Aluminum framed fat tire beach quad with lots of storage capacity.

Spidennis

New member
New guy here, I’m Dennis, from South Padre Island Texas.
My goal is to make an aluminum framed fat tired beach quad, with a PTO (power take off). It is a multi use vehicle , one is for a trip I’m planning, and then it’s life will be to aid in my sandcastle lesson business.
I already use a bicycle and trailer for my lessons so I know what freatures (a new term?!) it needs and what it has to do and how it has to do it.
Needless to say I’ve been researching all I can about designs, here, there, and everywhere.
The front wheels and steering I’m still wondering how to go about it. The rear axle seems fairly easy as it will be a straight axle with both wheels as drive wheels.
the transmission is a bit tricky, especially with the pto.
this will be an electric bike and awd ( all wheel drive) or 4x4, depends on how you look at it. I’ll use a hub motor in each front wheel which I’ll only use when I have to in those 4x4 conditions.
I’m thinking about a pinion gearbox and mid drive motor combination at my feet. That will drive the transmission which will drive the wheels or pto, or both.
parts seems to be troublesome to find. I do some horrible mig welding but now I need to learn aluminum. More about the trip and pto later.
I’ll get some pics up when I figure out how to do that. Apparently I need to link to them from where it’s already on line? (And not just straight off my phone/computer)
Oh, then there is the battery charging considerations while on my trip, and plenty of storage for camping. More on that later, lots more.
 
You won't be welding aluminium with a MIG. You need TIG and specifically AC TIG. DC won't cut it. The big drawback of aluminium as a frame material is it's in use as a beam on recumbents. In an regular bike the frame is a diamond (back to back triangles) with the stresses going along the length of the tubings. Aluminium is fine for that, but in beeam applications aluminium shows it's weakness as it has very little elasticity. This means stress fractures and failure. Unlike steel which fails slowly enough to see the issue long before it's a catastrophe aluminium will fail without much warning. Having said that it can be used but you'll end up using fairly fat tubes and saving very little weight because of the design calling for beams. I would suggest welding an aluminium recumbent frame is not an ideal 1st task for anyone new to AC TIG.

For the rear axle I'd suggest a freewheel diff rather than a straight axle. Freewheel diffs are brilliant in that they always supply drive to the wheel that needs it the most unlike a car diff. Danny and Paul both built one with a thread on here about it and I also have the same principle at the rear of my Church Pod quad. Again a thread is one here.

What do you plan to run off the PTO?
 
Welding ali with MIG is possible, if you have an HF AC setup. Doug from SV Seeker routinely welds with that.

Hub motors... maybe there are some heavy duty variants that have shafts strong enough. But I never have seen'm. Most have 3/8" axles. Not nearly strong enough for the job.
That is why I have a few of the older 250W hub motors here, to be adapted for 15mm shafts. If that works, I'll buy 2 gazillion watt sets, and create 2 front wheels for Grey Ghost.
 
Last edited:
All the hub motors I've seen use a M14 axle with flats to slot into a 3/8 dropout. The flats allow the axle to stay put whilst the hub rotates around it. With the flats vertical it may be fine but that will depend on the tensile strength of the axle. Given use on a quad with 4 wheels to share the load I'd expect them to survive.

I'd never even heard of an AC mig TBH.
 
Last edited:
You won't be welding aluminium with a MIG. You need TIG and specifically AC TIG. DC won't cut it. The big drawback of aluminium as a frame material is it's in use as a beam on recumbents. In an regular bike the frame is a diamond (back to back triangles) with the stresses going along the length of the tubings. Aluminium is fine for that, but in beeam applications aluminium shows it's weakness as it has very little elasticity. This means stress fractures and failure. Unlike steel which fails slowly enough to see the issue long before it's a catastrophe aluminium will fail without much warning. Having said that it can be used but you'll end up using fairly fat tubes and saving very little weight because of the design calling for beams. I would suggest welding an aluminium recumbent frame is not an ideal 1st task for anyone new to AC TIG.

