Hi Everyone - My name is Barb, and hubby is Frank and this is my first post.  Frank is retired, and I will retire in a couple of years.  We've owned a couple of TT's in the past and we plan on replacing our current TT with a fifth-wheel soon.  We will also need to purchase a new tow vehicle. 

We plan on purchasing a Keystone Montana, 40'.  We found a tow vehicle - a 2014 Ram 3500, 6.7L Cummins I6 Turbodiesel dually with 23000 miles and a fifth-wheel tow package.  While looking at photos on this website of member tow vehicles, I see a lot of F450's.  For those with F450's or 4500's, what are the issues with using a 3500 to tow a fifth-wheel like a Montana?

Any insight would be greatly appreciated.

Thanks!

Barb

Your choice of tow vehicle is entirely capable of towing the Montana, assuming you load out to it's published GVWR (not an easy thing to do for some "hard-core" FTers, but there are things you can do to compensate). The only "issue" you may have to deal with is fifth wheel trailer clearance over the bed rails of the PU truck. But that is true for any newer PU truck these days. If you drive on decent roads and don't drive over extremely uneven terrain to get into a driveway, CG or campsite you should be good to go.

Thank you Brian and Cindy -

We asked the Keystone dealer about that issue and he said that the fifth wheel could be adjusted somewhat to accommodate the higher bed in this truck.

Barb

You had it right the first time. The 3500 RAM is SAE rated as is the F450. They are basically in the same weight towing category. BIG problem with the 450 is it's low 9,100# rear axle rating subtract it's actual rear axle weight and your payload is VERY limited.

The 3500 RAM trucks from 13 on are really 4500's with a 3500 badge. The 3500's are Class three trucks along with the F450, it's all about staying 14K and under on GVWR for licensing/insurance purposes.

The Cummins engine and Aisin transmission are both Medium duty! The fuel injection pump the Cummins uses is a Bosch CP# the Ford uses a CP4. The CP3 is a very reliable proven pump with rare problems. The CP4 in the ford and GM's have had their share of problems. Ford basically has told many to pound sand with warranty claims and GM has been taking care of their customers.

If towing heavy be sure to get the Aisin trans and 4.10's. 27K and under get the Aisin with 3.42's for better mileage solo. Also the 3.42 in 5th gear is turning 1,750rpm @ 60 the same rpm as the 4.10 in 6th. That is a great rpm for towing.

The factory rear air ride first available in 2015 is really nice! Good ride solo and the truck will sit at a perfect ride height loaded up to 9,750#. My truck in pic has 9,580# sitting on the rear tires.

i.imgur.com/yNmu5Fcl.jpg">

Cummins - Thanks for all of the information.  I'll share this with my husband tonight who can better interpret what you've said.  I understand some of it - but not all of it.   From what I gather - the Ram 3500 should be a viable tow vehicle for the Keystone Montana.  We're going to look at the 3500 tonight.  Very excited!

Thanks again.

Thanks Jim - We're going to look at the truck tonight.  It may be the beginning of our RV Dream!

Barb and Frank wrote:

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Thank you Brian and Cindy -

We asked the Keystone dealer about that issue and he said that the fifth wheel could be adjusted somewhat to accommodate the higher bed in this truck.

Barb

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Well, maybe.  "It depends" and please take anything a dealer says with a grain of salt.  Remember, they just want to sell their trailer - not make everything correct for the truck.  Perhaps this one is an exception.

You may be able to raise the front of the trailer by raising the hitch to gain more bed rail to trailer clearance, but if one does that the trailer probably will not run level. It will be high in the front.  That puts more weight on the rear axle of the trailer and, among other things, increases the possibility of tire or axle failure due to a potential overweight condition.

I recommend 6" - 7" of truck bed rail to trailer clearance - minimum. 

The only way to deal with this issue correctly, other than the truck to have a hauler bed installed, is to lift the rear of the trailer along with the front to make sure the trailer and both truck run level when hitched and loaded.

