Dual axle aluminum trailer

[Tomfoolery]

That's a good looking piece of work there.

[1st Sail]

Questions and considerations: I currently have a steel trailer which is warehouse stored so I don't have the rust problems due to storage. less than 10k miles.
Questions/Considerations:
The steel trailer axel assembly is welded to the C channel and obviously needs to be cut off to relocate.
Is the C channel gauge sufficient for bolt on axel assemblies to balance tongue load?
Which axle is easiest to modify for load sharing leaf springs or torsion bar?
Retro fit older steel trailer or find a used Mac aluminum and add second axel sell the steel.

[Tomfoolery]

Being that it's a steel trailer, and almost everything about it is different from the OP's aluminium trailer, you might want to put this in its own thread. But here goes anyway.

The steel trailer axle assembly is welded to the C channel and obviously needs to be cut off to relocate.
Is the C channel gauge sufficient for bolt on axel assemblies to balance tongue load? The flanges are too narrow for effective bolting, and you'd need hillside (tapered) washers even if you could. Better to mount the spring hangers on a length of angle, then bolt through the web of the trailer channel.
Which axle is easiest to modify for load sharing leaf springs or torsion bar? Leaf springs can and should be installed with an equalizer. I don't know of any good way to equalize rubber torsion type axles - they just bolt to the frame. But having said that, they'll work just fine in a tandem setup without equalization. You just have to be careful to tow the trailer with the frame level so the two axles share the load equally. With equalized leaf spring (or air springs, for that matter), axle load remains essentially the same with the hitch either side of level (well, parallel to the road, really).
Retro fit older steel trailer or find a used Mac aluminum and add second axle sell the steel. I have an original '98 steel trailer that the PO's added an axle to, after relocating the original, so the midpoint between them is where the original single axle was. It's in good shape, and I have no plans on replacing it. I also have no experience with aluminium trailers. Which adds up to 'no opinion'.

[Highlander]

ur torsion axle trl suspension is independant on each wheel they do not need to equalize each other as do spring suspension
But no matter what type of suspension u have the trl still needs to be loaded correctly weight distributed evenly with proper tongue weight
J

[raycarlson]

if you want to run an unlevel aluminum trlr you just pull the lever arm off the splined torsion shaft and reclock the appropriate amount to equal the difference in out of level angle you want to run your trailer at, very simple and no additional parts needed in system.

[u12fly]

if you want to run an unlevel aluminum trlr you just pull the lever arm off the splined torsion shaft and reclock the appropriate amount to equal the difference in out of level angle you want to run your trailer at, very simple and no additional parts needed in system.

Yup... That's what I did with mine after I had everything done and the trailer fully loaded. I evaluated the position of everything and clearence in the wheel wells then adjusted each lever arm.

Last night I posted my trailer mod with a few pictures: http://www.macgregorsailors.com/modt/in ... ?view=1832

Chris.

[Russ]

Last night I posted my trailer mod with a few pictures: http://www.macgregorsailors.com/modt/in ... ?view=1832

Chris.

Excellent!

What did you use to make the trailer bunks? Is that aluminum?

[u12fly]

I bought a piece of raw stock, 6061 AU 2" wide and bent it identical to the original. I also copied the wood parts as well, making slight adjustments for how each brace will support the hull bottom. This worked out the best for me. If I had to do it all over I might concider running supports longways, perpendicular to the axles but that would take a little more engineering.

Chris.

[RobertB]

The axle bolts on, as you would expect with torsion on aluminium. No through-bolts visible in their pics, so I assume they're on the outside. But the bunks do sit on that axle, so I would think you'd want to add a galvanized cross tube in place of the axle and simply bolt it on (new holes required on the frame rails, though). Baloney slice the ends of the new cross tube so you can get the hardware in there easier. Being that the trailer weight will be transferred to the trailer frame instead of directly to the axle (and down to the ground from there), the connection will have to be somewhat robust.

This sounds like alot of trouble. The MAC hull below the waterline is thick - moving the supports a bit is no problem.
The axle bolts directly to the I-beams via the brackets welded to the axle. The stock bunks are attached to the axle with bolts and plates (no holes in the axle) and to the top of the i-beams with small bolts. When relocating the axle and bunk with the boat on the trailer, these last holes are the most interesting to drill (I used a small air powered drill).
I moved the stock axle forward 18 inches and kept the stock bunks on it. I added the second axle 36 inches behind the first and put a bottom bunk on. End result, yes, the support location has moved but now is spread between two points - less point loading on a thick hull. No problem not adding additional side bunks, the original number of two per side still works well.
As far as performing the mod with the boat on the trailer, except for the one set of hardware mentioned above, really pretty easy if you jack up the trailer at the rear of the trailer - the middle of the trailer falls away from the boat.

Or maybe it's ok to just move the axle and the bunks a couple of feet, but someone who's done it would have to comment on that. Hopefully, the outboard bunk support is also just bolted on. If moving the bunks instead of adding a new cross bar, then I'd probably elect to add a bottom-middle bunk (at the very least) to the new axle to spread the load on the hull, if that fits with whatever is going on with the bottom of the hull.

This is what I did as described above.

