All-Wheel-Drive Go-Kart!

[Hendersonjk]

Just an idea but couldnt you turn two mower axles on thier backs with a driveshaft inbetween ( or shaft driven atv) mount a sideways motor and put a sprocket on the drive shaft that runs the length of the cart?

 

[motor_head]

u joint hold up fine on the front of my 1 ton pickup it has u joints

 

[asdfasdf128]

how bout 2 sprokets and two sets of chains; one for the front wheels, and one for the back? (I have no official mechanical background so keep the bashing to a minimal if its an outlandish idea )

 

[Smurph]

how bout 2 sprokets and two sets of chains; one for the front wheels, and one for the back? (I have no official mechanical background so keep the bashing to a minimal if its an outlandish idea )

Depending on the overall length of my kart, I may have the engine turn a jackshaft that has two output sprockets (one for front, and one for back). The only problem will be routing the chain, keeping it from being floppy, and making guards for if/when it breaks. Shouldn't be too hard. You can see the mock-up I have on the video on page 3, and the images on page 2.

 

[honda02]

Run a chain tensioner to the non driven side of the chain, and depending on its location, as long as you have a straight shot from the drive to the diffferentials on the driven side of the chain, you can use spring tensioners to push it around cross braces and what not in your frame. We use a similar setup in gas powered AWD rc cars. engine to jackshaft, jackshaft runs two drive gears to front and rear diffs. I will say, they didnt turn to well at top speed, about 50 8]. but then again they dont weigh anything, and the slip angle on a vehicle like that is insane.

 

[Smurph]

Well the pictures as well as a lot of my design for a while was based on a low riding road machine. But I think my awd kart will be my off-road kart. I'm looking for something small, light, full suspension (Still haven't decided whether I want to do independent rear or not), and fast on dirt.

 

[honda02]

Something set up like this is gonna be hard to keep maintained if you're hopping dunes with it. Not to say it can't be done, but itll be difficult. I think deffiitely go with independent rear, since you're already buying cv joints. Also, look for a 2 stroke in the 250 range. That seems like your best bet as far as power and speed.

 

[Smurph]

Well. If I go with independent rear, that means two more CV axles, which cost money and weight. Not to mention the extra money for materials and fabrication which also adds to weight.

I'm in a wet humid area, so no sand dunes here. I do have a good bit of 4-wheeler trails through the woods I'd like to be able to get through. I have a 4-wheeler, but I just want to make my own machine.

I was thinking about a 250-300 2 stroke or a 350-500 4 stroke.

 

[Smurph]

New Idea I had for allowing this to remain shaft-driven and not divide power at the differential. The gears will come out of this huge differential I've bought. I'll need 4, I have 4. Score!

Notice that it will still use a chain. But that can be fully enclosed and the gear ratio there can be 1:1, or I can change the gear ratios there. The front and back will have to be identical, though.

Any ideas?

 

[joshpit2003]

ok, so I happened to run into this forum durring a google search.
I'm planning on building something similar and thought I could share some of my concerns.

firstly:
I have not yet determined whether a center diff is needed.
I DO know that in 4wd and awd vehicles the transfer case is typically an OPEN (or viscuous coupler) differential. Its for that reason they are "road safe" in 4wd and I believe it's because a t-case is LOCKED in Low-Range that they say NOT to drive on the roads in low range.

So... an open-diff t-case plays a role in drivability... how much of a role, I do not know. (all AWD vehicles that I know of have that open-diff t-case... take land cruisers for example... they have a "center diff" lock button in some models).

Secondly:
I believe putting car diffs into your go cart is complete over-kill. I've been searching the web for some smaller-scale diffs but cant seem to find much. my application only requires a 5 hp rated diff, but yours is closer to a quad ATV rating, so i would suggest you pull diffs off a quad.

Thirdly:
You may want to increase your front wheel steering... it looks like with the frame hitting the tires you will only have a HUGE turning radius.

ok, im gonna stop doing numbers now and just type:

I like your idea of using chains to power the front and rear axles, so i think it was a smart move to ditch the driveshafts.

my final suggestion would be to: JUST BUILD IT.
nothing will answer your questions better than a prototype.
i'm mainly saying this because it sounds like you want to build this thing cheap... so i'd suggest building it as cheap as possible and re-visit anything that doesnt work.

also:
you may want to build a scale model, heck just build it out of legos or something (i believe that they have differentials in some lego kits now). If you build yourself a scale model out of legos that could help to answer the center diff question.

if you can feel resistance turning the 2 diff. lego model and no resistance while turning the 3 diff. lego model then you know that a 3 diff. is necessary.

please keep us all posted on anything you do to test this. you've been doing a great job of keeping everyone up to date so far.

I cant wait to see this thing in the construction stage!

thanks.
-Josh!

 

[Smurph]

ok, so I happened to run into this forum durring a google search.
I'm planning on building something similar and thought I could share some of my concerns.

Welcome! It's a fun site, feel free to poke around.

firstly:
I have not yet determined whether a center diff is needed.
I DO know that in 4wd and awd vehicles the transfer case is typically an OPEN (or viscuous coupler) differential. Its for that reason they are "road safe" in 4wd and I believe it's because a t-case is LOCKED in Low-Range that they say NOT to drive on the roads in low range.

So... an open-diff t-case plays a role in drivability... how much of a role, I do not know. (all AWD vehicles that I know of have that open-diff t-case... take land cruisers for example... they have a "center diff" lock button in some models).

