Chassis Mods by Ford-Approved Subcontractor for PC -- Any Probs?

Following up on the "introduce yourself" page, here’s my first question: Ford E-Series cutaways are available in 138, 158, and 176-inch wheelbases.  I can understand Phoenix Cruiser and others stretching the longest chassis as-needed for their longest models, but wonder why there are some shorter models with wheelbases that would indicate a shorter wheelbase chassis was lengthened slightly or a longer one was shortened.  Wouldn’t it be better to adjust the length of body panels and fittings, instead?  I understand that with chassis mods involving driveshafts there is the risk of driveshaft balance problems, etc. which I’d assume would lead to finger-pointing between the RV manufacturer, the subcontractor who did the work (even if approved by chassis manufacturer), and the chassis manufacturer itself.  Model 2351 would seem to be have better load distribution and be more stable on the highway than Model 2350, but I’m wary of problems and wish it had the stock 176-inch wheelbase rather than be modified to 170 inches.  Has anyone had or heard of such problems on a PC or other makes that subcontract to (in this case) Ford-approved chassis modifiers?  And thanks for the warm welcomes!

Some of the answers lie with availability. These chassis units are very popular with sevral makers. When you order you may be limited to what is available. I have been in on that conversation. Not sure how much that has to do with the designers work at PC . I am sure they have certain prefrances  to build on to allow them to install their various configurations.  I have access to some Ford Information and shortages are not unusual on some models.  Patricia
P S  One. Consideration is the cost of the bigger unit and other problems you run into with the cost of operating the bigger unit when it is completed... They have a price point they want to offer and have had success in offering and that is a giant consideration.

That makes sense, and I see Ron Dittmar posted some on this issue in the past.  Reviewing this forum and others, it appears there are some occasional drive line vibration issues when the chassis is stretched or shortened, but switching to a completely different driveshaft system wouldn't be the financial end of the world except on general principal if I bought a new one that needed it, and that won't happen, anyway.

Hi Michelle and Patricia,

With regards to the various Phoenix models, I understand the wheel base adjustments Phoenix specifies is primarily determined by the floor plan.  The rear wheel wells stick up through the house floor in every model to lower the floor to lower the over-all center of gravity of the motor home.  In our 2350 with the unmodified 158" wheel base, the passenger side wheel well comes up under our galley base cabinet.  The driver side wheel comes up under our fridge and coat closet.

If model 2351 used the same stock 158" wheel base, the rear overhang would be too much and the front/rear weight ratio unacceptable.  Using the next size stock 176" wheel base would place the driver side wheel well out on the bathroom floor to be tripped over, so Phoenix reduces the 176" wheel base by 6" to shift the wheel well forward under the closet.  I suppose you could raise the bathroom floor, step up into the bathroom, but then people like me would not be able to stand up in the bath.

Phoenix would not be stretching or reducing Ford frames nearly as much by building the floor 4" higher to completely eliminate the wheel wells.  But then Phoenix Cruisers would sit that much higher, making it like most other class C motor home brands that have an extra entry step.  4" does not sound like much, but it heavily influences the handling of the motor home.

Another influential factor in changing a stock wheel base would be plumbing.  For example, Phoenix cannot place a toilet too close to the rear axle for there is a required minimum axle to waste line clearance because the axle moves up and down a lot, and a little in other directions too.  Adjusting the wheel base is essential to offer the nice selection of floor plans.  Unfortunately once in a great while, a stretched frame will have something strange going on like I recall one owner dealing with drive line vibration.  Fortunately they did get it resolved.

I believe both Michelle and Patricia understand this, so I am posting this primarily for others.  Phoenix does not do wheel base modifications.  They send the chassis to a Ford approved shop who's sole job is modifying chassis wheel bases for the RV industry.  There is a document that Ford publishes on how it is to be done.  I understand there are specific Ford components with Ford part numbers that are available to make it happen.  Iron work, fuel lines, drive shafts, wire harness, brakes lines, everything needed to stretch or reduce the chassis has a Ford part number......as I understand it.  So there are only so many different configurations of available wheel bases.  Again as I understand it.  So if the 2351 could get by with a 173" wheel base, that size is not available.  Phoenix is forced to go with a 170".  Once again, as I understand it.

Ron

That's a good explanation for me and for someone who didn't find earlier posts.  I hadn't realized the extent of wheelwell intrusion on these but, yes, I agree that a few inches increased height otherwise would make a big difference.  That's why a Roadtrek with its underfloor-mounted freshwater tank (and, of couse, that it's between front and rear axles) doesn't handle appreciably differently whether the tank is empty or full, or a typical Subaru with its low-mounted flat-four can best the competition when other factors are equal.  As in response to another thread, compromises, compromises....

In a perfect word, everything liquid, from fuel to water to waste would be just forward of the rear tires.

It is interesting that the Sprinter has the fuel tank in between the axles.  It is the black thing hanging under the frame, just behind the driver.  The fuel filler is in the door pillar, integrated in a way that you don't realize it's there.

It's cool they can hide the fuel filler door but it seems the gas fumes would frequently wind up wafting into the vehicle being so close to door and windows. It will be interesting to see how that works for people.

We had two Sprinter based motorhomes and neither had diesel fumes inside. The filler is not really in the door jamb, it has its own door which the driver's door holds closed.

I like the fuel filler and fuel tank location of the Sprinter.  I wished our E350 55 gallon was set up that way.  55 gallons of gas sitting behind the rear axle is bad for weight distribution for motor homes with extended rear frames like our 2350.