Axle upgrade?

[Cyclops69]

New to this forum and joined because I am going to upgrade the axles, rims and tires. I am in the research part of this project and am looking for any info that may help. I use my 28 grand surveyor about 8 months out of the year for work all over the nation. I am on my second bent axle and am tired of buying tires . Took the rig to a scale and she weighs 7400 pounds minus about 550 of tongue weight. This puts me right at the capacity of the 3500 pound axles that came on the trailer. Looking for maybe 5000 pound axles or 4500 pounds with 6 lugs hubs so I can also go to a higher load range tire on a bigger rim. This is the first of many upgrades I have planned and arguably the most important so any help as far as type or manufacture or deal to buy from will be helpful

Thanks in advance

Sorry forgot to mention the TT currently has AL-KO torsion axles

[69_Avion]

Having rubber torsion tandem axles instead of leaf springs makes this situation even worse. A rubber torsion tandem axle trailer will have the entire weight of the trailer (less the tongue weight) on one axle when the trailer goes over steep bumps like going out of a severe inclined driveway. Some rubber torsion axle manufacturers recommend using axles at 1.25 times the load required for the weight of the trailer to compensate for this issue. The leaf spring tandem trailers will have an equalizer that eliminates this issue for the most part.

[MUDDYNOLL]

I agree. After going through the expense of having to change them myself, that will be something I will look very closely at before buying another one. The manufacturers subtract the tounge weight when calculating the suspension weight requirements. This allows them to use cheaper components. When I weighed my camper the weight was the same with just the trailer wheels sitting on the scale with the TV off the scale, as it did unhitched with the full tounge weight and wheel weight on the scale. That tells me that the suspension should be rated to take the full weight of the trailer or a higher weight, not less. When you hit a bridge joint or road deformity at highway speed the full weight of that trailer is sitting on the suspension components. If they are not strong enough to handle all of that weight then things will bend or break as some of us have unfortunately found out the hard way.

[Highway_4x4]

One of the deciding factors on my Wind River purchase was the 5200 lb axles. many of the TT's still use the 3500's. I think that any TT with a UVW of 6000+ should have 5200lb's on it. I was going to upgrade the axles on my previous TT but decided to buy the 5200 axles with a new TT on them.

[MUDDYNOLL]

I suffered the same problem as you this year. I95 bent my rear axel on my 2011 keystone Passport 2910BH. I knew if I just replaced the axel I would be in the same position again as we travel long distances. Trailer weighed in at 6900 lbs. loaded on the scale. GVWR is 7200 lbs. Axels were 3500 lbs. with 1750 springs and 14 in. wheels and tires. I Upgraded to 5200 lb. axels, 2500 lb. springs , and 15 in. wheels with load range D tires. As stated above gained about an inch in ride height and it tows much better. I also put Dexter heavy shackles and wet bolt kit on as well. You also get larger breaks with the axel upgrade so they don't have to work as hard either. Cost About $2,000 to do the whole thing. Me and a buddy did the swap in a couple of hours. Not a hard job at all.

[Cyclops69]

Thank you for the post John U. That is exactly the situation that I am in. PM coming your way

[Midnightpumpkin]

A little history to begin with.

On our first trip with this trailer, a 2007 model Rockwood 8315SS, purchased in October of 2006, my first stop was at the scales. The weight on the 2 axles was 6640 pounds, which is 95% of the axle ratings, and does not account for side to side weight differences. This also represents a 92% loading factor on the tire ratings.

Early summer of 2009, I upgraded the tires to ST205/75R15 LRD. In doing this, I noticed cracks where the mounting brackets were welded to the axle tubes. These were Alko-Kober rubber torsion axles. I contacted Alko-Kober, they were very anxious to send me new axles, at thier expense. They did not want to work with me to upgrade to a heavier axle. I took the replacement axles and installed them in Sept of 2009.

Now 3 years and 25,000 highway miles later, summer of 2012, there were definete signs of tire wear on the insides of the tires.

At the time of the original axle failures, Alko-Kober gave me the complete specs on the existing axles.

I took these specs to Dexter Axle, and asked them to quote a 5200 pound axle, to replace the 3500 pound Alko-Kobers. Dexter sent me a very through and complete specification on a replacement axle.

The replacement 5200 pound axle has much larger spindles, and requires a 6 lug hub. So the upgrade involved not only replacing the axles, but the rims and tires as well.

I bit the bullet and ordered up the dexter axles, new rims and new MAXXIS ST225/75R15 LRD tires.

On Monday 11/26/12 I took the trailer to a friends shop and we swapped the axles. It was an easy swap, two mounting holes on the Dexters lined up with two of the mounting holes used by the Alko's. After getting the front axle in exact location, we drilled two new holes in the side mount flanges on the trailer to accommodate the Dexter mounting brackets. The entire process took 7 hours to accomplish.

We wired up the electric brakes and mounted the new rims and tires.

The result was that the trailer now sits 1 inch higher than it did before, clearance from the top of the tire to the wheel well top is greater than the recommended 3 inches.

The new limiiting factor on weight is now the tire rating of 2540 pounds per tire for a total of 10160 pound capacity. Now the 6640 load represents 65 percent of the tire rating and 64 percent of the axle ratings, a nice comfortable margin of safety!

I have only towed the trailer a short distance with the new setup, the trailer suspension did not seem overly stiff and it towed nicely as it always has.

Time will tell if this was money well spent, but for my personal peace of mind, knowing that I am no longer towing something that was loaded to the very max, it was worth the investment.

BTW we like this trailer a lot, or we would not have made this investment.

If anyone is interested in more details, PM me, I will share the Dexter spec and any other details you may be interested in.

This upgrade was done one year ago, I am very very happy with the result. We have towed it over 7,000 miles since the upgrade, tire wear is negligible.

John U

[wrvond]

moot post

[69_Avion]

You may want to consider Flexiride Axles from:

http://www.southwestwheel.com/store/p-2313-5200-lb-flexiride-torsion-axle.aspx

The prices are decent and the Flexiride axles use and adjustable splined torsion arm. Whatever you use, you need to make sure all the measurements are correct for the mounting system.

[B_O__Plenty]

smkettner wrote:
Don't forget new springs. I moved from 1750# to 2200# springs on my 3500# axles and it rides way better.

As long as you are getting complete new I would opt for disc brakes for just a little more. Dexter will set you up.

Torsion axles don't use springs.

B.O.

[Cyclops69]

NYCFive1 wrote:
Travel advice. You could avoid the Cross Bronx Expressway (I95) going through NYC.

Lol yeah unfortunately I learned that lesson the hard way. Not to mention the unbelievable high tolls for the Delaware memorial bridge the jersey turnpike and th GW. Now I go around on the way to and from Connecticut.

[NYCFive1]

Travel advice. You could avoid the Cross Bronx Expressway (I95) going through NYC.

[time2roll]

Don't forget new springs. I moved from 1750# to 2200# springs on my 3500# axles and it rides way better.

As long as you are getting complete new I would opt for disc brakes for just a little more. Dexter will set you up.

On edit:

Looks like you will need to weld on some spring hangers if you intend to go to a spring suspension.

[powderman426]

if you don't have shocks, that would be advisable as they really help cushion the blows.

[ScottG]

My TT weighs the same as yours but has 5200# Alko axles. They have performed great over about 50K miles and I would suggest them as an upgrade.