Low enough ratio?

[jman231994]

Hi guys, ive got another question haha.

I have managed to half source some ride on mower wheels quite cheaply. The scrap place didnt have any when i called them but they said they get them in quite regularly so ill just have to ring back a few times.

From what ive read, most ride on wheels are 16-20" diameter. Since im gonna be using a centrifugal clutch rather than a torque converter and my engine isnt overly powerful, I need to know if a 6.5 : 1 ratio with those wheels, would be low enough for light off road and going up some small hills. A top speed of 50km/h is more than quick enough for me.

If you guys think I need to go lower then ill have to use a proper 219 kart sprocket rather than a 35 pitch, the 35's only seem to go up to 78 tooth. Also does anyone know a cheap place in Australia to get 35 or 219 chain and sprockets. US web pages seem to have chain for less than 10 dollars for quite a good length of it. Whereas i can only find it for 30 dollars a metre. And sprockets are around 30 bucks....Is that an ok price?

 

[redsox985]

I don't think that 6.5:1 will be low enough for those tires, as they are usually 18". Try 40 chain for strength and use a jackshaft to reduce your ratio. 219 and 35 aren't as strong and 219 seems to be more expensive.

 

[B.M.800]

My kart has 18in rear tires with a 6:1(close enough to that) with a 6.5 honda... It goes fine.. or am I missing something here...?

 

[redsox985]

Do you have a TC or cent. clutch B.M.800?

 

[Doc Sprocket]

My kart has 18in rear tires with a 6:1(close enough to that) with a 6.5 honda... It goes fine.. or am I missing something here...?

Define "goes fine". Just because it hasn't cooked anything yet...

 

[r97]

i think that ratio would work fine on relatively flat land, but if you wan't to be off-road, going up hills...... i wouldn't bet too much on that ratio and a cen't clutch with your 6.5.

 

[B.M.800]

On flat/semiflat it goes great, slow take off because of lead butt though. It can take mild hills with a bit of speed. I cant start out on much of a slope while Im on it. My frame weighs about 150-200lbs, I weigh around 225lbs.

A TC is way out of my current wad o cash... quite unfortunately

 

[redsox985]

Just a rough gesstimate here, but 6.5:1 with 18" tires governed should go about 30, on paper. For me, that's more than enough speed, and if you plan on going anywhere but flat/small, gradual hills, it most likely won't satisfy you or your clutch.

 

[jman231994]

Hmm ok. Thats a pain. I dont have enough cash for a torque converter. I dont even know if i could make one fit on a victa haha. Im really limited to something with a 3/4" bore.

I would do a jackshaft setup but the reality is from what ive seen it would cost heaps to set up. 40# would be good but I cant really find much stuff for it that i could use. The sprocket needs to mount to a standard kart sprocket carrier.

I know if i dont do something that i'll probably lose out more with a burnt clutch but i really need to spend practically nothing on it apart from a clutch and a few little bits.

Anyone know if maxtorque makes 219 pitch clutches? It may be weaker than 40# but i can source the sprockets up to a 90 tooth or so and they are actually cheaper than the 35 pitch sprockets.

Who knows. I may get lucky and get some 14" wheels or something

Thanks for the help.

 

[fowler]

i find the best place to buy parts is a place that stocks acricultureal parts because they are cheap and machines are forever wearing out parts and doing bearings

also they will sell cent clutches for larger engines (13 to35hp) but should do the same job

i was going to buy parts from the us but the shipping is a killer and parts can always be soured local

 

[Wim]

For chain and sprockets in AUS try: http://www.bsc.com.au/

They have cheap sprockets and chain is about $60 for 3m.

 

[jman231994]

Hmm what sort of agricultural shop do you mean? Like a tractor spares place or something?

I can get a maxtorque clutch from the US for 55 bucks and 11 bucks postage. I honestly didnt believe it so i asked the seller and he said that its 11 dollars postage australia wide.

Thats why i wanted to go 35 pitch but i guess i can look around some more

 

[jman231994]

Thanks Wim. I've got a BSC about 5 mins from my place so I'll take a look. I see they have 35 pitch sprockets in the teethage (is that a word?) i require. Would they drill mounting holes in it for me? I can do it myself I guess. And do they do shorter lengths of chain? 3m is a bit much for this kart haha

 

[fowler]

Hmm what sort of agricultural shop do you mean? Like a tractor spares place or something?

we have a place in esperance called South Coast Bearing and Industrial Supplys

and Esperance Ag with sell uni joints and rose joints
they also have
cockies bags with is a bag full of random nuts and bolts and a list of what your getting (which is realy useful for building)

oh and for non aussies a cocky is an owner of a farm (or a bird)

 

[jman231994]

Haha. I'll have to see what there is around here that's like that. The bag of bolts sounds great for projects.

Again, thanks for the help

 

[Wim]

BSC only sell chain in 3m/10foot lengths boxed, unfortunately they dont cut lengths. I bought some (plenty left over for spares).

They are only a parts supplier, no machining (at least my local one doesn't). Most sprockets come with a 1/2inch pilot hole which you have to resize yourself (or go to a small engineering shop).

 

[jman231994]

Hmm that sucks. Ill try and source the chain somewhere else or see if anyone i know wants some haha. Could i resize the hole with a plasma cutter or is it too rough? Holesaw? Either way sounds like a good source for the sprocket and maybe a couple more parts.

Thanks

 

[fowler]

id get an engineering shop to do it unless u have one of those speical hole saws (u know the tapered ones?)

 

[jman231994]

Tapered hole saws? Is it necessary just to enlargen the central hole to fit over my 30mm axle?

Or did you mean for drilling the holes to mount it to the carrier?

 

[jman231994]

I think i forgot....What ratio would you guys recommend for that size wheel. The victas probably between 5 and 6 hp