Correct Spring Arrangement for 26S Trailer?

Robspan · Aug 16, 2011

Cruiser1 said:
Does anyone have photos of how their springs are arranged on thier 26S trailer? Would be paticularly good to see a photo of how the springs are arranged on a trailer still set up as it comes from the MacGregor factory. Perhaps mine is original but I have no way of knowing.

This was taken after I replaced the original axle. The placement of springs and axle is the same as the original. I hope this helps.

MrBill_FLL · Aug 16, 2011

IIRC, the fenders will rub tires if you put the springs below the axle.

Sumner · Aug 16, 2011

Springs can be either over or under. I have them under on my teardrop trailer to make it sit lower. I've taken it to the Arizona desert and turned the axle over and had them on top for more ground clearance while towing with our Jeep.

There will be a locator hole and pin that will center the spring and that is why I had to turn the axle over. The axle I'm talking about is a perfectly straight axle, so I could do that. A lot of trailer axles that appear to be straight really aren't. Some are bowed fore/aft to put some 'toe' into the axle and some are bent in the up/down direction so that under load they are 'straight'. You have to know if the above two conditions are present before you start messing with them.

Your springs/axle look to be correct and like the others said if you were to 'flip' the axle you would end up with fender and boat clearance problems. Get the new springs and new bolts/shackles at the same time and start towing again

,

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links

r.oril · Aug 16, 2011

Very good point, MrBill!

tkanzler · Aug 17, 2011

Here's a pic of a 26D or S (I think?) trailer I found somewhere (first pic - I haven't a clue who took them), but I believe the axle and springs are original from many of the details, not the least of which is the huge thickness of the leaves (0.43", if it's like mine).

Mine (last 2 pics), a 26X trailer, had a second 3500 lb axle added, and the leaves on the new axle are much thinner. I checked the spring rate on both, and the original is something like 2500 lb/in compared to about 1200 lb/in for the aftermarket springs. It would have been a pretty hard ride with the boat and trailer at rated gross weight on the original suspension, but I suspect that it was done that way in anticipation of great overload, as I think the 26X trailer and axle/wheel/tire system is underdesigned. Axle and bearings are 3500 lb rated, but the springs are much heavier. I believe the M uses a heavier axle, in fact, and possibly a heavier tire (8-ply rating?).

Yours looks like the same spring (26" eye-to-eye, 4-1/4" drop, 1-3/4" wide, 0.43" leaf thickness, 4 leaves) as the original 26X trailer. I doubt you'll find that spring in anyone's catalog, but the good news is that an aftermarket 4-leaf 1500 lb spring will be softer, or if you bump up to a 2000 lb (each) spring, it'll still be softer due to the thinner leaves, even though there are 5 of them and the load capability is greater.

My original springs are getting tired (leaves are starting to separate - a sign they're getting old), and next year I'll replace them with something much softer, as I have 2 axles now, with each one only taking half the original axle load. I'll probably also take one leaf out of the newer axle to drop it's spring rate and soften the ride a bit.

The last two pics are my trailer while I was retrofitting disc brakes. You can see the original leaf thickness vs the new axle with much thinner leaves. Different length and drop, but when it's sitting level on its tires, the equalizer is level, as it should be.

May not be much use to you, but it should give something to think about at least.

MrBill_FLL · Aug 17, 2011

top left: that's my (old) stock trailer, and it has the 1/2 a pvc tube over the axle... (really not needed).

this pvc does help protect the boat from the metal trailer:

http://i64.photobucket.com/albums/h169/ftldiver2/MACGREGOR/P1010398.jpg

http://i64.photobucket.com/albums/h169/ftldiver2/MACGREGOR/P1010008.jpg
http://i64.photobucket.com/albums/h169/ftldiver2/MACGREGOR/P1010006.jpg

^ Back yard engineering but it worked

tkanzler · Aug 17, 2011

I hope you don't mind my using it, then. I guess I found it here.

In the last pic, you can see the primed areas between the axles where the original hangars were welded. Mine has a 2" x 3" dropped axle, mounted above the springs, but it appears to be the same otherwise.

Here's yet another pic I found. I think it was for sale someplace. It's a 26X trailer, and aside from the mods made to mine, is otherwise identical.

