Chinook RV

I apologize, as the different years, and models of Concourse, and then the added issue I was informed (ball mount length decreases your Hitches weight capacity due to the distance from the fulcrum) when I contacted Curt and they told me to not purchase 6,000 lb extended length).

I purchased my 2004 Chinook Concourse to tow our boat (with our dog) on our trips from North Texas to Florida (visit my mother down in Tampa). I don't want to go to a state surrounded by water, without a boat.

I really appreciate the information this forum (thanks Blue) share on your personal experience with your Chinook, especially when you shared with me (I was originally looking for a Diesel) and towing a 4,500lb to 4,700 lb boat.

I need further clarification. Dry weight on my boat (I guess without engines) is supposed to be around 3,500lbs. I guess I should add another 1,000 lbs for the Single Axle trailer with the heavy duty (6,000 lbs) axles. I had never weighed my boat until this past weekend, after I had it hooked up to my recently purchased (for the first time) 2004 Chinook Concourse. After the first couple of days, the generator stopped working, and then after 2 weeks later I decided I may want to get that fixed to run the roof A/C while driving with passengers in this Texas heat. It spent 2 weeks in the shop, before they found it was a split fuel line from the Fuel tank, to the fuel pump for the generator.

I will admit, that while not using the boat too much this winter, and spring (once a month), and I found that the cheap price of fuel $1.15/gallon, I couldn't help but hook up the boat, tow to the local gas station, and put 36 gallons (I mix my 2 cycle oil with my fuel in the gas tank as I don't trust Mercury outboard pumps). After repeat fuel additions, I nearly topped off 82 gallon tank full of fuel. I also had 4 batteries (2 starting and 2 in the v-birth for the trolling motor), and I have 2 full size spares ST225/75R15 (for the 6,000lb heavy duty axle, and those probably weight 40lbs each).

When I visited these same scales a week earlier (required to get a weight in order register an out of state purchased RV in Texas), the
Steer Axle had 2920 lbs
Drive Axle had 7080 lbs
Trailer Axle 00 lbs
Gross Weight 10,000

I picked up the boat from my storage shed near the lake (70 miles from the house), and drove it home on the highway (the engine and transmission didn't have any issues pulling it) with a stop at a Love's truck stop.

I was very shocked (I had no idea I had a full (82 gallons) tank of gas in the boat) that the weights for towing was exceeded by at least 80lbs. What made it worse is that, while I was going into the station to pay and retrieve my weights, I stopped off at the pumps and I topped off the Chinooks RV fuel tank (added an additional 22 gallons) and that really lowered the back end.

Steer Axle had 2420 lbs (how did that drop 500lbs, as I was sitting in the Chinook both times I weighed).
Drive Axle had 8380 lbs
Trailer Axle 5080 lbs
Gross Weight 15,880 (I'm stll under the 18,500 GCWR for 1998 versions of the Chinook - no idea what the GCWR is for a 2004).

I know I can drop several 100's lbs (492 lbs) by reducing the amount of fuel (I normally tow long distances with a nearly empty tank) and I removed the 2 trolling motor batteries.

I believe that the Chinook is rated to tow 5,000 lbs (I have seen some advertise Chinooks indicating 7,000 lbs). Is that correct, as I'm now being informed that with a extended ball mount, it reduces your hitches capacity by 10% to 15%, and it is required to use an extended length ball mount to get past the spare tire, and the stairs (I found it necessary to remove the bottom stair).

I now recognize that I need to raise the ball, as it is several inches too short, and I'm considering a CURT ball mount for 2" hitches - 4" rise

I am now using a ball mount from etrailer (80232 Hidden Hitch Ball Mount - 3/4" Rise, 2" Drop - 15-3/4" Long - 6,000 lbs), and I'm now being told that while the receiver is rated to 5,000lbs, it is now more like 4,500 due to the extended length of the ball mount. Is this the receivers weight limit, and is the long tow bar length already factored into this 5k weight?

I appreciate any help and clarification you can provide. I will also post to the forum for further discussion.

Thank you,
Baitguru (Michael)

Hi Michael,

There is a bit to sort through here, but first of all let me say "more power to you" for actually getting scale weights. Now we are dealing with numbers, and we know you would like to be within spec.