This is an issue with all newer trucks - including the Ford, GM / Chevy and RAM.  They all have taller bed rails 2011 and newer and many trailers, to tow correctly and level, must be lifted in the rear.  This is done all the time after-market.  Don't be overly concerned.  Just continue your research and if this project comes closer to happening more information can be provided. 

Bill and Linda,

Thanks for the information - more details to consider in our quest for a tow vehicle.

Barb and Frank wrote:

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Thank you Brian and Cindy -

We asked the Keystone dealer about that issue and he said that the fifth wheel could be adjusted somewhat to accommodate the higher bed in this truck.

Barb

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 They can be adjusted somewhat…but doing that has some drawbacks. It obviously raises the overall height of the rig but that can be measured and just use the higher number for figuring out which underpasses to bypass. The bigger problem is that raising the front of the trailer increases the load on the rear axle of the trailer and reduces the load on the front axle. You need to worry about that effect and make sure you're not overloading an axle…or more precisely overloading one side of an axle. A 7000 pound axle means 7000 total on the axle but also a max of 3500 on one side. Depending on your trailer one side will be heavier. For most 5vers with the kitchen on the drivers side and the batteries frequently being on that side as well…your left side tires will be significantly more loaded than the right side ones. Our NH runs 500-700 pounds heavier on each left side wheel. That might not be a problem for your rig but you need to worry about it.

Bill's right…the only way to actually solve the problem is to put on a hauler bed. That will cost you somewhere between 12000 and 30000 depending on what you have installed on your particular bed. The only drawback to having the hauler bed is. weight. The actual numbers depend of course…but the empty hauler bed will 800 to 1000 pounds more than the pickup bed it replaces. Add in the aux fuel tank in the front of the bed that most folks put in…if it's a 60 gallon tank that's another probably 100 pounds for the tank and 500 pounds for the diesel that goes in it…so you're looking at the hauler bed increasing the rear axle load by up to 1500 pounds or so plus whatever you store in any hauler bed bins that wasn't in the pickup bed (toolboxes, spare parts, whatever).

One other option…you can have the pickup bed cut down so that it's sides are lower. This sort of looks funny but it only costs about 10K. I know of two folks that have done that…if you take a look at Ken and Lee Marks site at http://rvkenandlee.blogspot.com you can see their 450 that they had cut down.

Neil and Connie,

Thanks for the information.  We ended up purchasing a 2016 Landmark Key West fifth wheel and we are towing it with a Ram 3500 dually. The combination of the rig and tow vehicle is perfect.  The rig is level and the Ram tows so well we don't even feel like we are hauling 18000 pounds. 

Thanks so much to all of the forum members for sharing their knowledge.  We have learned so much!

Barb

Barb and Frank wrote:

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Neil and Connie,

Thanks for the information.  We ended up purchasing a 2016 Landmark Key West fifth wheel and we are towing it with a Ram 3500 dually. The combination of the rig and tow vehicle is perfect.  The rig is level and the Ram tows so well we don't even feel like we are hauling 18000 pounds. 

Thanks so much to all of the forum members for sharing their knowledge.  We have learned so much!

Barb

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 Yes it's nice to have a tow rig that makes for a relaxing experience.  I tow 23K and 33K combined and in the WA and OR storm traveling south on I-5 we never felt unsafe.

RonC wrote:

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Barb and Frank ... your rig sounds awesome! I know you are going to enjoy it for many years to come. Congratulations!!

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Thanks Ron! 

Cummins12V98 wrote:

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Did you get the rear air ride?

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 Cummins-

Yes - we recently installed an Air Lift system.  It works like a charm - we are very happy with the ride and feel better about the overall stability.  

The CUMMINS IS THE BEST DIESEL ON THE MARKET!!!!i....I have towed 13000+ in the moutains and the cummins tows perfectly.....I love mine....2012 ram 3500 4x4...6.7...

rocketman wrote:

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The CUMMINS IS THE BEST DIESEL ON THE MARKET!!!!i....I have towed 13000+ in the moutains and the cummins tows perfectly.....I love mine....2012 ram 3500 4x4...6.7...

