Community Forums

JimLuk · 08-29-2020, 04:29 PM

We had a recent demo ride in a used 2018 Tiffin Diesel 40xx (I can not remember the specific model)... Was a great price, appeared to be in good condition... The demo ride was a little "bouncy" (especidally while turning/changing lanes) and made my wife sea sick in the back... We are now looking at a new Diesel either the 33AA, 37BA, and the 37BH. What are the available STABILITY options? We love the 37BH and are looking buying new... I see that the "Air Ride 4 Air Bags" is standard... Is there something else I should consider for stability from x-winds, uneven road surfaces, etc. Any suggestions would be great. Thanks, Jim

**Lt Dan** · 08-29-2020, 04:41 PM

I don't know if this is your first motorhome or first diesel experience, but there is a certain amount of movement in any of them outside of a Prevost or Newell chassis. Some owners have installed Motion Control Valves to limit movement and some times new shocks will help. A Safe-T-Plus steering damper can help with pavement transitions and cross winds but increases the effort required to steer. Also, if the tire pressure is set too high it can result in road wandering and a harsh ride. You have to keep in mind that these are top heavy beasts riding on four air bags and not stiff like a sports car or smooth like a Cadillac.

hipkts2010 · 08-29-2020, 04:54 PM

I have a recommendation for you. We drove a 2007 allegro bus that had the best ride we had ever experienced in a Tiffin allegro bus. We bought the bus and before we departed the dealership I discovered the reason for the smooth ride. All of the tires were inflated to 90 psi or less. The inside tire on the passenger side extension was not even attached to the tire and had cobwebs in the back end where it should have been attached to the valve stem. That was just the beginning. The batteries would not take a charge and they replaced them and they would still not charge. They then replaced the inverter. That was after we had signed the papers and the sun came out and we discovered that most of the windows in the front of the coach were fogged.
My advice, is to get a certified rv inspector to look at the coach before you do anything.

Pigman1 · 08-29-2020, 06:44 PM

I had a 2008 40' Bus on a Freightliner chassis that we had to change out the front shocks before 30,000 miles. Traded it at 75,000 miles and never had an issue with the rear shocks. The change out improved the ride dramatically.

R.Wold · 08-29-2020, 07:21 PM

Quote:

Originally Posted by JimLuk

We had a recent demo ride in a used 2018 Tiffin Diesel 40xx (I can not remember the specific model)... Was a great price, appeared to be in good condition... The demo ride was a little "bouncy" (especidally while turning/changing lanes) and made my wife sea sick in the back... We are now looking at a new Diesel either the 33AA, 37BA, and the 37BH. What are the available STABILITY options? We love the 37BH and are looking buying new... I see that the "Air Ride 4 Air Bags" is standard... Is there something else I should consider for stability from x-winds, uneven road surfaces, etc. Any suggestions would be great. Thanks, Jim

Here’s the spec sheet for that chassis: https://cdn.fccchq.com/specsheets/5e...in-Phaeton.pdf . You won’t find any dealer provided options for suspension upgrades but there are aftermarket options. A lot of dealing with the rig bouncing around is driving technique, anticipating and learning to minimize suspension reaction to road surface changes.

You can install air valves as mentioned above (see link below) that allow full flow one way and limit it the other (my guess is in- normal, out slower but they don’t specify), and you can go to stiffer shocks, but this will also lead to a somewhat harsher ride.

Source Engineering is now providing custom shocks and air valves for Freightliner chassis. They quoted me $1276 for the package and then of course installation is on you. Koni also has a FSD (frequency specific dampening) shock for Freightliner XC chassis. Koni FSD shocks made my F53 ride a bit harsh but aided in controlling body roll.

Source Engineering Inc | Custom RV Chassis | Eugene, OR (be prepared for limited communication)

Source Engineering Inc | Custom RV Chassis | Eugene, OR (valves)

https://www.koni-na.com/en-US/NorthA...cts/Motorhome/ ($720 without the air valves)

I can’t say which is the better route, Koni and air valves from Source, or custom Bilsteins from source with air valves. I’m still in research mode. My advice would be to contact Jim Walls at Source and see what he has to say. jim.w@source1mfg.com You might find yourself reconsidering the 2018....

R.Wold · 09-08-2020, 06:02 PM

Quote:

Originally Posted by JimLuk

We had a recent demo ride in a used 2018 Tiffin Diesel 40xx (I can not remember the specific model)... Was a great price, appeared to be in good condition... The demo ride was a little "bouncy" (especidally while turning/changing lanes) and made my wife sea sick in the back... We are now looking at a new Diesel either the 33AA, 37BA, and the 37BH. What are the available STABILITY options? We love the 37BH and are looking buying new... I see that the "Air Ride 4 Air Bags" is standard... Is there something else I should consider for stability from x-winds, uneven road surfaces, etc. Any suggestions would be great. Thanks, Jim

Another option is to buy stock Bilsteins for your rig and get the valves from Source. This should be considerably cheaper as the stock Bilsteins for my XCR chassis are $144/ea and the air valves are fairly cheap. So I think the $1276 quote from Source includes a rather generous surcharge for their custom shock build, whatever that entails. I’m thinking $144 stock Bilsteins and source valves. Hope this helps.

Another option is Koni at around $180/per but I was not pleased with the Koni FSD shocks I put on my F53. Led to a really harsh ride which is exactly what they say they will reduce. So I’m going to pass on Koni this time around. YRmV.....