Off-Road Boat Trailer

Been hauling my Zodiac around on the trailer that the boat came with. Frame is fine but the tires/axles/suspension/bearings etc can not take the abuse that i throw at them when dragging into back lakes. This season alone i have gone through 3 tires and rims, 2 leaf springs, and ripped the slipper end clips right off the frame on both sides (not at the same time).

I plan on beefing things up as a winter project with the goal being more clearance, tougher rubber, and bearings/axle and suspension that will take more abuse. I have a few thoughts already but would like to hear first hand from people that have trailers that can handle 4 or 500 km a year off road with the only requirement being grease.

First before you start on anything will the frame handle? If your already doing it then I am sure it will, but just think where the weakness will be. Some extra bracing may be all you need to do...

With that said what do you need to know...

Example of my work...
Attachment 40905

Are you trying to make your trailer dual purpose - roadworthy and backwoods? Or do you just want an off road trailer? If off road, I would change out the tires to low pressure balloon tires, similar to what you see on the commercial bush buggies. I built my own bush buggy using an axle from an old utility trailer and used these tires, which also act as suspension.

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Originally Posted by delmer

Are you trying to make your trailer dual purpose - roadworthy and backwoods? Or do you just want an off road trailer? If off road, I would change out the tires to low pressure balloon tires, similar to what you see on the commercial bush buggies. I built my own bush buggy using an axle from an old utility trailer and used these tires, which also act as suspension.

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If his trailer uses drop/riser axles( axles the place the spindles above the axle tube) all he has to dois use straight axles to increase ground . He can even use heavier axles to handle the rougher terrain.

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Originally Posted by Snowwalker

First before you start on anything will the frame handle? If your already doing it then I am sure it will, but just think where the weakness will be. Some extra bracing may be all you need to do...

With that said what do you need to know...

Example of my work...
Attachment 40905

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Frame is not an issue and if necessary it is relatively simple to beef up. The pic you attached looks good but is pretty small and hard to really see any detail other than it has more clearance and a heavier axle/bearings/tires than my current trailer.

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Originally Posted by delmer

Are you trying to make your trailer dual purpose - roadworthy and backwoods? Or do you just want an off road trailer? If off road, I would change out the tires to low pressure balloon tires, similar to what you see on the commercial bush buggies. I built my own bush buggy using an axle from an old utility trailer and used these tires, which also act as suspension.

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Trailer needs to street legal. I don't haul it down the highway per say but do drive 10 to 30 km on normal secondary road to get to the trailheads i use to access the various back lakes.

Was thinking of going to an independent setup like this:

Attachment 40907

Thoughts?

Would require a minor modification to my trailer frame.

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Originally Posted by Species8472

Was thinking of going to an independent setup like this:

Attachment 40907

Thoughts?

Would require a minor modification to my trailer frame.

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Rubber torsion suspension will get destroyed by offroad use..

If you want independent suspension you would need to use a system with coil springs, shocks and limiting straps.

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Originally Posted by Species8472

Was thinking of going to an independent setup like this:

Attachment 40907

Thoughts?

Would require a minor modification to my trailer frame.

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I recently replaced a torsion axle for a guy that twisted apart on the 407. They are a pretty stiff setup and I don't think they like aggressive cyclical load.

Independent suspension makes sense but the forces on those stubs will likely Crack the mounting brackets. Depending on your welding skill I'd say you would rather a shackle mount leaf spring with light springs and larger softer tires for simplicity, (radial car tires even) given the weight of the boat. What's the max weight you think including gear?

You could also convert to some kind of coil spring suspension, depending on how far you want to go.

Smooth suspension travel saves parts. Just look at modern atvs and snowmobiles, they are super plush not only for grip.

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Originally Posted by dean.f

What's the max weight you think including gear?

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Pretty light:

Boat = 225 lbs
Motor = 90 lbs
Trolling motor = 35 lbs
Battery = 90 lbs
Fuel Tank Full = 25 lbs
Miscellaneous = 100 lbs

So all told somewhere between 550 to 600 lbs trailer payload. Weight of trailer i don't remember off the top of my head but pretty light as trailer payload rating is 1500 lbs.

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Originally Posted by Species8472

Pretty light:

Boat = 225 lbs
Motor = 90 lbs
Trolling motor = 35 lbs
Battery = 90 lbs
Fuel Tank Full = 25 lbs
Miscellaneous = 100 lbs

So all told somewhere between 550 to 600 lbs trailer payload. Weight of trailer i don't remember off the top of my head but pretty light as trailer payload rating is 1500 lbs.

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You should take a look at Cerka industries in milton, you can get a torsion axle that is the same as manufacturers use with a full length axle tube. It's still an independent suspension but much more rugged than a stub. I think they come in a lighter rating to suit your needs. You likely wouldn't have to modify your frame either to mount it.