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 Really?  There are a lot of Ford and Chevy owners who might have a different opinion.  Good, yes ... the best ... TBD.

-- Edited by RonC on Wednesday 30th of August 2017 09:47:07 AM

Rocketman has a limited number of posts, and I suspect that half of them may be comments against some brands and for one other.  It is certainly OK to have a good opinion of a truck, but unless one has actually looked at all the numbers or owned the other brands, then one should be careful of comments that are disparaging.

I've certainly liked my 2008 Ford F450, and it has the 6.4L engine that he finds troublesome.  I wonder how many of those Ford 6.0L's and 6.4L's he has owned?

Terry

For a 40' RV i would go with a 450,4500..

rocketman wrote:

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For a 40' RV i would go with a 450,4500..

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 Please explain???

I tow a 41' DRV combined 33K at or within axle ratings and tow ratings same with towing my MC trailer behind RV at 35,340#.  I have towed all over the West coast with temps and control all in check towing up to 14% grades up and down.  The RAM 3500 Dually is in reality a 4500 with a 3500 label.  The Ford 350 would be just fine also!

The original poster commented he went with a Landmark with an 18,000 gross weight rating. I hope it's proper to ask what gear ratio he went with or would be best for his combination of a 3500 Ram dually and that trailer?

I know tire size influences the gear ratio decision. Another point might be if one intends to spend much time in the mountains or flat land while hauling. I'd appreciate some advise on what gear ratio to go with. In particular maybe why a 4:10 ratio may not be needed. I've been reading miles per gallon makes little difference but gears might influence the ride of the truck when hauling or not. Not sure I've got that right.

Bill - I still intend to hit you up for more info once we have our trailer selected. I've been spending a lot of time on the truck forums and the gear ratio decision remains a mystery. We are planning to stay under 19,000 pounds on whatever trailer we might start with or even upgrade to later. Who knows how much time we might spend hauling in the mountains. We are from the Midwest and some of those hills in Arkansas and southern Missouri can get big as well. I'd like to have a couple choices for gear ratio which would increase our chances of finding a truck on a lot or for sale by owner.

Ideas on gear ratio or a rule of thumb would be appreciated.

Mark,

I can't speak to the GM's or Ram's, but with regards to rear axle ratio, the higher the number, the lower it is geared.  An axle with a 3.73 ratio would be more fuel efficient, but would have more problem with towing on grades like the mountains.  A higher number (4:10, 4:30, 4:88) would each get more efficient in the mountains but less efficient on fuel economy.

With our "style" of full timing, we stay in one place a longer time (1 year plus) before moving and do most of our running around in our second vehicle, thus our Ford F450 is primarily used for towing or the occasional hauling issue.  Ours has the 4:88 rear end and when told that our mileage would suffer, I simply stated that the truck was for towing, not exploring.  And, if we happen to be traveling with another RV couple, I will insist on being in front so that I don't have to pass them on mountain grades if their gear ratio is higher than ours.

Terry

mds1 wrote:

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The original poster commented he went with a Landmark with an 18,000 gross weight rating. I hope it's proper to ask what gear ratio he went with or would be best for his combination of a 3500 Ram dually and that trailer?

I know tire size influences the gear ratio decision. Another point might be if one intends to spend much time in the mountains or flat land while hauling. I'd appreciate some advise on what gear ratio to go with. In particular maybe why a 4:10 ratio may not be needed. I've been reading miles per gallon makes little difference but gears might influence the ride of the truck when hauling or not. Not sure I've got that right.

