harbor freight frame adjustments

[Rochester Coops]

I've read some on here, but would be great if someone could walk me through it. I want to move the axle back and lower the frame by installing the axle over the springs. I realize this could create some issues. I have the 1750 lb, non folding trailer with 12" wheels. The frame is in 2 sections joined by the leaf spring mounting angle. If i move this bracket back, how do I keep the entire frame rigid? On the axle, I read one horror story of bottoming out and I am concerned that the u-bolts/plate are not made to hold the weight of the trailer over the spring. What is everyones experience who has tried this? Is there enough room, are the parts strong enough?

Thanks

[bobhenry]

I've read some on here, but would be great if someone could walk me through it. I want to move the axle back and lower the frame by installing the axle over the springs. I realize this could create some issues. I have the 1750 lb, non folding trailer with 12" wheels. The frame is in 2 sections joined by the leaf spring mounting angle. If i move this bracket back, how do I keep the entire frame rigid? On the axle, I read one horror story of bottoming out and I am concerned that the u-bolts/plate are not made to hold the weight of the trailer over the spring. What is everyones experience who has tried this? Is there enough room, are the parts strong enough?

Thanks

Sounds like a lot of work ! When finished you will have a lot more tongue weight and the HF tongue is in my opinion a bit anemic already. I simply took 2" square tube and extended the tongue 18" +/- and had a reinforced tongue and a trailer with much better towing (and backing) manners. This accomplished you can cantilever the body forward and you have the exact same results.

[absolutsnwbrdr]

We moved the axle back about 6" on my friends build. We also lengthened/strengthened the tongue as Bob suggested. We built a rigid subfloor (2" tall framing, 1/2" plywood deck) which distributed the weight across the entire frame.

Bottom side of the rigid subfloor before being attached to the frame...


There was a little bit of flex where the 2 halves of the frame come together, but once we got the rigid subfloor bolted down and the sides attached everything was as solid as could be. The HF assembly guide only call for 2 bolts to hold the two halves together, but there are 4 holes so we added 2 more bolts for piece of mind.

[Nobody]

Not sure exactly how the current 1740# HF trailers front & rear chassis sections go together. When I bought my 1740# (variously listed as 1720, 1740, 1800, etc.) in 2006 the chassis assembled in 2 sections & the front & rear sections simply bolted together with 2 or 4 bolts thru the cross pieces, & the spring hanger (a piece of 'u' channel welded to steel angle) bolted to each half, reinforcing the chassis. I just removed the 2 cross pieces that bolt together, slipped 'em inside the 'c' channel side rails. drilled a couple of extra holes & bolted it all together. The 2cross pieces make excellent reinforcing pieces. I then moved the spring hanger mount back approx 4", drilled new holes after 'squaring' the axle to the coupler, & bolted it up. When I was ready to install my 5x9' floor on the 4x8' chassis I substituted a 'fitted' wood 2x4 for the 2 missing crosspieces. Made my maiden voyage in the TD in Sept 2006 & have towed it near 20K miles since with absolutely NO problems with chassis integrity. When I was rear ended Labor Day weekend 2010 my TD survived with little damage to the body & only damage to the chassis was to the rear cross member & 1 stabilizing jack. I credit part of that to the extra rigidity of the chassis side rails with the 'cross piece' inserts.

This is a diagram from HF showing how the 2 chassis sections fit together


Drilling extra holes for the 'cross pieces' nestled (clamped) inside the side rails of the 2 chassis halves, & new holes for he axle spring mount to be moved towards the rear.


Axle spring mount moved back to the rear chassis half (mostly). You can see the extra bolts & if you look carefully you can faintly see the 'butt' joint of the chassis half side rail just in front of the fender nearest the camera


The wood cross member that replaced the 2 metal pieces used in reinforcing the side rails. In the first 2 pix you can easily see the cross members bolted inside the side rails...

[Rochester Coops]

Thanks guys, appreciate all the replies. I will definitely look at reinforcing the tongue. That is a great idea of using the cross members as stiffeners Noboby. I checked out your pics of your td and want to know how high do you need to keep the floor above your tire? Looks you built over the wheels too absolute. Has the tire ever rubbed the wheel well? I'm still undecided on whether to keep it 4' wide or go out wider. If I do, I definitely won't 'lower' the axle.

Do you guys drill a mortise in the bottom of your wood floor framing where it sits over the harbor freight frame bolt heads? or do you leave off the harborfreight frame top side bolts and run longer bolts through your wood frame and the steel frame together?

[pchast]

First you can swap sides with the spring mounts without drilling holes. this will move the axle back.
Then I ...

9 ft of 2x2 1/8th and welded in a new tongue after inverting their coupling adapter. The tube fits through the old coupling adapter.



I also moved the axle to above the springs. the level trailer is now at the right unladen height for the car's hitch.
You need to turn over the locating bolt on the spring to do this. I clamped the springs in a vise to keep things together when I did.

[Nobody]

Thanks guys, appreciate all the replies. I will definitely look at reinforcing the tongue. That is a great idea of using the cross members as stiffeners Noboby. I checked out your pics of your td and want to know how high do you need to keep the floor above your tire? Looks you built over the wheels too absolute. Has the tire ever rubbed the wheel well? I'm still undecided on whether to keep it 4' wide or go out wider. If I do, I definitely won't 'lower' the axle.

Do you guys drill a mortise in the bottom of your wood floor framing where it sits over the harbor freight frame bolt heads? or do you leave off the harborfreight frame top side bolts and run longer bolts through your wood frame and the steel frame together?

I used a 1" Forstner bit & drilled flat bottom holes in the underside of my floor frame cross members where they sat on the trailer chassis bolt heads. That allowed a level fit & sacrificed little if any strength (also aided in quicker squaring/alignment when installing the floor ). A 'spade' bit would probably do just as well; I had the Forstner bit on hand & it makes cleaner holes

My floor frame is primarily 2x4's ripped in half, sitting on edge, & I built the 'wheel wells' using ripped 1x4's (nominally 3/4" thick). My measurements & test loads (concrete blocks & various steel objects) convinced me that would provide plenty of clearance for the tires. After 2yrs of use I saw where the tires had made momentary contact with the underside of the wheel wells on some very rough roads (not enough to wear any of the undercoating off but enough to cause me some concern). I fabricated some 1" thick blocks from tool steel, obtained some longer 'U' bolts & installed them as 'spacers' between the axle & springs. That gave me an additional inch of tire clearance & the tow/door entry height change was negligible during use. My TD now tows just slightly 'nose down' but not so much it is noticeable, & I'd much rather have it nose down than nose up. If I were building again I'd make the wheel wells another half inch taller. I believe that'd provide sufficient clearance without intruding much more inside the cabin.

[Rochester Coops]

Frame is built. Thanks for the advice. Axle is now 38" from the rear and your advice really helped.