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Old 07-21-2021, 03:41 PM   #1
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Alignment and steering looseness

In a previous post I commented that on the way home it felt somewhat loose in the steering. A comment was that it should drive like a Cadillac but of course that's a relative comment not exact. We're on a trip up in the NC mountains and I'll describe the handling as some oversteer tendency and loose. Obvious push by larger vehicles that pass. It's not dangerous by any means but annoying and has an increased workload driving. I know that the chassis are supposedly set/aligned by the Ford factory before delivery to the RV manufacturer and that Thor in this case makes no effort or alignment after the house is built on it. My local Ford dealer is a small one and doesn't have any alignment that can take large vehicles. I do know a truck shop that I used for tire and alignments with my previous DP on a FL chassis.

I have tried finding what Ford recommends or makes on the F550 chassis but having difficulty. Default searches end up with 150-350 which of course is mostly useless. For any here who took their F550 chassis RV to the alignment shop, do you remember what your alignment numbers were before and after aligning? Also what handling characteristics did you have before and how did the alignment fix that?

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Old 07-21-2021, 04:41 PM   #2
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Any business that will work on your motorhome alignment, will have the numbers.
Any customer who came on telling me where to set the alignment would be asked to leave because the liability would be huge.
The very adamant customer/housewife would sure lose their expertise/adamancy when in a witness box.

Trust the shop you trust.
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Old 07-21-2021, 05:43 PM   #3
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Originally Posted by ducksface View Post
Any business that will work on your motorhome alignment, will have the numbers.
Any customer who came on telling me where to set the alignment would be asked to leave because the liability would be huge.
The very adamant customer/housewife would sure lose their expertise/adamancy when in a witness box.

Trust the shop you trust.
Yes but I'd like to know what the starting figures are from Ford as opposed to what it has when taken in. I have confidence in the shop but I also like to be informed so they are not explaining stuff I already know, or should know. As a side question, doesn't anyone know what a 550 chassis weighs when delivered to Thor? Mostly a curiosity thing on my part.

I found alignment figures for up to 350 and there is a range. Going from one extreme of a range can have some handling differences and I'd like to optimize mine. If you don't know the answer perhaps someone else does.
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Old 07-21-2021, 07:42 PM   #4
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Quote:
Originally Posted by chunker21 View Post
In a previous post I commented that on the way home it felt somewhat loose in the steering. A comment was that it should drive like a Cadillac but of course that's a relative comment not exact. We're on a trip up in the NC mountains and I'll describe the handling as some oversteer tendency and loose. Obvious push by larger vehicles that pass. It's not dangerous by any means but annoying and has an increased workload driving. I know that the chassis are supposedly set/aligned by the Ford factory before delivery to the RV manufacturer and that Thor in this case makes no effort or alignment after the house is built on it. My local Ford dealer is a small one and doesn't have any alignment that can take large vehicles. I do know a truck shop that I used for tire and alignments with my previous DP on a FL chassis.

I have tried finding what Ford recommends or makes on the F550 chassis but having difficulty. Default searches end up with 150-350 which of course is mostly useless. For any here who took their F550 chassis RV to the alignment shop, do you remember what your alignment numbers were before and after aligning? Also what handling characteristics did you have before and how did the alignment fix that?
Since you have a solid front axle with coils, the same king pin angle as I and solid rear with leaf springs , I will assume the things that worked for me MIGHT help for you. My coach had way too much body roll on uneven surfaces and the coach did move over when trucks passed on two lane roads. Four Sumo Maxim springs took care of the roll and much of the bow wave push. The coach did not track true on smooth surfaces, so I had the springs shimmed to 6 degree caster and the toe in set to 1/16" over 66 inches. Lastly, I felt the dolly pull the rear on tight turns, so I added a rear track bar. The 18,000 lb coach now tracks true in all conditions and has limited body roll on uneven surfaces. 38,000 happy miles!
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Old 07-21-2021, 08:09 PM   #5
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Alignment and steering looseness

I have an appointment next Tuesday (7/27) to get an alignment on my 2020 Magnitude SV34. We have a two month trip and 6000 miles starting late August so I thought it made sense to get an alignment before we leave… especially now that I have 12,000 miles on the coach. Plus I recently added that 250lb heavy duty bumper and guard.

