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Old 08-28-2019, 07:29 AM
gibbywmu gibbywmu is online now
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Default American Challenger - Convert to Live Axle or Upgrade Gearing?

Hi All,

I'm trying to get some suggestions on what to do with this kart I bought for my son. I had this in another topic but I'm not getting the help/feedback that I thought I would .

It doesn't have quite the "oomf" from take off like the standard centrifugal (10T) to a 60T sprocket, I think because of this gearing. This system has a dual chain setup.

My gearing is as follows - 10T (clutch - brand new) to 23T (jackshaft).....then 9T (jackshaft) to a 22T bottom sprocket.

I believe this is a ratio of 5.62:1?

Now.......does anyone think it would be easier to just change to a direct drive system and "delete" the jackshaft out (or can it be done)? OR........does it make sense to do a live axle convert on this kart? I know that can be alot of work. I'm actually waiting on a welder, but I am inexperienced at it. I do like the TC setup though.

The bottom 22T sprocket is the drum/sprocket combo. I don't think they make a 60T sprocket w/drum.

Looking for some good advice...........pics attached. If anyone needs more pics or info I'd be happy to provide.

Thanks!
Attached Thumbnails
brakedrum.jpg   Clutch2.jpg  

Predator2.jpg   Illustration.jpg  

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  #2  
Old 08-28-2019, 07:47 AM
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landuse landuse is offline
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Get a larger 23T jackshaft sprocket. That would be the easiest at the moment
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Old 08-28-2019, 08:32 AM
gibbywmu gibbywmu is online now
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Not sure if I'm following.......... I'm all about what is the least amount of work for the best result! Just so I'm clear........you're referring to replacing the 9T to a 23T correct?

If I replace the 9T with a 23T, then according to my calculations that gear ratio would be:

23/10 on the top = 2.3
22/23 on the bottom = 0.95
which equals = 2.185.............that can't be right???? Am I missing something?


Someone chime in if I'm wrong......but it seems like putting an 8T on the jackshaft would make more sense?

23/10 = 2.3
22/8 = 2.75
equals = 6.325
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Old 08-29-2019, 09:41 AM
gibbywmu gibbywmu is online now
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Guys,

I know there are smart people on here.......can anyone else provide any insight? Not getting the responses I thought I would (based on other posts I've read in this forum and lots of feedback for others).... I know this forum is full of helpful people. Just want a better idea if a live axle conversion or gear change is worth it on this kart................or should I just swap for one that already has a live axle..........
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Old 09-08-2019, 05:27 PM
wenee9w wenee9w is offline
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Engine size? Big kart? Single or 2 seater? A lot of factors go into your question. Looks to me like the kart manufacturer is trying to make up for a under powered heavy kart.
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Old 09-09-2019, 12:32 AM
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Quote:
Originally Posted by gibbywmu View Post
Not sure if I'm following.......... I'm all about what is the least amount of work for the best result! Just so I'm clear........you're referring to replacing the 9T to a 23T correct?

If I replace the 9T with a 23T, then according to my calculations that gear ratio would be:

23/10 on the top = 2.3
22/23 on the bottom = 0.95
which equals = 2.185.............that can't be right???? Am I missing something?


Someone chime in if I'm wrong......but it seems like putting an 8T on the jackshaft would make more sense?

23/10 = 2.3
22/8 = 2.75
equals = 6.325
Sorry, I think I confused you there. I was saying that you can replace the 23T jackshaft sprocket that you currently have with something larger, like a 36T. This would give you a lower gear ratio and more torque at take-off.

If we do the maths, it would be something like this:

36/10 * 22/9
= 8.78:1

I am not too sure how tall your rear tyres are, but that is usually the limiting factor for sprocket size and why people use jackshafts to get a lower gearing. If you didn't have a jackshaft, to get the same gearing that I just calculated, you would need a clutch of 10T and a axle sprocket of 88T (not sure if 88T is available, but you get the idea). An 88T sprocket might be larger than your rear wheels, which would make it useless. This is why people then use jackshafts to get the same gear ratio.

Going to a live axle is not really going to do much for you regarding your gear ratio
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Old 09-09-2019, 09:58 AM
gibbywmu gibbywmu is online now
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Thanks landuse! I think I'm just going to leave everything "as is" for now. My son has just started riding, so I'd like him to get used to driving and all that comes with it before I start messing with anything else...........and spending more money! LOL

Wenee,

This is a Manco American Challenger Fox Go Kart (2 seater), with a 212 Predator on it. All tires are 14".
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Old 09-11-2019, 12:23 AM
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landuse landuse is offline
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Quote:
Originally Posted by gibbywmu View Post
Thanks landuse! I think I'm just going to leave everything "as is" for now. My son has just started riding, so I'd like him to get used to driving and all that comes with it before I start messing with anything else...........and spending more money! LOL

Wenee,

This is a Manco American Challenger Fox Go Kart (2 seater), with a 212 Predator on it. All tires are 14".
You could also get smaller diameter tyres to get a lower gear ratio. You would then not have to mess with the sprockets at all
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Old 09-11-2019, 08:09 AM
gibbywmu gibbywmu is online now
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That's a great idea too landuse...............recommendations on tire size? I also thought about swapping the 9 tooth to an 8 tooth.
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Old 09-12-2019, 07:40 AM
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Quote:
Originally Posted by gibbywmu View Post
That's a great idea too landuse...............recommendations on tire size? I also thought about swapping the 9 tooth to an 8 tooth.
You are going to have to look around for tyres. Maybe 11"? Depending on the chain pitch you have, 8T sprockets are very very very hard to come by
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