Re: Dual axle aluminum trailer
Posted: Tue Apr 16, 2013 9:58 am
That's a good looking piece of work there. 
Discussions relating to the MacGregor line of trailerable sailboats
https://www.macgregorsailors.com/forum/
https://www.macgregorsailors.com/forum/viewtopic.php?t=21751
1st Sail wrote: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'.![]()
raycarlson wrote: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.
Excellent!u12fly wrote:Last night I posted my trailer mod with a few pictures: http://www.macgregorsailors.com/modt/in ... ?view=1832
Chris.
This sounds like alot of trouble. The MAC hull below the waterline is thick - moving the supports a bit is no problem.tkanzler wrote: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 is what I did as described above.tkanzler wrote: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.
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.tkanzler wrote: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.
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!]u12fly wrote: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.
I did something similar with a few xhanges.u12fly wrote: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.RussMT wrote:
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?
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.



Fixed your image for you. I wanted to see what it was anyway.aviro wrote:
I ordered one from 6 roblees. They are "local" and looked up the part number. Thanks Highlander, that number matched. (Great forum of resources)u12fly wrote: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/