# Custom Tandem Axle for my 14'er



## Flat_Bottum (Mar 5, 2015)

Hello all, I am in the middle of rebuilding my Polar Kraft jet boat and am thinking or redoing the trailer while I am at it. It has more surface rust then paint, about 18" too short for the boat and is just all in all pitiful looking. Now, I have an idea of how I want my trailer to come out but need some assistance since I have never built one before. 

A few years so, I went to go pick up a transmission for my jeep and the guy pulled up at the meeting location pulling a little 4x8 utility trailer. What set it apart is the fact that he had done a custom tandem setup with twin 2k axles. Now, I know that it is not needed but it was just a scaled down version of a larger utility trailer and I fell in love. Well, I am wanting to do the same with my trailer. I am weighing the pros and cons of altering my current trailer or just building a brand new one from scratch. Im not sure if I will want to use a tandem hanger setup for the leaf springs but was thinking of using dual slipper style leaf packs but face the slipper ends facing away from each other so to save room and keep the tires closer together. Does anyone see any issues with this? Any advise will be greatly appreciated. Thank you.


----------



## lckstckn2smknbrls (Mar 5, 2015)

A standard tandem axle has an equalizer which keeps all the tires on the ground as it goes over uneven surfaces. A trailer with multiple individual sprung axles will lift one or the other set of tires off the ground as it goes over curbs putting all the weight of the trailer and load on just one axle and springs. If the total weight of the trailer and load doesn't excide the capacity of either axle and springs it can be done. 
There are trailers with multiple torsion axles. Google "Walking Beam Axle".


----------



## RiverBottomOutdoors (Mar 5, 2015)

A tandem axle trailer for a 14ft boat?


----------



## DaleH (Mar 5, 2015)

While I can certainly appreciate the COOL factor ... it sounds like a solution to a problem that doesn't exist ...


----------



## Johnny (Mar 5, 2015)

it is not about having a "problem" - it is about looking COOL going down the road.

Same thing as putting neon lights on everything you own.
Putting a poling platform on your boat and you are afraid of heights.
Putting jacked up 36" mudder tires on your Jeep and you never get off the grass.
Putting a 250 horse power outboard on your pontoon boat. (isn't a pontoon supposed to go SLOW ??)
it is all in the EGO factor ......

Just tell the boy to do it.... he's gonna do it any way.

If there is a lot of tight turns on concrete and asphalt, the tires will show wear
sooner than expected. (ask any landscaper that has a dual axle trailer)


----------



## DaleH (Mar 5, 2015)

Barefoot_Johnny said:


> Just tell the boy to do it.... he's gonna do it any way.


LOL  , or you mean more like:

_"Just tell the boy *NOT* to do it ... and he'll do it anyway!"_

In youths, that effect is due to the fact that the amygdala, the common sense center of the brain, is the LAST part of the brain to develop. That's why when you tell a teenager: _"Don't do the cinnamon challenge as it could hurt or kill you ..."_ They go out and do it anyway! Their brain processes it as if you had said: _"Do it and you'll be the coolest kid in your class!"_ :shock:

I guess some guys just never grow up all the way :wink: !


----------



## RiverBottomOutdoors (Mar 5, 2015)

I trailer a lot. I'd be concerned that tandem is too stiff for the load. Every bump at speed goes right into the boat/motor instead of dampened by the leafs.


----------



## lckstckn2smknbrls (Mar 5, 2015)

RiverBottomOutdoors said:


> I trailer a lot. I'd be concerned that tandem is too stiff for the load. Every bump at speed goes right into the boat/motor instead of dampened by the leafs.


Proper springs for the load are easy to do.