Basically with all the towing weight numbers, you have to not go over any of them to be in spec. As you found out, the GCWR is kind of a pie in the sky number. But that's because Ford has the chassis rated without knowing what will be put on it. So if you had, say, a lightweight flatbed instead of a heavy house, you probably could tow an 8,000# trailer, get up close to the GCWR, and still not overload the rear axle. But naturally you don't want to exchange your Chinook "house" for a flatbed

So let's take one thing at a time. We'll start with the rear axle, since that's basically a fixed number. That number is on the driver's door jamb as "XXXX# GAWR-R" most likely. Barring any changes for 2004 it can be expected to be 7,500#. So hey, you are only about 1.000# over Doesn't help that a 2004 probably has more weighty luxuries than a prior year(s).

Will you be able to get it within spec? I can't say for sure but since you already own it let's talk about what you can do before you re-weigh. There are a few ways you can chip away at it.

First of all, the further the weight is behind the axle, the more it "counts." This is due to the overhang and leverage. So for example, the 330# of tongue weight my boat trailer has, translates to 550# added to my rear axle. I believe that with the electric step, you have a touch more distance there (longer drawbar).

There are formulas for that, and I did those calcs before buying the Chinook (ruled out a couple other RV's with it), and when I weighed it was almost spot on to the results of the math. So tongue weight adds to your rear axle weight more than anything else, but other things count too (stuff behind the rear axle of the Chinook, see below).

So, a single axle trailer usually wants to have about 10% tongue weight (10% of the whole loaded trailer weight). BUT, a tandem axle trailer does just fine with 5-7% tongue weight. So you can save there with a different trailer. Aluminum would save a bit more weight, but only a small percentage of that on tongue weight. Also, unless you are going out to back of beyond, I'd go with trailer tires less than three years old and only one spare (saves weight). Likewise, you could consider towing the boat with empty fuel and water tanks (evaluate weight difference though based on tank locations). The Chinook fuel tank is behind the rear axle, so that makes a difference of up to 300# on the rear axle although you obviously can't tow with it empty. Chinook grey and black tanks are also aft of the rear axle (could add close to 500# between the actual fluid weight and the added factor of being behind the axle), so you'll want those empty.

Another place you can make a difference is with the Chinook spare tire. I moved mine to the front (have written up part numbers and details in a previous thread). Between losing the tire and bracket off the rear, and then adding it to the front, IIRC I calculated it took about 220# off the rear axle. I actually moved it just because I didn't like having it in my way right outside the door, but losing rear axle weight was a side bonus. BTW, the tire protruding made no impact on how long my drawbar needed to be even when it was on the back. But then boats are narrow at the front (usually) and sit back a bit on the trailer, so one doesn't tend to need extra clearance for cornering (as compared to say a V-nose cargo trailer.

On the hitch assembly itself, that is rated at 5,000# in literature I have seen, and having looked at it, I don't get the feeling they under-rated it (in other words, it looks like a 5,000# hitch). You could have that beefed up, within limits.

On the extended drawbar: I've only seen "official" 50% de-rating on the type that is an extended receiver, and then you plug your drawbar into that. But it only stands to reason that a longer drawbar puts more force on the receiver (especially with the dynamic weight of a trailer tongue) and with the electric step you need an even longer one that I do, with the less-protruding manual step. (Don't know if you could remove the lower step for towing and use a shorter drawbar.) So yeah, I probably would not feel comfortable putting max tongue weight (500#) on a super long drawbar. But then if you have that heavy a tongue weight, your rear axle will be overloaded anyway. So again reducing tongue weight will help.

So to summarize:

1) The 2004 year and the electric step combo mean a longer drawbar, and probably more weight on the rear axle to begin with (added luxuries), so you start out closer to ratings before you even hitch up.

2) A single axle trailer means more tongue weight for the same load (10% vs. 5-7%).

3) Any fluid in either the Chinook's fuel tank, or the black or grey tanks is behind the axle so adds more weight to the rear axle again.

4) Spare tire on the back contributes something like 200# (I think it was 220#) to the rear axle vs. moving it to the front.

