Cheap Handling Fix

[arcaguy]

Originally Posted by TeJay

It's time again to enlighten folks regarding the factory's insistence that all RV's need to be aligned after they are loaded. Lets look at facts that may not be apparent.

The F-53 chassis has two fixed axles. The front is a solid axle. It has preset front camber. To adjust camber the axle has to be bent cold which is not recommended by Ford. The front toe is adjusted by the tie rod and usually set around 1/16" towed in. The caster is set by installing shims.

The rear axle is a solid differential. There are no rear alignment angles: caster, camber or toe. The exception would be the position of the differential in relation to the frame . The axle should be at right angles.

So how can added weight effect the alignment? It won't!! Nothing regarding the set alignment angles changes. One aspect (caster) that can change. If the owner/builder adds to much weight to the front/rear the caster can change.

Caster changes all the time. We add/adjust liquid weight (water/waste/fuel/supplies) all the time. Level front to back is always changing. Just don't be way off permanently by added tools/gear etc.

Two more points. Why then do they always tell us to have an alignment after we load down the RV? If you have an independent front suspension Angles can change with added weight. Second reason is they are covering their butts. Why do I say that?

Second point. Our new RV pulled towards the ditch driving it home from Forest City Iowa. Ford agreed to pay for an alignment after 700 miles and ALL of the factory set angles were off.

Why do I believe they were all off? I know how to do alignments and I helped the alignment tech. We have 36,000 miles and little to no tire wear. After 4 years we had some slight front tire wear so he checked the settings and they were still OK.

There are only 3 reasons to perform an alignment.

1. The first or last alignment was not performed correctly by the tech.
2. There are worn front end parts:king pins, ball joints, tie rods.
3. A front end part was bent hitting something.

Any of the above reasons can cause tire wear but since tire wear can be caused by incorrect tire pressures is not a primary reason to perform an alignment. Of the three angles two will cause front tire wear: toe and camber.

I'm certain manufacturers will continue to tell us to have the RV aligned. I'm also certain many folks will still believe what they tell them. I do believe it is important to have the RV aligned because as was demonstrated to me they DID NOT perform an alignment at the factory or they did it incorrectly.

I'm confused. The first part of my confusion comes from TeJay saying that there are no angles to be adjusted on the rear axle. This is simply not true. If he is supposed to be trained in alignment of vehicles he would know that are two angles that can be changed on a live axle rear suspension.While adjustment of these two angles is uncommon and generally not performed on any street vehicle they can be and are changed for special purpose (racing) vehicles.

The first is the front to back position (squareness) of the rear tires on the vehicle. Oval track cars many times have the rear tires out of square to negotiate the left hand turn only tracks better.

The second of these is pinion angle (the angle of the centerline of the pinion in relation to the drive shaft). Again, this may not be a normal adjustment on street vehicles but on drag racing vehicles it is a normal adjustment to point the pinon gear down 1-2 deg. so when the car is under hard acceleration the pinion gear is more nearly in line with the driveshaft due to spring wrap. Again, these two adjustments only apply to live axle (leaf spring) rear ends and would not generally be adjusted from the factory setting.


The second issues I have is TeJay saying that the front alignment angles won't change with the weight of the vehicle. This is simply not the case. While Tejay is correct that the caster and camber will not change on a straight axle front end regardless of the weight, this is not true for the toe. (To be exactly correct here the caster will change ever so slightly due to the frame being tilted some small fraction of a degree from the weight added to the front or rear of the coach, but this change is completely immaterial and possibly not measurable with normal equipment.)


The steering gear is attached to the frame, and the wheels are attached to the front axle which is attached to the frame via springs. As the front end moves up and down, whether from bumps or weight, the distance from the steering gear to the front wheels will change as they move in relation to each other. Generally the tie rods on any vehicle are pointed slightly downward. As the wheel bounces upward the distance between the attachment point on the steering gear and the steering arm at the wheel will get shorter. As the tie rods are fixed in length while this is going on there will be a slight increase in toe out while the wheel is above it's normal ride position. As the wheel returns to it's normal ride position this toe out gain will return to normal. However, if the ride position (ride height) of the front axle is more or less permanently changed, as it is when the load on the front axle is increased, the toe angle will change permanently until the load is returned to "normal".



If as TeJay has stated, Ford doesn't know how to align vehicles, I guess all of the above-discussed angles should be checked. Personally I would just have the front end aligned with special attention being paid to the toe angle.



Sorry for the length, but TeJay was simply wrong with a couple of his blanket statements, and I felt I should set the record straight.

[twinboat]

It may already been done or a HD anti sway bar installed by the previous owner.

