Author Topic: This is doing my head in!  (Read 134 times)

Adrian

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This is doing my head in!
« on: 10 Mar 22, 02:43 pm »
Help!
I think my brain is addled.
On the T/C I have a 10 tooth pinion.
This drives a 60 tooth sprocket on a layshaft.
Also on the layshaft is a second sprocket which drives the diff on the rear axle
The diff has a 45 tooth sprocket fixed to it.
How many teeth do I need on the second layshaft sprocket to end up with an overall ratio of 6.5:1
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Andy_B

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Re: This is doing my head in!
« Reply #1 on: 10 Mar 22, 03:10 pm »
Do you really want us to answer the first bit  ;D ;D ;D

jim

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Re: This is doing my head in!
« Reply #2 on: 10 Mar 22, 05:01 pm »
I'm thinking You will need a layshaft sprocket slightly smaller than the diff one.
If you can drive round corners, you're not going fast enough.

Jimr1999

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Re: This is doing my head in!
« Reply #3 on: 10 Mar 22, 05:02 pm »
41 or 42
... You can lead a horse to water, but a pencil must be lead.

Jimr1999

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Re: This is doing my head in!
« Reply #4 on: 10 Mar 22, 05:05 pm »
... By my maths, which is not infallible, a sprocket of 41.538 teeth would be an impossibility
 ;D
... You can lead a horse to water, but a pencil must be lead.

GeoffM

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Re: This is doing my head in!
« Reply #5 on: 10 Mar 22, 05:21 pm »
Well In think you need a 65 tooth sprocket on the diff.
10 driving 60 gives 6:1
60 driving 65 makes final 6.5:1 maybe? cheers, Geoff

Jimr1999

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Re: This is doing my head in!
« Reply #6 on: 10 Mar 22, 05:30 pm »
... To explain my logic.
You have a 6:1 ratio from TAV to jack shaft, a ratio we see as standard on the Stevenson formula.

You require a ratio of 6.5:1

 your ratio is 0.923 of the ratio you have. (6/6.5)

0.923 of 45 is somewhere between 41 and 42 (41.53)
... You can lead a horse to water, but a pencil must be lead.

Mark Underdown

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Re: This is doing my head in!
« Reply #7 on: 10 Mar 22, 08:00 pm »
Jims Correct,

I worked mine out in the following way which may help.

10 tooth sprocket on the TAV
60 tooth sprocket on the layshaft
41 tooth sprocket on the other end of the layshaft
45 tooth sprocket on the diff.

10x41= 410
60x45 = 2700

2700/410.53 = 6.585

I have a similar set up but a 40 tooth sprocket on the layshaft.





Adrian

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Re: This is doing my head in!
« Reply #8 on: 12 Mar 22, 11:45 am »
Thanks for the responses. I know what I am going to do now in sprocket terms.
I have sort of figured out what I'm going to make. It will be a skid unit of sorts which carries the engine and the layshaft and this will be welded to the chassis.
Anyway, sort of sorted it........
Thanks again.
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