I'll be using open differentials. I may just use one in the middle. Although useful in road applications, this thing is gonna be meant to "tear A$$" haha. and It'll be alright if the two fronts and two backs are always locked to each other.

Secondly:
I believe putting car diffs into your go cart is complete over-kill. I've been searching the web for some smaller-scale diffs but cant seem to find much. my application only requires a 5 hp rated diff, but yours is closer to a quad ATV rating, so i would suggest you pull diffs off a quad.

I spent $30 on a mopar 8.75 differential. And yes. It is most certainly overkill. I don't have a clue why I thought a mopar differential wouldn't be too big. I think I'm just going to have to bite the bullet and get that one from northern tool.

Thirdly:
You may want to increase your front wheel steering... it looks like with the frame hitting the tires you will only have a HUGE turning radius.

The drawings I'm putting up are really proof of concept on the drive system. The more I think of it, the more I wanna put a full suspension on this and essentially build a mini-buggy. I'm not opposed to making it two-seater either. I'm still stuck behind the hurdle of not having a welder, or a 220 line in my garage, and I'm between jobs (start my next one in a week) and then we'll get the ball rollin'.

ok, im gonna stop doing numbers now and just type:

I like your idea of using chains to power the front and rear axles, so i think it was a smart move to ditch the driveshafts.

my final suggestion would be to: JUST BUILD IT.
nothing will answer your questions better than a prototype.
i'm mainly saying this because it sounds like you want to build this thing cheap... so i'd suggest building it as cheap as possible and re-visit anything that doesnt work.

also:
you may want to build a scale model, heck just build it out of legos or something (i believe that they have differentials in some lego kits now). If you build yourself a scale model out of legos that could help to answer the center diff question.

if you can feel resistance turning the 2 diff. lego model and no resistance while turning the 3 diff. lego model then you know that a 3 diff. is necessary.

please keep us all posted on anything you do to test this. you've been doing a great job of keeping everyone up to date so far.

I cant wait to see this thing in the construction stage!

thanks.
-Josh!

Thanks for the input. I should give the lego idea a try. I need to find some of those differentials. I used to LOVE legos when I was younger.

 

[mike75925]

go to the junkyard and find some of the old lawn mowers. i know a guy who has probably for of them. they have shorter axles than northern's, but you will be coupling u-joints on. shaft drive motorcycles have small u-joints and shafts. normally they have a 4 bolt u/j connector to the bikes output shaft.

 

[Kaptain Krunch]

since you already have a nice diff, why not step up your power and such and just make a buggy? you could find an old VW bug, use the engine, tranny, tires, etc, Im sure it would take some custom machined parts, but it would be bad ***.

 

[Thunderbird SC]

QUOTE Smurph Yeah, I've been thinking about it. There doesn't need to be a slip between front and back. I would like to always have 50% power up front to help me out. I think I'll just go to live axle between the drive sprockets.

Thats exactly how a Subaru drive train works in short, at least on the manuals, autos get a different way of dealing with the power delivery

 

[mike75925]

if running a posi rear end wouldn't it be better to have the bigger ratio to the front to help steer? say 45/55 or 40/60?

 

[newrider3]

No. It will fight like all hell if you're ratios are different. Do you ever see a 4x4 pickup with different ratios?

 

[freakboy]

ahaha unless your crawling its bucking......

 

[porsche930dude]

lol some of you need learn a bit more about 4 wheel drives before building one. Its true many cars built today have a "variable transfer case" which isnt fixed solid front and rear. But that has only come about in the last 10 years or so and is highly dependednt on computers to get the slippage right.
Iv aquired a set of spindles from the rear of a 4 wheel steering lawn tractor. I will be using a standard chain drive peerless diff same as would be used on the rear and probrobly just connect the front staight to the rear axle by chain. Third pic is just to show the type of diff ill be using. Itll be a little while before i adapt these to my kart but i thought id chime in.

 

[Smurph]

That last pic is pretty much what northern tool sells as far as differentials go. The first pic is similar to how I'm going to make my spindles. Check (I think) page 4 or 5 for some drawings that I've done.

Also. What would be a better way of learning about awd drive trains than trial and error through building one? I mean, I've spent a few months reading about them. It's not that hard.

Note, I'm not building a subaru here. Every single AWD car on the street will have a better setup than my KART. I'm building a rather primitive awd setup. Of course I'm not going to have an ECU controlling which wheel gets my power, I'm not going to have a lot of the things that CARS have...

Also remember that I don't have that big of a problem not putting a differential between front two wheels or back two wheels. As I mentioned above, they help a lot on cars, but my kart won't really be wide enough for the difference in the circles that the inner and outer wheels create during a turn to matter that much.

 

[porsche930dude]

with the size engine your planning on a little added weight wont be a problem. If your going mainly offroad with average kart sized tires you probrobly could get away with no diffs in the system at all. But one in the front would be helpfull in turning on hard surfaces and at low speeds. If you want to learn about how a 4wd ststem works i suggest you look an an older vehicle like a 60's or older jeep or a 80's chevy. not a modern subaru which is much more complicated than it needs to be. theres a good selection of cheap good quality peerless diffs here http://www.motorizedwheelbarrow.com/Details.asp?ProductID=2664
if you want to build it with suspention i suggest a simple system like this. would work front and rear