Just for comparison:

1) My Chinook is about 6,800# on the rear axle with about 1/2 tank of fuel and all my stuff inside. So I start out with more "headroom."

2) Trailer tongue weight is only about 325#

3) Drawbar is shorter due to manual step not sticking out as far.

Upshot is that loaded for bear and towing a boat, with a full Chinook fuel tank, I'm at 7,300# on the rear axle. This is with plenty of tools, stuff, etc. so it's about the most weight I'd ever have on the rear axle. Boat trailer weight at that weighing was about 4,400#, 350# of which was tongue weight (scale only weighs in 50# increments). That tongue weight is actually over 7% so could possibly be less and still tow okay (if you don't have enough tongue weight the tail can wag around which is unsafe).

Does this help? Did I miss anything?

I forgot about the drawbar rise, etc.

If you are going to change trailers, then obviously you'll want to hold off. A tandem wants to tow pretty much exactly level (equalizes weight and loading on tires etc.), whereas you have some leeway with a single (I still don't like it lower aft though).

For my Chinook, with the boat trailer weight on it, the top of the ball wants to be at about 19-1/2". That depends on your exact setup though. What I did was tow to a level parking lot and adjust my trailer until the frame rails were the same distance from the ground all along, Then I got a drawbar to suit. For me it's a bit of a rise.

But that can change. For example I put a new coupler on the trailer, and it sits at a different height. It's right between drawbar heights. So I got a hitch ball with a 1" rise in the shank, and then a drawbar with less of a rise, and I'm level again. BTW, the longer draw bars are very hard to find outside someplace like e-trailer. I once ended up far from home and wanting to tow a trailer and didn't have the drawbar with me is how I know Another factor I had to consider when choosing the drawbar was the distance before the rise started (so the rise did not hit my step).

PS: Presuming you can get your weight sorted out, I'd recommend a Scangauge II -- or any other gauge that can provide the same information. I started my first towing trip without one (in my previous Ford camper van) and it was like driving blind. All I had were "idiot" lights and gauges with no numbers. Would I suddenly overheat? Was the transmission running hot with no way to know? How was my alternator doing? I stopped half way 'cross country and picked up a Scangauge II. Fifteen minutes in the parking lot and I had it all set up (would be two minutes but you have to punch in some numbers to get transmission temp). For the rest of that trip (and ever since) I knew exactly where I stood... with numbers, not vague needles or only warning lights. Ahhh

As a side bonus, it can read out check engine codes which you can easily look up online. CEL comes on halfway through a trip. Is it something you can fix (loose gas cap), safely drive with until convenient to fix, or need to stop right now. The gauge gives you the code info. You can also dismiss codes which can be a helpful diagnostic tool. Say you get a code, then tighten a loose gas cap. You can dismiss the code and see if it comes back (there is something else going on) or not (you probably fixed it). And it's helpful info if you do need to take it to a shop.

There is a thread specifically about the SGII -- and there are some other gauges that can give similar info. I would still buy the SGII again now, but the main thing is just to have the information, however you obtain it.

Thank you very much.
Every time you have been very helpful, and that is greatly appreciated.

I dropped my Chinook off at a shop about 4 hours ago to have Firestone airbags installed. I have a different style of Firestone airbags on my Expedition, and it worked perfectly at keeping the ride level when towing this boat. Just trying to make sure it doesn't drop the back end, while I still master removing of weight prior to towing.

I had plans to tow the boat with the Chinook up to a lake in Oklahoma (free fishing weekend) this Friday night to meet my SCUBA club for some diving/spear fishing. They recognize that I may not bring the boat this year, but towing this boat was a major considering in getting a 21' Chinook RV.
We looked at a boxier, slightly longer, and much less attractive Winnebago motor home (the family really like the layout, and for less than what I paid for my Chinook) that the sales people indicated could tow 7,000lbs.

I wonder if can upgrade/replace the axle of this E-350 , like Upgraded the axle on the trailer. Does an E-450 use the same axle?

I have been taking many steps to decrease the weight off the boat, and the rear of the Chinook.

I am also looking to invest in an aluminum, tandem axle trailer. However, tandem trailers are much more difficult to manually maneuver, and aluminum trailers like to flex more than I want.

