Take a look under an early 80's Toyota mini-truck
The shackles for the front leafs are towards the rear of the vehicle, directly under the footwells of the passenger compartment.
Suspension Geometry With Various Caster Correnction
- Thread starter Walking Eagle
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Take a look under an early 80's Toyota mini-truck
The shackles for the front leafs are towards the rear of the vehicle, directly under the footwells of the passenger compartment.
- Thread starter
- #22
They hang down below the axle?
The greater fore/aft movment creates more bind in the bushings?
Whatcha thinking tank?
Take a look under an early 80's Toyota mini-truck
The shackles for the front leafs are towards the rear of the vehicle, directly under the footwells of the passenger compartment.
No kidding, I don't pay any attention to them but they are on the light side and can get away with it I guess. But if you look at 40s, 60s and such they are on the outside.
Come on Heath, you have the info here is this thread. Run through some situations in your head and brain it out.
I'll post up later tonight if it hasn't come to you.
- Thread starter
- #25
Like I'm a mind reader. I used about all my thinking power just to make sure I hadn't screwed up any of the dwgs!
Drop brackets have the advantage of coming up and back away from an obstacle. But that's been argued with shackle reversal for years. One theory is it comes up and back and that way isn't working against forward progress, the antithesis says that with shackles up front (or radius arm lift w/o drop brackets) that the up and forward motion pushes the tire into the obstacle and creates more traction.
Well, that's 3 potential advantages, but I don't know as though I've hit the one you're thinking of.
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I understand the definition, what I am driving at is the practical effect as felt by the driver. What we are implying here is that a stock mounted control arm on a 4" lift with 35" tires is going to physically steer the vehicle to the left when the right front tire hits a pothole, requiring the driver to correct.
One assumption you are making is that forward axle movement on impact compression (such as a pothole) is not absorbed by rubber bushing and/or large tire deflection rather than the axle and tire physically forcing forward into that impact. Given the weight and volume of a 35" tire that is typically paired with a 4" lift, I am not convinced that is a good assumption (or that the oversized tire itself simply takes the deflection).
And I say this because I haven't had any bumpsteer issues on the 80, and I know what direction affecting bumpsteer means having spent $4,500 on a custom 3/4 ton Ford high pinion front Dana 44 axle with a panhard mount set will below the hi-clearance steering mount level, so that every time you hit a bump the panhard physically turns the steering wheel by shifting the axle at a different rate than the draglink is moving.
Any bumpsteer that doesn't change the direction of the vehicle where the driver has to change it back doesn't actually exist except on paper. This is the kind of factor that is simply overwhelmed by modifications such as "35" MT".
- Thread starter
- #27
Well, since you said, and I quote ' A shift in the axle won't turn the steering wheel (bump steer)', and turning the steering wheel has nothing to do with bumpsteer, it seemed to me that we did need to come to a common understanding.
It's there. Weither it's enough for the driver to notice or not is a different issue. It's worse the more you put the radius arms at an angle. As in, at 3" of lift you're opperating in a different range than a 6" lift, and won't notice it at much at 3" as you would at 6".
The previous thread that became worthless due to 'you know who', left alot of confusing oppinions / information out there. I just figured as long as I'd done some work on drawing the 80 series front suspension, I might as well go a little further and put some numbers down to show what the differences are. Thought some others might have some interest too. Take it for what it's worth, which, it may not be worth anything to you. I at least thought it was interesting. Not going to change my set-up based on it, but it is interesting to me.
Are YOU going to notice the bump steer? I don't know, that's a personal thing. There are plenty of people on the forum who run 3, 4 and even 6" of lift with no caster correction at all and claim 'it drives just fine'. Others pasonately disagree that it is 'fine'. What no one can argue though is that the more you lift, the less caster you will have. This is the same type of deal, so you may find it's fine, you may not, but how you or I feel driving w/ a little more or a little less bump steer and roll steer is a matter of opinion. And how we feel about this doesn't change the geometry of what is happening. Sort of like seperating the truth, with how we feel about the truth.
All of that to say I won't argue if it's enough to notice or not. Just saying it's more or less. Stock arms have the most, longer arms slightly less, drop brackets the least. If you our I am sensitive enough to notice the effect, is a different matter (if I didn't already say that 3 times).
I got called out to NJ just after posting and didn't mean to leave it here so long.
Yes, the resistance to forward movement was where I was going. Any time one tire on an axle hits an obstacle there is resistance to progress. With the drop brackets it helps lessen this. And overall it will be a smoother ride.
I've thought about the traction thing but still not sure where I stand on it. For the most part I don't think drop brackets are at a disadvantage.
- Thread starter
- #29
Here’s some general observations and conclusions:
Binding of bushings during articulation Best to Worst
1. Dropped Brackets
2. Longer arms
3. Stock Arms
Clearance to back of wheel well at full compression Best to Worst
1. Longer Arms
2. Stock Arms
3. Dropped Brackets
Clearance to front of wheel well is reverse of above.
Clearance to lower back of wheel well, where the mud flap under full extension.
1. Dropped Brackets
2. Longer Arms
3. Stock Arms
Least effected by Bump Steer / Roll steer effect.
1. Dropped Brackets
2. Longer Arms
3. Stock Arms
Clearance under the axle
1. Dropped Brackets and Longer Arms are likely the same – depends on the exact shape of longer arms, but guessing it’s a wash
2. Stock Arms with caster plates. When they rotate the axle up, they push the front of the arms down.
Clearance under the frame.
