Gear Ratio? Big Kart, Big Tires, Small Engine

[bob58o]

Brand new to karting and forums and wrenches.

Putting a Predator 212 Hemi on a fairly large off road, 2 seat buggy/kart. Governor removed, Upgraded Intake, Exhaust, Carb Jet. Stock springs, stock connecting rod, stock flywheel.
Ordered a Torque Converter kit with a 12T #35 and a 10T #40.
What's would be a good gear ratio if mostly used on flat asphalt??
What's a good gear ratio if used on flat to lightly hilly ground??
This used to be powered by a 200cc 2-stroke and has a 40 tooth sprocket.
I'm putting a 212cc 4 stroke on this heavy frame with a torque converter and 16" Tires.
Should I go 10T #40 / with 60T on axle?? Or 72T?? or 54T??

Wanted to use Lifan 420 but it wouldn't fit between the rear suspension easily. Not sure this engine will push this kart

 

[chancer]

Flat Asphalt with 16" tires and a TC 6:1 should be fine.

 

[Tonyzsi]

I agree. I have a YD3203 that is supposed to weigh just over 300 lbs. and I usually ride it on the street with my 2 kids so our total weight is around 300. I have a similarly moded Predator 212, my governor is still in and I'm running a 6.667:1 (9T JS x 60T axel gears) on 20" tires. The kart usually runs around my flat neighborhood @ 26 mph, but I have gotten a couple extra mph now & then. I'm going to 18" tires to get even more low end which I would then match your 10T/60T w/ 16" tires. I expect my ~600 lb. kart-(w/ riders) to zip around great with the 18"s and the same ratio you'll have.
Have fun!
-T

 

[bob58o]

Thank you. This is the king of info I was looking for. Greatly appreciated

---------- Post added at 09:36 PM ---------- Previous post was at 09:34 PM ----------

Thanks. I was going to start with 6:1 and see how it went, but I figured I'd ask first before buying

 

[landuse]

6:1. Nothing higher

 

[bob58o]

I agree. I have a YD3203 that is supposed to weigh just over 300 lbs. and I usually ride it on the street with my 2 kids so our total weight is around 300. I have a similarly moded Predator 212, my governor is still in and I'm running a 6.667:1 (9T JS x 60T axel gears) on 20" tires. The kart usually runs around my flat neighborhood @ 26 mph, but I have gotten a couple extra mph now & then. I'm going to 18" tires to get even more low end which I would then match your 10T/60T w/ 16" tires. I expect my ~600 lb. kart-(w/ riders) to zip around great with the 18"s and the same ratio you'll have.
Have fun!
-T

Looking to buy sprocket hub, sprocket and chain.
Will either #35 OR #40 be ok, or is the 35 too small???

I was concidering a ~$20 hub with 5.25" bolt circle
and a $15 two-piece #35 72T sprocket to use with the 12T #35 TC sprocket???

Will that be ok??

 

[ezcome-ezgo]

72T/12T = 6/1 or 6:1 ratio. See Landuse reply above. #35 chain should be ok with an unmodified Pred, IMO.

 

[bob58o]

72T/12T = 6/1 or 6:1 ratio. See Landuse reply above. #35 chain should be ok with an unmodified Pred, IMO.

Thanks. Ya this time I was wondering about the parts holding up. The 212 will be ungoverned, with intake, exhaust and carb jet upgraded. Still think 35 works?? And any input on the cheap two-piece sprockets??

 

[ezcome-ezgo]

A little research tells me that the max working load of #35 chain is 400-450lbs, #40 chain is roughly twice that. If your kart is close to 300#, go with the #40.

Not familiar with "cheap two-piece sprockets". Where are you sourcing these?

 

[bob58o]

A little research tells me that the max working load of #35 chain is 400-450lbs, #40 chain is roughly twice that. If your kart is close to 300#, go with the #40.

Not familiar with "cheap two-piece sprockets". Where are you sourcing these?

Thank you so much.... I might want to get a 420cc later.
The sprocket I was thinking about was this...

http://vi.raptor.ebaydesc.com/ws/eB...877&category=175614&pm=1&ds=0&t=1452029357056

But maybe I'll go with a #40 set up. Thank you a bunch

 

[chancer]

The 2 piece Sprockets make it ALOT easier to change gear ratios in the future.
BMI karts has a good supply on their website.

If you are buying Everything new... I would go with 40 or 41 Both are readily available and the 41 is stronger than the 35.

 

[bob58o]

Thanks I got the sprockets and chain for #41. Thanks very much. This forum has been very helpful. Thanks for sharing the knowledge