New back tires needed

[Corsonmcnash]

Hey all, After getting my kart running agian, I soon realized one of the largest problems. My tire size gives my sprocket about half an inch of clearance... when no one is in the kart. I don't want to get a smaller sprocket, and reduce the top speed. I'm left with one option: new tires. I was wondering if anyone here could identify the type of wheels and treads that would fit my frame, I believe my current tires are 10 inches in diameter, I was looking for something maybe 12 or 14 inches in diameter. Ill include a picture of the kart, but I'm fairly sure my wheels are the four bolt type, not sure what size the rims are though, if there's a standard they look to be 4'... not sure though.

[Disclaimer: I know the engine mount is wood, that will be cured later this week, uncles bringing up the welder, grinder, etc.. so no hate!]

 

[Russ2251]

I don't want to get a smaller sprocket, and reduce the top speed...I was looking for something maybe 12 or 14 inches in diameter.

Increasing tire diameter is equivalent to getting a smaller driven sprocket.

 

[Corsonmcnash]

Wait a minute, Larger tires will increase top speed... oooooh ****, I'm an idiot, I had it backwards. Well besides that confusion, I'm interested in larger tires anyway. Anyone have an suggestions?

 

[jrmints1415]

rim and tire or just tire??

 

[B man]

why not just up tire size on all 4?

 

[Corsonmcnash]

Well, If its possible I would like to keep the wheels and just size up the tires. They are tubed rims, Does anyone have an experience, and can offer 12 or 14 inch treads and tubes?

 

[landuse]

Wait a minute, Larger tires will increase top speed... oooooh ****, I'm an idiot, I had it backwards. Well besides that confusion, I'm interested in larger tires anyway. Anyone have an suggestions?

You might increase your ultimate speed, but you will decrease your torque, and depending on what clutch you have it might be a problem. (Just playing devils advocate).

 

[Corsonmcnash]

You might increase your ultimate speed, but you will decrease your torque, and depending on what clutch you have it might be a problem. (Just playing devils advocate).

Right, Well I'm using this guy in 40/41 chain size http://www.hilliardextremeduty.com/extremeduty/. But either I need to get bigger tires, or a smaller sprocket (preferably larger tires, for the overall ground clearance addition) regardless, and I assume they will both have the same effect. This is primarily a road going cart, and since I live in a city I really wont be doing much hill climbing and stuff, just bombing around flat parking lots and stuff. So if it will be okay on flat ground and minor grades, that's cool by me, (will it?)

 

[r_chez_08]

Yeah you should be ok with the bigger wheels.

 

[Doc Sprocket]

Another option worth consideration is a jackshaft. It is possible to retain your current tire size and overall ratio, and yet have a smaller rear sprocket.

 

[Corsonmcnash]

Sorry kind of new to this stuff, to have the same ratio as I have now i would have to reduce both the drive, and driven sprockets right? what exactly does a jackshaft do? Also I meant to increase tire size to give the sprocket extra clearance with the addition of top speed. I just went outside and checked my ratio. Its poor, uh quite poor. 10 inch tires 60t driven sprocket, 10t drive @ 3600 rpm ive got a top speed of 18 mph That would also explain my brisk acceleration at the moment hahah.

I think larger tires, as well as a smaller sprocket may be in order. I wanted it to push 30.

I looked at my driven sprocket and it's directly bolted to the brakes! How would I go about replacing it with, say a 48 tooth sprocket? (pictures upon request)

 

[r_chez_08]

That would work fine.

 

[Doc Sprocket]

Sorry kind of new to this stuff, to have the same ratio as I have now i would have to reduce both the drive, and driven sprockets right? what exactly does a jackshaft do? Also I meant to increase tire size to give the sprocket extra clearance with the addition of top speed. I just went outside and checked my ratio. Its poor, uh quite poor. 10 inch tires 60t driven sprocket, 10t drive @ 3600 rpm ive got a top speed of 18 mph That would also explain my brisk acceleration at the moment hahah.

I think larger tires, as well as a smaller sprocket may be in order. I wanted it to push 30.

I looked at my driven sprocket and it's directly bolted to the brakes! How would I go about replacing it with, say a 48 tooth sprocket? (pictures upon request)

I just ran some numbers for you. Perhaps, you don't need to change sprockets. As we already know, changing to a larger tire has the same effect as a smaller axle sprocket. Since you do not wish to maintain your current ratio, I present to you the following-

*Locate and purchase 16" Turf tires, or 16" tires of your choice.
*Keep your existing 6:1 final reduction ratio
*New theoretical top speed becomes 28.56 Mph
*You gain an estimated 3" of sprocket (and ground) clearance

Food for thought. I don't know what your existing rim dimensions are, but 16x6.50-8 turfs are pretty common and easy to find. I'm guessing these will not fit your current rims, but you should be able to get some fairly easily. 4x8 trailer rims will fit those tires and are very common, and available in a standard 4-on-4" pattern.

 

[Corsonmcnash]

Awesome, sorry to revive a dead thread but gotta say thanks. (Been busy working)