16" LT tires now a subframe lift? UPDATE Subframe complete!

UPDATE: pictures of subframe on page 4!

So I originally created a post on upgrading 15” ST tires to 16” LT tires (https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/27525229.cfm) and finally got around to doing this on my 2014 Forrest River Palomino Puma 259RBSS fifth wheel.

I went with BFGoodrich Commercial TA LT215/85r16 on 16” steel Dextar wheels. Old tires were Akuret ST225/75r15. I have plenty of clearance between the two tires but have about 1” of clearance on the rear axle from the top of the tire to the darco materiel on the underside of the trailer. I was going to drive it around town to see if and how much it may rub but have not had the time yet.

Now my trailer has never been level with my 2012 Ram 3500 SRW. It has come up a little with the added 1” in height on these BFGs compared with the old STs. But I’m sure I’m going to need more clearance with these new tires.

SO I have two options that I can tell,
LPI Correct Track which gains 2” or a full sub-frame build. I got a local quote for the Correct Track installed ($925) and another for a full sub-frame build ($750). I’m obviously leaning to the Sub-Frame build as it’s going to be sturdier if built correctly as well as cheaper. I initially wanted to tackle the Correct Tract install myself but don’t feel comfortable supporting the trailer up.

My question is, does anyone here run with similar (1-2”) clearance between tires and underbelly without any issues? I have a short camp trip in a few weeks and may not have time to get the sub-frame build done in time. Wondering if I can make it there and back or if it’s a bad idea. It’s about 250 miles back and forth on standard CA highways.

Here are some pictures of the new tires and wheels,
New and old tires side by side

New LT on left and old ST on right

Both new LTs installed

Old OEM ST set up

Clearance between wheels,
LT

And how the trailer sits mounted with truck on old ST (no current pictures with LT tires)

ScottG
Nomad
Nov 12, 2014
I have about the same clearances with my 15" setup. Just looking at your rig I think it looks fine.
dockmasterdave
Explorer
Nov 12, 2014
Is the axle flip out of the question?
jaycocamprs
Explorer
Nov 12, 2014
2" I might try, 1" I would not. When I made the swap on the 07 JayFlight we had I dropped the springs in the adjustable spring hangers. That 2" was all I needed, gave 3" above the tire and never rubbed. When you get it worked out it will be worth the effort, it was for us.
wuhungsix
Explorer
Nov 12, 2014
Axles are already under springs.
P_Kennedy
Explorer
Nov 12, 2014
4 pieces of 2" steel to make risers, 4 2" longer center bolts, 8 longer u bolts, job done. Risers have to be full width of spring and as long as the distance outside the u bolts. Machine shop probably build and drill for about $40 a piece max. U bolts exactly 2" longer and use the long spring nuts. 4 hours of you time and a torque wrench. Always torque u bolts after putting load back on springs.
path1
Explorer
Nov 12, 2014
I'm thinking about doing the same thing. Yours looks good.

Do you know how many inches you have between center of bearing cap to center bearing cap?
JIMNLIN
Explorer III
Nov 12, 2014
SO I have two options that I can tell,
LPI Correct Track which gains 2” or a full sub-frame build. I got a local quote for the Correct Track installed ($925) and another for a full sub-frame build ($750). I’m obviously leaning to the Sub-Frame build as it’s going to be sturdier if built correctly as well as cheaper. I initially wanted to tackle the Correct Tract install myself but don’t feel comfortable supporting the trailer up.

Your on the right track for lifting a trailer. If you notice the trailer axle industry or RV trailer manufacture industry doesn't offer lift blocks as a option nor are they recommended.

My question is, does anyone here run with similar (1-2”) clearance between tires and underbelly without any issues?

Dexter recommends 1" minimum between tires.
I have one equipment trailer with 3/4 inch on one side and no rub/wear issues.
My current 11200 gvw with 5200 lb axles 5er has LT215/85-16 E with 1 1/4" between the tires and 2 3/4" at the top and 1/2" next to the shock and no rubbing issues other than the top of a tire will contact the wheel well slightly when the tires roll/step through a deep ditch.
Me_Again
Explorer III
Nov 12, 2014
Drive the trailer onto blocks until is sitting level and then subframe it that amount and install 2x2x1/8"" square tube side to side, gusseted hangers to per Lippert's suggestion.
MFL
Nomad II
Nov 12, 2014
Those tires should be a really nice upgrade!

I would not take a trip, with only one inch of clearance, between the tire, and top of wheel well. The wheel well material is not very rugged on most trailers. Just one bump at speed, could do major damage.

You should have 2"s minimum, closer to 3"s would be better.

You know it needs to be raised, so I would raise it, before using it, if it were mine.

Good luck,
Jerry
makmoto
Explorer
Nov 12, 2014
Cannot see very well, but your equalizer between your tires do not look right. Check them our, they should be symmetric.