F53 handling problems,

[trx430ex]

Better half, O, no you did not just bring new leaf springs in the house,,,,, O, yes I did !!!



Just ripped out and replaced the 2006 22k springs in the front and replaced them with the 26k chassis springs. A world of difference. [with sumo's]




Getting set up in truck shop



Will get pics of install soon, just very busy trying to go south.

[trx430ex]

Another interesting find, and reason to replace the entire spring set. Reason, the bushing sets do where out and fail. Below is an image of the left front bushing pinched through the bushing, then rested on the steel of the spring. This definitely through the front end out of alignment.



The previous owner did say it went out of alignment a couple years ago. They re-aligned the rig with a wounded spring bushing. And the rig had some weird tire wear issues.

[TeJay]

Another lesson regarding alignments. There are only three thngs that can change the proper alignment settings:
1. The Last alignment was not done correctly.
2. Parts are worn out.
3. The owner hit something and bent something out of place.

Every good alignment begins with checking tire pressures. The next step is to do complete inspection and checking of all steering and suspension parts.

Performing an alignment with worn parts does not help anybody or anything except the shops cash drawer!!!

[trx430ex]

Finished 26k front springs, installed in 22k chassis F53. Max chassis spec.

[blueridge-fl]

Just so I am clear on this, you all are discussing increasing the spring rate to make the ride better (smoothness)? Or are you discussing making the handling better by increasing the spring rate?

[TeJay]

Increasing the spring rate is always a mixed bag of results. Most/many/some will say adding more SR makes the ride harsher or stiffer depending on your word of choice.

Example! Adding more or stiffer sprnings makes the ride stiffer or harsher. It also adds more sway control which is a handling issue. Changing shocks should be a ride and sway control issue but some will say it makes it harsher. That also depends on the shock or spring dampener used.

When trying to make decisions campare apples to apples. That is also a mixed bag. The difference between RV's is so varied even when comparing similar lengths and chassis weight we can achieve different results. That is due to the tire pressures used, traveling weight of each RV loading front to rear etc, etc.

We can say for certain that tire pressures can be adjusted similar to anothers RV but even then the different tires will have some effects on ride and handling.

On thing each owner can do is only make one handling/ride (MOD) change at a time and evaluate the results.

Also listening to result by others can help guide you. Many like the KONI shocks for a better smoother ride. Then again some don't. This fact I learned just a few years ago and was kind of surprised. Bilstein makes a shock for the F-53 but they list the same rear shock number for all chassis weights. I always thought shock designs and valving was changed based on the weight it was trying to dampen. I guess I was wrong.

About 4 months ago I added another set of shocks to our front. There are currently Koni's on all 4 corners. I added a set of Monroe truck shocks in the front. Most posters who added more shocks reported improved ride/handing. I wanted to give it a try!!!

We also noticed improved ride/handling and even though most said it would ride harsher I felt little to no greater ride harshness than before.

I do understand it will be stiffer or have better dampening from attempts by wind/semi's to roll/sway the RV. As far as I'm concerned that's just fine. The more solid the ride the better.

The F-53 chassis is a leaf spring truck chassis with 4 solid axle wheels. There is no independent suspension. I'd like a Cadillac ride but we will not get it.

I also added air bags to all 4 wheels and IMHO the ride is slightly better. Even if I can only achieve a 5% improvement I'll do it. Every 5% improvement is just that.

I've done and read a lot about the F-53 chassis and now with 43,000 + miles on this 18,000 LB 31' long chassis this is what I understand much better.

1. Start your tire pressures where the manufacturer says you should start. It's on the inside sticker. Don't worry about some accelerated tire wear. Most likely your tires will time out before you wear them out. Keeping the tires at a lower pressure will give you a smoother ride. If it's a little bit to low you will accelerate tire wear some. We got 40,000 miles on our first set and drove it from August 2014 until December of 2020 before we changed them.

2. The CHF is the best and cheapest MOD you can do and it has greately improved the F-53 chassis more than any other single MOD. Even the original RV wner John McKinley with the CHF back in 2010 never did anything else except move the links while in AK.

