Community Forums

n5pht · 07-01-2013, 04:08 PM

Hello,

I have a Montana High Country - 343RL. It is a 2012 and I bought it new. Axle is Dexter 5200 pound 6 lug. I believe it is too light duty for the 5er.

My calculations: Trailer dry weight: 10040 lbs
Max Payload: 2400 lbs
Tongue weight: 1720 lbs

NOTES: The dry weight and max payload figures on the sticker on side of trailer and the 2012 Montana specs page is a little different but not much
(9580 and 2920) and the tongue weight I got from specs and don't see that listed on trailer.

So, to calculate the axle need: dry weight + payload and then subtract tongue weight and divide by two (2 axles): ((10040+2400))-1720/2 which then equals 5360 pounds per axle.

AM I MISSING SOMETHING OR DID KEYSTONE PUT TOO LIGHT DUTY OF AXLES?

I have not weighed us loaded but certainly believe the axles should be able to handle the load as noted above. Some calculations I have seen would take off 10% for tongue weight and that would result in an even worse situation on the axles.

My action: I have sent the above to Keystone today (1 July) and they claim they will investigate and get back to me within 2 days. I have sent the above to Dexter to see the possibilities of upgrading to a higher rated Dexter axle.

I bought this new last year and I am now in Washington State (Spokane) and the dealer is in Shreveport, LA so I have not yet contacted them for comments.

We searched for this floorplan and love it - with nice desk for my ham radio activities and the floorplan is perfect for us. I think the Montana Mountaineer 362RLQ is the exact floor plan but I think it has 7000 pound axles - don't know the weights exactly. But I think Keystone should do something with this situation - are all Montana High Country models in likewise situation?

Your thoughts greatly appreciated.

Gary Stone
903-227-9005
n5phtgs@gmail.com

Roam America · 07-01-2013, 04:54 PM

the pin weight (you are saying tongue weight) is more like 18-20% of the trailer weight for a 5er (TT's are around 10%). Use the GVWR of the trailer since that is the max weight you should load the 5er up to. Now to truly be accurate, you should weigh the 5er without the truck to get the true Pin Weight but if you use 20% you will be fairly close.

Using your numbers, the GVWR would be 12440 (10040 dry weight + 2400 payload). 20% of 12440 is 2488 which is the pin weight being added to the tow vehicle. That would leave 9952 on the axles. Assuming the trailer is sitting perfectly level front to back, that puts 4976#'s on each axle (9952/2 = 4976) which is within the 5.2K specs of your axles.

Hope this helps.

JohnT · 07-01-2013, 05:10 PM

John is correct on the pin weight of 18% to 20% of the trailer GVWR. I weighed my 5th wheeler with the usual trailer stuff with and without the truck. My rig was 11,880# and my pin weight was 20% - 2375# to my 14k# GVWR. AND I was 256# overweight.

with 6k axles. I upgraded the axles and suspension.

Skip426 · 07-01-2013, 05:22 PM

Many units out there that are on the limit on axles and TIRES, manufacturers way of skimping out to save a few bucks.

If your axle weights are that close to the line take a close look at your tire's ratings as well.

greystroke · 07-01-2013, 05:52 PM

You might try the forum at montanaowners.com

There you can ask the owners of this model. I had a Montana before buying my current motorhome and found that most Mfgrs of 5er's don't give much safety margin in their axles. On some models I know they increased the axle size for the reasons you cited. The pin weight for my 5er was 23.5 % of total weight. I was ok but right on the border line for my axles. But I lost contact now with the owners. Love a 5er though. I kept my truck just in case I go back.

TXiceman · 07-01-2013, 06:09 PM

While the axles are OK if the load is balanced and the trailer is level, the load on the axles should be very close to the same. If you load one heavier than the other, you do not have very much room on the axle load if fully loaded. You might also check the tire rating for this trailer.

Ken

hjsdds · 07-01-2013, 06:14 PM

You might want to check this.
http://www.irv2.com/forums/f272/bewa...ry-108558.html
I checked the specs on the tires that you are supposed to have on the rig, ST235/80R16E. If you have those they are rated at 3420 lb each (fully inflated). So 4 of them should be good for 13,680 on the axles alone. Add to the pin weight in the bed of the truck and that's your theoretical gross weight that you should be able to "abuse your Montana" up to. 5,200 pound axle on a 34 footer with slides is idiotic. I can't imagine the conversation between the folks who decided that this was the axle that belonged on that rig. It was not two or more engineers calculating things based on the utility and use of the rig, it was two morons arguing how to "cheapen" that model. Not Dexter's fault, Dexter makes any axle you might need, up to 10K and more, somebody at Montana or its parent, Thor, made that decision.
You should check on the brakes you have, some 5,200 pounders might have 12" x 2" brakes shoes, but you could also have 10" x 2" brake shoes (something slightly north of pop up needs), not that 12" x 2"s are anything to brag about (from 6-7K axles).
I got educated on this 36 footer.

