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Mathguy · 09-17-2013, 10:32 PM

I just had an RV dealer replace a damaged axle on my Shamrock 23RS trailer. The technician made an error and replaced my U29 front axle (which has a 3000 lb rating with a U35 axle with a 3500 lb rating. Do I need to have the U35 replaced with a U29 so they match or is it safe etc. to use 2 different rated axles on my trailer? Thanks for any knowledgable responses from well informed people.

TRAILERKING · 09-17-2013, 11:01 PM

Really won't matter as long as didn't go from heavier to lighter capacity. As long as dimensions are the same and braking and wheel size and tire spec.

Mathguy · 09-19-2013, 09:40 PM

Thanks TRAILERKING for trying to help me with this situation. It turns out there is a real problem with the two different axles (old rated 3000 lb and the new 3500 lb). I took the unloaded trailer to a government weigh scale. With only a small load in the truck bed, the load on the front (3500 lb) axle was approx 1200 lb. The weight on the older real axle (rated 3000 lb) was approx 2400 lb - about twice the amount on the front axle. There was a more serious problem with tongue weight. We unhooked the trailer and found the weight on the tongue only was over 900 lb. the max rating for the trailer tongue weight is 600 lb. When we contacted the RV dealer and explained this, they claimed the axle they were sent was not the one they ordered. They offered to order another 3500 lb axle and match that with the other 3500 lb one. I thought you would likely be interested in hearing how this played out.
Mathguy

Mr_D · 09-19-2013, 09:56 PM

Still doesn't change the overloaded tongue though!

Skip426 · 09-19-2013, 10:42 PM

Mathguy, changing the axle won't change the load on the axle or on the tongue.
Was the trailer level behind the truck , when the axle weights were taken ? High in the front , is the only reason I can think of for the trailer suspension to be transferring that much weight to the rear axle.
Particularly if your weighing heavy on the tongue.
I'm also wondering about the 600 lb rating of the tongue.
I thing that some how the advertised tongue weight is being confused here. Is the weight rating stamped into the coupler ?

Only way to lower the tongue weight is to move the axles forward, or load every thing you carry into the back of the trailer.

Mathguy · 09-20-2013, 10:52 AM

Hello Skip426,
The trailer was perfectly level when the weights were taken. My son is the knowledgeable one here. From his research (which he does thoroughly) he learned the angles on the torsion suspensions of the 3000 lb axle and 3500 lb axle are quite different. So somehow this has transferred 2/3 of the weight on the axles to the rear axle and has seriously increased the tongue weight. The tongue weight rating is actually 700 lb and is stamped on the tongue. I certainly hope that this will all get resolved when the RV Dealer installs a second 3500 lb axle to replace the 3000 lb one. Of great concern is the tongue weight when I fill the fresh water tank which is right at the front of the trailer interior.
Mathguy
PS: loading things in the back of the trailer would just increase the already excessive load on the rear axle. Filling the fresh water tank would likely shift some weight to the front axle but that would likely also increase the weight on the tongue.

TRAILERKING · 09-20-2013, 11:14 AM

Quote:

Originally Posted by Mathguy

Hello Skip426,
The trailer was perfectly level when the weights were taken. My son is the knowledgeable one here. From his research (which he does thoroughly) he learned the angles on the torsion suspensions of the 3000 lb axle and 3500 lb axle are quite different. So somehow this has transferred 2/3 of the weight on the axles to the rear axle and has seriously increased the tongue weight. The tongue weight rating is actually 700 lb and is stamped on the tongue. I certainly hope that this will all get resolved when the RV Dealer installs a second 3500 lb axle to replace the 3000 lb one. Of great concern is the tongue weight when I fill the fresh water tank which is right at the front of the trailer interior.
Mathguy
PS: loading things in the back of the trailer would just increase the already excessive load on the rear axle. Filling the fresh water tank would likely shift some weight to the front axle but that would likely also increase the weight on the tongue.

Now that's more info......Now knowing you have a torsion set up and not spring c/w walking beam.
You have a serious problem. Having two different angles on the torsion arms you will have axles at different heights. A spring with walking beam set up is forgiving with heights and angles but not torsion. With torsion the axles need to be identical and always run the trailer as close to level as possible otherwise you put more load on one axle than the other and distribute tongue weight differently.
So in the end it will be fine to upgrade to the heavier axle but make sure they're all the same.
No way around it. The stupid repair center should have known better but that goes to show you what's out there and just what they'll do nowadays to make a buck.
If I did crap like that I'd be out of business.

Skip426 · 09-20-2013, 11:18 AM

Mathguy; Thanks for the info, I had not checked out any specs on your trailer so I did not realize that it had " torsion suspension " . Sorry

But ; now you need to check with the RV dealer, to make sure that the extra capacity of the axles will not make the trailer ride so rough that everything in it gets shaken to bits.

DW's cousin had this issue on a new 5er. First trip out they had a lot of damage due to excessive suspension strength.

I'd have to check with them to see how much overrated their suspension was.