I know on a parallel 4 link suspension, the link bars will be parallel at ride height. but how do you go about setting up a canti set up. ive read about mounting the bag a 1:1 or 2:1 ratio on the bar. I believe 2:1 will give more lift since its close to the tightest point of the angle of the canti. but do you want your canti to be parallel at ride height also?
canti-lever air suspension questions?
- Thread starter bagged00
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Parallel 4 link bars are parallel with the ground because they are load bearing bars from acceleration/braking/cornering. Cantilever bars are do not matter because get a purely just for lifting the vehicle. A cantilever bar setup is always going to have a lift ratio. The only 1:1 ratio is bag on axle
I guess you could say that but from my understandings, is basically bag location on the bar. 1:1 being the center of the bar 2:1 being half of 1:1. That's my understanding which would in turn give you different amounts of lift. So how do you determine measure to for mounting canti? I searched google and couldn't find much info
Here's the deal, you have to decide how much lift you want and the maximum length your bars can be. The kp cantilever is a 1.5:1 ratio, you get 8" of bag stroke and 12" of lift at the axle.
Cantilever setups are simple trigonometry, you get 7" of stroke and you want 13" of lift at the wheels and your link bars are 15" long. The tangent of the angle the bar makes with the frame at the pivot point is represented by lift divided by the distance from the pivot point. So you want 13" of lift at the axle and a 15" link bag. Your bag stroke is 7", so divide 13/15 and get .8666667. Divide bag stroke by .8666667 and get the position of the bag from the pivot point is 8". So your lift ratio for that setup will be roughly 1.85:1.
So what about deciding the length of the canti? Obviously there's some window you'd want to be in? Are there downfalls to having a shorter or longer bar? How bout mounting how high from the ground? How the hell did you figure all this shit out?hopefully in few years I'll have project to get hands on experience with
It's all vehicle specific. What ever room you have to work with. The shorter the bar the smaller the ratio. For instance, if you take the same setup as above and use a 10" link bar, with the bag placed the same 8" from the pivot point, the lift at the axle lift will only be about 8.75".
A cantilever setup is basic trigonometry, you should read up on basic right triangle geometry.
I understand the reason for asking questions to learn but your thinking your questions have a definite answer but that isn't the case. There are a lot of factors that go into account when building a suspension from scratch. I can build 10 different cantilever setups for a nbs truck.
When it comes to designing a suspension with specifics, you need to take a ton of measurements so it can be designed properly.
A cantilever setup is basic trigonometry, you should read up on basic right triangle geometry.
I understand the reason for asking questions to learn but your thinking your questions have a definite answer but that isn't the case. There are a lot of factors that go into account when building a suspension from scratch. I can build 10 different cantilever setups for a nbs truck.
When it comes to designing a suspension with specifics, you need to take a ton of measurements so it can be designed properly.
oh yeah. I understand that. I personally work well with examples and use them to solve problems. I guess what Im looking for is where you take would take measurements from? from your example on bag placement, to figure out where youd mount the back. you would do half the length of the bar(7.5") times the 1.85 ratio which equals 12.95", and this would tell you where to mount the bag on the bar correct? this would be 12.95 inches from the pivot point on the axle, or the frame?
You choose how long a bar you want to use based on your available room, my example was 15" link bar. Then you decide how much actual lift you want at the axle, I choose to have 13" of lift. Now you look at your bag an see how much stroke it has, I said it has 7" of stroke.
Now, from right triangle geometry, the angle at the pivot point is shared so the tangent of this angle is the same for each lift to distance ratio.
So (13/15)=(7/?). The question mark is the distance from the pivot point to the bag. So you divide 13 by 15 and get .866667, then divide 7 by .866667 to get ~8". Whoever told you to start at halfway when deciding on placement has made things a lot more difficult than it has to be. You choose the amount of lift you want and the length of the canti bar because that is the least amount of math to get the placement.
There are other ways, but there is no reason start from the center of the bar.
Now the type of lever setup I'm talking about has the fulcrum on one end of the bar. If you place the fulcrum in the middle of the bar then things are different.
