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Sky_Boss · 09-19-2012, 08:50 PM

OK Folks...I am looking for some thoughts on a 2004 Newmar Mountain Aire, 4302 tag regarding weight.

I'm looking at pulling the trigger on purchase of this MH.

Used 2004 Newmar Mountain Aire Class A Diesel Motorhomes For Sale In Wauconda, IL - CRV80948 - Camping World

Given my better understanding of weight and balance with my current rig I had the dealership weigh it. Bless their hearts, they did and here is what I have with full fresh water, full LP and 1/2 tank (75 gals) of fuel:

Total Front - 12,240 (GAWR 14,200)
Driver Front - 5, 720
Pax Front - 6,520

Total Drive and Tag - 21,200 (Combined GAWR 30,000)
Driver rear - 10,120
Pax Rear - 11,080

They did get the total tag weight separate on the first run and it was 7,120 so that gives a pretty good feel for that situation.

OK...now for "real life" use we need to add in 75 Gal fuel adding 525, me as driver 200, Sandee as copilot 150, dogs and crates 200 and then finally 2 new tires of higher rating adding 50. Since the fuel tank is right behind the front wheels I am saying all that weight goes on the front axle. I'm also assuming "da family" is also on the front axle. That leaves me with 833 that I can add to the front axle and be within the front GAWR of 14,200.

So, what's the problem? I'm just a bit concerned that any weight I add between the axles might be more towards the front than rear. OTOH, I guess any weight I add to the bedroom actually unloads weight on the front...a tiny bit but now I am getting anal.

Now, here is the $64K question...Does any one think they have 833# of STUFF in their coach besides "family"? I mean stuff like clothes, tools, food, supplies and such. I know, kinda sounds...no really sounds like my watch spring a little too tight.

To be honest, I'm having a hard time imagining I can't easily manage 1,000 to 1,200 lbs by judicious placement to avoid loading it all on the front axle. With a little effort I would expect I could stuff 1,500 lbs. in it and keep most of it from being on the front axle. Maybe I am answering my own question but...all thoughts are welcome.

THANKS IN ADVANCE

sc3283 · 09-19-2012, 09:00 PM

Don, I would say "YES" I have more than 833lbs....take all your food and place it in boxes...weigh those boxes and you will see just how fast everything adds up

TurtleKent · 09-19-2012, 09:00 PM

My understanding is that you can reduce the weight on the front axle somewhat by raising the tag axle slightly, and vice-versa. I believe I read this somewhere when I was attempting to balance out my four-corner weights. I'm sure someone will jump in if this is incorrect.

Sky_Boss · 09-19-2012, 09:09 PM

Quote:

Originally Posted by TurtleKent

My understanding is that you can reduce the weight on the front axle somewhat by raising the tag axle slightly, and vice-versa. I believe I read this somewhere when I was attempting to balance out my four-corner weights. I'm sure someone will jump in if this is incorrect.

Interesting... I was surprised that the drive axle had 14,080 (20,000 rating) and the tag had 7,120 (10,000 rating). I guess I was expecting more weight on the drive axle but I have no experience to argue with that for now. That being said, those weights doesn't seem too far off. Each axle is carrying close to 70% of their individual GAWR. at face value that seems a good balance and probably shouldn't be adjusted, if it could be.

TurtleKent · 09-19-2012, 09:23 PM

Two other discussions you might refer to
RV.Net Open Roads Forum: Class A Motorhomes: Tag axle adjustment

Axle Overloading - Lack of Standards - FMCA Motorhome Forums

bbeane · 09-20-2012, 03:49 AM

Don, yes I would bet I have more than 800 lbs of "Stuff" easy and we don't have all of the storage anywhere near full. As others have said if you take everything into consideration, (tools, lawn chairs, grill, table, clothes, food, extra cords hoses, and the list goes on) it adds up quick. Once a year we have a big clean out and get in all the corners to find stuf that hasen't seen the light of day in a year, last year we had 18 coffee mugs, there is only 2 of us!

Sky_Boss · 09-20-2012, 04:58 AM

So, I suppose the next question is whether or not can distribute the weight so that most of it is at least 1/2 way between the front and rear axles or further back.

So, "thinking out loud"...

1. It is pretty clear that items aft of the bathroom will be nearly 100% on the drive or tag axle combo. Little or no impact on the front NO chance of overloading that combo. 300# of clothes, little used items and such would be reasonable to get back there.

2. Items between the bathroom and to the front of the galley area will probably average out to 70% on the rear and 30% on the front so 500# in that area (refer, food stores, and house keeping stuff) would add 150# to front.

3. Items from the the front of the galley forward, including most of the useable basement area, would put on average 30% on the rear and 70% on the front so 1000# there would add 700# on the front axle.

Based on those assumptions, I could have nearly 1,800# of "stuff" and about 850# would be added the front axle.

Anyone want to blow some holes in that theory for me?

I guess all that theory is based on THINKING that where a load is between the rear and front axles will distribute relative to the position from those axles. Any physics smart folks have a counter to that?

