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Old 12-17-2019, 02:11 PM
5814SpeedCo 5814SpeedCo is offline
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Default Gear/Sprocket Ratio....

Is the preferred gear ratio for an off-road kart 6:1? Or is a 5:1 acceptable?

The last thing I need to get other than brakes are sprockets. I want to do an axle setup kind of like Grind Hard Plumbing did on their Barbie jeep to help protect the axle and the chain. So I want a relatively smaller diameter sprocket and used the speed calculator on here to configure a 5:1 ratio on the kart.

Is this to much for an off-road kart that will be more for low to medium speeds rather than maxing it out? Should I be worried about going through belts as well with something of what is mentioned below? Well occasionally I'll let her rip!

On the calculator I selected 22" tires, 3800 RPM's for a stock Predator 212, 40T sprocket on the axle and an 8T sprocket on the torque converter. Speed came out to 50mph as well.
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Old 12-17-2019, 03:24 PM
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I mean that gearing should provide a good low end torque,I'd get a cvt set up tho would preform way better than a centrifugal clutch
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Old 12-17-2019, 04:01 PM
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Originally Posted by rushking19 View Post
I mean that gearing should provide a good low end torque,I'd get a cvt set up tho would preform way better than a centrifugal clutch
I have one, would that still be a good ratio or would something be better?
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Old 12-17-2019, 04:01 PM
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Nonono, 5/1 is about the minimum for a 12" tire street kart!!
With 22" tires off road, I'd say the minimum is a 10/1 ratio.
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Old 12-17-2019, 04:12 PM
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Actually I'm running 6.6:1 on 22 inchers. But I have a 7" driven on the TAV. But I'd at least get a 60t. Maybe the 66t option on the split sprocket gopowersports sells.
https://www.gopowersports.com/split-sprocket-41-420/

JT, you're thinking with a centrifugal clutch in mind, he said he has a torque converter.
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Old 12-17-2019, 04:35 PM
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I know he has a TAV, there's still only so much a CVT can do though.
Are you running your kart off road?
Also he's only planning for a stock Predator 212.

---------- Post added at 05:35 PM ---------- Previous post was at 05:32 PM ----------

And we do need to know a little more about the vehicle, like is it a Yerf Dog Spiderbox or a Dingo 285?
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Old 12-17-2019, 05:51 PM
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It will be running off road and only gearing for stock now, I have a SV650 buggy build for going fast.


This is the kart that is getting a makeover. I k ow some of you are purist but oh well!!!
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Old 12-17-2019, 05:58 PM
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Alex (itsid) made this app for smart devices and it's a life saver. Put the settings to standard (as 400kg and 400lbs are way different) and go at it. http://app.kartcalc.net/#home
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Old 12-17-2019, 06:05 PM
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Ehh, that's your Carter Bros kart, right? Never really cared for them. Not that pretty and have a tendency to have weird sized parts(i.e the clover hub).
It would still need to be geared down for 22" tires.
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Old 12-17-2019, 07:00 PM
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It is, it's awkward and really dislike the jackshaft setup. I have a full ATV suspension that I want to graft on to it.
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Old 12-17-2019, 08:30 PM
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Quote:
Originally Posted by JTSpeedDemon View Post
I know he has a TAV, there's still only so much a CVT can do though.
Are you running your kart off road?
Also he's only planning for a stock Predator 212.

---------- Post added at 05:35 PM ---------- Previous post was at 05:32 PM ----------

And we do need to know a little more about the vehicle, like is it a Yerf Dog Spiderbox or a Dingo 285?
Lol, "there's only so much a CVT can do". Those things can pack a serious punch if your not careful. And I'm doing 5:1 on a 6" and 18" tires...they really do kick some torque when you ask for it. You watch CarsAndCameras, you've seen the difference. It's quite impressive for basically 5 parts.
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Old 12-18-2019, 06:04 AM
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Could you get us the sizing numbers off the tire sidewall? Those don't look like 22s to me. Anyway, I'd say that kart'll move well enough with 6:1 gearing and a tav, with 22" tires. My kart is a lot bigger than that one, well, longer and taller.
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Old 12-18-2019, 07:10 AM
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Quote:
Originally Posted by J.S.@SMS View Post
Could you get us the sizing numbers off the tire sidewall? Those don't look like 22s to me. Anyway, I'd say that kart'll move well enough with 6:1 gearing and a tav, with 22" tires. My kart is a lot bigger than that one, well, longer and taller.
Those are not the tires I'm trying to gear for. I am going to a live axle setup with custom made front and rear hubs to use trx400 wheels that will both be 22" front and back. Also fabricating on the front end to go to double A-arm suspension.
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Old 12-18-2019, 07:45 AM
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If you're going to add suspension too, gearing down is a must due to the weight.
At the very least go somewhere upwards of 7 to 1. Otherwise you may end up in the woods with a smoked belt.
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Old 12-18-2019, 08:37 PM
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Gearing it lower will make the belt last longer. 8:1 might be better, but are you using a 212 with a 40 series?
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Old 12-18-2019, 09:27 PM
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On my 20” tires I geared it 60/8 with a 7” driven to get the torque that I felt was acceptable. Kart will climb anything and still hit 37mph.
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Old 12-19-2019, 12:29 PM
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Quote:
Originally Posted by Kartorbust View Post
Gearing it lower will make the belt last longer. 8:1 might be better, but are you using a 212 with a 40 series?
I have a 30 series.
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