I would also buy an axle with the same disk brakes, both for safety (unless towing with a dually PU or first-generation Hum-Vee), and for legality in all states. Many states in the north-east and mid-atlantic USA require brakes on all axles, and for the few extra bucks, I think it's worth it.

I did not do this. Maryland does not require (I live in Maryland) and I really do not believe I will be cited for a ticket in another state if my vehicle is legal in the state it is registered in. If so, this would in my opinion go against federal interstate trade laws (and open up a whole lot of issues - "sir, you only have one license plate - do you know in this state you are required to have two?"). If I ever did need/want to add brakes, all I would need to do is buy the disks and calipers for the new axle (no other changes needed at the wheels), add two brake lines, and the most difficult part would be to upgrade the master cylinder. Keep the tongue a little low and you will keep weight on the braking wheels. I do admit, that in a hard stop, there is a bit of skidding but with a good tow vehicle (F150) there is no problem.

[RobertB]

I added the second axle a few years ago... Not sure why the price has jumped that much - but I am pretty sure it was just under $300.00 delivered to my local trailer shop. The axel manufacture does not sell direct so you need to order via a distributer. I used Six Robblees’ Inc, they have about 20 dealerships in the North West: OR, WA, ID, MT, WY, and CA http://sixrobblees.com/locations/
When I ordered mine, they did not care about the measurements or specs or what trailer it was built for, all they needed was the P/N S/N off the original axel (it is on a tag in the middle of the axle). They built an exact duplicate of the axle I had, and it only took about 4 weeks. They can add or subtract the brake parts and you can always put them on later if you want to. (I had them delete the calipers and brakes)
If you do put dual brakes on the trailer you need to change the master rod at the trailer hitch. I think they make two different part numbers, the alternate one produces more fluid which is needed to properly actuate all four brake discs.
Chris.

Yeah, the axle is pretty low cost but that is just for the axle with the splines on the end. Oh, do you want the trailing arms? and how about the hubs - these may be usefull? Bolts, you should have said something. Oh, and you really may want to buy bearings and races. Add a few wheels and fenders, the price is real close to $1000. [Yeah, the conversation really did go that way with Waymires - felt like I was buyin a car and the salesman asking me if I wanted wheels with it!]

[RobertB]

Did you have to move the trailer bunks and/or add a new one to the new axle?
What did you do for the fender?

What I did on mine was to add a bunk at the new axle, so essetially I have three aft bunks that the boat sits on and of course the V bunk at the front. I did this because I have slowly been increasing the overall weight of my boat as I add more mods to it. I wanted to have more support under the boat, however with the three bunks in relatively close proximity you need to be sure that they are all properly built such that one is not higher or lower otherwise you will not be distributing the load.

As far as the fenders goes, I built new metal fenders - There are a few companies out there where you can buy pre-formed diamond plate aluminum. I built the inner fender wells from plywood, and covered them with bunk carpet for a very professional look then made alluminum brackets to mount them securly in the correct loction.

There is VERY LITTLE extra room between the tires, fenders, and the boat with this design. So I would recomend you have all the parts in hand and you have a good plan of atack before you start this trailer mod. I've been trailering this mod for a few seasons now with no issues at all. My tires don't rub, and the boat has never bumped the fenders.

Chris.

I did something similar with a few xhanges.
First, got to buy narrow fenders - really about the width of the tires. There is really no room between the fenders and the hull.
Second, instead of cutting the fenders, I had brackets bent and mounted these to the outer surface of the fender. Had to get custom brackets because the fender was still at a angle at this point and the brackets match it. I also added a support between the wheels for stability - worked real well when the boat rode up on the fenders on a steep ramp - the fenders held.
Did not close out the fenders towards the boat - left them open.
Finally, because the fenders do touch the boat on one side or the other (or at least are REALLY close), I added Taylor dock edge bumpers http://www.sportsmansguide.com/net/cb/t ... x?a=572846 to the top edge of the fenders.
http://www.macgregorsailors.com/forum/v ... rs#p238533

[aviro]

hi
i did the work last fall bib job but the best mods you can do
i by all at waymire with the sest service and all fit toguether. i spoke with skip and he know exactly wath a was needing.no problem of double spear parts
i install dual breakes required in Quebec and beef up the frame a littlebit
to try the job i travel from Quebec to Florida hitting a big snow storm going down i dont sugest to go in the snow with a boat but i'm shure i was not able to pass with the single axle.
it is a little bit tricky for the ballance
i'going to finish the job (cosmetic) this summer
Jean-François

[aviro]

here an other pics

[Tomfoolery]

Fixed your image for you. I wanted to see what it was anyway.

Very nice work! I wish my reworked OEM steel trailer looked half as good.

[Russ]

I added the second axle a few years ago... Not sure why the price has jumped that much - but I am pretty sure it was just under $300.00 delivered to my local trailer shop. The axel manufacture does not sell direct so you need to order via a distributer. I used Six Robblees’ Inc, they have about 20 dealerships in the North West: OR, WA, ID, MT, WY, and CA http://sixrobblees.com/locations/

I ordered one from 6 roblees. They are "local" and looked up the part number. Thanks Highlander, that number matched. (Great forum of resources)
So when it comes in I'll post my mods. Looks to be fairly straightforward.

Again, thanks to this forum for the information.