Thursday, December 8, 2022


Did upgrading the suspension on my F-53 chassis work?


So, did upgrading the suspension on my F-53 chassis work? Well, the bottom line is…

It didn’t make much difference.

I spent about $8,000 to add KONI shocks, SumoSprings®, Roadmaster track bars, and enhanced stabilizer and steering equipment; I didn’t notice much difference in the ride. Here is my assessment:

I took my newly upgraded rig on a 3-week trip up Interstate 5 to visit my family in Oregon. I was very excited about driving with my cats without my teeth chattering and cabinet doors flying open. You can read about my Newbie saga and my rants about the Ford F-53 chassis here. I have learned a great deal from all of you and from my friends here at So, before my trip I did the following:

  1. I installed a tire pressure monitoring system (TPMS) that measures real-time pressures and temperatures of all six of my tires.
  2. Downloaded the tire load/pressure table for my Toyo 265/75R22.5 tires so I knew the real limits for the tires and not the maximum as stated on the tire wall. 
  3. I weighed my rig at a CAT Scale before loading and after loading. Ideally, I would have done a four-corner weight, but I was only able to do a front and rear axle weight. 
  4. I did a better job of securing my cargo in cabinets. I was grateful Jose fixed the refrigerator brackets so the fridge wasn’t flying out of the cabinet when we hit bumps. (Again, read my Newbie Saga.)
  5. I tried to keep my expectations low.

My first leg of the trip took me out of the Coachella Valley and through greater Los Angeles to hit Interstate 5. OMG! What a nightmare! I now call the greater Los Angeles area Mordor! Almost every mile of the freeway was or had been under construction, so my new suspension was tested to the max. It did not fare too well. The four-foot concrete potholes and cracks in the road nearly took the coach apart. (You must know by now, I love hyperbole). I did appreciate the nice, tight steering provided by my Safe-T-Steer equipment, but I inwardly moaned about the money I spent.

Weigh your rig!

Fortunately, I had the weights. Thank you, Roger Marble and Ross Regis, for the continued education regarding tire safety and GVWRs. Keep in mind this Newmar Canyon Star is on the Ford F-53, 26,000 lb.-rated chassis, and each axle has its own weight rating. I consciously lowered my cargo weight for the trip by removing several hundred pounds of unused bunk beds in the garage. I added a propane quick-connect hookup so I did not need to lug a separate portable tank along for the grill. The new suspension equipment likely added some weight to counterbalance.

Weights before loading:  Front axle: 8,400 lbs.; Rear axle: 15,120 lbs.

Weights after loading (1/3 fresh water tank, empty gray and black tanks, full gas tank): Front axle: 8,700 lbs.; Rear axle: 16,080 lbs

The tires were rated at a maximum 110 psi. I had them filled to 100, knowing my rig was only 24,780 lbs., well under 26,000. When I consulted the Toyo tire load and inflation table, I was able to lower the pressure to 90 psi and still be well within the safety limits. 

Note: Every tire manufacturer has this table, so you can set your tire pressures accordingly.  Ideally, each corner of the motor coach should be weighed and pressures set. With only a two-axle weight, I had to combine the loads and multiply the single and dual load limits by 2x and 4x for my front two tires and my four rear dually tires. Also note that each coach or trailer has individual axle weight limits which are well below the above tire pressure/load ratings. Your rig’s weight must be within both the axle and the tire load limits.  ** Table has been corrected. Thanks Bill!

It was only when I reduced the tire pressures did I notice a distinct improvement. Lowering the tire pressures made a huge difference in my ride. Interstate 5 outside of LA was pretty smooth driving, but I still encountered many rough spots so I could judge the difference— much better. I wasn’t expecting a cushy ride at all. The rig still drove like a truck, but it drove like it should, for the most part. I was quite comfortable and felt safer.

Did I just waste $8,000?????

The nagging question is this: Did I just spend $8,000 to get a better ride when I could have just reduced the tire pressure??!! I can’t tell if the new shocks and springs make an appreciable difference; I think they are making some. The steering upgrade made a difference—I had no instances of being blown sideways by a passing semi and the rig steered very straight with no drift. 

But to get this ride, I limited my carrying capacity to be able to set my tires to lower pressure and do it safely. The limiting factor was the front tire loads. I had room to add weight in the rear, but I think keeping the weight lower helped with the ride.

In hindsight

If I had to do it over again, I would have considered the LiquidSpring as a required option on this F-53 chassis, or I would have bought a diesel pusher. But maybe I should follow my friend Tony Barthel’s advice and buy a V-8 gas truck and pull a towable. However, I would have to leave the cats at home and that wouldn’t be good for my mental health. 

Let’s hold Ford and the RV manufacturers to better standards: No more F-53 chassis!

I firmly believe that Ford and the RV manufacturers should not be selling motor coaches on the F-53 chassis without a minimum shock and spring upgrade. But they should also make available the LiquidSpring suspension as an option from the factory floor.

I am in agreement with many experts that no coach on the F-53 should be longer than 32 feet. This is my humble non-expert opinion. Many have accused me of placing blame on Ford and the manufacturers when I should be blaming myself for being so uninformed, making poor choices and likely driving overweight. Okay. I will take the blame for my mistakes. And now I want Ford and the manufacturers to own up to their culpability. I emphasize that I air my problems and mistakes so that you all can avoid and learn from them; I certainly hope it helps.

Future trips will feature light loads and lower tire pressures and, I hope, a more comfortable Karel and her cats. 