Thor recommends we get our coaches aligned after delivery because they are not aligned by Thor…. only Ford as a cab chassis config… and everything changes once the coach has been built with the added length, height and weight.

I haven’t had it aligned yet so I will let you know what they say. I have a Ford Commercial Truck Service Center close by I have used but I’m taking it to a place that specializes in heavy truck alignment, suspensions, etc and has a very good reputation. I’m also having them check the front and rear springs to get their opinion as to whether the stock suspension is adequately holding the weight and keeping the coach level.

They said they would need to do any spring changes before they align it. They also said the F-550 has a pretty stout suspension and if it is sitting level they won’t need to do anything.

I felt my steering was slightly “loose” but nothing like my Outlaw 29H was before I made several suspension upgrades. The steering wheel is also slightly off center. I have also read the stock steering damper isn’t the best (there is actually a TSB for it). I just replaced mine with a Bielstein model because it was plug-and-play. I would have preferred the Roadmaster but I didn’t want to mount it with a bracket. I took one short trip since I replaced it and the steering feels a little better.

We’ll see what the alignment shop does and I’ll report back. I’m taking it in with a full load of fuel and water and pretty much loaded down the way it will be on our trip.

As an FYI…. The Sumo Springs I installed did soften the ride over bridge transitions and rougher roads.
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Old 07-21-2021, 08:43 PM   #6
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Originally Posted by chunker21 View Post
As a side question, doesn't anyone know what a 550 chassis weighs when delivered to Thor? Mostly a curiosity thing on my part.
I have the Super Duty Chassis Cab brochures and spec sheets but none of them list the dry weight of the chassis cab as delivered. There are also four different wheel base configurations for the F-550 and I don't know which one Thor purchases from Ford. My wheelbase is 249" and the longest one available from Ford is 205".
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Old 07-21-2021, 08:45 PM   #7
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Originally Posted by Judge View Post
I have an appointment next Tuesday (7/27) to get an alignment on my 2020 Magnitude SV34. We have a two month trip and 6000 miles starting late August so I thought it made sense to get an alignment before we leave… especially now that I have 12,000 miles on the coach. Plus I recently added that 250lb heavy duty bumper and guard.

Thor recommends we get our coaches aligned after delivery because they are not aligned by Thor…. only Ford as a cutaway chassis… and everything changes once the coach has been built.

I haven’t had it aligned yet so I will let you know what they say. I have a Ford Commercial Truck Service Center close by but I’m taking it to a place that specializes in heavy truck alignment, suspensions, etc and has a very good reputation. I’m also having them check the front and rear springs to get their opinion as to whether the stock suspension is adequately holding the weight and keeping the coach level.

They said they would need to do any spring changes before they align it. They also said the F-550 has a pretty stout suspension and if it is sitting level they won’t need to do anything.

I felt my steering was slightly “loose” but nothing like my Outlaw 29H was before i made several suspension upgrades. The steering wheel is also slightly off center. I have read the stock steering damper isn’t the best. I just replaced mine with a Bielstein model because it was plug-and-play. I would have preferred the Roadmaster but I didn’t want to mount it with a bracket. I took one short trip and the steering feels a little better.

We’ll see what the alignment shop does and I’ll report back. I’m taking it in with a full load of fuel and water and pretty much loaded down the way it will be on our trip.

As an FYI…. The Sumo Springs I installed did soften the ride over bridge transitions and rougher roads.
Beau and judge thanks. I equate the looseness to a wandering of sort. Requires more attention and corrections that I think should be required. Overall ride quality is good but we did hit one bridge transition that I thought my teeth might come out. Nothing inside fell off but we do have the cabinet contents pretty secure. The ride/looseness is pretty consistent with road surfaces. The oversteer is a bit disconcerting because of the seemingly inconsistent amount of steering needed in turns. That results in that looseness feel and wandering. Steering wheel itself has no play and is set straight.
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Old 07-21-2021, 08:55 PM   #8
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Originally Posted by chunker21 View Post
Beau and judge thanks. I equate the looseness to a wandering of sort. Requires more attention and corrections that I think should be required. Overall ride quality is good but we did hit one bridge transition that I thought my teeth might come out. Nothing inside fell off but we do have the cabinet contents pretty secure. The ride/looseness is pretty consistent with road surfaces. The oversteer is a bit disconcerting because of the seemingly inconsistent amount of steering needed in turns. That results in that looseness feel and wandering. Steering wheel itself has no play and is set straight.
I would agree that the "looseness" is more of a wandering. I would not say it wears me out or is a white nuckle experience but more of a nuisance. My E-450 Outlaw 29H with the stock suspension was a white knickle drive. After 5 hours of driving it I was worn out. I have driven as long as 12 hours with the F-550 and while tired at the end I was not worn out from keeping it between the lines.