OP: If clearance is an issue, just mount the new springs the same as the old. Make sure the springs are heavy enough for the gross trailer weight, and opt for more leaves of thinner material and the same load rating, if you want a softer ride. If the mounting plate is a bit wide, it will only cause the springs to be a bit stiffer, but not that you'd notice.

tkanzler · Aug 18, 2011

Cruiser1 said:
Yes pretty close to it, but yours may be a bit heavier. Mine currently measure about 685mm (27") eye-to-eye with the boat on the trailer and the back hanger sitting almost vertical.

You have to jack it off the springs to measure length, but yes, it's eye center to eye center. Also know that the hole may be elongated, and if there's a rubber bushing, it's probably shot, too. New ones usually have a nylon bushing instead of rubber. I don't know what the Mac trailer used in those days. Point being, the bolt centers may be skewed by worn bushings, and they're certainly further apart with the load on it. Common center distances are 25-1/4" [641mm], 26" [660mm], and 27" [686mm]. I'd guess yours were/are 26" with the load removed, but that's just a guess.

Cruiser1 said:
My leaf thickness is a bit less at about 9.5mm (3/8").

Common thicknesses for trailer springs around here are .323" [8.2mm] and .360" [9.14mm], among many others (above and below). Yours may actually be .360", since it was made here, but I would imagine you could easily find a local source or internet supplier with something close. I've never seen a replacement spring with the same leaf thickness as my original, though (.430"), and wouldn't want it anyway - too stiff for the axle, IMO.

Cruiser1 said:
The 26S has an officially specified unladen weight of 748kg - I suspect a bit lighter than the 26X??

I think the X is supposed to be 2300 lb, give or take, plus trailer at another 700 lb (all steel). With all the stuff the PO's had in my boat, it's no wonder they added a second axle. Took me and my FIL an entire day just to empty it when I first got it.

Cruiser1 said:
I assume you measure the drop between a line across the middle of the eye centres and the top of the spring. Would that be correct?

Yes. Regardless of where the axle mounts, the drop (or arch height) is to the top surface of the master leaf, oriented eyes-up (like a smile). Since your axle is under the spring, a thicker spring will raise the boat off the axle. But so will a longer shackle, if clearance is a real problem. If yours is all original, you may want new shackles and bolts anyway, as well as U-bolts, of course.

Sumner · Aug 18, 2011

Cruiser1 said:
.... The trailers look very flimsy but I think Roger MacGregor knew a thing or two about engineering design ....

Actually the factory trailer we have (1990) is very flimsy in my opinion. I think Roger designed them feeling that most owners were going to tow to a nearby lake and maybe occasionally a little further.

The single axle on ours was bent before we bought the boat/trailer and had no brakes. I'm not sure what the regulations were in '90, but now in most states here a trailer with a weight of over 2000 lbs. is required to have brakes. Maybe one can get around that if the trailer without a load is under 2000 lbs., I don't know, but do know that driving long distances at highway speeds or even around town where someone can pull out on you or cut you off is dangerous without brakes on a trailer our size.

A couple years ago we pulled 3000 miles to Canada and back with the orginal trailer, I had put new springs on it and had to buy tires on the trip due to the bent axle and almost had problems with the tow vehicles brakes on two very long and steep mountain descents along with almost frying the transmission coming down one of them in a lower gear using engine braking. The only thing that made the trip possibly was that we were towing with a '99 Chevy Suburban which is a great tow vehicle.

Since then I've strengthen the frame with a....

... sub-frame and also extended the frame back so that ...

....I could add a third bunk which I feel better about since our boat is quite a bit heavier than a stock one and at the same time added a.....

.... second axle...

... with surge disc brakes. The trailer now tows and stops much better, and I feel a lot better about the strength of the ....

... trailer overall. Since we have to tow some distance to any lake and like to take longer trips like the 5000 mile one to Florida working on the trailer has really paid off. I'm not sure what your requirements are.

On the springs some places will spec them out as a pair and will tell you they are (as a pair) for a 3500# axle and the springs would be two 1750 lb springs. Other places just tell you the specs per spring so be be sure you know which they are doing. We have 1750 springs, 4 of them, and the trailer with our boat rides great with them. Not too soft or too stiff.

