DTSFab.com (Desert, Trail and Sand)
Automotive Powered Off Road (AKA: Buggys, Jeeps, Trucks, Etc,Etc. ) => Chassis and Suspension => Topic started by: fabr on January 21, 2009, 09:14:27 PM
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OK,I need some input/opinions of the pros/cons of different caliper clock position as it applies to an a-arm independent rear suspension. Caliper front,caliper top,caliper rear.
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Sorta subscribing to this as I wish to see if anyone has a good arguement on it.
I do not see one lick of differance. You mount it where the bleed screw is up and thats should be all thats required "I THINK"!
It will generate the same force at any spot on the disc and trasfer it to the hub assembly just the same. (again I think this)
The only plus is in board vs outboard with inboard being better but thats not what you be askin....
Thats my take on it.
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I would think puting it towards the top front (think 2:30) would be best for keeping sand out. Could be bad if you rip your wheel off on impact, but I guess you would have worse problems then anyway..
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Straight on top....12:00. Keeps it out of the way of the stuff you drive over....use a vacuum to bleed it if you have to.
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Won't front or rear mount make the car want to squat or rise depending on front or rear mount when braking?
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Won't front or rear mount make the car want to squat or rise depending on front or rear mount when braking?
It all rotates around the same axis. if the caliper was mounted to your arms, I would say yes. Hopfully it's mounted to your bearing carrier/upright.
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Won't front or rear mount make the car want to squat or rise depending on front or rear mount when braking?
I do not see how. Its transmitting a turning force to the whole assembly. So front or rear its just gonna try to turn it the same direction.
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Straight on top....12:00. Keeps it out of the way of the stuff you drive over....use a vacuum to bleed it if you have to.
I would also vote for 12:00 IF it is not in the way of other mounts.
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I do not see much to gain from it being at the 12:00 position myself.
Unless the bleed screw was set to where it was highest at the 12:00 position. If you really run in that bad of terrain mounting it on the back would take care of it. Even on the front side of the bearing carrier for somthing to hit it to damage it its already tore the front end up most likely.
Thats if its not inside the rim. If it was then it really would not matter.
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if it was mounted on the back it would be a dust/sand collector. Mounting on the front would allow the casting to shield the pads. If the bleed screw isn't at the very tip top that's okay. park it on a hill or jack it up to bleed. I've even unbolted calipers and bled them, then bolted them back on. you just have to have a spacer in between the pads.
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if it was mounted on the back it would be a dust/sand collector. Mounting on the front would allow the casting to shield the pads. If the bleed screw isn't at the very tip top that's okay. park it on a hill or jack it up to bleed. I've even unbolted calipers and bled them, then bolted them back on. you just have to have a spacer in between the pads.
I don't see it. With the CV in the way and a better part of the bearing assembly that will defelct most of anything flying in there anyways. If you bury it in the sand it will get sand in it front or rear or top even.
Even mud lovers get mud in them no matter what. Where its at makes little differance.
Bleeder up is still my fav.
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Bleeders up! I agree.
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I think you guys are missing something. Maybe I'm wrong tho and that's why I'm asking. Rear mount is going to impart an upward force on the a arms due to the rear mount of the caliper. THe opposite is true for front mount?Or am I full of crap?
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I think you guys are missing something. Maybe I'm wrong tho and that's why I'm asking. Rear mount is going to impart an upward force on the a arms due to the rear mount of the caliper. THe opposite is true for front mount?Or am I full of crap?
Crap!!!
Someone mentioned it earlier, but Torque is what the brake applies to the upright. It is either clockwise or counterclockwise depending if you were going forward or back when the brake is applied. Doesn't matter where the caliper is clocked 360 degrees.
That being said, on say the front, the point where the heim's connect in relation to the center of the spindle will affect how much force each arm see's.......
On most design's the lower arm is connected closer to the spindle stub. If it was connected centerline with the axle, and we assume the heims are free to rotate, the lower arm would have no affect from the brake TORQUE. The Top arm would control all of the brake torque. The lower arm would see all of the force induced from the tire trying to stop the car, while the top arm would see all of the torque loads.
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Well i think i read some were before a certain ford truck had the same caliper on both sides, and on one it was rear mounted, and the opposite side was front mounted, Would this lead us to believe ford engineers feel it has no difference in dive/Lift etc?
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I fully understand the self cleaning and that it induces no pull or steering effect. I'm still not convinced that it does not cause some lift or squat depending on front or rear mounting.Someone PLEASE straighten me out by telling me why I'm not seeing this right.I admit I may be totally wrong but need it explained to me so I get it right in my pea brain.
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Crap!!!
Someone mentioned it earlier, but Torque is what the brake applies to the upright. It is either clockwise or counterclockwise depending if you were going forward or back when the brake is applied. Doesn't matter where the caliper is clocked 360 degrees.
That being said, on say the front, the point where the heim's connect in relation to the center of the spindle will affect how much force each arm see's.......
