Ford F53 suspension Class A mods

[Thor29.3inAZ]

I did a search and found nothing in regards to the F53 chassis. So.... I live in AZ and the roads are the roughest I've come across in years. The I-40 across the state will make you think you are on a off roading trip.
What I would like to know from other F53 class owners is.... What mods have you done that made the biggest difference in ride and handling. I have done the "Cheap Handling Fix" but that is about it right now. I did find that tire pressure made a difference in ride for sure. However, from some of the tire shops, have different ideas from what my placard says. We had a blow out from damage in between the rear duals and the tire guy said I should be running my pressure at 110 psi (max labeled on the tire: 245/70 19.5). But.... the recommended psi on the placard is 85 psi. From some research it is recommended to weight the coach and go from there. I called Thor and asked what the weight was when if left the factory. 17,890 lbs. We have a 29.3. For the sake of argument, I'm sure it will be a bit heavier on the driver side due to the slide out. And normally run the tire pressure around 90 psi.
So one shop mentioned to try a different shock. He had installed a set of Koni's and said it made a big difference in ride. Many say the Bilsten's make a big difference too.
So to get this to ride a little better should I...... Install the Koni's or Bilsten's? Add a beefier sway bar or stay with the CHF? Keep the tire pressure at max or what Thor has recommended? Any input would be great!

[axis earl]

Originally Posted by Thor29.3inAZ

I did a search and found nothing in regards to the F53 chassis. So.... I live in AZ and the roads are the roughest I've come across in years. The I-40 across the state will make you think you are on a off roading trip.
What I would like to know from other F53 class owners is.... What mods have you done that made the biggest difference in ride and handling. I have done the "Cheap Handling Fix" but that is about it right now. I did find that tire pressure made a difference in ride for sure. However, from some of the tire shops, have different ideas from what my placard says. We had a blow out from damage in between the rear duals and the tire guy said I should be running my pressure at 110 psi (max labeled on the tire: 245/70 19.5). But.... the recommended psi on the placard is 85 psi. From some research it is recommended to weight the coach and go from there. I called Thor and asked what the weight was when if left the factory. 17,890 lbs. We have a 29.3. For the sake of argument, I'm sure it will be a bit heavier on the driver side due to the slide out. And normally run the tire pressure around 90 psi.
So one shop mentioned to try a different shock. He had installed a set of Koni's and said it made a big difference in ride. Many say the Bilsten's make a big difference too.
So to get this to ride a little better should I...... Install the Koni's or Bilsten's? Add a beefier sway bar or stay with the CHF? Keep the tire pressure at max or what Thor has recommended? Any input would be great!

I have a cousin who bought a slightly used Itasca on the F53 chassis. He added Koni shocks, Saf-T-Plus and adjustable airbags. Seems quite happy with the results. Weighing the rig and setting the tires' air pressure that would be recommended is also a must. I would suggest talking with a reputable RV service center in your area rather than throwing money under the coach.

[DocP]

I also had the Koni shocks and Saf-T-Plus steering stabilizer installed (after having the alignment checked), and felt that there was a significant improvement in handling. With regard to tire air pressure, my dealer had all of the tires set at 95 psi - this was what was on the sticker inside the coach on the driver's side.

I felt that the ride was a bit harsh at 95 psi, so I had the coach weighed on all 4-wheels. Here’s what mine came out to be (fully loaded, with full tank of gas and water):


Left front: 3380 lbs
Right front: 3360 lbs
Left rear: 6140 lbs
Right rear 5660 lbs
Total front: 6740 lbs
Total rear: 11800 lbs
Total vehicle weight: 18540 lbs

We then went to the Goodyear tire charts. Based on my weights, it was recommended that I run 80 psi on both the front and rear tires (and not the 95 psi that the RV dealer had them set at). I was told that I could go as low as 75 psi if I was still not satisfied with the ride. I’ve got to tell you that the new psi made it a much smoother ride, so the money spent on the 4-wheel weighing was well worth it.

[SuperD]

You need to stay away from the shop that told you to run 110 psi, they're morons! DocP is correct, get accurate weights and set your pressures accordingly.

