Overhang Clearance to truck rails - Montana Owners Club

spadasak · 07-25-2006, 05:11 AM

I have a new F350 with the 20" chrome wheels and find that the clearance between the overhang of the FW and the rails is maybe 4". The trailer sets level but I am concerned that even minor changes in ground elevation side to side may cause damage to the TV or the FW. What can I do to increase this distance??

Montana_1240 · 07-25-2006, 06:02 AM

I've heard that you should strive for at least 6". You'd be surprised how much tilt you can get on the nose just moving around a bit in many a campsite, or when entering and exiting fuel stations or dining establishments.

Look at your hitch, and see if you can raise the pin platform by moving it and re-bolting it to other holes.

Of course, that will likely raise the nose of the FW a bit. As long as you're not past about 3 degrees off level, it won't bother the fridge's functioning. But it will alter the weight loads on the trailer's tires a bit.

Is there a reason you have 20" wheels on the TV? And, you do still have tires with an "E" load rating, right?

Steve

8.1al · 07-25-2006, 06:08 AM

Steve is right, 4" is too close, I would try for 6" minimum.

richfaa · 07-25-2006, 06:19 AM

our 3400 sits level on our 05 1 ton dually Ford with 17 inch wheels.We have the 16K draw-Tite hitch,It has 4 height adjustment holes and ours is in the 2nd one from the bottom.It could still decrease in height by at leat 2 inches if in the top hole... BTW..although our distance is a good 6 inches we were told by the hitch installer that "fist" height was acceptable???????

Montana_1240 · 07-25-2006, 06:24 AM

Rich,

That advice from the installer saved him from the effort of adjusting the hitch he just put in. I'd classify it right along with "You've got enough truck, there," coming from an “Alfa Gold” salesman, to a guy with a Ford Ranger, as they do the handshake for a deal.

I know 6" is acceptable. And it may just be minimal. But AT LEAST 6" is what I'd say, because I have it, and still came close to the rails in some situations.

Steve

richfaa · 07-25-2006, 07:15 AM

Yea..We rolled our eyes at that one and did not ask him anymore questions.We wanted 6 inches Min and level and got it with no problem. I would not really want much less. We have watched that guy rock back there ,,Fist height...HUmmmmm.

spadasak · 07-25-2006, 08:43 AM

The 20" wheels were part of the Lariat package that came with the TV, I guess I didn't know it may cause a problem or I would have opted for the standard offering. I could change the hitch plate height but as you folks have indicated, this would make the FW not as level as it should be. What about changing the tire size on the FW?? I guess the other question is, why didn't the RV dealer point this out knowing that I am a novice?

richfaa · 07-25-2006, 09:02 AM

Because the dealer was selling you a RV.. and they took advantage of you being a novice.A good 4 inches of clearance is not all that bad.How long have you had the truck.Maybe something can be worked out with your Ford dealer in switching wheels???.

Montana_1240 · 07-25-2006, 09:10 AM

Wow! I haven’t been looking at many Ford lots, lately. I didn’t know they had that option. In my head, I had this image of some “hoopty” configuration. An ostensibly stock vehicle that has had 20” or 21,” (usually chrome,) wheels put on, and had those very low profile tires added. When I see that done to an SUV, or even a semi-large pick-up, I had to ask myself why the owner ever got the Off-Road or Towing package in the first place!

I post from personal experience, whenever I can. I had a problem with tire wear on our first Monty. It was a 3380RL, and the kitchen was on the driver’s side, in front of the wheels. We had just started fulltiming, and had loaded way too many canned goods out of our brick & stick house, into the kitchen area. Those, along with the pots and pans, and all, made that particular area heavy. The factory looked at my rig, weighed each tire, and told me to shift the stuff away from there. (They also gave me an entire aluminum rim, with a new Tacoma tire, to use as soon as that front tire gave up the ghost. I LOVE that factory!)

Anyway, that’s why I even mentioned tire weight loads. Lifting a rig up too far in the front, or letting it ride too low in the front, can and probably will affect tire weight loads, as well as wear. The mention about the fridge is because it does need to be within 3 degrees of level for the heat exchange to function without burning it out due to the flame hitting one side or the other of the unit’s equipment.