----------



## Flat_Bottum (Mar 5, 2015)

First of all, I aint no boy nor a teenager. Im 29 years old and dont give a crap what other people think. I saw a home built trailer that someone did this too and thought it looked neat. Do I NEED to do it? No. Would I want to? Sure, would be unique. Do not come at me like I am some punk young kid with my neon under glow lights or 20' wheels on my mall crawler. I asked a simple question and would appreciate a simple answer without people jumping to conclusions that I am some worthless punk kid that only wants to do something because others will think its cool. It was just an idea, just like the first person who said "hey, I wonder how this jet ski engine and pump would do in my little fishing boat?" Is it needed? Nope, but people still do it. Thank you to those that did respond with a mature answer. To those who did not, good day.


----------



## lckstckn2smknbrls (Mar 5, 2015)

I think you need to relax and reread the post.


----------



## slick (Mar 5, 2015)

I have a 1986 cj7 jeep. I would love a set of 36" tires. I made the half century mark a while back. 
It's your choice. If we all had the same opinion and loved the same woman, the world would be a mess!!!


----------



## Flat_Bottum (Mar 5, 2015)

lckstckn2smknbrls said:


> I think you need to relax and reread the post.



I was not referring to any of your posts. You was helpful. I was referring to to the other comments. In my opinion, if someone wants to put 4 axles under a 12' boat, that's their prerogative. Being compared to a teen or an individual who just wants the "look at me" factor isn't cool at all. I understand how tandem trailers work and their purpose and understand fully that I dont need a tandem setup. My current axle is rated at 2,000 lbs and I am no where near that mark and never will be. I just had an idea to mimic a similar setup that I had seen back when and thought it was neat. If my idea will cause more damage then good, then its not worth following. If I came off angry then I apologize since that was not my intent.


----------



## Johnny (Mar 5, 2015)

and I passed the " half century " mark almost two DECADES ago !! 

it is YOUR build - do it the way YOU want it . . . . 
you do not have to take ANY of this free advice..... pick and choose notes
from here and there and make your own decisions, good or bad, you can always do it over,
fix it, or sell it....... simple as that.
for example: rides too stiff, remove a leaf spring or two, buy a new set for the weight you carry.
You could probably go to the junk yard and get a set of Jeep springs that will work perfectly.
Just do your homework - YOU are the one pulling it down the road at 60 miles per hour - not us.
Good Luck. Be Safe.


Jus my dos centavos


----------



## Flat_Bottum (Mar 5, 2015)

i have been trying to do some information searching on the torsion axles for trailers. I have never pulled a trailer with them before and from what I have found, they are rated for around 2,000 lbs. Does anyone know how they ride compared to leaf springs? Regardless if I stay a single axle or do pull the plug and try to fab up the tandem, I will be upgrading all of the axle components in the trailer since they are old and time to be replaced. Would like to possible go with the torsion type if they are worth it.


----------



## huntinfool (Mar 6, 2015)

A slipper spring facing forward will not slip. Think of direction of travel. I work on trailers daily, part of my real job. You could use tandem 2 leaf springs with an equalizer, but it may ride rough.


----------



## lckstckn2smknbrls (Mar 6, 2015)

There is also a axle-less set up made by Tembren suspension .


----------



## Flat_Bottum (Mar 7, 2015)

lckstckn2smknbrls said:


> There is also a axle-less set up made by Tembren suspension .



I believe that I have seen this (or something similar) on a buddies trailer a long time ago. I the main concern with doing something like this would be the rid quality of the trailer and it beating the inside of my boat apart. If I do twin leafs with the equalizer then I may do some experimenting with a leaf pack and remove a couple of the bottom leafs to see how soft I can get it. My current leaf springs are a bit on the soft side for the boats weight now and it bounces purdy bad on the rough roads. So If I could stiffen up the ride a little bit so it pulled like it used to then I think that would do good. Thanks again everyone for the advise thus far. Also never thought about the slipper not slipping while facing forward...makes perfect sense though once you think about it.


----------



## lckstckn2smknbrls (Mar 7, 2015)

Did you look up the walking beam axle? It has 4 tires but just one pair of leaf springs.


----------



## lugoismad (Mar 8, 2015)

2 sets of these would fit the bill

https://www.etrailer.com/Trailer-Axles/Timbren/ASR3500S05.html



> Specs:
> Fits: 1-axle and 2-axle trailers that use regular tires
> Not recommended for triple-axle applications
> Weight capacity: 3,500 lbs
> ...