The last I knew his rear springs were sagging and he was talking about adding some air bags to fix that issue. I'd guess he has about 80,000 miles on his 2008-ish RV. Probably 40,000 + miles had the CHF. In fact we picked up our 2014 RV at the factory in IO with 40 miles on the odometer and I performed the CHF on it before we headed back to AR.

3. A steering/shock dampener is a great addition to improve handling.

4. The F-53 has had a front TB (Track Bar) from the factory since about 2006-ish. They still do not have a rear TB. Add a rear TB and that will greatly reduce lateral movement between the chassis and the suspension. Great addition.

5. I tried Sumo springs and did not like them. They are just another stiffening device but they will also add some harshness and more SR. Not a fan for the price. Some do like them so there we go again!

6. I'd like to see an adjustable shock for the F-53 chassis. We don't have many choices for shocks.

7. If you want a true air ride suspension spend another $30,000 and buy a diesel pusher.

[Nickd]

This is a great thread for both newbies and veteran f53 owners alike.
I have seen a few threads mentioning all the mods Tejay discusses here and have done a few of them with great improvement to the ride of our 18k F53.

However, this thread has one subject I had not seen much info on. The change of leaf springs with the addition of a spring.

Most here fear spring rate increase as the f53 rides like a log truck in most builds already.

I had thought Air bags would help with ride quality and according to Tejay, 5% improvement is at least noticeable.

The 2021 F53 has different springs for a reason. There was a lot of room for improvement on all versions. Nice of Ford to finally put appropriate sway bars on too. Welcome changes if you are in the market for a new rig.

But re-designing the spring packs on our rigs, adding ride height and a more progressive curve of that spring rate could really be a game changer in improved ride quality.

Thanks again Rigley for writing about your spring mod. Real world experience adds value to these threads and helps everyone in the community.

[Rigley]

Originally Posted by Nickd

This is a great thread for both newbies and veteran f53 owners alike.
I have seen a few threads mentioning all the mods Tejay discusses here and have done a few of them with great improvement to the ride of our 18k F53.

However, this thread has one subject I had not seen much info on. The change of leaf springs with the addition of a spring.

Most here fear spring rate increase as the f53 rides like a log truck in most builds already.

I had thought Air bags would help with ride quality and according to Tejay, 5% improvement is at least noticeable.

The 2021 F53 has different springs for a reason. There was a lot of room for improvement on all versions. Nice of Ford to finally put appropriate sway bars on too. Welcome changes if you are in the market for a new rig.

But re-designing the spring packs on our rigs, adding ride height and a more progressive curve of that spring rate could really be a game changer in improved ride quality.

Thanks again Rigley for writing about your spring mod. Real world experience adds value to these threads and helps everyone in the community.

Nickd
Finally got the coach back from the shop.
Took a 100 mile road trip freeway / roadways. After adding the rear track bar, front sway bar and the Safe T Steering Stablizer wow what a world of difference .
With the new added spring on each corner new bilsteins and rear sway bar . I can honestly say it rides great. Not stiff or harsh on the roads. Just fine with passing simi trucks . Handling my wife even will drive it now. As stated not cheap but as in my case the coach is a keeper so worth it. Good luck with everybody decisions

[trx430ex]

More backstory to why I am doing what I am doing.

1st off, this rig is a 2006, 14 years old @86,000 miles, these springs are not only tweaked out but also aged out. The old springs had waves running through the length of the spring, having been tweaked by some highway mishaps.

2nd this is the 3rd vehicle I have resprung & 2nd motorhome, improving with each iration. One of the biggest lessons was defending from North Carolina bridge approach [WWF] full body slams. Where the entire coach is picked up,,, then slammed back down on the bridge deck. That damaged the new spring set on the Tioga. Turns out Ford is a bit to blame for that with the design having 6 inches before the frame stops. When you push a spring set that far up, it will literally tweak the steel.

Hence the Sumo springs, stand in, to stop the spring set from going past spec and damaging the spring set. The spring set is designed to go so far down and so far up and that is it.

The ride is pretty good, [like stiff ride], but could use some more dampening.

This is still a work in progress, just like replacing all 6,-10 year old tires with new Sumitomo's, I am done with Michelins on the RV.

Were getting there.