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Originally Posted by dean.f

You should take a look at Cerka industries in milton, you can get a torsion axle that is the same as manufacturers use with a full length axle tube. It's still an independent suspension but much more rugged than a stub. I think they come in a lighter rating to suit your needs. You likely wouldn't have to modify your frame either to mount it.

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Googled them. I work down that way regularly. I think i will stop in there next time i am in that area. Their web site looks pretty good.

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Originally Posted by Species8472

Frame is not an issue and if necessary it is relatively simple to beef up. The pic you attached looks good but is pretty small and hard to really see any detail other than it has more clearance and a heavier axle/bearings/tires than my current trailer.

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Yes wanted to be sure it uploaded..

Ok. So to start my trailer started life with :
3500lbs Single axle
Spindles 4 inch above axle tube.
Hubs were 5 stud with 10 inch electric brakes.
Leaf springs were spring under.

I switch to a Stright 5200lbs Single axle
Which moves the trailer up 4 inches.
I set the axle up to be spring over moving it up 2 to 2.5 inches plus the width of the springs of 1.5 to 2 inches.

Total lift 7.5 to 8.5 inches

The new hubs are 6 X 5.5 studs which matches the bolt pattern for my toyota.
Now my tacoma, the 4runner and the trailer can share wheel.
(Chevy has the same bolt pattern. )

The spindles have a grease fitting on the end under the hub cap, which makes it easy to grease.

The hubs have 12 inch electric brakes now...

To figure out your spring perch and pins placement measure the frame from the outside on the left to the outside on the right.
My pins are 1 inch from the outside edge of the frame on two inch tube.
For example if your frame is 72 inches wide with 2 inch tube the pins are 70 inches center to center, and your spring perches are 72 inches outside edge to outside edge..

Is that the kind of info you want?

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Originally Posted by Snowwalker

Yes wanted to be sure it uploaded..

Ok. So to start my trailer started life with :
3500lbs Single axle
Spindles 4 inch above axle tube.
Hubs were 5 stud with 10 inch electric brakes.
Leaf springs were spring under.

I switch to a Stright 5200lbs Single axle
Which moves the trailer up 4 inches.
I set the axle up to be spring over moving it up 2 to 2.5 inches plus the width of the springs of 1.5 to 2 inches.

Total lift 7.5 to 8.5 inches

The new hubs are 6 X 5.5 studs which matches the bolt pattern for my toyota.
Now my tacoma, the 4runner and the trailer can share wheel.
(Chevy has the same bolt pattern. )

The spindles have a grease fitting on the end under the hub cap, which makes it easy to grease.

The hubs have 12 inch electric brakes now...

To figure out your spring perch and pins placement measure the frame from the outside on the left to the outside on the right.
My pins are 1 inch from the outside edge of the frame on two inch tube.
For example if your frame is 72 inches wide with 2 inch tube the pins are 70 inches center to center, and your spring perches are 72 inches outside edge to outside edge..

Is that the kind of info you want?

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Yes. Thanks. Good plan with tires being matched between trailer and truck. Your trailer is likely overkill for the loads associated with my boat but if I can figure out a way to make the trailer work for more than just the boat by having the boat supports removable with a deck below than it would be worth it.

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Originally Posted by Species8472

Yes. Thanks. Good plan with tires being matched between trailer and truck. Your trailer is likely overkill for the loads associated with my boat but if I can figure out a way to make the trailer work for more than just the boat by having the boat supports removable with a deck below than it would be worth it.

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Ok... The 48% increase in axle capacity was not to carry more weight. The idea is the axle can stand up to more abuse.

As for tires, you need to use an LT tire with a good side wall so you can lower the pressure and not damage them. I don't know if you lower tire pressures for you type of offroad trips or not.

You are going to need to add shocks to dampen the bumps, potholes and corrugated road surface..

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Originally Posted by Snowwalker

As for tires, you need to use an LT tire with a good side wall so you can lower the pressure and not damage them. I don't know if you lower tire pressures for you type of offroad trips or not.

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Usually drop the pressure by 15 to 20 psi or so once i leave the pavement and than reinflate once back on the pavement when using the truck. Narrow trails where the truck can't make it I have an 8 ton float trailer that fits the ATV and the boat trailer. 8 ton gets parked at trail head and I unload the ATV and boat trailer and haul the boat with the ATV.

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Originally Posted by Species8472

Usually drop the pressure by 15 to 20 psi or so once i leave the pavement and than reinflate once back on the pavement when using the truck. Narrow trails where the truck can't make it I have an 8 ton float trailer that fits the ATV and the boat trailer. 8 ton gets parked at trail head and I unload the ATV and boat trailer and haul the boat with the ATV.

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Yes you did say you were wrecking tires and rims.. Trailer tires don't like to be under inflated, and it only gets harder on them the smaller they are.

