Caster Question
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Laughing Gas
Joined: Dec 2017
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Caster Question
The real world experience of a lot of FTE users seems to point to an increase in positive caster as one possible solution to various shuddering, death wobble or sustained steering wheel oscillation, whatever you want to call it. This makes sense to me since positive caster is generally associated with high speed stability. But, the TSB for wobble that Ford was going by for a while recommends reducing caster to “the lower end of the specification”. To me, that’s saying they want it closer to straight up and down which is opposite of what those aforementioned FTE users are having success with. Any insight out there on what they were trying to accomplish with that reduced caster?
Posting Guru
Joined: Feb 2018
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You might want to do some independent research to understand the purposes of caster angle. As you note, it is being referenced as one of the solutions to the problem of steering oscillation. There are other solutions. Everyone swears by their favorite. I personally don't see why increased caster angle would have some beneficial influence. I can see why reducing the angle would. But I'm not going to rain on anyone's party. If you think it does, then there you go.
Tuned
Joined: Feb 2020
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You might want to do some independent research to understand the purposes of caster angle. As you note, it is being referenced as one of the solutions to the problem of steering oscillation. There are other solutions. Everyone swears by their favorite. I personally don't see why increased camber angle would have some beneficial influence. I can see why reducing the angle would. But I'm not going to rain on anyone's party. If you think it does, then there you go.
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Laughing Gas
Joined: Dec 2017
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Sooooo....... Would it be reasonable to say that the stability that comes from positive caster is due to the tendency of the wheels to return to center but too much positive caster can cause more of that return to center tendency than we want. So there’s a sweet spot between achieving the most benefit while minimizing negative effects. And Ford believes the sweet spot is at the low end of the spec range.
Fleet Mechanic
Joined: Apr 2018
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Sooooo....... Would it be reasonable to say that the stability that comes from positive caster is due to the tendency of the wheels to return to center but too much positive caster can cause more of that return to center tendency than we want. So there’s a sweet spot between achieving the most benefit while minimizing negative effects. And Ford believes the sweet spot is at the low end of the spec range.
You’ll find caster closer to ten than zero in some European performance cars. Some caster is better, provided you’ve got the rest of yourself in order.
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Hotshot
Joined: Jul 2013
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intuitively speaking..which may not be correct...one would think there would be more instability with + than with -. we talk about this because some lift kits will increase + castor and compensating is needed....adjusting back in the - direction.
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From: Northeast PA
My race cars are over 9 on the caster and they track like lasers on the straights.
Just knowing what "I think" I know about how to set up a race car and handling if I set a car up with 0 caster or near that it would be all over the place in a straight line.
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Laughing Gas
Joined: Dec 2017
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Yep, my gut would say to me that if I was having this wobble that i read so much about (I have a 2wd I dont think they get it) I would be taking my truck to my alignment guy and having him crank in as much caster as possible.
My race cars are over 9 on the caster and they track like lasers on the straights.
Just knowing what "I think" I know about how to set up a race car and handling if I set a car up with 0 caster or near that it would be all over the place in a straight line.
My race cars are over 9 on the caster and they track like lasers on the straights.
Just knowing what "I think" I know about how to set up a race car and handling if I set a car up with 0 caster or near that it would be all over the place in a straight line.
Senior User
Joined: Feb 2004
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From: Northeast PA
The “wobble”, for lack of a better term, on mine sends the truck straight down the road. But while it’s traveling in that straight line it’s shuddering and the steering wheel deflects rapidly back and forth. So from what I can gather, increasing positive caster will help with wander while decreasing positive caster will help with wobble. Somewhere in the middle is the best spot to achieve both. Or at least that’s as far as I’ve made it trying to scratch my head on this stuff!
These are new trucks. They should not be having the issues you would expect on a worn out POS 1974 truck.
I feel for you guys having to diagnose a problem that should never be.
So glad that it doesnt appear to afflict 2WDs
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Laughing Gas
Joined: Dec 2017
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I drove my previous F250 for 14 years. It was a 2004, the last model year with a leaf sprung front end. It drove better after 14 years than my new 2018 drives today. Don’t get me wrong, I’m happy with the new one aside from this one nagging issue. Once it gets sorted out I’ll be even happier but there’s no way I can put up with this for the next ten years so I’m determined to figure it out. I don’t get a new one very often so gotta get this one shaped up. I agree though, it’s an issue we shouldn’t have to be dealing with.
Mountain Pass
Joined: Aug 2017
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That is so messed up. I have read so many posts on the flaws in these SD front ends, wobble, wander, Death Wobble and I cannot believe Ford doesnt fix this.
These are new trucks. They should not be having the issues you would expect on a worn out POS 1974 truck.
I feel for you guys having to diagnose a problem that should never be.
So glad that it doesnt appear to afflict 2WDs
These are new trucks. They should not be having the issues you would expect on a worn out POS 1974 truck.
I feel for you guys having to diagnose a problem that should never be.
So glad that it doesnt appear to afflict 2WDs
Every suspension design has flaws or weaknesses. You wont get wobble on an ifs chevy but you get a host of other issues. especially additional service items and significant loss of strength.
Freshman User
Joined: May 2020
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From: Houston, TX
Add caster, moog makes bushings (metallic) to increase. They are $15. That and the stabilizer kits that are on the market. There are good videos online that discuss this.
This is a great video explaining the whole deal:
This is a great video explaining the whole deal:
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