You can spend LOTS of money on suspension goodies but you have to understand you are driving on a truck chassis with a house on it. The MH is never going to have a car like ride, it's always going to rattle.

A set of Bilstein or Koni shocks will help SOME, they are an improvement over stock. Even a DP with air suspension rides rough on bad roads, just not much you can do about that. I-40 is rough every where, not just Arizona!!!

[EA37TS]

Thor29.3

First, the tire pressure that is listed on the sidewall of the tire is just that, the max pressure for which the tire is rated. The tire pressure that is listed on the label/placard inside the coach is the pressure at which you would run the tires if you were loaded to full axle weights and GVWR. My tires (22.5) are rated at 110 max and based on coach weight and Michelin chart I run 90 front and rear.

I had air helper springs (Firestone Air Ride) on the rear of my prior class C and in my opinion they did not help with ride comfort. They did help to distribute the load, changing the level of the coach from front to rear and side to side, which did improve handling a little. The ride comfort was still controlled by the rear leaf springs and shocks.

One thing you did not mention was the alignment. Before making any modification to the coach it should be loaded, weighted, tire pressures set for weight and then aligned. Until those things are done you really don't know what you need and are just changing and praying (changing parts and praying there's a difference).

Before investing any money ask yourself what is most important, ride comfort or coach handling. As another person mentioned, remember, you are driving a truck.

[Beau388]

Originally Posted by Thor29.3inAZ

I did a search and found nothing in regards to the F53 chassis. So... I called Thor and asked what the weight was when if left the factory. 17,890 lbs. We have a 29.3.

I doubt your coach weighs 17,890 lbs unless it is fully loaded. The GVWR is 18,000 lbs. My coach on the 190' wheel base (same as yours) weighs 15,920 lbs empty with just a little fuel (1/4 full). Loaded for a four week trip with us aboard it weighs 17,360 lbs. My water tank is up forward just behind the door. Traveling with it full (420 lbs) helps with the ride quality.

[DenverTransplant]

[QUOTE=Thor29.3inAZ;65708]I did a search and found nothing in regards to the F53 chassis.]

Try looking in the irv2 F53 chassis forum. Lots of discussion around F53 suspension issues....enough to totally confuse you.

Ford Motorhome Chassis Forum - iRV2 Forums

The basic suspension topics you will find

- CHF - I have on both front and rear
- Track Bar - A must, especially for something like my ACE 30.1 where the fresh, black and grey tanks are behind the rear wheels. I have SuperSteer, but there is discussion on others. Probably the single best improvement I did.
Steering Stabilizers - I have Safe-T-Plus, but lots of discussion on others
- Replacement shocks - Koni vs. non OEM Bilstiens. I went the Koni route and am very happy I did
- SumoSprings - I haven't done this yet, but there are many happy folks and some that felt it didn't do much for them

Also lots of posts on engine and transmission topics.

[Thor29.3inAZ]

Such great feed back from you all. Thank you. I did forget to mention I had a front end alignment. The handling after the CHF was very much improved also. So I think the next step might be to weight the unit in it's true state and adjust the tire pressure accordingly. Lets see if I can at least stop the interior from coming apart at the seams! LOL

[SuperD]

Most all of the mods mentioned do a great job of improving the handling, even the shocks. The shocks will improve the ride a little but not a lot.

[Jegdrum5050]

I have the Bilsteinshocks and its a great ride! also the CHF and safeTPlus. Makes life great.

[Hudsoner]

Here is what I did, , and I did it one change at a time!

I am now at the point that I can steer the thing with one hand, even when semis pass me! However, the ride over bad road sections is still harsh (I will be working on this over the coming summer).
What I have done so far on my unit, Koni shocks, Steer Safe steering help, CHF in the front and the rear, rear track bar (Tiger Track from Blue Ox), and Sumo Maxim springs in the front. I am still debating if it is worth the while to put Sumo's in the back.

All in all, I thinks the handling of my motorhome is as good as it gets for a unit with the 190 wheelbase. Once I have the harsh ride eliminated, it should handle and drive like the bigger cars of the 80's (Ford Crown Victoria, Chevy Caprice, etc.). It will never be a sports car, but I do not expect this from a truck/school bus chassis, but it should be a pretty comfortable to drive cruiser with it's own bathroom and bed in the back!