However. I don’t believe that raising the nose just an additional two inches will do any great change. You’re level, right now, so it’d just mean a little change. And as you may already know, as you travel down the highway, you will see rigs that are far more than just three degrees off kilter going by. If you spot one in a CG, ask the guy if he’s had any inappropriate tire wear, or has had to get his fridge worked on.

Ask a dealer. One with a good service department. Or, place an e-mail, or a call into Keystone. As RichFAA has said, there is always one guy that can give you the correct answer.

Steve

Trailer Trash 2 · 07-25-2006, 12:44 PM

Quote:

quote:Originally posted by spadasak

The 20" wheels were part of the Lariat package that came with the TV, I guess I didn't know it may cause a problem or I would have opted for the standard offering. I could change the hitch plate height but as you folks have indicated, this would make the FW not as level as it should be. What about changing the tire size on the FW?? I guess the other question is, why didn't the RV dealer point this out knowing that I am a novice?

Just out of couriosity on those 20" rims what is the rating on the tires C, D, or E, and what Psi. do you put in them,

TT2

richfaa · 07-25-2006, 02:22 PM

Ford has a wheel/tire option of LT275/65x20E OWL all-terrain..however..the spare is listed as LT 275/70Rx18E..Whats that all about..If you had flat on one of your duals the spare would not touch the ground???? )it is a load range E tire...

Montana Sky · 07-25-2006, 04:48 PM

I have not had my coach hooked up to the truck in awhile, but memory seems to tell me I have 6-7" between my truck rails and the coach.

H. John Kohl · 07-25-2006, 10:24 PM

This was posted in my R&R topic. I think I had about 6 inches clearance and that was not enough.

Well we had one OOPS

Lesson when you drop on front wheel a foot or so check the rear bed rail and the trailer.
One flat cause by a bad valve stem and one blow out cause (tread separation I guess - I heard it pop)

Lesson - Check your tires anytime you stop. Do a walk-around.
Good luck and tow safe

Ozz · 07-26-2006, 01:11 AM

Ouch!
Were the tires Mission brand? Did your insurance take care of the damage for you?
Sorry it happened.
Take care, Ozz

Wrenchtraveller · 07-26-2006, 04:06 AM

Just for the record, 20" tires are an option, my Lariat came with 18" wheels .
On a SRW ,to get the max GVWR, you get 18" E 275/70 which have a load capacity of 3640 pounds.

The 20" are also rated for the max GVWR.

The duallies come with 17" tires and the good part about that is you have a bigger choice in tires.
Right now in 18" tires with 3640 rating, You only have the Continentals which are just an M/S tire. There will be more brands coming on line soon I hope.

On the original topic, 6" is the absolute minimum I would want and I have that now. Even with 6" in extreme cases , you can make contact.

Years ago I sold an old Wilderness Fiver and I had to deliver it.
I had to back it up a steep driveway and the slab on top was level.
I dented the very rear corners of my 1981 Ford F250's box.
The hitch I have now is a slider hitch which I don't need for my 8 foot bed , but if I were to have a situation like I just described, I would slide the hitch back to give me more clearance.

spadasak · 07-26-2006, 07:04 AM

I don't know what the rating on the truck tire is currently, but I will surely check. My TV is a SRW and I will also check the spare size. So, really there isn't any way to increase the rail clearance. Buyer Beware!!!

Fordzilla · 07-26-2006, 08:17 AM

My question is are the outside diameters of the 20's about the same as the 18" spare? I think the 20" rims just have lower profile tires and the outside measurements are all within a half inch. Otherwise Rich is right you wouldn't want to go far with the spare on the truck. I suspect they are pretty close and Ford only does it to save a few$$$.

As for the original question I have at least 6 inches as a minimum as I am one of those people who have rubbed the tops of the bed while leaving a particular campground we frequent.

spadasak · 07-26-2006, 08:54 AM

These aren't low profile tires on the TV they are full size. Can the FW suspension or axle be shimmed?

Fordzilla · 07-26-2006, 04:15 PM

Some manufactures make kits to flip the axle so the springs are higher. And you may be able to buy a bigger shakel to replace the stock ones on the trailer.

spadasak · 07-27-2006, 01:52 AM

That is a good point. I looked in my files and they gave me two different booklets, one from Dexter the other from Ak-bo or something like that. I will check the dexter website for more info. Thank You all. I am glad I joined the MOC forum!

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