Originally Posted by Linc2014

I previously had a 30' Holiday Rambler Arista with no suspension mods and it was a white knuckle affair when big rigs passed or when I was slammed by a crosswind. Our drive to the Grand Canyon from San Diego last year was exhausting! I recently sold the Rambler and purchased a Coachmen Mirada 35BH.

We recently took our first long(ish) trip in the Coachmen to Mammoth Lakes in the Sierras which is about 400 miles one way from our home, lots of steep grades, two lane freeways and tons of semis. I fully planned on doing the CHF before leaving, but time didn't allow so we made the trip without. I was fully expecting the worse, but I was stunned by how well it handled, I barely felt the big rigs or crosswinds and this is without any suspension mods. I'm sure the longer wheelbase (242") combined with the bigger chassis (22K), has a lot to do with it or maybe it was my experience with my previous rig, but I really was pleasantly surprised.

I guess my question is to the other members with similar size chassis and wheelbase that have done the CHF. How much of an improvement did you see? Perhaps the CHF benefits motorhomes with lighter chassis and shorter wheelbase? I'm currently happy with the way it drives, but if the CHF can further improve things, I'm in.

Thanks
Mike

[twinboat]

Toe out and in does not change on a solid front axle. The single tie rod goes from the left wheel to the right wheel. Everything moves together.

The drag link goes from the left front wheel to the steering box pitmin arm.

With independent front suspension, the toe changes slightly when the wheels articulate.

Originally Posted by arcaguy

I'm confused. The first part of my confusion comes from TeJay saying that there are no angles to be adjusted on the rear axle. This is simply not true. If he is supposed to be trained in alignment of vehicles he would know that are two angles that can be changed on a live axle rear suspension.While adjustment of these two angles is uncommon and generally not performed on any street vehicle they can be and are changed for special purpose (racing) vehicles.

The first is the front to back position (squareness) of the rear tires on the vehicle. Oval track cars many times have the rear tires out of square to negotiate the left hand turn only tracks better.

The second of these is pinion angle (the angle of the centerline of the pinion in relation to the drive shaft). Again, this may not be a normal adjustment on street vehicles but on drag racing vehicles it is a normal adjustment to point the pinon gear down 1-2 deg. so when the car is under hard acceleration the pinion gear is more nearly in line with the driveshaft due to spring wrap. Again, these two adjustments only apply to live axle (leaf spring) rear ends and would not generally be adjusted from the factory setting.


The second issues I have is TeJay saying that the front alignment angles won't change with the weight of the vehicle. This is simply not the case. While Tejay is correct that the caster and camber will not change on a straight axle front end regardless of the weight, this is not true for the toe. (To be exactly correct here the caster will change ever so slightly due to the frame being tilted some small fraction of a degree from the weight added to the front or rear of the coach, but this change is completely immaterial and possibly not measurable with normal equipment.)


The steering gear is attached to the frame, and the wheels are attached to the front axle which is attached to the frame via springs. As the front end moves up and down, whether from bumps or weight, the distance from the steering gear to the front wheels will change as they move in relation to each other. Generally the tie rods on any vehicle are pointed slightly downward. As the wheel bounces upward the distance between the attachment point on the steering gear and the steering arm at the wheel will get shorter. As the tie rods are fixed in length while this is going on there will be a slight increase in toe out while the wheel is above it's normal ride position. As the wheel returns to it's normal ride position this toe out gain will return to normal. However, if the ride position (ride height) of the front axle is more or less permanently changed, as it is when the load on the front axle is increased, the toe angle will change permanently until the load is returned to "normal".



If as TeJay has stated, Ford doesn't know how to align vehicles, I guess all of the above-discussed angles should be checked. Personally I would just have the front end aligned with special attention being paid to the toe angle.



Sorry for the length, but TeJay was simply wrong with a couple of his blanket statements, and I felt I should set the record straight.

[phil-t]

Originally Posted by arcaguy

I'm confused.

I get your "point"! Let us know when you see an oval race event for F53 Motorhomes. LOL

Can't wait for the new F53 chassis specs to be released by Ford. Hoping for some big changes, there, other than engine and transmission that will improve the handling for Class A Motorhomes.

[TeJay]

arcaguy,

I don't know why you are confused. What part of this quote says that I forgot how and why caster changes when weight is added??? I thought it was fairly clear.

"Caster changes all the time. We add/adjust liquid weight (water/waste/fuel/supplies) all the time. Level front to back is always changing. Just don't be way off permanently by added tools/gear etc. "

This is a quote from your response. Why mention something that is not often performed especially on an RV?

"While adjustment of these two angles is uncommon and generally not performed on any street vehicle they can be and are changed for special purpose (racing) vehicles.