For the rear axle I'd suggest a freewheel diff rather than a straight axle. Freewheel diffs are brilliant in that they always supply drive to the wheel that needs it the most unlike a car diff. Danny and Paul both built one with a thread on here about it and I also have the same principle at the rear of my Church Pod quad. Again a thread is one here.

What do you plan to run off the PTO?
Al mig is a thing but what I hope to do is bolt it all together if I can. I understand the problem, aluminum boat trailers are bolted together. For where I live it will be an aluminum frame.
I’ll be hunting down these other threads. I’d love to see the dual freewheeling rear axle. I don’t quite understand how that would work though.
 
New guy here, I’m Dennis, from South Padre Island Texas.
My goal is to make an aluminum framed fat tired beach quad, with a PTO (power take off). It is a multi use vehicle , one is for a trip I’m planning, and then it’s life will be to aid in my sandcastle lesson business.
I already use a bicycle and trailer for my lessons so I know what freatures (a new term?!) it needs and what it has to do and how it has to do it.
Needless to say I’ve been researching all I can about designs, here, there, and everywhere.
The front wheels and steering I’m still wondering how to go about it. The rear axle seems fairly easy as it will be a straight axle with both wheels as drive wheels.
the transmission is a bit tricky, especially with the pto.
this will be an electric bike and awd ( all wheel drive) or 4x4, depends on how you look at it. I’ll use a hub motor in each front wheel which I’ll only use when I have to in those 4x4 conditions.
I’m thinking about a pinion gearbox and mid drive motor combination at my feet. That will drive the transmission which will drive the wheels or pto, or both.
parts seems to be troublesome to find. I do some horrible mig welding but now I need to learn aluminum. More about the trip and pto later.
I’ll get some pics up when I figure out how to do that. Apparently I need to link to them from where it’s already on line? (And not just straight off my phone/computer)
Oh, then there is the battery charging considerations while on my trip, and plenty of storage for camping. More on that later, lots more.
New guy here, I’m Dennis, from South Padre Island Texas.
My goal is to make an aluminum framed fat tired beach quad, with a PTO (power take off). It is a multi use vehicle , one is for a trip I’m planning, and then it’s life will be to aid in my sandcastle lesson business.
I already use a bicycle and trailer for my lessons so I know what freatures (a new term?!) it needs and what it has to do and how it has to do it.
Needless to say I’ve been researching all I can about designs, here, there, and everywhere.
The front wheels and steering I’m still wondering how to go about it. The rear axle seems fairly easy as it will be a straight axle with both wheels as drive wheels.
the transmission is a bit tricky, especially with the pto.
this will be an electric bike and awd ( all wheel drive) or 4x4, depends on how you look at it. I’ll use a hub motor in each front wheel which I’ll only use when I have to in those 4x4 conditions.
I’m thinking about a pinion gearbox and mid drive motor combination at my feet. That will drive the transmission which will drive the wheels or pto, or both.
parts seems to be troublesome to find. I do some horrible mig welding but now I need to learn aluminum. More about the trip and pto later.
I’ll get some pics up when I figure out how to do that. Apparently I need to link to them from where it’s already on line? (And not just straight off my phone/computer)
Oh, then there is the battery charging considerations while on my trip, and plenty of storage for camping. More on that later, lots more.
oh, forgot, I don’t want to use a chain(s).
where I live the salt and sand destroys ferrous metals, so I want to go the belt route.
yeah, it kills electronics just as well if not better. Rust never sleeps. It will be a challenge.
 
All the hub motors I've seen use a M14 axle with flats to slot into a 3/8 dropout. The flats allow the axle to stay put whilst the hub rotates around it. With the flats vertical it may be fine but that will depend on the tensile strength of the axle. Given use on a quad with 4 wheels to share the load I'd expect them to survive.

I'd never even heard of an AC mig TBH.

Tensile strength of Chinesium hollow steel threaded, and holed axles... Well cured chewing gum comes to mind.

HF/AC MIG, I have seen and tested a few of those in the 35 years I'm welding. But I never liked welding aluminium.
To add the capacity to my home welder, I was planning to use the wire feed part of an affordable, but decent MIG and use my AC/DC TIG as powersource. Again, one of the projects on the heap of good intentions... Will happen when I really need the capacity.
 