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18 days ago

We picked up our 2018 Georgetown XL just last week from getting front and rear Liquid Springs. We then took it from Hagerstown, MD to Richmond, VA for a test ride and back home to NoPA, a total of about 600 miles, both interstates and windy, hilly, country roads. HUGE improvement. Bridge transitions no longer rattle your teeth and compress your spine. You hear them, maybe feel a bit of rumble in your seat. But the biggest thing that struck us was how quiet it is in the coach now. My husband would catch himself yelling to talk to me and then realizing that he didn’t have to do that anymore. No (or minimal) rattling of the door, the dishes in the cabinets, and everything else that contributes to the cacophony of background noise. Yes, it was expensive, but far less expensive than upgrading to a DP. We travel from PA to SoCAL in the winter months. We are eager to see how the LS perform on the really horrible southern state interstates that we saw last year.

18 days ago

Sorry for all the hassles you’ve been having! Just wondering why the kitties would have to stay home if you went with a towable? I know several folks who travel with their kitties while towing a trailer. Good luck with all the suspension issues!

19 days ago

I have a 97 Fleetwood Southwind on the F 53 chassis. I also have a lot of experience with medium duty trucks as I was a truck mechanic before I retired. The F 53 is not the best but it is far from the worst. Regular maintenance on sway bars and tires is a good idea. Shocks are almost a waste of money if everything else is in good shape. I do have the road handler steering damper on mine but I don’t think it’s really necessary. Sway bars and good tires have made the biggest difference for me. When I bought it I had trouble keeping it on the road when I’d hit a rough spot or if the wind was over 20 mph. After rebuilding the sway bars I can handle a 40 mph wind or big trucks blowing by with one hand. I try not to get much above 60 mph unless it’s a real smooth road and I’ve got a good tailwind. You will get better handling with larger wheels and tires but the expense goes up considerably.

Steward Smith
19 days ago

I own a Bay Star on the F53 platform. My biggest improvement came from replacing the awful original tires with Michelins. I did this thru the FMC program and had the distributor do the install and balance, road force balancing. My coach now rides like it is on pillows. Road Force balancing is matching the tire to the rim and then a precision balancing.

19 days ago

Karel, in the load/inflation table in your example, the single and dual capacities are backwards. The tires are downrated for dual service, so the dual maximum load is always less than the single maximum load.

That would mean on the 85 psi line, the front axle could support 8,880 pounds and the rear axle could support 16,160 pounds. So, 85 psi is the MINIMUM pressure required to support your measured axle loads, and you are correct to go up to allow for the real world variations you will encounter, including the likelihood that the loads are not equal on each side of the axle.

RVSEF, Escapees, and some RV dealers can steer you to a place to get individual wheel weights, or you might try the state police or highway patrol to see if they will have a temporary weigh station set up near you.

Dave H.
19 days ago

Thank you for posting this series of articles and sharing your experience! I have learned a lot from what you have posted and it has definitely shaped our future plans.

John H.
19 days ago

I think a lot of people who are unfamiliar with driving anything bigger than a passenger car or smaller SUV have unrealistic expectations adding to their disappointment. They buy a lower cost RV to fit their budget, and don’t realize the differences from what they are used to require a different driving style. The higher end RV’s have better suspensions to cater to their customer. I drive for a living and a lot of times I just slow down to preserve my equipment and my comfort. I don’t care if someone behind me is in a hurry, I drive for road conditions. If the road was under construction, slow down, expecting those potholes and grooved pavement. Experience is a great teacher, enjoy learning and thanks for sharing the tire info. So many won’t look it up but it makes a huge difference, like you pointed out!

Bob p
19 days ago

There’s not much you can do to improve a truck chassis. I owned a ‘99 Bounder 36’ on that chassis, after 1 year I traded it on a 2002 Newmar Mountain Aire 38’ on a Chevy Workhorse chassis, the difference between the two was unbelievable. The ride, handling, and power was amazing, and the engine was bigger but got better mpg’s. Unfortunately that chassis was sold to International in the 2009 bankruptcy. I always hoped International would decide to continue to build that chassis as it was designed for RV’s. If RV manufacturers ask for it International might build it but they have to know the market would be there.

Scott R. Ellis
19 days ago

To some extent, the bottom line here is that you spent a lot of money on upgrades designed to improve *handling*, not ride quality.

Charlie Sullivan
19 days ago
Reply to  Scott R. Ellis

I agree. Two different issues.

18 days ago

Koni shocks do most of their dampening on rebound, not compression. I think Sumo springs are more for roll and sway, so no.
You have to modify the conestoga wagon leaf springs to really improve the ride, i.e. Liquid Springs or the Kelderman air springs.

Jesse Crouse
19 days ago

Manufacturers continue to use a medium duty truck platform for a RV. All of this for cost cutting. We owned a 98 Bounder on a F53 chassis for 14 years and finally up graded to a Tiffin diesel coach on a Frieghtliner chassis. Now in RV heaven. You get what you pay for.

19 days ago

You missed the one component that makes the most difference, the rear track bar. I added the track bar, auxiliary rear sway bar, and steering stabilizer. I can now drive comfortably with one hand on the steering wheel.

Hubert Rosch
19 days ago
Reply to  Tim

I agree with you Tim. I added a track bar before heading on a 3 month Alaska trip…big improvement. Also added a steering stabilizer and CHF fix to the sway bars. Pretty comfortable driving.

Dave Gobel
19 days ago

When I bought my latest motorhome – 2016 Tiffin Allegro Open Road 34PA – the ride was the worst I have ever experienced. My mechanic called me to say that he had never been in a vehicle with a worse ride. Long story short – we took the Sumos off the front and left them on the back. We put Koni shocks on all 4 wheels AND we lowered the tire pressure from 110 to 90. We also tightened one of the stabilizers on the front. But we didn’t add anything. The ride is very good now. Not a diesel but we are not getting bounced to pieces.