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Speed winch gear ratio for 6.5hp engine

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Bmonsensen
Posts: 4 - Karma: 148
So me and my friend have been working on building our own speed winch for a while now. We are using a 6.5hp engine with a 9 tooth centrifugal clutch. We have already tried two gear ratios. We used a 30 tooth sprocket on the axle to start but the max speed was less then we hoped. We then tried a 16 tooth sprocket, but the engine didn't have enough power to accelerate us fast enough to be of use. To save us having to buy more parts, and modify are winch more than whats needed, does anyone know what the optimal gear ratio would be?
Dec 10 2012 4:39PM
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JeremyClarkson
Posts: 1599 - Karma: 1,934
All I know about this stuff is if you're not getting enough power then you need more tourqe which means you need a higher gear ratio.
Dec 10 2012 4:47PM
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loganimlach
Posts: 5132 - Karma: 14,054
i think that a 9 tooth is a little on the low end for your clutch. I use a 12 tooth clutch and a 36 tooth sprocket with a 7.5 horse and it works great. you gotta find a happy medium in your ratio, from 30 down to 16 is a huge gap when you're talking torque ratio. if you dont want to change out your clutch, id say got for a more intermedite rear sprocket (22-24 range).
Dec 10 2012 4:54PM
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Adam_Berton
Posts: 4 - Karma: 46
loganimlachi think that a 9 tooth is a little on the low end for your clutch. I use a 12 tooth clutch and a 36 tooth sprocket with a 7.5 horse and it works great. you gotta find a happy medium in your ratio, from 30 down to 16 is a huge gap when you're talking torque ratio. if you dont want to change out your clutch, id say got for a more intermedite rear sprocket (22-24 range).


In diameter how big is your spool because that can effect the winches power?
Jan 7 2015 3:20AM
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aob
Posts: 134 - Karma: 81
I used a 5-1 ratio with a torq a verter and a spool with about a 2 ft diameter. My engine is a 12hp. I think you may need a bigger engine. Harbor freight sells decent ones for about 250-300
Jan 7 2015 3:57AM
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loganimlach
Posts: 5132 - Karma: 14,054
2 ft diameter spool?! fuck me, lets see some pictures of that beast. 5:1 @ 12 hp and that big a spool, how fast can you go? like 60 mph?
Jan 7 2015 7:08AM
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FunkySane
Posts: 616 - Karma: 1,203
Watch and learn.
https://www.newschoolers.com/videos/watch/745030/Nipwitz---Brain-Massage-MOVIE
Jan 7 2015 7:12AM
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JGWI
Posts: 2842 - Karma: 7,812
Big in the front, small in the back and a whole lot of RPM's...


Will probably get you nowhere. But if it did work you could get launched to the moon.
Jan 7 2015 12:52PM
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