Ok, so I've done some searching and found posts about bolting a spocket in place of the crown/ring gear/wheel and possibly encasing it or leaving it open but.....

Can someone explain how these work as a diff as opposed to being fixed? i.e. both wheels turning with the same force.

From the examples I've found I can't see a planetary gear. Can someone explain it to me or point me at an idiots guide of some sort?

I really like to take a Sierra diff, pull it apart, bolt a sprocket on and whack it in so what would I keep and what would I disgard?

My limited diff knowledge is being led by this Wikipedia image...

I may be interpreting your description incorrectly but it sounds like you will be using the diff exactly as it was intended except rather than the crownwheel driving a perpendicular, tapered gear to the prop it will simply drive the chain directly...this still having the full differential functionality?

All i would say is do your sums when deciding what sized sprocket to put on otherwise you may end up with a very strange diff ratio!

In a nutshell all you'd need to do is remove the gear that the prop connects to (not in pic) and modify the crownwheel.

[Edited on 15/5/2008 by Trems]

[Edited on 15/5/2008 by Trems]

Have a look HERE and HERE for some ideas.

HTH

Neil

You simply remove the crownwheel & replace with a bike sprocket, the rest of the diff stays in place & connects to driveshafts as usual - I think there is/are some pics in my archive.

Ok so I get it now... I was missing the fabricated housing most have around the other gears.

So as per the borrowed photo below, it's a case of...

pull a Sierra diff apart
make some bearing holders (blue bits in pic)
make a gear housing to contain lubricant (shiny silver tube in pic)
make up "sides" plus any supports etc
assemble



Chain driven diff

Sounds easy... not.

[Edited on 16/5/2008 by andyd]

you could always do it like on a kart, and have a solid rear axle, with a sprocket on it

quote:

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Originally posted by Davey D
you could always do it like on a kart, and have a solid rear axle, with a sprocket on it

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Hi, This is exactly the problem i see. How do you stop the chain from jumping off of the sprocket? If mounteed in the back of the car (as i plan) then the diff will be lower than the engine, so when you hit a bump, the chain falls off??

I thought about a solid axle, but with good old uk roads, im a bit concerned about vibration and chassis fractures from speed bumps etc.

Hanging the arse out, and being a bit of a handful isnt really a worry, just the losing power or breaking down bit...

How are you gettin on with yours?

I'm "on hold" at the moment due to "life" getting in the way.

To discuss one of your fears though...

My engine will be hard mounted as will my diff so once the correct distance is set to get the required chain tension it'd be nearly impossible to get the chain to jump off. I say impossible... I'm sure someone has made it happen but I doubt that's "normal road conditions".

I see, though "Normal Road Conditions" where i live are normally Shocking to start with!!!!
I see how i could fix the diff, if going for IRS, but i was thinking of a "Go Kart" axle... What a laugh that would be!! My fears are that the vibraion would damage the chassis, or make stuff fall off!!