Brigadoon · 09-20-2012, 07:34 AM

Here's a couple of questions for you:

What axle is there in the front end? Is it the 14,600 lb axle? Note, I'm not asking about the rating by Newmar but the actual axle. You may have to crawl under the front end to identify it.

Second what size and what load rating are the front tires?

Sky_Boss · 09-20-2012, 07:47 AM

Quote:

Originally Posted by Brigadoon

Here's a couple of questions for you:

What axle is there in the front end? Is it the 14,600 lb axle? Note, I'm not asking about the rating by Newmar but the actual axle. You may have to crawl under the front end to identify it.

Second what size and what load rating are the front tires?

The front axle is rated by Newmar at 14,200. Are you saying that they may have installed a different axle that was stronger? I will call Spartan to see if there is more to this.

2 years ago all 8 Michelin 295/80R.22.5 LRH tires (max single weight 7830#) got replaced with Bridgestone 295/75/22.5 LRG (max single weight 6175#).

What were they thinking!? This deal will will not go through if they don't replace the front tires.

FWIW, the rear tires are sufficient to support both the drive and tag axles at max weight and still have some room for imbalance from left to right also.

Brigadoon · 09-20-2012, 08:02 AM

Yes, I'm saying that your front axle may be a 14,600 lb axle. Newmar often rated their units by tire limitations. If the 14600 axle is under the front and you went with say a Michelin XZA2 Energy load range H tire (295/80 LRH), you would have more capacity than indicated in your original post.

By the way, there is an identifying tag on the front of the axle that will identify the axle and load rating.

Sky_Boss · 09-20-2012, 08:16 AM

Quote:

Originally Posted by Brigadoon

Yes, I'm saying that your front axle may be a 14,600 lb axle. Newmar often rated their units by tire limitations. If the 14600 axle is under the front and you went with say a Michelin XZA2 Energy load range H tire (295/80 LRH), you would have more capacity than indicated in your original post.

By the way, there is an identifying tag on the front of the axle that will identify the axle and load rating.

MAN!!! YOU ARE A LIFE SAVER!!!

Just got off the phone with Spartan and they told ME exactly what you just said and identified it as a 14,600 axle but because of the tires that came with it for Newmar was rated down to 14,200.

YOU MADE MY DAY!

I have a new rig to negotiate on now!!!

MADP4301 · 09-20-2012, 08:49 AM

Stock wheels up front are 7.5" and will not support 295/80R22.5 tires. Depending on the tire manufacturer you need 8.25" or larger wheels to accommodate that size. With the 275/80R22.5 LRH you have a max of 14,320 lbs up front. To get the additional 280 lbs you need bigger wheels and tires. That's a bit of cash for 280 lbs. I think those wheels are ~$400 a piece.
Also, I don't know if there are any clearance issues either. There might be interference at max angle or during a full bag air dump. Something to investigate…
A positive to larger tires up front besides the extra 280 lbs carrying is running lower PSI. You might have a ride improvement running 295/80’s at 110 PSI versus the 275/80’s at 120 PSI.

Sky_Boss · 09-20-2012, 09:14 AM

Quote:

Originally Posted by MADP4301

Stock wheels up front are 7.5" and will not support 295/80R22.5 tires. Depending on the tire manufacturer you need 8.25" or larger wheels to accommodate that size. With the 275/80R22.5 LRH you have a max of 14,320 lbs up front. To get the additional 280 lbs you need bigger wheels and tires. That's a bit of cash for 280 lbs. I think those wheels are ~$400 a piece.
Also, I don't know if there are any clearance issues either. There might be interference at max angle or during a full bag air dump. Something to investigate…
A positive to larger tires up front besides the extra 280 lbs carrying is running lower PSI. You might have a ride improvement running 295/80’s at 110 PSI versus the 275/80’s at 120 PSI.

Per Spartan Rep

4VZBT1D974C047236 Spartan Chassis with the VIN # was built with a Tuthill 1460S suspension. The original tires that were shipped with the chassis were Michelin XZA2 295/80R 22.5. The GAWF is 14,200 and the GAWR 30,000 GVW 44,200 GCWR 54,200

Perhaps it was something I typed but 275s have never been on the MH. But I do type badly at times. LOL

I believe the wheels are original but they replaced all tires with 295/75R Bridgestones instead of 295/80Rs. The MH never had 275s on it. Maybe you were thinking of the 80R vs the 75R numbers? (lots of numbers in these postings) The Michelin XRV2 295/80Rs fit on both 9.00" and 8.25" wheels. The comparable Bridgstone tires have the same wheel and weight specs as the Michelins.

Based on the above, I don't think it came stock with 7.5" wheels.

Am I still missing something?

Brigadoon · 09-20-2012, 02:23 PM

I guess while you are doing your due diligence, you could check the wheels that are currently on the MADP to make sure that the wheels are at least the 8.25 inch variety. Who knows, maybe the guy who swapped the tires for the 295/75 LRG's also swapped for smaller wheels. I would check that to make sure there will be no issues swapping back to the 295/80's. Otherwise it looks like you would be good to go.