Just something I want to point out though....if you really don't need the extra weight capacity, this is 2 extra tires you'll have to replace just as frequently.


----------



## KMixson (Mar 8, 2015)

Flat_Bottum said:


> My current leaf springs are a bit on the soft side for the boats weight now and it bounces purdy bad on the rough roads.



Are you sure the springs are too soft? My pick-up has very hard springs under the rear. It rides very rough compared to other trucks I have driven with soft springs. It jars your teeth with every bump in the road. It will even loose traction sometimes as it bounces. The good thing about it is that I can haul much more weight (about three times as much) than similar trucks with soft springs. Standing on my rear bumper it does not sag at all. Other vehicles I have driven sag a lot standing on the rear bumper but they ride smooth when empty.


----------



## Flat_Bottum (Mar 9, 2015)

I looked at those axle less suspension units and while being really nice, the price is not haha. The boat pulled good before I did the jet conversion and afterwards, I have noticed that its very bouncy and seems all over the place for a second or two after a good bump. This could have been due to the worn out garbage tires that were on the trailer and now that they are replaced, it might be a different story. I have not seen the walking beam axle yet but will be looking into it. Thank you guys for the advise and input so far. I know this isn't needed and if I cant do it safe and without breaking the bank then I will do it. The 4 lug tires on the boat are around $30 at wal mart for the wheel and tire combo and with as much and how far I tow the boat, I wont be too worried about wearing tires out and having to replace them. Thanks again everyone.


----------



## Flat_Bottum (Mar 14, 2015)

After working on the boat for the past couple of days, I have realized that it in fact is not my suspension that is struggling with the added weight but its the tires. I have installed brand new tires and wheels (4 on 4) and I think I am pushing the load rating of them. I noticed they looked a bit squatty and so I got in the boat myself while watching them and they were not happy at all. So, at this point its either a larger tire/wheel combo or the tandem. I was thinking about making a walking beam which would allow me to keep my single axle and suspension but add two extra tires. I like the smaller tires since I usually launch at garbage, muddy boat ramps and it makes it a lot easier to load/unload the boat. The thing I am curious about is will the center hub which the walking beam attaches too hold up. Its not a solid axle so there will be no bind when turning but adding another tire on a walking beam would create some bind when turning sharp...so Im not really sure what to do at this point.


----------



## lckstckn2smknbrls (Mar 15, 2015)

What size are your tires and what load range are they?


----------



## Flat_Bottum (Mar 15, 2015)

I will have to check when I get home from work. They are the pre mounted ones you can get at wal mart, home depot etc.


----------



## lckstckn2smknbrls (Mar 16, 2015)

What's the weight of your boat, motor, trailer, fuel and the gear you normally have in the boat when trailering?


----------



## Flat_Bottum (Mar 18, 2015)

I haven't been able to weigh it just yet but am planning on taking it down to a local scale to find out. I do know that with the boat completely empty, in its original form, it took 3 guys to lift and flip it and it was a struggle to say the least. I remember reading somewhere that the boat weighs in around 400ish pounds but will have to double check that. So, with 400 lb boat-120 lb engine- 40 lb ski hull-approx 200 lb decking and flooring- 125 lb for full 16 gal fuel cell-40 lb battery...Id give it a guesstimation of around 925-1000 pounds when its all said and done.


----------



## lckstckn2smknbrls (Mar 19, 2015)

And the weight of the trailer puts you close to if not over 1200 pounds. If the tires are 480x8 load range B they are rated at 590 pounds each 1180 pounds for the pair. You should go up to a load range C tire or higher.


----------



## Flat_Bottum (Mar 20, 2015)

Thanks for the information on the tires. I haven't really been able to get to the boat in the last few days but will definitely check them out. Thank you again.


