4WD Karts

[Kartorbust]

So basically you used something like this 1 input 2 output right angle gearbox? https://www.surpluscenter.com/Power...-RA-Gearbox-3-Shafts-All-Keyed-13-1423-3K.axd

Basically one in the front and rear, ran a drive shaft to the inputs with a sprocket on the driveshaft to the engine? Is that what you did or am I missing something here?

 

[JTSpeedDemon]

Thank you for starting to explain it!
Some of the folks on here were just a little suspicious since it's such a big idea, it's almost like believing in Bill's Miracle Tonic.
I'm just trying to summarize what other people were thinking basically. Don't shoot the messenger.

That is a very interesting idea, with the two output gearboxes! I've never thought of that to use kinda like a diff.

 

[Functional Artist]

Correct me, "if" I'm wrong
...but, that's just a gear box NOT a differential.

Basically a "live axle"
...it just has the input 90* from the output shafts

 

[JTSpeedDemon]

Correct me, "if" I'm wrong
...but, that's just a gear box NOT a differential.

Basically a "live axle"
...it just has the input 90* from the output shafts

I know, I know.
For lack of a better word, I'll just call them gearboxes.

 

[4WDKarts]

Gearboxes

You folks are getting some really good conversation going here with the gearboxes. Let me throw in a couple of comments, and I'll let you folks take off on it. There are two types of gearboxes that work on these karts. One gets the job done, but the 2nd has an advantage. As a member said it's just 90 degrees and 2 shafts. You have a live axle automatically. The first type of gearbox is s miter gearbox. They are always 1:1 ratio. The 2nd type is called a bevel gearbox. Typically this gearbox has a reduction of 1.5:1, 2:1 and sometimes you can find 3:1. The reason why I would want this gearbox is because I can lighten the 1st and secondary drive. The final reduction comes at the axle. So, the torque is lower. Remember we have to get to a 21:1 ration at least. The live axle is an issue when it comes to the front drive axle. Whenever you turn the front wheels they rotate opposite of each other. So they appose each other when turning. This makes it hard to turn on concrete, pavement or any surface the tires can hook on to. Now that you have the center driveshaft idea, figured out some ways to disengage the front differential, axle and driveshaft.

 

[Functional Artist]

You folks are getting some really good conversation going here with the gearboxes. Let me throw in a couple of comments, and I'll let you folks take off on it. There are two types of gearboxes that work on these karts. One gets the job done, but the 2nd has an advantage. As a member said it's just 90 degrees and 2 shafts. You have a live axle automatically. The first type of gearbox is s miter gearbox. They are always 1:1 ratio. The 2nd type is called a bevel gearbox. Typically this gearbox has a reduction of 1.5:1, 2:1 and sometimes you can find 3:1. The reason why I would want this gearbox is because I can lighten the 1st and secondary drive. The final reduction comes at the axle. So, the torque is lower. Remember we have to get to a 21:1 ration at least. The live axle is an issue when it comes to the front drive axle. Whenever you turn the front wheels they rotate opposite of each other. So they appose each other when turning. This makes it hard to turn on concrete, pavement or any surface the tires can hook on to. Now that you have the center driveshaft idea, figured out some ways to disengage the front differential, axle and driveshaft.

Looks like OP is looking for us to figure it out, for him.
...still not a single pic, even one with a kart (accidentally) in the back ground

Maybe he's just been thinkin' about 4WD karts since the 70's

Here is a quote from his other thread
"4WD Karts require a lot of torque. The reason why is because four wheels in mud or suction mud is very resistive. You also have to take into account the weight of the kart and the driver. I'd say the reason why we don't have 4WD Karts on the market today is because of the complecated drive train. If you don't know mechanics of materials or don't understand metal alloys you may be in a trial and error type of deal.

You will need to use front and rear differentials. Cost is a major contribute r. Chains will not handle the torque required or make the drive train simple. The first thing you have to figure out is weight. This determines everything."

1.) Differentials & gear boxes are NOT the same thing
…& do NOT produce/provide the same function or effect (not even close)
2.) How is anyone gonna figure the weight until they have at least a "rough" idea of what parts/materials their gonna use?
...sounds like circular logic, to me

 

[ezcome-ezgo]

I want to sell you a car. Problem is, I need a ride to where it is located.

 

[Tpdingo]

I want to sell you a car. Problem is, I need a ride to where it is located.

Simple, you push it.

That would also make it 4WD, since no matter which wheel is on the ground it still gets powered.

 

[4WDKarts]

Push?

Not sure what you mean by that, but yes you have real 4WD. Most vehicles on the road today that are 4WD really aren't true 4WD. The gearboxes that I mentioned work just fine on 4WD karts. Although functionally they don't have spider gears in them they do work great for giving you a live axle at both ends and transferring the power to the front axle.

Oh and for the member who made the smartass remarks about I been thinking about this since the 1970's! Well your right! Since I built the first one in 1978 I have been thinking how to improve and make them better. I was was 15 yrs old at the time! How old are you now? If you are older than 15 does that mean a 15 year old has to figure it out for you?

