CraigJ
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| posted on 24/6/09 at 06:23 PM |
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HELP any one good at maths......Sprocket calculations
I need to work out what size sprockets to use in my project but unlike normal it will be 3 sprockets not 2 and i need to know how to work it out.
Ideally the final ratio needs to be 3. so normally it would be a 14 tooth front and a 42 tooth rear but now im fitting two engines i need to work out
how to do it. If i could get a standard 14 tooth front it would be fine but they dont make a 14tooth for the zx10 so im stuck, the smallest i can find
is a 15 and the rear has to be a 42 for space issues.
So:
15 front - Middle ??? - Rear 42
Answer must equal around 3 to 3.2 to be ideal.
what needs to go in the middle? i have no idea how to work it out.
[Edited on 24/6/09 by CraigJ]
[Edited on 24/6/09 by CraigJ]
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JoelP
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| posted on 24/6/09 at 06:26 PM |
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you wanted 14:42.
You've had to use 15:42
So you need a further 1/15 reduction.
So the middle cogs, two linked together, need to reduce it by 1/15th. You could do this by having a 15 tooth input cog and a 14 tooth output cog.
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CraigJ
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| posted on 24/6/09 at 06:32 PM |
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So if i go 15 front, 14 middle and 42 rear it will give me a final ratio of 3?
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Steve G
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| posted on 24/6/09 at 06:35 PM |
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You're planning 2 short chains rather than one longer one?? YI think you may have problems if thats the case as they're going to get very
hot and wear out in no time flat. Worth checking this out before you go any further.
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JoelP
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| posted on 24/6/09 at 06:37 PM |
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quote:
Originally posted by CraigJ
So if i go 15 front, 14 middle and 42 rear it will give me a final ratio of 3?
no, for the middle cog(s) to do anything, you need two chains, else the middle one is just an idler.
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matt_claydon
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| posted on 24/6/09 at 06:38 PM |
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Nope, you need a 14 and a 15 on the same shaft in the middle.
If the two on the centre shaft are both the same, the ratio will just be based on the engine sprocket vs the axle sprocket - the idler sprockets have
no effect. If you want to use the centre sprocket to change the overall drive ratio you need different sprockets on input and output sides.
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designer
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| posted on 24/6/09 at 06:46 PM |
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On here is exactly what you need.
http://www.briery.com/vortex/index.html
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CraigJ
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| posted on 24/6/09 at 06:53 PM |
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This right?
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CraigJ
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| posted on 24/6/09 at 06:59 PM |
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Just done a little working out and i need the final ratio to be 3.2. this will give me a top speed of just under 130mph. which is what i need as my
tyres are only rated at 130 lol.
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JoelP
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| posted on 24/6/09 at 07:01 PM |
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that gives you a final drive of exactly 3. Basically the 15s cancel out, leaving just the 14:42, which is 3.
if you have a 13:42 is 3.23, so if you use a 13 tooth cog on the middle of the middle shaft you're sorted.
[Edited on 24/6/09 by JoelP]
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flak monkey
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| posted on 24/6/09 at 07:03 PM |
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One of these?
http://www.speedtechpower.com/servlet/the-133/Vortex-Sprocket-Front-14T/Detail
Also lists the other bikes which the same sprockets fit, so might ease your search.
[Edited on 24/6/09 by flak monkey]
Sera
http://www.motosera.com
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02GF74
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| posted on 24/6/09 at 07:05 PM |
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yes.
think about it.
the engines turn one rev and the gears -drive 15 and 15 idler - will mean the idle shaft does one turn - in other words it is like the idler was not
there. In effect you have put the 14 T on the engine.
finall ratio 42/14 = 3
or mathematicall 15/15 * 42/14
in fact as long as the engine and idler have the samme number of teeth e.g. both 16 or both 30 or whatever, the end result will be the same.
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flak monkey
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| posted on 24/6/09 at 07:09 PM |
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And here's some in the UK
http://www.moto-racing.co.uk/cat--Kawasaki-ZX6R-ZX6RR-Ninja-Race-Sprockets--All+ZX6+Race+Sprockets.html
Sera
http://www.motosera.com
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CraigJ
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| posted on 24/6/09 at 07:24 PM |
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Right guys i now understand. thanks for the help.
Flak monkey:
Forgot to say the engine is the late 80's model not the new 1.
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flak monkey
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| posted on 24/6/09 at 07:27 PM |
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quote:
Originally posted by CraigJ
Flak monkey:
Forgot to say the engine is the late 80's model not the new 1.
Ahh bugger, sorry 
Sera
http://www.motosera.com
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