Have you got any good Trailer parts supply shop up your way ? The one I use in london has been great to work with. They help me iron out a few bugs in my build as well.

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Originally Posted by Snowwalker

Yes you did say you were wrecking tires and rims.. Trailer tires don't like to be under inflated, and it only gets harder on them the smaller they are.

Have you got any good Trailer parts supply shop up your way ? The one I use in london has been great to work with. They help me iron out a few bugs in my build as well.

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Closest is an hour. That's why I was thinking of hitting Cerkas in Milton next time I am in that area for work.

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Originally Posted by Species8472

Closest is an hour. That's why I was thinking of hitting Cerkas in Milton next time I am in that area for work.

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Ok. Don't forget you have to leave room between the back of the tire and frame/fenders and stuff. This I think is one of the harder guesstmations you'll have to do. If you using rims with the same bolt patten you can just bolt them on and add a few inches to the new axle to get clearance.

Do you plan to use the same rims and tire size as your truck?

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Originally Posted by Snowwalker

Do you plan to use the same rims and tire size as your truck?

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Probably not an option really. Truck is a SRW 1-ton diesel (to pull the 8 ton float with mini-ex) so tires are 8 bolt (8 x 180 mm, not 8 x 6.5 inch like most 8 bolt trailer wheels), 10 ply, load range E and i typically run Duratracs (285 65R18). Not your typical off-road truck but it is lifted 2 inches and with the singles on the back plus front and rear diff lockers it does pretty decent. Only thing it does not like is deep mud - bad scene - too heavy. Has enough clearance and with tires deflated to 35-40 psi it handles everything else.

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Originally Posted by Species8472

Probably not an option really. Truck is a SRW 1-ton diesel (to pull the 8 ton float with mini-ex) so tires are 8 bolt (8 x 180 mm, not 8 x 6.5 inch like most 8 bolt trailer wheels), 10 ply, load range E and i typically run Duratracs (285 65R18). Not your typical off-road truck but it is lifted 2 inches and with the singles on the back plus front and rear diff lockers it does pretty decent. Only thing it does not like is deep mud - bad scene - too heavy. Has enough clearance and with tires deflated to 35-40 psi it handles everything else.

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Well that is only a 32.6" tire, you could still use them with a 18" rim with a 6 X 5.5 pattern on the trailer. You could not directly swap your truck spare on to the trailer, but if swapping rims gets you out of the bush..

You sure your rims are 8 X 180? Not 8 X170 or 8 X 200?

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Originally Posted by Snowwalker

You sure your rims are 8 X 180? Not 8 X170 or 8 X 200?

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Positive.

I can't find the pictures of my axle work when I lifted my trailer, but I'll link the video from my buddy in UT.

It may give you some ideas...

https://www.youtube.com/watch?v=zME68JOJDpo&t=307s

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Originally Posted by Snowwalker

I can't find the pictures os my axle work when I lifted my trailer, but I'll link the video from my buddy in UT.

It may give you some ideas...

https://www.youtube.com/watch?v=zME68JOJDpo&t=307s

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That's a good video and one that coincidentally i already watched LOL. Lot of good videos on his channel. Love me something like this:

Attachment 40953

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Originally Posted by Species8472

That's a good video and one that coincidentally i already watched LOL. Lot of good videos on his channel. Love me something like this:

Attachment 40953

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Ya, been thru his place in Hurricane. We spent some time comparing notes on recovery gear, and showing him where to find a couple things. You would think a guy in the towing business would know where to find stuff. But it's different tools for a different job, just like I don't know where to find J hooks.

Man is a fabrication wizard..👍
You should the custom recovery vehicle he is working on as his next toy..

Ok find them. I will post a couple of them and describe them and what I was doing.

Attachment 40954
Here you can see the original axle in it's original setup. Spring under with the spindles 4 to 6 inches above the axle tube .
Attachment 40955
Nicely tucked up in the fender but no real ground clearance.
Attachment 40957Attachment 40956
The spring pad is welded to the axle and uses the bolt as a centering pin. I only needed to remove one end of the spring to move the axle from the top to the bottom, but figured since I was in there I would replace and grease things as needed.

more to follow...

part 2

Attachment 40959Attachment 40960
so with the new parts in and everything on the springs greased up I mounted the axle under the spring with the spindles now 4 to 6 inches below the axle tube.

Attachment 40961Attachment 40963
So after reinstalling the wheel and tightening everything up I found I had 10 to 12 inches of lift on the trailer.

Well it pulled well and was stable on the road at highway speed It was just a little too high off the ground and if I was going to change the hubs and use 33 inch tires like the Tacoma and 4runner the height was only going to get worse.

I figured since I was going to be buying new hubs and a new axle I would use a stronger axle and one that would be easy to get parts for. A 6 X 5.5 hub is not common on a 3,500 lbs axle, but they are fairly common on a 5,200 lbs axle.