I like the idea of moving the spare to the front of the Chinook. That would provide a lot more clearance in the back (I need to review what you have accomplished). Hitting that spare tire cover (and not the stairs) was the driving reason for the extended length ball mount. Frequently, When I am backing the trailer down a boat ramp, or into the driveway, I frequently need to "cut" the trailer at nearly sharp angles (75 to 80 degrees or more which is easy to do in a single axle) to fit it in the correct position for launching or parking. I always need to physically "manhandle" the boat/trailer in order to maneuver the rig and it's wide 8' 6" wide axles (normally used on my larger boat trailers) to best fit in the side parking spot next to the driveway.

While backing up the trailer/boat, I have had the "Trailer Valet/Swivel Jack and Trailer Mover " come in contact with the rear bumper (leaving a dimple). That spare tire cover would be too easy of a target for me to accidentally damage, so the 15" ball mount really helps clear it, but moving it to the front could (especially on long tows) allow me to greatly decrease that length.

I am also strongly considering removing one of those spare tires from the trailer, located way up front of the trailer (under the bow). I have recently experienced excellent reliability with a set of Maxxis trailer tires.

This past Sunday, I started off by trying to lower the boat's weight. The Deep cycle Batteries (42 lbs each) in the very front of the boat (v-berth) have always been a concern) and I removed these. I believed very little of that weight is carried by the axle of the boat while towing. I may transport those under the dinette on long tows where I plan to use a trolling motor. I had a boat mechanic think he was going to move my boat around his shop with his 4-wheeler (he uses it to move much larger boats on multi-axle trailers), and he quickly found his 4-wheel, having 2 front ties up in the air. When towing with either our truck, Expedition (with the airbags), or my son's navigator, it wasn't much of a problem.

I should have dumped the (black/gray tanks) at the truck stop, as this truck stop is the only place in my area where I have access to a dump station (only $10). I returned this past Sunday morning, and emptied all tanks, and did not fill the tank in the Chinook. I really didn't have too much liquid in these tanks after I first dumped them 2 weeks ago ( I attempted to get some soap/water, and even a little bleach in an attempt to clean the tank level sensor that continues to read "full"). It took me about a minute to drain the black tank (all clear), and a few seconds for the gray.

I have managed to knock off a lot of weight from the boat (still have approx. 35 gallons of fuel) by towing it to the lake with our truck. and running it around with the family.

The after market, heavy duty 6,000lb single axle trailer, and the modified shackles, greatly increases the height of the boat trailer. Normally, I like this, as I can completely lower the outboard (with Extended length lower unit) and still have 5" of clearance under the prop (I couldn't do that with the original axle).

I find that that from the pin hole in the receiver to the end of the top stair is 10". The 14 1/4" Curt receiver that I mentioned (CURT ball mount for 2" hitches - 4" rise 6" drop) Model 45280 comes out 8 1/4 inches from the Pin hole where it starts to lower (rise) to 6" drop (4" rise). I had hope that others used this ball mount, to determine if it that rise (still 1.70 inches from the top of the ball mount to the bottom of the stair) clears the top stairs. I am still working to obtaining a raised ball mount (local shop has the Curt 45280 on order) than I can attempt to fit, and confirm it will work.

Thank you very much for your suggestion. I am still working on cutting weight.

I have attached pictures of the ball mount and several with the boat connected to the Chinook.

pictures of chinook and boat trailer

I got not much to contribute, but I read that other has look into replacing the axle with E450 differential limited slip:

https://www.rv.net/forum/index.cfm/fuse ... t/true.cfm

If I remember correctly, the longer Chinook (Summit, for example) were build on the E-450 chassis.

Baitguru wrote: June 3rd, 2020, 1:24 pm We looked at a boxier, slightly longer, and much less attractive Winnebago motor home (the family really like the layout, and for less than what I paid for my Chinook) that the sales people indicated could tow 7,000lbs.

