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1963tradewin 10-06-2008 11:55 AM

Axle holding weight
 
I was wondering if anyone knew how much weight you can put on a 5200 lbs axle? The reason I ask is that someone told me if you have 4500 and go over big bumps it puts more weight on the axle, is this true? What is a safe driving weight for a 5200 lbs axle? Thanks for the help:wally:

boatdoc 10-06-2008 01:56 PM

Quote:

Originally Posted by 1963tradewin (Post 624553)
I was wondering if anyone knew how much weight you can put on a 5200 lbs axle? The reason I ask is that someone told me if you have 4500 and go over big bumps it puts more weight on the axle, is this true? What is a safe driving weight for a 5200 lbs axle? Thanks for the help:wally:

Hi 1963tradewin;
Axle's manufacturers stated capacity is just that, [capacity] 5200 lbs is 5200 lbs. It is nice to have some 10 percent margin of safety. While up and down motion of the trailer going over bumps does place extra load on the axle, the torsion rods can only compress so much before they bottom out [reach max compression] Use of factory shock absorbers prevents abuse to the rods by slowing down the time of compression and impact. Too high of axle rating will shake your trailer loose by riding hard. Thanks, "Boatdoc"

HowieE 10-06-2008 03:25 PM

As noted above a 5200 lbs axle is designed to support a max. of 5200 lbs. The axle at rest with that load on it should have sufficient remaining travel in the springs or torsion bars to absorb and road shock. That is not to say you should load to the max ever time you travel.

Take a look at your springs or torsion bars and make sure they still have travel distance remaining. Springs should still have a bow that puts the axle mounting plate below the spring ends. Torsion axles should still have the trailing arm pointed downwards as it goes from the axle to the spindle. If these conditions do not exist you your suspension is either overloaded or worn out.

Another consideration for ride quality is that most RVers grossly over inflate their tires. Tires should be inflated to the manufactures rating based on load not the pressure stamped as MAX on the sidewall. I have tires stamped 80 lbs. max and run 45 lbs. in them. Weigh your trailer and inflate the tires based on that load.

1963tradewin 03-21-2009 12:41 PM

I'm sitting around 3500 now and still need to put front u couch and kitchen countertop, sink, faucet, stove, and furnace. With all this plus maple I'm estimating and hoping :) that she will be 4100 or under. Also my tires are only rated to 2300lbs for a total of 4600. They have the 80psi max and that is what I have ran because thought it was best. So If I run 45 psi that is better?

HowieE 03-21-2009 02:41 PM

Quote:

Originally Posted by 1963tradewin (Post 678917)
They have the 80psi max and that is what I have ran because thought it was best. So If I run 45 psi that is better?

Tires should be inflated against the manufactures inflation chart for a give axle weight. Weight your trailer when finished and loaded for the road. Go to the chart for your tire and look at the proper pressure.

My trailer weights 8900 lbs and has 3 axles. I run E rated tires. The chart calls for less than 40 lbs however I over inflate them to 45 on the chance I will have to run in on a flat.

You will have to go in the net to find the proper chart because there is not a tire dealer in the world that will even know what you are asking for. This is the Goodyear chart for most tires we would be using.
https://www.goodyear.com/rv/pdf/rv_inflation.pdf

If you can not find your manufactures chart, Michelin has removed their chart for smaller tires but will give you the answer if you call their service center, the Government standards for tires are the same size for size and you can use any manufacture's and be in range.

Action 03-21-2009 09:00 PM

The axle manufacturer publishes specs for static weight of the max load. The manufacturer knows that the dynamic load will be greater, such as going over bumps.

If you are rebuilding the unit I would construct the items so they don't exceed about 85 to 90% of total load. This gives you room to put propane, food and other stuff. Don't forget that the tank holds fluid and that would weight some thing too.

Do not exceed max pressure for the tires. At max pressure the tires will be at their max load capacity. I feel comfortable if the actual load is 90% or less of the max tire capacity.

>>>>>>>>>>>>Action

HowieE 03-22-2009 09:12 AM

Quote:

Originally Posted by Action (Post 679034)
Do not exceed max pressure for the tires. At max pressure the tires will be at their max load capacity. I feel comfortable if the actual load is 90% or less of the max tire capacity.
>>>>>>>>>>>>Action

If you study a manufactures inflation chart you will see a very wide range of pressure for a given tire over a range of load. The reason for this wide range of pressure is to maintain the designed foot print with the pavement. If you inflate a tire. If you inflate a 225 75 15 carrying a 1600 lb load per tire, with a suggested 30 lbs per the inflation chart, to 65 lbs as printed as max. on the side of the tire you will be riding on a pin point.

Yes it is a fact that many trailers are designed with the lightest tire possible for the weight carried, cheap to manufacture, and thus the chart would have you inflating the tire close to the max tire pressure as printed on the tire. But for those who have up graded their tires checking with the chart becomes critical.

1963tradewin 03-22-2009 12:02 PM

What is a good brand of tire to use? I bought this pair I have on now on ebay 2 yrs ago, and am thinking I will upgrade to be safe as I do not want to have a blowout. My truck tires are load c and hold 2535 35psi max but the d's I have on the trailer only hold 2300 with a 80psi max. Should I get tires that hold 2600? Thats what I was thinking but have no idea.

Action 03-22-2009 03:42 PM

The tire question can only be solved once you know the total load answer.