On most design's the lower arm is connected closer to the spindle stub. If it was connected centerline with the axle, and we assume the heims are free to rotate, the lower arm would have no affect from the brake TORQUE. The Top arm would control all of the brake torque. The lower arm would see all of the force induced from the tire trying to stop the car, while the top arm would see all of the torque loads.
I think the short version is....suspension mounts affect squat or rise, not caliper mount. I agree.
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Boost pretty much summed it up with one sentance.
If you want it dive or antidive you need to build it into the suspension mounting points.
Maybe Fabr what you are thinking here is when you hit the rear brakes the front goes down? Thats just weight transfer as the rear tires introduce the rotating torque they generate into the suspension and then to the frame. It may seem like lift or squat (in this i.e. case) but its just sending the torque the brakes make to the least possible resistance.
Even hitting front brakes only on a suspension with no anitdive built in you get some weight trasfer and the front may drop. This may appear to be affecting the rise or squat but its really just the suspension dealing with the weight load placed upon it for the most part.
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This may also be a reason to consider inboard brakes.
You get a better protection of the calipers from the frame if thats an issue.
You have less unsprung weight. Thats ALWAYS good.
You get much less torque transfer to the suspension and its pivots with inboard brakes. This makes the suspension move smoother thru rough especially with the brakes on. There is less bind in the suspension joints with inboard brakes. VS outboard brake system trying to deal with HOW MANY POUNDS of force (in torque. Could be a lot.) the brakes are generating and sending thru the suspension pivots/arms??
Your suspension (with inboard brakes) will move more smoothly and wear out a lot slower scince the joints will have many less pounds of force on them while cycling.
Some say this (inboard brakes) wears the CV's more and thats true. But its a trade off (compromise) for less wear on evething else. Most CV's fail due to being over extended in the degree mode. If you do not over travel them degree wise the extra load they deal with with inboard brakes should not effect thier live expectancy enough to worry. They are still dealing with far far more loads pushing the vehicle forward over thier lifetime.
You can still get antidive or antisquat with inboard brakes. You just need to exaggerate (multiply) it a bit more at the mounts due to the reduced torque effects at the wheel to generate this lift.
But going to far might make a suspension that is not like you like while simply driving forward with no brakes on. Its that dang compromise again.
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You can still get antidive or antisquat with inboard brakes. You just need to exaggerate (multiply) it a bit more at the mounts due to the reduced torque effects at the wheel to generate this lift.
I think you need to re-examine this idea. Or explain how it might work when the "reduce" torque effects are in fact only the drag in the bearings and seals.
I fully understand the self cleaning and that it induces no pull or steering effect. I'm still not convinced that it does not cause some lift or squat depending on front or rear mounting.Someone PLEASE straighten me out by telling me why I'm not seeing this right.I admit I may be totally wrong but need it explained to me so I get it right in my pea brain.
I think the short version is....suspension mounts affect squat or rise, not caliper mount. I agree.
I agree with your summation Boostin, but Fabr needs more explanation not less.
That being said, Fabr, explain to us how the "lift" or downward force from the caliper has any affect on the suspension. I believe that when you think through your explanation, you will find the error. What would the "lift" be leveraging on....... This is where the misunderstanding is.
Get a large box, stand in the middle now grab the sides of the box and lift yourself off the floor......... Same principle. There is no net lift, outside the closed system.
Reminds me of a joke, after the Redneck got off his first flight, he told his friend: I still don't trust that airplane, I never did put my full weight down in the seat.
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Sometimes I just like to go :t also. :m ff: :m :P :P :P
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I suspected you were on a fishing trip, but it is a question people ask. So it is still useful. I was thinking that somebody that could build buggies and design gearboxes should be able to figure this out....
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You can still get antidive or antisquat with inboard brakes. You just need to exaggerate (multiply) it a bit more at the mounts due to the reduced torque effects at the wheel to generate this lift.
But going to far might make a suspension that is not like you like while simply driving forward with no brakes on. Its that dang compromise again.
I think you need to re-examine this idea. Or explain how it might work when the "reduce" torque effects are in fact only the drag in the bearings and seals.
If I am wrong here please correct me. With the suspension pivots at 90 degrees to the ground your wheels will move straight up and down. And only due to weight transfer. (Given no bumps. Just suspension action talking here)
Now (This is meant to be radical on purpose) Angle the suspension pivots to 45 degrees. If you angle them forward 45 degrees then under deceleration the suspension will try to lift the vehicle as the tire attempts to go slower than the chassis. This will happen with inboard or outboard brakes. Its just the leverage factor. You will tend to get more with outboard brakes s you get the turning force applied by the brakes AND the tires force of forwards or backwards (depending on rotation)
On the rear accelerating will make the rear squat and then rise on deceleration.
On the front just hitting the brakes (saying it has front brakes) would make it rise as well.
Same goes for if you angled them backwards 45 degrees. In the rear under accleration it would lift. Under braking or any resistance weather it be brakes applied or simply backing of the throttle hard the rear would drop due to the force applied to the angle.
The point??
With inboard brakes you still have any angles in the suspension arms in relation to the frame will still deal with the forward and reverse leverages different angle apply.