Al mig is a thing but what I hope to do is bolt it all together if I can. I understand the problem, aluminum boat trailers are bolted together. For where I live it will be an aluminum frame.
I’ll be hunting down these other threads. I’d love to see the dual freewheeling rear axle. I don’t quite understand how that would work though.

Are you going to use aluminium bolts? Because using steel bolts will induce galvanic corrosion like no tomorrow.
And I have to admit, your plans sound very ambitious and contradictionary. I suggest you read Emiels Quad build thread. That is also an ambitious project that is nearing completion.
 
I doubt a bolted aluminium chassis will be any lighter than steel. Steel bolts weigh a lot and I can't see aluminium bolts doing the job. Even using aluminium bolts you are adding a lot of metal over a welded construction. I would suggest a welded stainless construction for a corrosive environment. I used stainless for my last tilter project (thread on here). The only issue is the need for first class drill bits. Even good quality die at the altar of stainless. You need the type of bit that have a small pilot and then go flat for effectively milling through.

iu
 
Last edited:
Last edited:
If you want the best of all worlds, I would suggest a welded titanium frame and stainless steel bolts. But that ain't a budget build.

On the other hand, I don't know a lot of people willing (let alone, able) to work with titanium.
 
One other alternative is to have a mild steel frame galvanized. Cheap and simple to initially build. Much will depend on if you have a galvanizer in your area. The downside is any later modifications will ruin the zinc coating. On a similar note how about sacrificial zinc anodes as used on boats?
 
Ok, y’all got me looking at the other builds and suggestions. This might take awhile!
the new pinion gear box and motor is not going to be available any time soon in the USA so I’ll scrap that idea.
I’m liking that 1” square tube build! Plus I already have some.
weird ideas are nothing new to me, check out this I build.
 
How much power do you want? If you can adjust your plans to have the wheels use "classic" double sided mounting you can use commercial hub motor wheels. Chances are 4 of those are cheaper than the E-Pinion, have more power, and avoid- for the chain driven wheels- straining the chain...
 
How much power do you want? If you can adjust your plans to have the wheels use "classic" double sided mounting you can use commercial hub motor wheels. Chances are 4 of those are cheaper than the E-Pinion, have more power, and avoid- for the chain driven wheels- straining the chain...
How much power do you want? If you can adjust your plans to have the wheels use "classic" double sided mounting you can use commercial hub motor wheels. Chances are 4 of those are cheaper than the E-Pinion, have more power, and avoid- for the chain driven wheels- straining the chain...

I dont need a lot of power, not for very long anyway, just in sections where on the beach i absolutely need it, deep soft sand...
I'd not mind using bicycle forks for the front but they are kinda big and cumbersome , and I hadn't seen a way of easily steering a pair of them.
What is this "ALUMINUM" is it anything like the metal Aluminium?
Is it a "one-eyed" version of the real metal? ;)

tony stark isnt giving up his trade secrets!
 
I would give serious thought to some suspension. Aluminium is not a forgiving metal. With no suspension every force not taken by the tyres has to be bourne by the chassis. With suspension in use the chassis gets a lot of isolation from those forces and as such is more likely to survive. I'd also look to some means of welding rather than bolts. Bolts and crush tubes are going to add a lot of weight and will limit the design of the chassis as bolts are going to require areas overlapping and right angles. If it must be bolts give some thought to gluing the joints too. Glue keeps a Lotus Elise together.
 
As you go aluminium and bolt it together, than I would say, go for steel tubing. You won't be lighter with aluminium, because you need more and thicker aluminium.
The weight of the bolds and nuts is higher than you think.
Also after a while you get movement in the frame and you need to tighten it each time.

But as you really want to use aluminum, you can also use extruded profiles. You can bold it easily togheter.

Still, I would choose for steel.

The Man in the video was ad the eating where I was last year. His trike wasn't that light. It was still Missi g a lot of parts snd already heavier than my full build trike.
 
Back
Top