[jpstakun]

Before throwing money at it with expensive suspension upgrades, get the front end aligned properly. That's probably responsible for your handling problems. Why do some coaches handle well and others don't? After Ford delivers the chassis, they have no control over how the coach builders pile stuff on top. When the suspension compresses with weight, the alignment changes.

[TeJay]

If you don't mind I'd like to clarify this alignment issue. There are basically 3 alignment angles that should concern us. Those are toe, caster and camber. The toe is adjusted by turning the tie rod in or out to change the toe angle. It's usually set to a toe in angle around 1/32" to 1/16". It is set in so as the parts involved wear the angle will gradually toe more and more towards an angle OUT. That will cause the tires to wear and changing the worn part is how it should be fixed.

During this time the toe is toed in slightly then goes to a neutral position then to a toe out position as the parts wear. YES toe angle is also a wear angle. Understand there is no perfect toe angle setting. It is a compromise. The best part is the heavy duty truck chassis steering parts do take many, many miles before they start to show signs of wear.

The next angle is camber. The F-53 chassis has a solid rear differential and a front cast iron axle. The desired camber or tilt in and out of the front tires is decided by the manufacurer. It is really not adjustable and some shops actually tell you it's not and other shops tell you is can be done. HOW? They have to cold bend the axle using hydraulic jacks. I know because I watched them adjust mine back in 2014.

Ford does not recommend they be adjusted (bent cold) but if your camber is off they probbly won't change the axle either. Where the manufacturer places the RV storage tanks, compartments and appliances has absolutely no effect on CAMBER. WHY?? You'd have to add enough weight to bend the front axle.

That's not to say that an RV manufacturer or an owner might screw up loading weight to the point that your RV leans but it still won't change the camber.

The laster angle is CASTER. That's the tilt fore and aft of the front wheels. That is adjustable using shims and yes weight effects how far each axle is compressed which may change the caster. In reality your caster is always changing slightly based on your storage tanks weight.

The best example I can give you of excessive postive caster is a MC chopper. The front wheel is way out. That is what allows us to ride our bicycle with no hands. All we have to do is lean left and right. The weight pushing down on the tires also forces the steering wheel to return to center.

It is adviseable to have your F-53 chassis set to as much + caster as they will allow. Some shops refuse to go beyond what the manufacturer recommends.

Lets start with a level chassis frame. If the frame is level and the caster is say 4 degrees +. If you add 400 lbs to the front and 600 to the rear you will probably change the caster since the rear may be lower than the front. If after loading your RV it's at the same level position then it won't change caster.
Since in the latter case it didn't go lower we can assume the leaf spring suspension is supporting the weight keeping it level. If you fill the rear fresh water tank (40 gallons at 8 lbs /gallon = 320 more lbs) beause you are going boondocking it may not be level and your caster will change.

Changing caster will not effect tire wear but it will effect how it handles. Most of us over the years have over filled a pickup truck with fire wood or bags of concrete and noticed how differently it handled going home. It usually felt a bit squarriley or disconnected from the road.

Most RV manufacturers will tell you they aligned your RV after it was built. That's supposed to make you feel better. When I took mine in to have the alignment checked EVERY single angle was incorrect. They adjusted all three angles and all was well for the next 43,000 miles. When it had about 35,000 I noticed some front tire wear and they checked all angles. They were as set before. The tires were showing some signs of wear based on my slightly lower tires pressures. I was happier driving an RV that rode smoother and had some slight tire wear. I added a few lbs of pressure and all went well until we changed the tires at 40,000 miles.

[trx430ex]

just got the front end alignment.



Seems to be tracking better, but need to put some miles on.

Also have 6 new Sumitomo tires on all 4 corners now, sure that helps, 10 year old Michelins are gone.

[TeJay]

I'm sure my caster is closer to 6# than 5#. I wanted it that way to have more weight pressing down on the tires to force the steering wheel straight ahead. That extra weight also helps to fight the winds trying to push the front end around.

As stated on my post above some shops refuse to go beyond what the manufacturer specifies and they did not change your caster in the least.

They did increase your total toe in from .05 to .10 degrees so maybe that helped with tracking but with no change to caster you may not like it.

I don't know what 10# of toe translates to in inches. Most truck shops recommend 1/32" per side or total toe of 1/16".

[Harvard]

Starting to see examples of F53s at +7 plus some.