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I re-postioned the axles under my previous TT and the results were great.
Before re-postiing axle "under" the leaf spring packs, I'd also average load and "scale weigh" the trailer. Then, round up 2 x sizes higher. For example, let's say your trailer weighs 6,380 lbs. By dividing by 2 (assume 2 x axle TT), weight on each existing axle would be 3,190 lbs. Instead of upgrading to NEW 3,200 lbs axle, I would upgrade to 2 x 3,600 lbs axels. Or even better, upgrade to NEW 4,000 axles. And, upgrade with matching 3,600 / 4,000 leave springs as well. Upgrade next size up is good safey buffer for double railway tracks and/or those deep hidden bumps in CGs. And/or, those rare times one loads heavy and didn't realize it.
When "scale weighing" a trailer, I don't subtract the 13% (average) of its tongue weight. I simply scale weight the trailer and use that number. For example, I drive both TV and Trailer on the scale (hiway scale or local gravel pit scale), get the number, disconnect the trailer, drive "only the TV" on the scale, then get its number. Then, I subtract the lower number from the higher number. Thus, giving you the true average loaded weight of the trailer (when NOT connected to a Tow Vehicle).
If replacing axle(s), do measure them from HUB face / HUB Face as well. If needed, order axles slighly longer or shorter. For my one trailer, it needed more gap between the inner tire and its inner fender. When replacing that axle, I simply bought an axle 1" longer. Thus, created 1/2" more gap on the inner wheel area. Nice improvement for that specific trailer.
If trailer's existing leaf spring packs are 15+ years old, I would replace the leaf spring packs as well. Unknown to some folks, leaf spring steel gets brittle over time. They loose their flex and without notice, do snap. If leaf spring packs 15+ old (especially 20+ old), do replace the leaf spring packs. Very low cost parts - compared to damage when a leaf spring pack does snap.
When re-postiing my trailer axles (done 5 so far), I plan 2 day job.
Day 1: Jack up the trailer using its frame rails (use both bottle jacks and safety axle stands), remove the exiting axle and measure. I visit a few local parts stores and buy the needed parts. re: Axle saddles, U-Bolts, replacement hangers, New Axle (if needed), New Leaf Spring packs (if needed), etc. etc. I then take the axle saddle and axle to my local welding shop, and they "weld them up". I then wire brush the old axle down and hand paint. And, let dry.
Day 2 (after paint dries): Iinspect / replace inner hub brake parts (if needed), then re-install. After the install, I then replace its factory linear brake wiring with much better STAR Design wiring.
re:
- default factory wiring - - much better STAR design wiring - Many recommend trailer axle alignment after this change. For me, I only get its axles re-aligned if the tires wear funny. So far, none of my axle re-postions needed professional alignment.
Yes. Axle re-postion, to new axles/leaf spring packs replacements, to wire brush / painting, to new wiring is a large scope of work for some folks. Especially for folks who want instant results. But if one plans to keep their Trailer for many years, "doing it right" and pacing themselves over a few days is always worth it. Especially the upgrade of much better brake wiring design using thicker 10 gauge wiring as well.
Hope this helps.
