, air line, fittings and all of that.

12-02-2003, 11:10 PM	#1 (permalink)
nissanmini2000 Registered User Join Date: Dec 2003 Member # 24917 Location: Grand Junction Colorado Posts: 599	has any one know the mathmatics for four link suspensions I have a custom nissan hard body almost every thing is shaved . And I am geting ready to do an engin swap to a vg30et out of a 1984 300zx turbo car. And probally when the engine is out I want to four link the front and rear and put air bags on all four corners. But I dont know the mathmatics and equasians to do it. Any info would be greatly apreciated.

12-03-2003, 01:16 AM	#2 (permalink)
bignissan Registered User Join Date: Oct 2002 Member # 14644 Location: Magnolia, Texas Posts: 2,013	i don't know the "math", but if you search in the general section..it has been covered A LOT. not really many equations to it, just trial and error more than anything after you find a good basis to start from...good luck greg __________________ 1986.5 Nissan crawler - dual cases, one tons, 42's... 2003 SV650 1997 F350 DRW PSD

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

12-03-2003, 05:26 AM	#3 (permalink)
LoFrontier Registered User Join Date: Sep 2003 Member # 23105 Location: PITTSfield, MA Posts: 56	so this is like a show quality 4x4 truck? When I think shaving and bags I think of my lo-lo's. You might want to pick up a suspension design book for the technical ins and outs like instant center and all that fun stuff. A rolling sleeve bag will give you a lot of lift and would be the best choice if you were going to mount the bags directly over the axles. They don't like a lot of misalignment between the upper and lower cups but they get a lot of lift and will give a nice ride. Double convoluted bags can stand more misalignment yet less lift. They'd be best used in a leverage setup, i.e. between the frame and a 4 link bar. This type of setup will give good lift and will mellow out the high spring rate of the double convoluted bag. Oh, and sleeve bags need to be strapped to limit their travel. If they over extend they will blow out. www.airliftcompany.com has some tech specs on some Firestone bags like size, inflated height and deflated height. I'd go with a triangulated 4 link that way you don't have to mess with panhard bars and the axle will always stay centered under the truck. A triangulated 4 link up front will probably require you to run hydraulic steering because the axle will want to move straight up and down and the steering link will want to move in an arc resulting in bump steer. Most parallel linkage front suspensions I've seen have the panhard bar and steering arm set up to be parallel to each other to reduce bump steer. I'm just talking generalities here. My only 4 link experience comes in getting trucks to lay frame. I'm just throwing out some things that you're going to want to look at. I can help you locate good compressors, valves, gauges, air line, fittings and all of that.