I don't have a good page up on the above upgrades yet, but there are a few more pictures here....

http://purplesagetradingpost.com/sumner/macgregor2/misc-pics-18.html

....and other trailer mods here...

http://purplesagetradingpost.com/sumner/macgregor/trailer-mods-index.html

Good luck,

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links

tkanzler · Aug 18, 2011

Anyone ever tell you that you do nice work?

Bunk replacement is done, but I'm still working on my brakes. New discs on the rear axle only, plus a new surge coupler and all new lines. Not quite done grinding off the old coupler (my kingdom for an acetylene torch). New coupler is just the bolt-on disc brake version of the original DICO unit, but with a normally open solenoid. I may use a ball valve instead of the solenoid, as it won't vent off trapped pressure as delivered, and that means I won't be able to back up if I stop aimed downhill unless I stop on flat ground and turn a ball valve manually, with no pressure in the lines.

New LED lights all around are still in the works, as the original trailer didn't seem to even get close to DOT requirements, and requirements aside, more lights means more visibility on the highway in heavy rain and spray. There weren't even any holes for the ID lights in the back, nor for side markers in front. I don't know how this trailer was legal even 12 years ago.

I added an amber clearance light/side marker (at 45 degrees, like yours) with SAE PC lens code to the front of the front fenders, similar to yours. The 'over 80' taillights are far enough apart to cover the rear clearance requirements.

Existing wiring is just temporary so I could get the boat in the water. I mounted a junction box to the ladder support to make it easier to repair and troubleshoot, if necessary.

I want to try some canal boating (Erie Canal) soon, so I've gotta get this trailer ready. Hasn't even been inspected, yet, so technically it's not legal yet.

Sumner · Aug 18, 2011

Cruiser1 said:
....I have been puzzling over other photos of what looked like a sub frame arrangement you had Sumner - all explained . You certainly have a good solid towing arrangement.

I finally took the day off from the boat and started posting more details on the trailer mods I did last year

. If you didn't see it, only been up a couple hours, here is a link to the sub-frame...

http://purplesagetradingpost.com/sumner/macgregor-trailer/trailer-mods-10.html

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links

Sumner · Aug 19, 2011

Cruiser1 said:
... Sounds like I will probalby not find the exact spec easy to find in town - may have to have them custom made yet...

Before we took our first long trip when we still had the single axle I replaced the two springs and couldn't find the right length locally and needed to do something the same day. I got some slightly different length springs and two new hangers. I cut one old hanger off on each side and weld a new one on at the right distance for the new springs.

That would probably be cheaper and quicker than having springs made and would/should be a quick an easy thing for a welding shop to do, so shouldn't cost that much.

Don't forget you are working on a trailer and not a sports car. Close is good enough

.

1750# springs are available in different lengths...

http://www.championtrailers.com/springs.html

...find two of those and you should be good to go.

http://www.easternmarine.com/em_store/tech_info/leafspring_tech_info.html

http://www.truckspring.com/trailer-parts/trailer-suspension/measuring-trailer-springs.aspx

Good luck,

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links

tkanzler · Aug 19, 2011

Cruiser1 said:
Sounds like I will probalby not find the exact spec easy to find in town - may have to have them custom made yet.

I would do almost anything NOT to have custom springs made. My original springs measure 25-1/2" [648mm] to 25-3/4" [654mm] with no load, so there's no telling what they really were when new. They're very beefy (about 2500 lb/in spring rate - roughly twice that of 'standard' 1750 lb 4-leaf units), but very old.

I can't tell you what the original center distance was, since the seats were cut off to move the axle and add another. From the pic, yours looks original, so just go with that. It looks like the shackles are folded under a little while under load, so I don't think you can use the 26" [660mm] without causing the hangars to fold under too much. It's probably best to do as Sumner suggested - buy two new spring hangars, one for each side, and use 'standard' 26" springs. Remember that the 26" units have a deeper arch height than the 25-1/4", which you probably need on your trailer.

If it were me, I'd leave the front hangers alone, so the axle alignment isn't at risk of being messed up, and replace the rears, where the shackles go. Slight alignment issues there won't change the axle alignment relative to the frame.

You could always put on 26" springs, and see how it sits on the shackles. Then make a decision about moving the hanger. Perhaps have the trailer shop you spoke with do the work of replacing the hanger. Not hard to do at all, but you need welding capability, and enough experience to do it well.

Correct Spring Arrangement for 26S Trailer?

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