So you need to decide on that as well.
Now, from right triangle geometry, the angle at the pivot point is shared so the tangent of this angle is the same for each lift to distance ratio.
So (13/15)=(7/?). The question mark is the distance from the pivot point to the bag. So you divide 13 by 15 and get .866667, then divide 7 by .866667 to get ~8". Whoever told you to start at halfway when deciding on placement has made things a lot more difficult than it has to be. You choose the amount of lift you want and the length of the canti bar because that is the least amount of math to get the placement.
There are other ways, but there is no reason start from the center of the bar.
Now the type of lever setup I'm talking about has the fulcrum on one end of the bar. If you place the fulcrum in the middle of the bar then things are different.
So you need to decide on that as well.
so im looking at these pics and trying to envision the 6 link in motion so I can think of how the dog bone works? so brett i got the length thing down, but i still find my self wondering about the mounting of the dog bone and how to determine the mounting how far it hangs from the bottom of the frame? on outward of the frame, youd just keep it parallel to the 4link?
shit i totally didn't grasp that whole part. so itd be: bag stroke/(lift at axle/link bar length)=bag mounting location. in your example, 8" from the pivot point against the frame?
video i found seeing dogbone in action
http://www.youtube.com/watch?v=fo70p7uvtUw
shit i totally didn't grasp that whole part. so itd be: bag stroke/(lift at axle/link bar length)=bag mounting location. in your example, 8" from the pivot point against the frame?
video i found seeing dogbone in action
http://www.youtube.com/watch?v=fo70p7uvtUw
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the dogbone link is so the suspension setup can be mounted lower than you want the axle to travel and to provide a joint so the cantilever bar doesn't pull or push the axle forward or back against the link bars.
The set up doesn't have to be in line with the 4 link bars, it's just that way on the kp kit because the 4 link bars and cantilever dogbones all mount to the same axle bracket.
The cantilever setup is a completely separate setup from the regular link setup. It's sole purpose is to lift the vehicle. You can place above the frame or below the frame, it's doesn't matter. It's all in the available room you have. You can build it inside the frame rails or outside the frame rails. You just have to make sure the link bars won't ever touch the ground and the bag doesn't rub anything.
Lever action suspension setups have unlimited possibilities, it's all in the amount of knowledge you possess and skill set to build what you vision. You can mount the bags vertical, horizontal, parallel to the axle, perpendicular to the axle or combinations of them. I could draw up 10 different setups in 30 minutes that would lift the vehicle an all be classified under cantilever.
It's just too broad of a question to actually make for sure answers to. You can add get really crazy an replace dog bones with coilovers setups and develop even more ride adjustment.
Cantilever setups could be discussed for 3 hours and still not hit an example for every setup.
The set up doesn't have to be in line with the 4 link bars, it's just that way on the kp kit because the 4 link bars and cantilever dogbones all mount to the same axle bracket.
The cantilever setup is a completely separate setup from the regular link setup. It's sole purpose is to lift the vehicle. You can place above the frame or below the frame, it's doesn't matter. It's all in the available room you have. You can build it inside the frame rails or outside the frame rails. You just have to make sure the link bars won't ever touch the ground and the bag doesn't rub anything.
Lever action suspension setups have unlimited possibilities, it's all in the amount of knowledge you possess and skill set to build what you vision. You can mount the bags vertical, horizontal, parallel to the axle, perpendicular to the axle or combinations of them. I could draw up 10 different setups in 30 minutes that would lift the vehicle an all be classified under cantilever.
It's just too broad of a question to actually make for sure answers to. You can add get really crazy an replace dog bones with coilovers setups and develop even more ride adjustment.
Cantilever setups could be discussed for 3 hours and still not hit an example for every setup.
The whole scenario I want to achieve is like a kp 6 link. My best riding vehicle was on a kp 6 link. I know some will say then buy a 6 link. But 1 I think building will be cheaper and 2 I'm always wanting to learn new things. I'll have a fairly knowledgeable buddy helping me but I like to research before I jump into things.