The 45 degrees was indeed radical but it was just to help show the force will affect a vehicle some ireguardless. Even a few degrees as most suspensions are will be affected SOME.
Still dont buy it? Try pushing directly 90 degrees to a hinge. (If on a door to a room this would be straight up or down. (That simulates a suspension with the arms at 90 degrees to the frame) It aint going anywhere more then the slop in the hinge. Yet for every degree of angle you push on it it becomes easier to move. (That simulates a suspesnion with the arms raked however many degrees you are pushing on the door from). But the point is even a few degrees of force WILL affect what they are connected to.
So the force of the tire against the ground accelerating or decellerating will transmit this force into the angles you build in and still affect it with dive or antidive. As I mentioned above with no brakes on an axle you would need pretty prominent angles to get the effects. At the cost of sacrificing many other aspects of the suspension you might not wish to for dive or antidive or squat/antisquat.
Thats my view on it. What say you? (you being anyone who sees it differently!) I believe I am right. But if you can correct me on it please do so.
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Yeah I posted it cause many do not understand the principle and it is good info to get out there.I still think it's clear as muddy to some after this discussion and if someone ere to post up some paint about it it would REALLY help clarify it to those that still don't possibly understand why.
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Now back to the topic. ;D ;D
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You brought it up. so where do you stand?
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If I am wrong here please correct me. With the suspension pivots at 90 degrees to the ground your wheels will move straight up and down. And only due to weight transfer. (Given no bumps. Just suspension action talking here)
Now (This is meant to be radical on purpose) Angle the suspension pivots to 45 degrees. If you angle them forward 45 degrees then under deceleration the suspension will try to lift the vehicle as the tire attempts to go slower than the chassis. This will happen with inboard or outboard brakes. Its just the leverage factor. You will tend to get more with outboard brakes s you get the turning force applied by the brakes AND the tires force of forwards or backwards (depending on rotation)
On the rear accelerating will make the rear squat and then rise on deceleration.
On the front just hitting the brakes (saying it has front brakes) would make it rise as well.
Same goes for if you angled them backwards 45 degrees. In the rear under accleration it would lift. Under braking or any resistance weather it be brakes applied or simply backing of the throttle hard the rear would drop due to the force applied to the angle.
The point??
With inboard brakes you still have any angles in the suspension arms in relation to the frame will still deal with the forward and reverse leverages different angle apply.
The 45 degrees was indeed radical but it was just to help show the force will affect a vehicle some ireguardless. Even a few degrees as most suspensions are will be affected SOME.
Still dont buy it? Try pushing directly 90 degrees to a hinge. (If on a door to a room this would be straight up or down. (That simulates a suspension with the arms at 90 degrees to the frame) It aint going anywhere more then the slop in the hinge. Yet for every degree of angle you push on it it becomes easier to move. (That simulates a suspesnion with the arms raked however many degrees you are pushing on the door from). But the point is even a few degrees of force WILL affect what they are connected to.
So the force of the tire against the ground accelerating or decellerating will transmit this force into the angles you build in and still affect it with dive or antidive. As I mentioned above with no brakes on an axle you would need pretty prominent angles to get the effects. At the cost of sacrificing many other aspects of the suspension you might not wish to for dive or antidive or squat/antisquat.
Thats my view on it. What say you? (you being anyone who sees it differently!) I believe I am right. But if you can correct me on it please do so.
Nutz, I agree with 98% of what you said, and the disagreement is probably a misunderstanding. I will clarify what I disagree with.
We discussed on another thread "anti-dive". On that thread we were refering to it as having the A-arms not parallel to each other, specifically to lift or "anti-dive" the front end under braking. If the brakes are inboard on the rear I don't believe that the force of braking will react on the suspension in a way that will "lift" the car. That doesn't mean that the front won't go down, and the back come up, but I don't believe it is from the brake torque twisting on the arms that causes it.
I agree 100% that Rake front or rear will cause lift or squat under accel or decel. And this can include the rake or negative rake that occurs when the car leans forward on braking.
On Fabr's car, with no rake, when the brakes are hit, and the weight transfers forward, and the front starts to dive, the anti-rake that occurs will actually cause the front to try to lift some.
Actually what you describe will have a big affect on a trailing arm or 5-link. Whether the brake is inboard or not. On a trailing arm if the arm is angled down 20 degrees toward the tire, and you hit the brakes it will try to pull the frame down more in line with the axle, by the tire trying to hold the frame back.
Rear A-arms except for the rake or anti-rake would be almost completely insulated from these affects.
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And there is my opinion.Yes I will be using 0 rake in rear( and front also).I've never had a car like that and it will be interesting to see if I like it or not.
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And there is my opinion.Yes I will be using 0 rake in rear( and front also).I've never had a car like that and it will be interesting to see if I like it or not.
Thanks for the explanation!! :-* :s :t :t mm: :b
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If your axles angle forward from the gear box to the hubs with inboard brakes, there will be some downward pressure on the arms.