I try to work out my rear suspension on my hotrod build. The usual traditional way to mount a rearaxle is difficult to get streetlegal here in sweden. What would be best look and most practikal for me would be a upside down and reversed K-link with a model-A rear spring. Do you think it will work properly? Some crappy pics what i have in mind.
Should be OK As long as the top two links are parallel and close to level at ride height and the bottom two are at the same angle. The buggy spring doesn't allow much suspension travel so binding is minimized. Use good bolts and weld the brackets solid to the frame.
Looks strange but it's similar to what we see on a regular basis,only upside down. Should work fine, HRP
If anybody is intressed this is what i find out and my solution. It dosn't matter if the angled bars goes as usual from the middle of axle and out or from outside of the axle and in. The ideal K-link is that the angled bars should meet as close to the middle as possible to handle twisting better. And the bushings should have a lot of rubber in oem style for the same reason. The front mount on the frame is ideally above eachother to keep the pinionangle thru the suspensiontravel. The rollcenter will be at the same lever as the angled bars and acording to what i read its needed to be lower in the front then the back. This is to keep the car slightly understeered which is good for the handling. This mean you problaby gonna need a Panhardbar in front to lower the rollcenter if you angled the lower bars. Whitout Panhardbar the rollcenter is in the middle of the axle where the top of the spring is mounted. Knowing that howe the axle can move is something that will be checked in the techinspection here in sweden its no idea to take a chanse to do as i first wanted. The tiny bushings in the rodlinks would not gonna give the twisting i need to passed. So i buy two trailingarms to LandRover to use as the lower bars and used the shorter links from the set i have as the upper bar. The upper bars is ca8 inches shorter than the lower but if they where longer they will interfere whith the seat inside the car. I have not done the inspection yet but i think it should work good enugh for streetuse. EDIT: I forgot to mention that i made a ordinary 4-bar not a K-link. The pinionangle is something that worried me thru the suspensiontravel and here at travelheight it is 3° And when i lower the axle 6 inch i got 2° When raising 4 inch wich is maximum before i hit the frame it is 3,5° This would be good enough. In twisting i got 12° now and that is 9inch differense between the wheels in height before binding. This should allso be enough for a streetdriven car. Have not desided yet if i gonna use Panhard in the rear or not. will see. Ihope this is understandible becouse its a lot eaysier to write in swedish.
You cannot use a panhard bar with a triangulated rear suspension. The 2 move on different arcs and will bind. The roll centre is where the 2 triangulated bars meet. If the bars are further apart the instant centre will raise up and down with suspension movement [a cantilever effect] If the 2 triangulated bars meet with a common pivot point, that IS the roll centre. If this pivot point is on the rear end, the R/C height never changes. If the 2 triangulated bars meet at a common point forward in the frame the R/C height will change with ride height. You can actually use 2 sets of triangulated bars back to back [eg: Uppers pointing rearwards , and lowers pointing forward ] One pair of bars does NOT need to be parallel as commonly believed. This set up gives you 2 instant centres, so the RC is actually a Roll Axis between the instant centres. By having the rear instant centre high and the front instant centre low, the roll axis causes the wheelbase to shorten under compression and to lengthen under extension. This actually is a desirable feature which promotes roll understeer which is more stable than roll oversteer. GM did this with their Metric Chassis
Get onto Google images and search lotus Cortina rear suspension. They were smart people. Don't worry about bushings handling twisting. 3° or 4° of body roll is the same regardless of how far apart the pivot is. here's a bit of reading on the GM metric rear suspension http://www.hotrod.com/how-to/chassis-suspension/ctrp-0909-metric-four-link-suspension-design/
Your sketch, minus the leaf spring, is pretty much what Ford did on the OT fox chassis cars like the 79-93 Mustang.
this is called a satchel link, from what I've heard is better than a triangulated 4 link. lower roll center and more anti-squat.
You already HAD a perfectly acceptable rear suspension in the Landrover arms alone...until you cut off the rear bushings. By design they work well in 4x4's with their requirement for a lot of articulation and would have no issues at all in a street car. I know that the common thought is that you never use just two parallel links for suspension as it produces binding, but the Landrover arms address this issue by using 3 large diameter rubber bushings to give great flex to the suspension with no binding until an extreme angle is reached. An angle you are unlikely to ever reach in a street driven vehicle.
I did the same on the roadster in my profile pic (but with coils instead of the buggy spring) and it drives great. I did have to add a panhard bar though as I was seeing some side to side movement which seems to have come from deflection in the overly large bushings I used.
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