First a slightly OT:
Quote:
Originally Posted by ShrimpBurrito
Another issue to keep in mind when considering the lift kit is that you will need additional height when lowering the stabilizers. Raising the frame 4" ....
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IIRC, and I'm pretty sure that I do, the lift kit for my model year (2006) added about 2.5". 2006 is the current welded-on setup, I needed to order it at build time if I wanted it. The increase in height caused by upgrading from the "small axle" and 14" rims to the 3023/3124 "big axle" and 15" rims is about the same-- a bit of height in the tires, most of the difference comes from the height in the axle itself. ShrimpMan, maybe your 4" was a figure for both, combined? If so, it's closer to 5". My garage could handle one or the other, and I wanted the big axle and tires because I don't like the idea of running the small ones so close to their max rated capacity so often. But either one would have been a good match for my garage door height.
Now for the title subject. I've got the upgrade and quite a bit of experience driving it, and I think that the advice to Scott-O wasn't correct: You
can have the big axle/wheels/tires and
not shake a 2619/2720 to death. (My experience does include some not-so-good roads.) But you must lower the air pressure in the tires, by a LOT. Maybe the factory didn't think of this-- my TM owner's manual says to always pump them up to the maximum cold PSI shown on the sidewall of the tire-- 50 PSI for the 14", 65 PSI for the 15" Marathon tires. Goodyear disagrees,
strongly, when the tires aren't fully loaded. Air Pressure helps the sidewalls
resist flex, while the loading from the Trailer
causes flex. Goodyear wants you to run with the correct sidewall flex characteristics, and in order to get that, you must TUNE your PSI up and down according to the tire's load.
I stay pretty close to Goodyear's Marathon loading chart, which has the "big" tires at about 45 PSI cold on my 2619 (even loaded really heavy, ABOVE the official load capacity of a 2619 without the axle/tire upgrade). My TPMS shows 48-49 PSI after warming up for a few miles. I add a few more PSI if driving non-California freeways and planning to drive at more than 50 MPH for an extended period. Just because they're capable of 65 PSI (and they allow even higher for fast freeway driving), doesn't mean that you should run them "rock-hard" when loaded so much less than capacity!
Coming home, without full water tanks and drinking water bottles (and wine, and beer, and food), I'm usually choosing about 42 PSI cold. The table actually recommends less than 40, but I haven't got the guts to leave 'em down that far.
The not-over-inflated tires are an important component in making the suspension more "cushy", and they're also much safer being run this way. (Too much PSI in the tire, under "light" loads, causes too small a contact patch with the pavement. The tire is prone to bouncing off the road, and when your TM is flying with one or even both tires in the air, it isn't traveling safely.) Stuff in the TM enjoys a nice ride-- stuff doesn't fly around in the cupboards, the stove top doesn't fall off, and stuff set on the floor doesn't move around while towing.
So the factory is correct about shaking the trailer to bits-- but only if you follow their
REALLY BAD advice, pumping the D-rated tires up to 65 PSI all the time, even when traveling lightly loaded. Follow Goodyear's instructions, they really do know more about it.
Because my 42-45 cold PSI doesn't leave a lot of headroom if/when something bad happens, I've got a TPMS running all the time too.