That being said.... I am somewhat like you. I want it to track straight with as little input needed as possible on straight, even roads. I think the alignment will get it where I want it to be. Since Thor does not align the coaches once they are built, I am sure the Ford factory alignment is no longer valid based on the build.
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Old 07-21-2021, 10:12 PM   #9
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Originally Posted by Judge View Post
I would agree that the "looseness" is more of a wandering. I would not say it wears me out or is a white nuckle experience but more of a nuisance. My E-450 Outlaw 29H with the stock suspension was a white knickle drive. After 5 hours of driving it I was worn out. I have driven as long as 12 hours with the F-550 and while tired at the end I was not worn out from keeping it between the lines.

That being said.... I am somewhat like you. I want it to track straight with as little input needed as possible on straight, even roads. I think the alignment will get it where I want it to be. Since Thor does not align the coaches once they are built, I am sure the Ford factory alignment is no longer valid based on the build.
My thoughts exactly and was hoping I could find "some number" to compare with what it has and what I get.
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Old 07-21-2021, 11:09 PM   #10
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I had mine aligned sometime after I got it. Don't recall the numbers. Could maybe find it with digging. Actually I probably posted about it here a long long time ago. I had it done at Josams in Orlando.
I really should get it done again...it's been too long

Also, search for posts by a user named Harvard. Not 100% certain he posted here but I've seen lots of posts by him over the years I think on multiple forums. Anyway he had some plausible suggestions re. camber angles.

I'll say this....in my experience tire pressure is perhaps a more critical variable regarding this issue. Once I aired my steer axle down based on weight, my handling greatly improved. That + the alignment and I see no need for my rig for any of the fancy steering centering devices (although i would like to have one for their intended purpose of helping during a blow-out).

Anyway, if you don't know, you should set tire pressures based on load, not on the sidewall spec or on the door jamb placard. Those are max load numbers.
Micehlin I know publishes the numbers....and contrary to popular believe these are not brand specific numbers.... it's industry standard based on size.
odd...I can't find a link to michelin's chart at the moment
but here's one from toyo
https://www.toyotires.com/media/3729...s_20200723.pdf

one last thing...a nice handling guide for better understanding
linked to in this post
https://www.rvforum.net/threads/coac.../#post-1168464
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Old 07-22-2021, 12:18 AM   #11
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All RV manufactures start with a bare chassis. They then add a ton of weight to the chassis. You need to find out how much weight should be on the front end and how much is on the front. With a light front end you will feel the wind and semi passing much more and it will not handle well until the rear is lifted to shift enough weight onto the front to stabilize it. Everything else is a band aid and will not fix it. Then a front end alignment. After that, other things if needed.
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Old 07-22-2021, 12:37 AM   #12
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Originally Posted by blw2 View Post
Anyway, if you don't know, you should set tire pressures based on load, not on the sidewall spec or on the door jamb placard. Those are max load numbers.
Micehlin I know publishes the numbers....and contrary to popular believe these are not brand specific numbers.... it's industry standard based on size.
odd...I can't find a link to michelin's chart at the moment
but here's one from toyo
https://www.toyotires.com/media/3729...s_20200723.pdf

one last thing...a nice handling guide for better understanding
linked to in this post
https://www.rvforum.net/threads/coac.../#post-1168464
I have Continental Tires and I have their pressure-to-weight recommended inflation chart. Based on my front end weight my pressures should be 85 cold and I am right about 85 - 87 depending on temperature fluctuations.