The idiots at Cobra (Corsica) installed 15 inch tires on it, I was popping them like popcorn 10K max rating on the tires 12.5K weight. Trailer got totaled eventually (I was happy). Bought an MDT to pull it and STOP IT!!

hjs

JIMNLIN · 07-01-2013, 07:51 PM

Website shows the 343 RL has a 9731 lb dry weight with a 2389 lb CCC = a 12120 GVWR.

Twenty percent pin weight of 12120 GVWR is 2424 lb pin weight.

Subtract 2424 lb pin weight from 12120 gvwr = 9696 lbs on the axles.

Or 2424 lbs per tire requirement.

I see nothing wrong with 5200 lb axles on a 12120 GVWR 5th wheel trailer however actual scaled weights will tell the real story. If your going to do battle with the mfg you need those actual scaled weight numbers if the axles are truly under sized.

oldbeek · 07-01-2013, 11:28 PM

My 27ft alpenlite single slide came stock with 7,000 lb axles. Never a wheel or tire problem. For you scale guys, what is the weight on that 5200 lb axle just after it pops over a Yukon frost heave that is 6 inch tall and the entire trailer weight comes crashing back down on it???? They sell lots of axles and springs in Whitehorse, NW territory.

n5pht · 07-01-2013, 11:40 PM

Thanks for all the replies. However, if the pin weight is that high Keystone is wrong in their own specs sheet. Look at their own web page and the pin weight is 1720 lbs. So, if indeed the actual pin weight is 20% then the axles are close to ok. However, Keystone's own page states the pin weight is 1720 lbs.

IF Keystone's pin weight is wrong then perhaps the other weights are also? Oh well, if you go with Keystone's own specs the axle is too light. If their dry weight and cargo allowance weights are correct and their pin weight is incorrect then perhaps the axles are ok? So, outside of taking the trailer to get weighed who knows?

We should be able to use the printed specs from Keystone and if you do that the axles are too light!

RE: tires - thanks for the comments and after a blow out I have already replaced all tires with Truck tires and got rid of the "China Bombs" Keystone put on the trailer.

n5pht · 07-02-2013, 12:19 AM

OK - will be interesting what Keystone tells me but here is what I suspect: (it occurred to me their listed pin weight is dry not loaded)

10,040 dry weight and 2400 cargo and the Keystone stated pin weight is a DRY pin weight - 1720 pounds. So, add 15 % to their own figures for the pin weight to arrive at a LOADED pin weight and that makes the pin weight 1978 lbs. Then do the math and the axles have to handle 10,462 lbs - or 5231 each! Well, that is probably their answer but I still would feel better with 7,000 - 8 lug axles.

caissiel · 07-02-2013, 05:48 AM

Quote:

Originally Posted by n5pht

OK - will be interesting what Keystone tells me but here is what I suspect: (it occurred to me their listed pin weight is dry not loaded)

10,040 dry weight and 2400 cargo and the Keystone stated pin weight is a DRY pin weight - 1720 pounds. So, add 15 % to their own figures for the pin weight to arrive at a LOADED pin weight and that makes the pin weight 1978 lbs. Then do the math and the axles have to handle 10,462 lbs - or 5231 each! Well, that is probably their answer but I still would feel better with 7,000 - 8 lug axles.

you will only see 7k axles on trailers with above 14000 lbs GVW. and they are rare by Keystone. They usualy max at 6000lbs axles.

That is the reason they are so popular due to their lighter weight and construction.

hjsdds · 07-02-2013, 07:53 AM

The business with the manufacturers specs, expectations, "lightweight popularity", price point, value, is this or that adequate, is all nonsense, because it doesn't take into account human nature and behavior:
"Buy the biggest thing, for the cheapest money, cram everything you can think of into it and then see what happens".
RV industry and the RV salespeople are nothing if not experts at reading human nature.
Been to many national RV Rallies and at almost everyone they do weigh-ins. With the exceptions of the real big triple axle rigs and particularly on the shorter rigs folks reading the weigh-in sheets results were either pale face or chagrined.
We are talking real world here, traveling, loaded for a bear, going to a Rally, having "fun", against the other real world (identified on the weigh-in sheet), axle ratings, tire ratings, actual weights front to back and side to side (with everything heavy, kitchens, appliances, etc., on the left side).
Some guys were ready to cry.

hjs

RustyJC · 07-02-2013, 07:59 AM

Quote:

Originally Posted by caissiel

That is the reason they are so popular due to their lighter weight and construction.

Generally these types of rigs are popular because the unsuspecting buyer is impressed with lots of "foo-foo" cosmetics for the price and doesn't know enough to check out the important foundational elements that separate these from a true full-time 5th wheel.

Rusty