1. Longer Arms and Stock Arms have same mount – so pretty even there.
2. Dropped Brackets obviously have less clearance. Interesting comparison though is the drop bracket vs. the catalytic converters and / or the converter protection on sliders. My 3” drop brackets are not any lower than my slider outrigger / cat protection, and my cat has been raised, and is an aftermarket Magnaflow unit that has more clearance than stock. I don’t have Slee, or Hanna, or Metaltech sliders, so I can’t 100% compare, but I can compare to stock ’97 exhaust, and pontificate that with 3” drop brackets, you’re not loosing much if any more clearance on the passenger side than you do with stock exhaust and sliders. Just an observation.
Motion while attacking obstacle – best to worse:
1. Drop Brackets
2. Longer Arms
3. Stock Arms
The theory here, and it could be argued, is that with the tire going up and back, instead of up and forward, it is not preventing forward progress as much.
I tried to keep the conclusions and observations limited to what is fact, and keep the opinion out of it. That’s why I just ranked them best to worst, or highest to lowest, without judgment as to if the lowest or most is acceptable, or if there is enough of a difference to matter
Binding of bushings during articulation Best to Worst
1. Dropped Brackets
2. Longer arms
3. Stock Arms
Clearance to back of wheel well at full compression Best to Worst
1. Longer Arms
2. Stock Arms
3. Dropped Brackets
Clearance to front of wheel well is reverse of above.
Clearance to lower back of wheel well, where the mud flap under full extension.
1. Dropped Brackets
2. Longer Arms
3. Stock Arms
Least effected by Bump Steer / Roll steer effect.
1. Dropped Brackets
2. Longer Arms
3. Stock Arms
Clearance under the axle
1. Dropped Brackets and Longer Arms are likely the same – depends on the exact shape of longer arms, but guessing it’s a wash
2. Stock Arms with caster plates. When they rotate the axle up, they push the front of the arms down.
Clearance under the frame.
1. Longer Arms and Stock Arms have same mount – so pretty even there.
2. Dropped Brackets obviously have less clearance. Interesting comparison though is the drop bracket vs. the catalytic converters and / or the converter protection on sliders. My 3” drop brackets are not any lower than my slider outrigger / cat protection, and my cat has been raised, and is an aftermarket Magnaflow unit that has more clearance than stock. I don’t have Slee, or Hanna, or Metaltech sliders, so I can’t 100% compare, but I can compare to stock ’97 exhaust, and pontificate that with 3” drop brackets, you’re not loosing much if any more clearance on the passenger side than you do with stock exhaust and sliders. Just an observation.
Motion while attacking obstacle – best to worse:
1. Drop Brackets
2. Longer Arms
3. Stock Arms
The theory here, and it could be argued, is that with the tire going up and back, instead of up and forward, it is not preventing forward progress as much.
I tried to keep the conclusions and observations limited to what is fact, and keep the opinion out of it. That’s why I just ranked them best to worst, or highest to lowest, without judgment as to if the lowest or most is acceptable, or if there is enough of a difference to matter
Now let me throw a wrench into all your conclusions.
Going down the road, I agree that the axle moving up and back is beneficial to the ride and comfort of the passengers.
HOWEVER! When you go to climb a rock ledge or some other similar obstacle, the power to the axle is attempting to pull the axle forward while the suspension is trying to counteracting that movement. This is much more obvious in the exaggerated case of leaf springs with shackles in the front or the back. W/ the shackles in the rear, the truck will ride much better, but in the front, the suspension will climb much better.
Sorry
Going down the road, I agree that the axle moving up and back is beneficial to the ride and comfort of the passengers.
HOWEVER! When you go to climb a rock ledge or some other similar obstacle, the power to the axle is attempting to pull the axle forward while the suspension is trying to counteracting that movement. This is much more obvious in the exaggerated case of leaf springs with shackles in the front or the back. W/ the shackles in the rear, the truck will ride much better, but in the front, the suspension will climb much better.
Sorry
- Thread starter
- #31
Now let me throw a wrench into all your conclusions.
Going down the road, I agree that the axle moving up and back is beneficial to the ride and comfort of the passengers.
HOWEVER! When you go to climb a rock ledge or some other similar obstacle, the power to the axle is attempting to pull the axle forward while the suspension is trying to counteracting that movement. This is much more obvious in the exaggerated case of leaf springs with shackles in the front or the back. W/ the shackles in the rear, the truck will ride much better, but in the front, the suspension will climb much better.
Sorry
I don't know about you, but when I climb a rock ledge or some similar obstacle, my tires are trying to go up.
Not really throwing a wrench into ALL my conclusions, just the one, that Landtank originally suggested.
And it's not a wrench that I didn't already give you in post #25
'Drop brackets have the advantage of coming up and back away from an obstacle. But that's been argued with shackle reversal for years. One theory is it comes up and back and that way isn't working against forward progress, the antithesis says that with shackles up front (or radius arm lift w/o drop brackets) that the up and forward motion pushes the tire into the obstacle and creates more traction.'
or in the list of observations and conclusions as well -
'The theory here, and IT COULD BE ARGUED, is that with the tire going up and back, instead of up and forward, it is not preventing forward progress as much.'
Personally, I think coming up and back from bump is probably better. But that's an oppinion. And I only say that cause of my experience with VW Baja Bugs. Watch how easily the front tires come up and back to allow the rear to keep driving forward instead of it having to fight the front suspension trying to push the car back.
With shackels, I've heard the argument both ways. I've read articles on the argument. Seems you'll read in the same magazine two articles six months apart, one which says front shackles is better, and the other that says rears are for climbing. Most honest article I've read on the subject is what I based post #25 on. It said some think one way, and others think the other way, and there is no hard proof one way or another. I think once you have a strong opinion about it one way or the other, you're not going to be swayed (generic you, not you specifically).
Sorry, your wrench doesn't bother me