I need to get weighed again since I added the heavy duty front bumper.

I am sure an alignment will help given the length, height and weight added to the bare chassis aligned by Ford.
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Old 07-22-2021, 12:40 AM   #13
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I weighed it a couple weeks ago, see "trip to the scales" post on this sub-forum here. My weight distribution is 32-68% and under GVWR by 1300+# and under both axles GVWR. I figure that's within 500 of our travel weight which will have us nicely under GVWR. I have continental tires and couldn't find a weight vs psi chart for them. I looked at the charts by blw and Toyo tires, but they don't show any my size, 19.5.
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Old 07-22-2021, 12:42 AM   #14
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Originally Posted by Judge View Post
I have Continental Tires and I have their pressure-to-weight recommended inflation chart. I am near the max weight on my front end so my pressures should be 87 cold for that weight and that is right about where I am.

I am sure an alignment will help given the length, height and weight added to the stock chassis.
Judge can you send me the link. I couldn't find one for Continental. I'm currently running the 95 and 110 and would certainly be willing to run less if I had a good figure.
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Old 07-22-2021, 12:53 AM   #15
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Originally Posted by chunker21 View Post
Judge can you send me the link. I couldn't find one for Continental. I'm currently running the 95 and 110 and would certainly be willing to run less if I had a good figure.
Here you go.....
Attached Files
File Type: pdf ContinetalTire-medium-radial-chart-data.pdf (98.6 KB, 19 views)
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Old 07-22-2021, 12:58 AM   #16
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Originally Posted by Judge View Post
Here you go.....
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Old 07-22-2021, 01:11 AM   #17
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This is an interesting read on handling and tire pressures. Now it is a car and not a coach but I believe the same principles apply.

https://www.tirerack.com/tires/tiret...e.jsp?techid=2

This is also good to read....

https://www.tirerack.com/tires/tiret...e.jsp?techid=1
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Old 07-22-2021, 01:14 AM   #18
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Originally Posted by Judge View Post
Here you go.....
A brief look at that chart and I should probably be running 80 and 95 instead. Basing that on my scale numbers and estimated weight for this trip. Regardless the Thor recommended numbers of 95 and 110 are too high based on the Conti chart. I'll drop the pressures tomorrow and see how it drives Saturday our next travel day. I'll study the charts tomorrow also without the help of my current adult beverage.

Edit; PSI correction
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Old 07-22-2021, 03:58 AM   #19
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I am running 85psi front and 95psi rear. I have not had mine aligned and it does not need it, fully loaded and a 14' trailer behind with a Kawasaki Teryx on it, it drives perfect, one handed driving you can take your hand off the wheel and it does not wander off, tracks straight, even my wife enjoys driving it. It just turned over 13k miles on our last trip, and the wife drove all the way across Nebraska.
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Old 07-22-2021, 12:24 PM   #20
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Originally Posted by kwplot34 View Post
I am running 85psi front and 95psi rear. I have not had mine aligned and it does not need it, fully loaded and a 14' trailer behind with a Kawasaki Teryx on it, it drives perfect, one handed driving you can take your hand off the wheel and it does not wander off, tracks straight, even my wife enjoys driving it. It just turned over 13k miles on our last trip, and the wife drove all the way across Nebraska.
I don't remember from your previous posts but have you weighed it and what rationale did you use for those figures? Based on my scale ticket, there is no way I can exceed either axle weight rating without exceeding GVWR. And it would be very difficult to put weight so that I exceeded either axle weight. I was 1380 under GVWR and on the trip I have added HER, our clothes, some groceries, and my hoses etc. I figure I used about maybe 600# of that mostly distributed midships. Using the Continental tire chart that judge provided, I found my axle weights, rounded up to the nearest 5 psi and came up with 80 and 95. That's what I'm got to set today for Saturday's drive. If I come across a CAT scales I'll jump on it. IF this fixes the handling then I'll postpone alignment.

I'll have 4 weeks before the next 3 week trip and several things to do such as replace 2 seater couch, install crossfire, wash and wax, and fix myself some small "warranty items" that are easier for me to do than wait on Thor and CW.
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