If some of you members just want to make negative comments to me you can save your BS for someone else. I'm only interested in those who have real questions and that are interested in how to build one and what works.

 

[mckutzy]

OK... I dont know how... The Idea occurred to me but I have no Idea where to start......
Lets see what you built, Maybe I can come up with something similar...

 

[4WDKarts]

McKutzy

Hi, if you are serious about building one we can form an off-line communication. I will have pictures in a few more weeks of my new designs. A couple of things you are going to need to be able to do is some basic math, maybe be able to weld and have a machine shop and a metal shop you can trust to make some parts for you.

 

[Kartorbust]

Have you at all tinkered with high/low range gearbox designs over the years at all? Mainly one that you can select mostly on the fly and not have to stop and swap a chain around to get a different ratio.

 

[Tpdingo]

Have you at all tinkered with high/low range gearbox designs over the years at all? Mainly one that you can select mostly on the fly and not have to stop and swap a chain around to get a different ratio.

I mean if I were building one, I would go immediately for the 5 speed lifan that CarsAndCameras used. If they made a 4 speed + reverse motor, that would be even better, especially given the obvious use case for the 4WD go kart. Also, 16HP would be quite beneficial over say 6.5HP given the drive train losses.

Plus 16HP launches on all 4 wheels....well that sure to put the "life" in Lifan.

 

[Kartorbust]

I mean if I were building one, I would go immediately for the 5 speed lifan that CarsAndCameras used. If they made a 4 speed + reverse motor, that would be even better, especially given the obvious use case for the 4WD go kart. Also, 16HP would be quite beneficial over say 6.5HP given the drive train losses.

Plus 16HP launches on all 4 wheels....well that sure to put the "life" in Lifan.

The thing is though, I've looked at those Lifan 5 speeds and the rare 4 speed with reverse that Red Beard had, but I'm not that big into shifting through gears. I'm mainly looking for a low/high range option. Have a low end crawling ratio, then a high range cruising. Baja SAE teams usually either build their own, or get one from eBay. The ones that build them, are highly secretive on anything really. I'm still waiting for Chris (Rather B Welding) to finish his 3 speed with reverse gearbox, to see how he gets it to work.

The other one I've looked at is similar to Chris' but its probably the one he copied, http://www.thepixelpump.com/widdershins/how-to-2speed-transmission.php

However the drawings suck to look at...not very thought out. But something like this is cost effective and can be modified for my specifications. Having a final drive of 13:1 with gear reduction, on top of the extra 2 or 3:1 with a CVT would be an excellent crawler, then shift to say, 8:1 for cruising. For myself, I'm leaning towards a Baja SAE build for myself, since they follow a decent set of rules for safety.

 

[JTSpeedDemon]

The thing is though, I've looked at those Lifan 5 speeds and the rare 4 speed with reverse that Red Beard had, but I'm not that big into shifting through gears. I'm mainly looking for a low/high range option. Have a low end crawling ratio, then a high range cruising. Baja SAE teams usually either build their own, or get one from eBay. The ones that build them, are highly secretive on anything really. I'm still waiting for Chris (Rather B Welding) to finish his 3 speed with reverse gearbox, to see how he gets it to work.

The other one I've looked at is similar to Chris' but its probably the one he copied, http://www.thepixelpump.com/widdershins/how-to-2speed-transmission.php

However the drawings suck to look at...not very thought out. But something like this is cost effective and can be modified for my specifications. Having a final drive of 13:1 with gear reduction, on top of the extra 2 or 3:1 with a CVT would be an excellent crawler, then shift to say, 8:1 for cruising. For myself, I'm leaning towards a Baja SAE build for myself, since they follow a decent set of rules for safety.

Or you could do a two speed mechanism, like on the C&C Colt minibike:
https://www.youtube.com/watch?v=quiVvew4tcA&t=0s



Anyway, let's not derail the thread guys, it's about 4WD go karts.

 

[4WDKarts]

Good Discussion About Ratios & How to Get Them

As I've said before you really want to get to the 21:1 ratio in low and then be able to change to about 7:1 or so. This gives you the "crawler" speed as you called it, but also gives you a high speed. Depending on what size tires you have it will come out around 5 mph in low and about 20-25 mph in high.

If you use a Comet Torque Converter with the 7" driven it has approximately a 2.43:1 to 3:1 ratio variance. So, if the rest of your drivetrain equals 7:1 then you have the variable reduction you need. Hope this helps!

---------- Post added at 08:23 AM ---------- Previous post was at 08:13 AM ----------

Please be aware that increased horsepower also means increased torque. When you change horsepower you will need to increase shaft diameters. The drivetrain changes due to the torque demands.

 

[Flyinhillbilly]

I just caught up on this thread and I just want to say that I’m still interested in seeing what you’ve got cooking. The u joints you are talking about are the same ones I was looking at when I was thinking about this. I’ve used them in race cars and they’re incredibly strong. The rest of your drive train plans has me intrigued.

 

[DangrDan]

This sounds really cool

Looking forward to pics and seeing how your builds progress


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