Live Axle vs. Differential

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Functional Artist

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It's probably been covered before but, I'll ask anyway.

1. What are the pros & cons of using a live axle on a kart?

2. What are the pros & cons of using a differential? :cornut:
 

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mckutzy

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Live axle needs one brake disc, Diff needs 2(both wheels).....
Diff's are expensive, and have there own axles, so they restricted to the length they are made and in what ever configuration( stepped/not, keyed/not, w/wo threads ect)

Live axle is just what ever you need it to be, in what configuration(as in it can be made by oneself or at a machine shop easily)....
 

machinist@large

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A live axle gives you 100% power delivery to both wheels, irigardless of which wheel has the most traction. That's what makes steering an issue, because when you turn, the drive wheels need to be able to rotate at different speeds, depending on how tight the turn is.

A differential allows the drive wheels on the same axle to adjust to the radius of the turn smoothly, with one disadvantage; the wheel with the least traction becomes the outlet for all motion. Think one tire on dry pavement and one on solid ice; the one on ice will be the one that spins. Torque follows the path of least resistance, which unfortunately is a differentials Achilles Heel.

Look at it this way; if most or all of your riding will be on firm ground with lots of traction, the diff will most likely make you the happiest. On the other hand, if your idea of fun is nothing but mud and loose sand, the one piece straight axle is the way to go. Each has its limits. Pick and choose which way you plan to play......
 

chancer

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Steering is not an issue if set up correctly.
Or if in dirt or grass where you steer with the throttle anyway.

Live axle is nice and simple. Like a kart should be.
 

itsid

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FULL ACK with Pat and Eric here..

unless someone makes a autolocking diff for karts you'll have to choose the lesser evil ;)

Since I guess we talk about that Dingo up there.. live axle is what I'd choose.
it's narrow enough and set up well enough to steer just nicely with it.

A two seater heavy buggy might be a different (-ial ;)) story,
but this? Nah.. no reason to add a diff IMHO.

'sid
 

Functional Artist

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FULL ACK with Pat and Eric here..

unless someone makes a autolocking diff for karts you'll have to choose the lesser evil ;)

Since I guess we talk about that Dingo up there.. live axle is what I'd choose.
it's narrow enough and set up well enough to steer just nicely with it.

A two seater heavy buggy might be a different (-ial ;)) story,
but this? Nah.. no reason to add a diff IMHO.

'sid

Really! I got a problem wit my rear end & your makin' jokes.

"different (-ial ;))" thats a good one! :lolgoku:

I agree. :thumbsup: The Dingo doesn't need a diff.

I was just wondering if there was a reason why more karts weren't set up with a diff. (other than cost that is)

And gathering info/putting together ideas for the next potential build.

I always seem to be thinking about the next project or project's before I am even done with the one I am working on.

When designing/building a kart, especially an electrical powered kart, I try to maximize performance while minimizing energy consumption.

If both type of axles provide the same torque to the road, doesn't a diff accomplish both? No binding & less resistance.(on pavement or a hard surface)

The live axle set up seems to waste so much energy & momentum when turning. (on pavement or a hard surface)

With an ICE/live axle set up you just kinda use brute force to muscle thru everything & the clutch or TC takes the abuse when things don't add up.

An electric powered kart is different. Since they are usually direct drive (no clutch) the motor takes the abuse & the batteries take some stress too. All Bad! :mad:

I agree! A live axle is definitely more fun off road! :thumbsup:

But, your still wasting energy.
 

chancer

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Karts are just as simple as possible by design. It is just there nature.

Adding a differential and Rack and Pinion and suspension
In my Opinion is just NOT a Kart.
 

itsid

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.. I try to maximize performance while minimizing energy consumption.

If both type of axles provide the same torque to the road, doesn't a diff accomplish both? No binding & less resistance.(on pavement or a hard surface)

The live axle set up seems to waste so much energy & momentum when turning. (on pavement or a hard surface)

With an ICE/live axle set up you just kinda use brute force to muscle thru everything & the clutch or TC takes the abuse when things don't add up.

An electric powered kart is different. Since they are usually direct drive (no clutch) the motor takes the abuse & the batteries take some stress too. All Bad! :mad:

I agree! A live axle is definitely more fun off road! :thumbsup:

But, your still wasting energy.

I'm not sure..

in fact I rather doubt it tbh..

Yes, in corners the live axle has it's disadvantages.. BUT
there is not much additional load on the motor because of that
as opposed to going straight.
it'll wear the inside tyre which yes.. wasting energy.
But the torque is taken by the axle itself not the motor..
the motor only has the sprocket to work against and that's the only speed it cares about.

And with a differential you have additional friction no matter if your going straight or in a corner (second set of bearings needed to support the half-axles)
And as you'll certainly know differential gears wear down over time..
means they too remove energy from the system (just like a chain and sprockets)
but instead of just in corners, that energy is also 'wasted' on straights no matter if the differential has to do it's job or not;
not to mention the additional weight.

And in case one wheel slips (mud, wet cobblestone, leaves [october's visible from here])
you waste ALL the energy to a rotating wheel on a stationary kart.

I can't tell what adds up faster,
the constant minimal waste of a set of bearings and contacting surfaces of the diff gears or the rubber removal in corners, but I'm pretty certain that as soon as you have a free spinning wheel on the diff, you basically lost the energy competition already.

Exaggerated:
in quick corners, (like you see on racing karts) the inner rear wheel lifts off the ground, and there's no additional loss at all with a live axle.
doing the same with a diff and you'll have 100% loss

So if you're about energy efficiency, then the weight of the diff is the first thing you should care about ;)

'sid

PS bob, suspension, more than one seat, wheels larger than 14" and you have a buggy... a mini buggy perhaps, but a buggy...
add a diff and you have a fancy mini buggy ;)
But no worries mate.. buggies are welcome as well (but personally..please don't call it Kart ;))
 

B.M.800

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I have a couple differentials Id like to use for a kart.
My thought was by using a big 10-15hp and a TC I might get some wheel peel, even if only one side. it would still be cool.
 
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