Hi jerdew,
I may be able to help some in your situation. I had a similar sizing issue with my camper, 2 times no less. The first time when I converted to the EZ flex and then when I upgraded to 16" LT tires from 15" ST's.
To the first question "1. Are my axles undersized for my GVWR ?"
Well, the trailer manufacture picked 10,400# of axles to support a GVWR trailer of 12,400. Or 2,000# less axles then GVWR. They are "counting" on 2,000# of your GVWR to be pin weight and born by the truck. This is technically and legally OK. However I do not agree with it as it leaves you with out a lot of reserve rating on the running gear when you load the camper and start approaching the 12,400#. You have to watch your weights and especially the side to side camper weights. Floor plan drives where you can load gear and water tanks and you can real easy if your not watching it, overload one wheel or wheel set on one side of the camper. You should get the camper weighed with full towing water and cargo weight, axle by axle and left side and right side along with a pin weight. Only then do you know if you are at or under the ratings. This is a case for tire overload when you approach ratings or go over.
Your manufacture elected to size the camper to a set of ratings leaving it to you to make sure you have to follow all the fine print and not overload one side of the camper. For not much more $$ they could of upgraded to 6,000# axles, springs and then tires. But that cost them $$ in a very high competitive industry. If your VIN tag says 5,200# GAWR then the springs and tires have to meet that. I suspect you "might" have ST225/75R15 load range D tires, do you? That is another heads up to start understanding tires failures when you approach full axle weight
To this question
jerdew wrote:
Hole spacing on current equalizer is 6 1/8 wide, and 2 3/8 tall. I have some questions/problems:
1. Are my axles undersized for my GVWR ?
2. Which would be the correct Dexter EX-Flex kit for me? The K71-652-00 is rated for up to 6K GAWR, and would take 3/4 inch away from my clearance at the top of my tires. It also seems borderline as to the GAWR. The K71-653-00 kit supports up to 8K, but spacing is 7 1/2" on the bottom holes. Doing the geometry, this would mean that my shackles would be narrower at the top than at the bottom. I suspect this would be a problem.
Your thinking is correct, there are some problems to think through on how to over come the spacing issue. As far as load ratings, the Dexter small equalizer will handle the axle weights, again making sure to not overload one side of the camper. The Larger dexter is a beast compared to the smaller one and the spacing is bigger. It will work as far as capacity but fender clearance is the concern.
Regardless of which rubber equalizer you select, the trailer will settle lower then it did on the rigid equalizer. How much less, depends on your weights and the rating of the equalizer to start with. In my case, I had to move hangers down in order to get the rubber equalizer to not have a bump and rub clearance with the top of the tire and the inside of the fender well. And when I went to LT tires and 16" rims, I again had to deal with the equalizer.
These are your options for adjusting ride height.
1. Deal with the hanger height. Some times 5th wheels have multiple holes in the hangers to adjust truck bed rail height.
2. Change shackle length, There are different sizes that can help. I went heavy duty shackles and the sizes are limited in the heavy duty but there are at least 2 lengths.
3. Change brands of rubber equalizers.
- Dexter has 2 sizes. You know about them
- Trail-Aire has 2 sizes. In your weights, skip the small one, only consider the larger one.
Trail-?Aire by Lippert- Mor-ryde has a rubber equalizer. I have seen this up close and helped a buddy with his axles on his Jayco and I like this equalizer. Better then the Trail-aire in my opinion.
Mor-Ryde equalizers Also Morryde sells longer heavy duty shackles then Dexter
See if those options help you. The Mor-Ryde equalizer was not available when I did my corrections and Lippert bought out Trail-Aire by the time I made it buying mine. The Equalizer is the same but the quality has changed or at least on the vintage I bought. I hope they fixed that issue by now.
These posts may help as they show the evolution of ride heights I went through.
PS. Make sure you have at least a bare bottom minimum of 2" fender clearance. Ideally this is 2.5 or 3" or more. Much less then 2" and your going to hit. Point: Starting at 2.25" with a brand new rubber equalizer can turn into 2" after a few hundred miles
ST225/75R15 to LT225/75R16 Conversion Hanger stiffeningPart of John's LT upgrade post with other good linksST Tire Failure Analysis (Long - Lots of Pics)John's orginal EZ flex conversion in this Sticky post