Bill - I still intend to hit you up for more info once we have our trailer selected. I've been spending a lot of time on the truck forums and the gear ratio decision remains a mystery. We are planning to stay under 19,000 pounds on whatever trailer we might start with or even upgrade to later. Who knows how much time we might spend hauling in the mountains. We are from the Midwest and some of those hills in Arkansas and southern Missouri can get big as well. I'd like to have a couple choices for gear ratio which would increase our chances of finding a truck on a lot or for sale by owner.

Ideas on gear ratio or a rule of thumb would be appreciated.

-- Edited by mds1 on Friday 8th of September 2017 05:01:43 PM

mds1,

Our 2016 Ram 3500 has a rear axle ratio of 4.10.  We have had no problems towing in the mountains.  

mds1 ... you will find very limited options on rear axle ratios from the big three ... they might offer two different (at most three) ratios and to get anything different than is sitting on the dealers lot will require a special order or a trip to a shop to get the ratios changed on your dime (remember that 4x4's have two axles). The ratio that the manufacturer puts in the truck as standard is very likely going to be fine.  My 2016 Ford has a 3.73 rear axle ratio and 17" wheel rims and is fine in the mountains. My truck has 440 HP and 860 lbs ft of torque. Both are significantly higher than Terry's 2008 Ford (which I believe is rated at 350 HP and 650 lbs ft of torque and 19.5 " wheel rims). Diesel Engines and transmissions have come a long way since 2008. Gear ratios do matter but modern engines and transmissions make that much less of a concern. Whereas a 4.88 might pull a 7% grade in 5th gear and the 3.73 might need to drop down to 4th gear ... both are going the speed limit (and probably turning similar rpm's) so there really is no need to sacrifice the mileage on flat ground for the occasional mountain pull. When in the mountains or steep hills, I usually lock out 6th gear to reduce the constant downshifting and in 5th gear my overall gearing is very similar to having a 4.10 rear axle.  Besides, the mountains are no place to go much over 55-60 mph anyway. At least that is MHO.

-- Edited by RonC on Sunday 10th of September 2017 08:18:38 AM

-- Edited by RonC on Sunday 10th of September 2017 08:25:21 AM

-- Edited by RonC on Thursday 14th of September 2017 10:23:49 AM

-- Edited by RonC on Thursday 14th of September 2017 10:34:46 AM

Although not directly related to the question of gearing and mileage ... I recently had morRyde install their Independent Suspension on my 41 foot 5th wheel and my fuel mileage went up nearly 1 mpg. I used to get 10.5 towing mpg overall ... since the IS I am getting 11.4 mpg. I assume it's due to the wheels actually being in alignment as opposed to "sorta" in alignment and the resultant reduction in rolling resistance.

Cummins12V98 wrote:

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RonC

IMHO I really think your mileage improvement would be more likely having your engine becoming more efficient.

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 Just curious, how did installing the morRyde IS increase my engine's efficiency? 

Cummins12V98 wrote:

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They become more efficient when they have more miles.

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 Ahh ... hadn’t considered that, but you are correct, of course.  I now have a bit less than 15,000 miles, so still not really fully broken in yet.

RonC wrote:

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Cummins12V98 wrote:

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They become more efficient when they have more miles.

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 Ahh ... hadn’t considered that, but you are correct, of course.  I now have a bit less than 15,000 miles, so still not really fully broken in yet.

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 At 15k your engine is not fully broken in but will be much more than when new.  

Ford 6.0 and 6.4s keep me in business every time i see one on the road i know that they will be in my shop soon.....and yes i've known alot of people that owned them and i've talked to numerous people at campgrounds and they have shared their horror stories with me....

rocketman wrote:

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Ford 6.0 and 6.4s keep me in business every time i see one on the road i know that they will be in my shop soon.....and yes i've known alot of people that owned them and i've talked to numerous people at campgrounds and they have shared their horror stories with me....

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 You do realize that the Ford Diesel is now a 6.7L and has been since 2011?  The Ford 6.7 is a very good (built by Ford) Diesel.  You’re talking about older Fords ... those have either been trouble free or  ”bullet proofed” by now, let’s move on.