But I also have to say that my son is doing all the modifications, and he is a master mechanic at the largest Ford dealer in the state. He has all the tools and knowledge, to do those things.

Making the ride softer might require changing the springs in the front to types with softer spring rating. By the end of the year, I will know more about what works, and what doesn't!

[Romsey2016]

I had the Safety T steering system installed on my 16 Challenger last week, so far so good with that. I decided to do the CHF on my coach, it was pretty quick work on the front. However, when I looked at the rear sway bar, there was a bracket on the passenger side of the coach missing where the sway bar is attached (the rubber bushing is still there). Is this something that Ford has to fix, or can I get the part and install it myself? Has any one else run into this issue? I have a trip planned in 2 weeks and would like to get this resolved quickly and I don't have a Ford dealer close by that handles motorhomes.

[Hudsoner]

Originally Posted by Romsey2016

I had the Safety T steering system installed on my 16 Challenger last week, so far so good with that. I decided to do the CHF on my coach, it was pretty quick work on the front. However, when I looked at the rear sway bar, there was a bracket on the passenger side of the coach missing where the sway bar is attached (the rubber bushing is still there). Is this something that Ford has to fix, or can I get the part and install it myself? Has any one else run into this issue? I have a trip planned in 2 weeks and would like to get this resolved quickly and I don't have a Ford dealer close by that handles motorhomes.

This seems to be a pretty common issue with newer F53 chassis, Ford changed the design a few years back, and cheapened it down.

There is a long thread about this over at iRV2
ATTENTION !!!! Ford F-53 Owners READ!! - iRV2 Forums

[Chance]

Originally Posted by Thor29.3inAZ

....cut....

So to get this to ride a little better should I...... Install the Koni's or Bilsten's? Add a beefier sway bar or stay with the CHF? Keep the tire pressure at max or what Thor has recommended? Any input would be great!

Stiffer sway bars makes vehicles ride harsher on rough roads. The same can be said of stiffer springs or higher tire pressure, which also makes a tire stiffer.

To improve ride quality on rough roads, you need more suspension compliance, not less.

Unfortunately, adding suspension compliance normally affects handling adversely on any vehicle. Only you can decide where the optimum tradeoff between handling and compliant ride is for you.

[Hudsoner]

Originally Posted by Chance

To improve ride quality on rough roads, you need more suspension compliance, not less.
.

Yes,you are right. However Thor decided with my motorhome type to put as little weight as possible on the front axle (and who knows with how many others). The only weight I have on this heavy duty front axle is the drive train, the coach battery, and to some extend the house batteries, and, of course, any passengers in the front seats. This is way to little weight for the layout of the front springs. To add injury to insult, they decided to put the fresh water tank as far to the back as they could, It touches the rear end cap of the motorhome! And also the generator, the gas gasoline tank and the propane tank are located behind the rear axle. All this weight tries even more to unload the front axle, and the result is a very harsh ride in the front, because the springs re never in their most efficient position.
I am currently trying to figure out, how much additional weight I need in the front to get an appropriate ride quality (I use steel plates with known weights for this). For the case that I need some weight close to 400 lb, I will install the next softer truck springs from a Ford vehicle. The softer springs, in combination with the Sumo maxim springs I have installed already, should provide me with a similar front axle ride quality as can be found in the Kelderman modifications.

[Thor29.3inAZ]

So, again I want to thank all who are giving me some great input. Today was a day I went out and did some testing with tire pressure. I'm thinking this should be the first place to start. As I might have mentioned, we had a blow out due to a rock wedged between the rear dually and the tire guy said I should be running the max tire pressure listed on the sidewall. If not the tires will run hotter than need be. So I upped the pressure from 90 psi to 110 psi. And as you might expect, the ride was crazy harsh. Dropped the pressure today back down to what my placard has on it, 85 psi. Yep, now it is nice and smooth. My cupboards now were not trying to fall down, the TV wasn't banging around and my teeth are not chattering. I also tried 90 psi and was just a little stiffer but not crazy harsh. I also went to 100 psi and now the crazy harshness returned. So for now, I'm going to run them all at 85 psi. I still need to weight the coach but what an improvement. I might still entertain new shocks as the stock Ford ones seem a bit smaller in diameter that say the Koni's or Bilstien's. Along with a steering stabilizer, these will be next things on my list to install.

