Dual Sprocket Centrifugal Clutch

[canumovespenny]

I am presently designing a plan for a go kart something like the Spiderkarts Arachnid and I was thinking that i would get a 10 tooth dual sprocket centrifugal clutch on it and put two sprockets on the rear axel. One 15 tooth for a really high top speed and one 50 tooth for really good torque. Would a 15 tooth sprocket be alright on the back axel? I feel for some reason like it would have a much lower durability. Although it would go WAAAAYYY faster, would it be worth it?

 

[Doc Sprocket]

Not gonna work. Two chains cannot be engaged from the clutch to two different axle sprockets at the same time. Literally, your kart will not move an inch.

Also- the 10-50 combination (5:1) will not be at all torquey, and the 10-15 (1.5:1) won't even move the kart. too steep.

You'll need 6:1 or better depending on a few factors.

 

[canumovespenny]

Sorry, I forgot to mention some vital info. Lol ... I was thinking that i could have the a chain tensioner for each sprocket and switch the chain from sprocket to sprocket to fit the situations needs.

 

[Doc Sprocket]

Okay, little better. Keep in mind that if there's a BIG difference in the two available ratios, the tensioner will not likely do it, as there will be a large difference in the required chain lengths. That said, I don't think you'll need such a massive difference- already knowing that the 15T axle sprocket is completely unrealistic.

 

[canumovespenny]

Ok, what do you think would the lowest I should go for the axel sprocket?

 

[souperman000]

with a ten tooth clutch, you should be good with a 60 tooth sprocket (The 6:1 ratio Toystory was talking about)

How big are your rear tires?

 

[canumovespenny]

I am not sure yet but I am thinking 12-14" dia. So if I can find a 12 tooth clutch, what do you think would be my best bet. Should I just stay with a single sprocket clutch?

 

[souperman000]

I am not sure yet but I am thinking 12-14" dia. So if I can find a 12 tooth clutch, what do you think would be my best bet. Should I just stay with a single sprocket clutch?

Yes. With a twelve tooth clutch, a 72 tooth sprocket will let you keep the 6:1 ratio. That should work good with those size tires.

 

[canumovespenny]

Ok, but if I want to really boost the top speed, could I go down to say a 12-60T for a 1:5 ratio. What is the ratio and why is it so important? Really sorry for this, but I am new to this kind of in depth engine and go kart kind of stuff and I am really quite interested.

 

[souperman000]

Ok, but if I want to really boost the top speed, could I go down to say a 12-60T for a 1:5 ratio. What is the ratio and why is it so important? Really sorry for this, but I am new to this kind of in depth engine and go kart kind of stuff and I am really quite interested.

Its alright.

The trade off is more speed for less acceleration. You could do a 5:1 (not 1:5), but not accelerate as fast. You also risk extra wear and tear on your clutch. You could get a torque converter, which is the best of both worlds. Those cost some money though.

(I hope I explained that right?)

 

[Doc Sprocket]

Nothing wrong with asking questions. But I do suggest you search the forum for answers. Odds are really good you'll get a solid head start on what you need to know, just by looking around here.

Another tidbit of advice- Design your kart on paper. Decide on your engine, tires, wheels, axle, clutch, seat- everything. Firmly decide on all the major components before building anything. Order your materials and parts, and don't actually build anything until you get them. You'll more than likely find that you'll have to adjust the plan a few times to fit what you want, and it's a lot easier to adjust a plan BEFORE you physically build it. By having the part on hand, you can lay them out on the shop floor, and do all the measurements and mockups you need.

 

[landuse]

To be realistic, you are never going to get any sort of "fast" speed out of your Arachnid with using a centrifugal clutch. An Arachnid is not a small light kart, so you are going to have to gear low using a centrifugal clutch. This means at least 6:1 or lower (eg (8:1). I would suggest lower, because 6:1 is pushing the limits with the Arachnid IMO. Gearing lower will therefor mean that you sacrifice on speed. Play around with the speed calculator HERE, and you will get some idea on sprocket sizes etc. Just don't use sizes that will give you a ratio of higher than 6:1.

