You are welcome. I learned a lot the hard way, so figured passing the findings along may help someone else.
I had the EZ Flex when they first came out. Dexter had issues with the rubber from a sub supplier then, it was too soft. They stood behind the warranty and gave me new ones. The EZ Flex in my case lowered my bump clearance which started a lot of work to get the clearance back.
When I upgraded to 16" LT tires, I had to deal with low bump clearance again and the Dexter, even the larger unit was a no go. I switched to the Trail Aire rubber equalizer and with some hanger adjustments I made it work. I'm still using the Trail Aire today.
Since you are changing the suspension, think of creating a way to adjust the wheel alignment. You may be into a hanger change to go from 1 3/4" wide to 2" wide on the bigger springs. There is the Lippert Correct Track system, and they used to have 2 style of hangers, one that incorporated the correct track in the hanger (a better setup) or the one you bolt on your existing hanger. The correct track is not as good as the adjustable axle seat which you can dial in what ever is needed, (within reason) but being able to adjust the axle position for sure helps. And, make darn sure the place welding the new hangers on, take extra care to place them close to perfect. You do not want to eat up all your axle alignment from a poor hanger location to start with. I had one hanger welded on 1/2" off position from the factory.
I can attest that having the axles aligned to Dexter spec's, tire wear is close to perfect for a trailer. If you plan on many miles before tires age out, it is worth creating an axle alignment method. I never found any fuel savings, but I for sure did find out how good true running wheels can be. And I aligned mine in my shop.
If you do not have shocks now, they make a major difference. The shocks tame down the number of suspension oscillations after the bump. Before I added shocks, my long camper would flex up and down 6 full cycles after just about any little bump. It would do more on larger bumps. After the shocks, it went to 1 full cycle and stopped. Yes, that dramatic. It was amazing and took all that extra flexing out of the camper and frame. A good thing if you plan on keeping a camper a long time.
Since your toy hauler is that heavy, read up on frame cracks. Make sure your trailer has the right left to right hanger support and hanger attachment support to the main frame rail. They are still making trailers without enough support at the hanger area which can and will result in cracked frames, especially off road camping as the flex in the system is worse. I worked through this too.
You are doing the suspension upgrade, don't stop short and make sure you fix all the issues. It is sad that many of the camper manufactures do not offer a heavy duty or off road upgrade package from the start. This is all doable a lot easier and cheaper from day one. And less heart ache on the owner dealing with the problems after the fact.
Good luck
John
2005 Ford F350 Super Duty, 4x4; 6.8L V10 with 4.10 RA, 21,000 GCWR, 11,000 GVWR, upgraded 2 1/2" Towbeast Receiver. Hitched with a 1,700# Reese HP WD, HP Dual Cam to a 2004 Sunline Solaris T310R travel trailer.