[Chance]

Originally Posted by Hudsoner

Yes,you are right. However Thor decided with my motorhome type to put as little weight as possible on the front axle (and who knows with how many others). The only weight I have on this heavy duty front axle is the drive train, the coach battery, and to some extend the house batteries, and, of course, any passengers in the front seats. This is way to little weight for the layout of the front springs. To add injury to insult, they decided to put the fresh water tank as far to the back as they could, It touches the rear end cap of the motorhome! And also the generator, the gas gasoline tank and the propane tank are located behind the rear axle. All this weight tries even more to unload the front axle, and the result is a very harsh ride in the front, because the springs re never in their most efficient position.
I am currently trying to figure out, how much additional weight I need in the front to get an appropriate ride quality (I use steel plates with known weights for this). For the case that I need some weight close to 400 lb, I will install the next softer truck springs from a Ford vehicle. The softer springs, in combination with the Sumo maxim springs I have installed already, should provide me with a similar front axle ride quality as can be found in the Kelderman modifications.

The subject you describe is difficult to analyze correctly because ride harshness is a function of many variables, including the effective mass affected by the springs and dampers, not just the weight supported by the springs. And there is a difference, particularly when motorhome is built like the one you described.

[Hudsoner]

Originally Posted by Chance

The subject you describe is difficult to analyze correctly because ride harshness is a function of many variables, including the effective mass affected by the springs and dampers, not just the weight supported by the springs. And there is a difference, particularly when motorhome is built like the one you described.

I am in the experimental stage to see, what I can do to reduce the ride harshness. I looked closely how Kelderman is doing this, and I try to mimic it as much as possible.
I am in the lucky situation that my son is a master mechanic at the largest Ford Dealer in the state, and has all the tools and information available to play around with the chassis.

I have done all other possible modifications, except Sumo springs in the back. I might put those in or air bags, to push some of the weight towards the front.

[Chance]

Originally Posted by Hudsoner

I am in the experimental stage to see, what I can do to reduce the ride harshness. I looked closely how Kelderman is doing this, and I try to mimic it as much as possible.
I am in the lucky situation that my son is a master mechanic at the largest Ford Dealer in the state, and has all the tools and information available to play around with the chassis.

I have done all other possible modifications, except Sumo springs in the back. I might put those in or air bags, to push some of the weight towards the front.

It doesn't quite work that way. Installing air bags or Sumos in back may lift the rear, but it won't push weight forward appreciably. You may get a couple of percent due to new motorhome angle shifting Cg forward a tiny amount, but that's about it.

Also, when you have springs working in parallel, combined they become stiffer in total. That should make ride firmer/harsher and not softer.

I wish there was a simple solution for you, but I don't know of one.

[Hudsoner]

Originally Posted by Chance

It doesn't quite work that way. Installing air bags or Sumos in back may lift the rear, but it won't push weight forward appreciably. You may get a couple of percent due to new motorhome angle shifting Cg forward a tiny amount, but that's about it.

Also, when you have springs working in parallel, combined they become stiffer in total. That should make ride firmer/harsher and not softer.

I wish there was a simple solution for you, but I don't know of one.

Thanks for reminding me about the dynamics I plan to go this way because I have no problem with ride harshness in the rear, but if I can shift some of the weight (by using the rear axle as a load point) to the front, it would increase stability and drive comfort (by whatever small amount), and it also would bring my motorhome into a more leveled position (front to back). At that point I can really play around with the front suspension to see what can be done to soften the front a little more. My son feels that the springs of an F450 4x4 Truck would do the job. It seems that those are the springs, Kelderman is using in the front. They use airbags, but I hope that the Sumo Maxims will function similar, and I would not to have to mess with air lines and a compressor by using them.

It would very involved to copy the rear suspension mods Kelderman does, but I have not a real problem with the rear, the Koni shocks seem to do a good job there (and the rear weight bias of my unit). I will be happy, if I can reduce the hard hits in the front and can achieve a more comfortable ride this way.