----------



## Flat_Bottum (Mar 22, 2015)

After reading through the advise and information that I have had given to me on this thread so far, I have decided to hold off on a trailer build for now. I will be looking into a little heavier tire to help hold the new weight of the boat and gear and just start gearing up for a trailer build later on. Once I do start it, I will be sure to post a build thread so I can continue getting the good feedback like I have so far on this forum. Thanks again everyone, I really appreciate it.


----------



## JL8Jeff (Mar 23, 2015)

The 14' jet sprint boat I recently bought has a custom trailer with a drop axle. I bet it's good for 2000-2500 lbs and has 5 lug hubs/wheels. You could probably convert to a drop axle if needed or maybe just get new hubs with 5 lugs which will give you a better options for tires and wheels to handle the load. Here's a picture of the custom trailer with the drop axle, it has some decent wheels/tires as well.


----------



## Flat_Bottum (Mar 24, 2015)

I like the look of that trailer. Would you mind taking a closer photo of the axle setup and suspension if you get the time?


----------



## JL8Jeff (Mar 24, 2015)

I'll see if I can get a good picture after work. It looks like the drop axle is one I found from Pacwesttrailers.com, I know the boat and trailer came from out in ID then OR.

https://pacwesttrailers.com/catalog/axles/3500lb-trailer-axle-beams.php


----------



## JL8Jeff (Mar 24, 2015)

It looks like a typical trailer frame with some crossmembers u-bolted to it and the leaf springs bolted to the crossmembers and axle. The upper bracket is for mounting the fenders and is a bit of overkill.


----------



## Flat_Bottum (Mar 25, 2015)

Thanks for those pictures, that helps out a lot. It might be a little over kill as you said but its solid and sturdy and dont look like its going anywhere. I have never thought about changing tire size since with the height of the boat on the trailer, the smaller tires help out a lot when launching in the shallow and muddy river launches. But If I can copy the design like your trailer, then I can up the tire size but keep my ground clearance. Thanks again.


----------



## JL8Jeff (Mar 25, 2015)

Yeah, the drop axle can get you down quite a bit lower even with bigger tires. This trailer hauled the boat across the country from OR to NJ back in Feb so I think it's pretty solid. When researching the drop axles out there, check the spindle dimensions closely to see what hubs fit and then which hubs (4, 5 or 6 lug) will give you the best wheel/tire options. The 5 lug seems to have a better selection available for wheels/tires.


----------



## Flat_Bottum (Mar 28, 2015)

Thats what I was thinking as well. Thanks again for all of your help and input.


----------



## nlester (Mar 29, 2015)

From a rocky start to a solid exchange of ideas. I have enjoyed watching this topic develop and grow.


----------



## Flat_Bottum (Apr 1, 2015)

Thats the way threads should go in my opinion. I know that my original idea was not needed but its unique and Id like to try it. I will still be looking for a second trailer that I can play with while I use my current one. That way, the boat will still be usable while I tinker with the other trailer.


----------



## ColtonS (Apr 2, 2015)

I think a mini tandem would be pretty nice for maneuvering the trailer in reverse.

As far as shallow launches go I have a tilt trailer which helps but have seen trailers with the bunks on a separate frame that hinges at the front and is lowered/lifted by cables in the rear.


----------



## Tallpine (Apr 7, 2015)

Yes, a tilt trailer is the kitty's whiskers for shallow launches. I had a 15 foot Smoker Alaskan with a tilt trailer and we launched it in the Columbia river right off the beach and in lots of lakes with shallow launches.


----------



## ColtonS (Apr 8, 2015)

LOL probably 75% of my launches are off a gravel bar on the river bottom farm I live on.


----------



## Flat_Bottum (Apr 12, 2015)

My trailer is a tilt as well. My goals for right now are to finish up the boat so I can actually use it and then buy another trailer to play with. I am currently keeping my eyes peeled for a small trailer that I can tinker with to see if my idea is even feasible. I may buy me a couple new hubs to swap out on my current trailer and then use the old ones to mock up a walking beam...but again, not fully sure.


----------