A torque converter will be the way to go for you if you want the best of torque and speed.

You are going to have to use one sprocket, because trying to push a chain over from one sprocket to another like on a bicycle is just not going to work. A bicycle chain is made to have lateral flexibility, while an industrial chain (or ones used on karts).....not so much. You won't be able to get that flexibility you need to shift like a bicycle.

 

[canumovespenny]

I was kind of thinking that I could literally just take the chain off one sprocket and move it to the other. I would have the duals sprockets on the clutch lined up with two sprockets on the rear axle and I could take the chain of and put it back on whatever sprocket I needed.But I do understand the fact that I can't gear that high with the Arachnid. If I got a torque converter does anyone have any idea what my top speed could be? I am looking to go over 50 mph if that is at all possible... Also, I will sacrifice acceleration for speed if that is necessary.

 

[FatCat]

I was kind of thinking that I could literally just take the chain off one sprocket and move it to the other. I would have the duals sprockets on the clutch lined up with two sprockets on the rear axle and I could take the chain of and put it back on whatever sprocket I needed.But I do understand the fact that I can't gear that high with the Arachnid. If I got a torque converter does anyone have any idea what my top speed could be? I am looking to go over 50 mph if that is at all possible... Also, I will sacrifice acceleration for speed if that is necessary.

I smell what your cooking on the double sprocket thing. It would work but the chains will be different lengths. You'd need to carry the second chain with you. Along with a master link(and a couple extra's) and the tools to switch them. What kind of terrain do you ride on? You might reconsider giving up your bottom end for more top speed. I guess it depends on it's purpose. If your going to the bonneville salt flats I understand the need for speed but if this is a yard cart you'll probably be disappointed. It'll be a turd down low.

 

[gvfc2]

couldn't you use a dual belt clutch and you can make it to shift on the fly with just some belt tensioners

 

[canumovespenny]

It will be used in the yard but by no means will be used as a yard kart. I have many fields and flat areas that I plan on driving it in. I can use a dual belt clutch but the centrifugal clutch is so much cheaper. I will invest in a torque converter if it the only way to get a high top speed. I really only want it to go about 50mph. I can get 50mph with a 12 inch diameter tire, 3600 RPM, 30 T axle sprocket and 12 T on clutch but thats a 2.5:1 ratio and thats not very practical. Do I need a torque converter?

 

[FatCat]

It will be used in the yard but by no means will be used as a yard kart. I have many fields and flat areas that I plan on driving it in. I can use a dual belt clutch but the centrifugal clutch is so much cheaper. I will invest in a torque converter if it the only way to get a high top speed. I really only want it to go about 50mph. I can get 50mph with a 12 inch diameter tire, 3600 RPM, 30 T axle sprocket and 12 T on clutch but thats a 2.5:1 ratio and thats not very practical. Do I need a torque converter?

Yes, if you want speed and acceleration that will be your best bet. If you've got the coin it's worth it. CVT's are great. Always in the perfect gear.

 

[getting kart smart]

I have a torque converter on my kart and top speed is 43. It is 4.2 to 1 ratio with 20 inch tires. It works great for a very short time. You will be going through belts like water and they are not cheap. $27 for mine. Because of my tire size I am going with a bigger axle sprocket to save my belt. Good luck and happy building

 

[Doc Sprocket]

I have a torque converter on my kart and top speed is 43. It is 4.2 to 1 ratio with 20 inch tires. It works great for a very short time. You will be going through belts like water and they are not cheap. $27 for mine. Because of my tire size I am going with a bigger axle sprocket to save my belt. Good luck and happy building

That's because you are geared too steep. In that same vein, I don't think 50 MPH is a feasible expectation, without having a HOT engine.

 

[mckutzy]

Maybe a TC isnt the way to go at all. Why not a motor off a motorcycle or dirt bike. It will have a clutch/trans/lights maybe. For all the work of a top speed potential with a TC, a bike engine will have that right off the bat.

Have you built anything of this yet or just in the planning stage and fleshing out the details of the cart?