Since you have an older TW that has a single axle your tire choices will be limited.

Your TW was designed by Airstream for (From the Airstream website) .....
1963 TRADE WIND 24 TWIN & DOUBLE 3500 dry weight 415 tongue weight 19.5 hitch ball height


I would think your total load should not exceed 4500 #s. So the tire that have the load capacity of 4600 # would work. And weighing your trailer in full camping trim before you make a tire decision is a must.

All of this assumes the rest of your running gear is is good working order. If the axle you have is original, I would be highly suspect of it being in good working order. Axles of the era had issues with small spindles and snapping. If you have replaced your axles you should be OK.

>>>>>>>>>>>Action

HowieE 03-22-2009 05:32 PM

Quote:

Originally Posted by 1963tradewin (Post 679226)
What is a good brand of tire to use? I bought this pair I have on now on ebay 2 yrs ago, and am thinking I will upgrade to be safe as I do not want to have a blowout. My truck tires are load c and hold 2535 35psi max but the d's I have on the trailer only hold 2300 with a 80psi max. Should I get tires that hold 2600? Thats what I was thinking but have no idea.

You may want to check your numbers against the inflation chart. I am assuming you are running a 225 75 25 and that in a D range only goes to 2540 at 65 lbs.

Here is a chart.
https://www.goodyear.com/truck/pdf/da...dInflation.pdf

An E rated tire of that size would go up to 2830 lbs. at 85 lbs.

1963tradewin 03-23-2009 07:48 PM

I got a new axle 5200lbs, and am running tires 7.00x15 that hold 2300lbs a piece which hold 80 psi and are also new 2 yrs ago. I got these on ebay for cheap 60 bucks a piece, I'm thinking of switching to that 225 75 15 with a load of 2600 a tire. I got a couple months before the roads get cleaned up around here just want to get this stuff outa the way :)

1963tradewin 03-23-2009 07:58 PM

That chart is a help, thanks.

Grand Master 03-23-2009 08:11 PM

My '63 Tradewind weighs 3960 lbs. on the axle + 440 lbs on the hitch totaling 4400lbs.

My question concerning tire pressure is:
do I use the weight on the axle, or the total gross weight?

Mike Brumback

HowieE 03-24-2009 08:21 AM

Quote:

Originally Posted by Grand Master (Post 679671)
My '63 Tradewind weighs 3960 lbs. on the axle + 440 lbs on the hitch totaling 4400lbs.

My question concerning tire pressure is:
do I use the weight on the axle, or the total gross weight?

Mike Brumback

I would inflate for 4,000 lbs. load. You do not want to error on the low side as that will cause heat to build in the tire and cause a blowout. If you note in my comments above my tires are slightly over the chart, but no wheres near the 80 lbs. that the tire can be inflated to under max. load.

1963tradewin 03-24-2009 05:41 PM

Quote:

Originally Posted by Grand Master (Post 679671)
My '63 Tradewind weighs 3960 lbs. on the axle + 440 lbs on the hitch totaling 4400lbs.

My question concerning tire pressure is:
do I use the weight on the axle, or the total gross weight?

Mike Brumback

What are your tires rated to in weight?

Grand Master 03-25-2009 10:10 PM

My tires are "D" rated Towmax radials. They have a 65 lb. max pressure rating.

As stated in an earlier post, my 1963 Tradewind weighs 3960 on the axle + 440 lbs on the hitch for a total gross weight of 4400 lbs. (loaded to travel).

According to Goodyear:
50 psi = 2150 lbs per tire (4300 lbs total)
55 psi = 2270 lbs per tire (4540 lbs total)
60 psi = 2380 lbs per tire (4760 lbs total)
65 psi = 2540 lbs per tire (5080 lbs total)

The question is............. what is the optimal tire pressure to balance safe load carrying ability, and "smooth" ride?

Thanks,
Mike

HowieE 03-26-2009 09:09 AM

Based on those numbers I would go with 55.

Grand Master 03-26-2009 06:18 PM

Thanks for the reply. I aapreciate someone sharing their experience and knowledge.

I am amazed how difficult it is to get an expert opinion on something as simple as tire pressure. The tire manufacturer and retail agent had no opinion other than the max was 65 psi.

Airstream puts 65 psi in all of their trailers regardless of weight. I specifically called tech support and asked for the recommended tire pressure for a new 19' Flying Cloud (it is a single axle with a weight comparable to my '63 Tradewind). They stated 65 psi.

The Goodyear chart states that tire psi should reflect the trailer weight. It does not seem like a good idea to me to ever use the maximum rating.

I would appreciate other practical experience comments, but until I hear new information I am going to inflate my tires to 50 to 55 psi depending on how loaded the trailer is.

Mike

1963tradewin 04-02-2009 04:45 PM

I found that the new Airstreams have Goodyear Marathons on them. Rated to a little over 2500lbs a tire. This is what I will go with. Hope this helps someone wondering what kind of tires to get.

1963tradewin 11-05-2009 05:08 PM

Ok, so I found out Goodyears are not good, and are known for blowouts. I just bought 3 Towmaster 225 75 15 bias ply max psi 50 with a load rating of 2540 per tire. I'm just wondering if I should have gone with radials instead? I usually don't take long road trips, but will be driving to Ohio in the spring and was wondering if anyone knew if these tires would hold up alright? I have been reading alot about blowouts and it makes me scared for my body panels. Any advice would be great!


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