Often I skip insignifiant bits of info based on how necessary it is to mention. This was one of those times. Why waste time with unnecessary responses and comments concerning things that are not generally performed on an RV chassis???

Please be careful making false statements. I never stated that FORD didn't know how to perform an alignment. Here's my quote concerning that issue.

"I do believe it is important to have the RV aligned because as was demonstrated to me they DID NOT perform an alignment at the factory or they did it incorrectly. "

"They" is referring to the WBGO factory and not FORD. WBGO does state their MH's are aligned after the build and before they leave the factory. I don't know what Ford might do concerning an alignment with a bare chassis. And it's the builder who tells us to have the chassis aligned following the build. As stated I still firmly believe it's just a way for the factory to cover their butts.

See you at the drag strip!!!

[Waiter21]

I can see how added weight would make a very, very small change to caster, but it would be insignificant. Same with toe, insignificant..


The next time I check my toe, I'll do it with different axle heights and take some measurements..

[sask934]

I did the cheap fix on my Motorhome and had the shocks replaced as well. It was better for sure. The mechanic who works on a lot of motorhome said that I had the sway bars incorrect. I showed him this thread and he was intrigued and said he wanted me to let him know how it went.

[MathComp]

Originally Posted by sask934

The mechanic who works on a lot of motorhome said that I had the sway bars incorrect. I showed him this thread and he was intrigued and said he wanted me to let him know how it went.

Interesting that he'd never seen it before. I wonder how many motorhomes out there have the CHF and how many don't and how many owners and mechanics have never heard of it.

A used Winnebago Vista showed up for sale yesterday at the RV dealership down the road from me. DW and I had to check it out, of course, just because we're nosy. I looked underneath and, sure enough, CHF in front, but not back. Made me smile. It also had a Safe-T-Plus steering stabilizer, but that's off topic.

Thanks,
MathComp

[sask934]

Originally Posted by MathComp

Interesting that he'd never seen it before. I wonder how many motorhomes out there have the CHF and how many don't and how many owners and mechanics have never heard of it.

A used Winnebago Vista showed up for sale yesterday at the RV dealership down the road from me. DW and I had to check it out, of course, just because we're nosy. I looked underneath and, sure enough, CHF in front, but not back. Made me smile. It also had a Safe-T-Plus steering stabilizer, but that's off topic.

Thanks,
MathComp

This thread started a long while ago. I am from Saskatchewan Canada and the mechanic I took my motorhome to has done a lot of work in motorhome sand he had never heard of it. He said it should make a difference. His shop is a 4th generation shop and he is a quality mechanic who does good work at a fair price. He does all the mechanic work for a large RV outfit here. I am not surprised that people did this as just my drive to and from the mechanic was a lot better.,

[Waiter21]

the mechanic I took my motorhome to has done a lot of work in motorhome sand he had never heard of it.

Not surprising... I like to do my informal survey when I'm p[arked in RV parks. I walk around and usually from the road, I can see the front sway bar and can tell if the CHF has been done. I'd say 1 in 100 have the CHF.

[EdInArk]

Originally Posted by Waiter21

Not surprising... I like to do my informal survey when I'm p[arked in RV parks. I walk around and usually from the road, I can see the front sway bar and can tell if the CHF has been done. I'd say 1 in 100 have the CHF.

Same here. It seems almost nobody has even heard of it. I told a young man about it last fall and emailed him a link to this thread. He emailed me a couple of weeks later raving about the improvement.

[TeJay]

WE are on our third MH. Two of them were on the F-53 chassis. It wasn't until our 3rd MH that I decided to investigate and determine which brand and chassis I wanted to buy. That was back in 2011 or 2012 and I found this forum and started the journey. We looked and studied until 2013 and then ordered the RV that we currently have.

Most folks just go to an RV dealer and listen to the sales pitch. Because we owned two others I knew I needed to do some research.

[blueridge-fl]

As I previously mentioned, I set the front SB to the CHF+1 position using TeJay's plates. This past weekend we went on a 350 mile trip and the setting provided a big improvement over the regular CHF setting. There was less push in the front end from passing trucks and it took curves in a nice steady fashion (no longer needed to adjust the steering as I went through the curve). At the same time, I could detect no negative effect from the setting. This is definitely how I will leave the CHF going forward. This is on a 2018 Winnebago Vista 32YE (18k chassis).

[pkunk1]

I did the CHF many years ago. 4 days ago I pulled over for lunch into a somewhat unlevel pulloff and snapped the right swaybar bolt. Found some new grade 8 bolts at Ace Hardware to replace both and the origonals were not grade 8! It made a noise like a gunshot when it broke and the other had quite a bit of wear.