Well, I'd say that's meaningless. Most salespeople have no idea what a vehicle weighs, much less what it can tow. Both RV's I have towed with had "towing weights" or GCWR far in excess of what could actually be towed without going beyond some weight ratings (usually rear axle, but also hitch rating, front axle, etc.). They can't know all that unless they have studied all the ratings AND weighed the vehicle when loaded. Show me a salesperson who does that (and if there is one, it's a welcome exception).

Buying an RV on the E-450 chassis is no guarantee, because they may be heavier or have a longer overhang. The best best would be a small RV on the E-450 chassis, or something like a Super C on a medium duty chassis. Or adjust the load to the RV. I'd say until you are into Super C's or some big diesel pushers, 5,000# is a good rule of thumb. But of course once there is a specific RV, one can do the math.

Baitguru wrote: June 3rd, 2020, 1:24 pmI wonder if can upgrade/replace the axle of this E-350 , like Upgraded the axle on the trailer. Does an E-450 use the same axle?

The E-450 axle has a wider track. You *can* put one on an E-350 Chinook. I say this as I have seen some 4X4 conversions that have used it. It is wider. I can't imagine the hoops to get weight ratings officially changed so you would need to not care about that. Also, you still have the hitch to modify. I would also then convert to bigger brakes. Otherwise you can just make a new weak link. Tires are fine as you have a large margin to the weight rating at 80psi.

Personally, I would either get a different RV, consider something like another member of the party towing the boat with a truck, or make enough small changes to get under ratings. It's not like the vehicle is going to break if you go a little over, but 1,000# before you even get going is too much, IMO. The hitch I would say does not have much of a cushion in heavy dutyness.

Also, I would want to have brakes on all trailer axles (I have disc brakes on all four boat trailer axles). Especially if you have the stock E-350 brakes which are a bit wimpy. I changed to a 2104 front axle/suspension setup, mainly for the much larger brakes.

Baitguru wrote: June 3rd, 2020, 1:24 pmI have been taking many steps to decrease the weight off the boat, and the rear of the Chinook.

I think you might be able to make it.

Baitguru wrote: June 3rd, 2020, 1:24 pmI am also looking to invest in an aluminum, tandem axle trailer. However, tandem trailers are much more difficult to manually maneuver, and aluminum trailers like to flex more than I want.

I'm not one to "dis" single axle trailers, but tandems do tow nicely. I accept the slightly worse maneuverability. All trailers I've seen for smaller boats flex so I can't comment on that. I've always felt you are strapping the trailer to the boat, in reality. I have a galvanized tandem.

Baitguru wrote: June 3rd, 2020, 1:24 pmI like the idea of moving the spare to the front of the Chinook.

Sounds like that could help in a number of ways. It was fairly easy and not too expensive. While it sticks out in front, it doesn't really affect cornering since it is only in the middle. But it does make the rig a foot or so longer (not an issue for my use).

Baitguru wrote: June 3rd, 2020, 1:24 pmI am also strongly considering removing one of those spare tires from the trailer, located way up front of the trailer (under the bow). I have recently experienced excellent reliability with a set of Maxxis trailer tires.

As long as you keep enough tongue weight if sticking with your single. That's your biggest overweight driver though. I went with Maxxis also (I get new tires every three years on trailers), but I would have gone Goodyear Endurance if they made them in my size (they don't, boo).

Baitguru wrote: June 3rd, 2020, 1:24 pmThe after market, heavy duty 6,000lb single axle trailer, and the modified shackles, greatly increases the height of the boat trailer. Normally, I like this, as I can completely lower the outboard (with Extended length lower unit) and still have 5" of clearance under the prop (I couldn't do that with the original axle).

I'm the opposite, and my boat rides low on the trailer. I do have to tilt and support the motor, but I think I'd have to back in too far to launch if it were higher. I had a nervous moment last time I launched: Had Chinook backed in, heavy duty rubber chocks in place, and both my rear axle and generator were out of the water with some margin. Then a boat went by sending a huge wake up the ramp. It was okay but I would not have wanted to be backed in deeper to accommodate a taller trailer.

If you can reduce the drawbar length by temporarily modifying the steps that might be a good idea (I'm not clear on tat since mine are different).

Baitguru wrote: June 3rd, 2020, 1:24 pmThank you very much for your suggestion. I am still working on cutting weight.

You are welcome.
BG