Centrifugal clutch idea.

I have a working knowledge of centrifugal clutches, mainly from how they work on chainsaws. I want to run an idea across some of you who know more and see if I'm correct though. Say you run a centrifugal clutch on the motor and run directly to a multi-speed mower transaxle. If the clutch grabs at a few hundred RPM above idle, how would it react when shifting through the gears of the transaxle? Would you just let off the throttle, then shift, then get back into the throttle? Would it be a smooth transition, and would the motor slow down fast enough to shift before the vehicle slowed its speed down?

I'm thinking of making a 2wd utility type vehicle similar to the golf cart bades ones. Those run a CVT and a single speed transaxle. All of that is more expensive that a centrifugal clutch and manual mower transaxle. I know someone will say why not run a manual clutch, but the fewer controls the better on this project.

All i can say is 'try it' and see - clutches 'activate' at higher rpms, and keep getting tighter as they increase more- and making it go faster.

Problem id see, is when you let off in a higher gear it might bog down a bit. The 'shift on the go ' setup on my murrays was neat- no clutching involved- the gear shift lever automatically engaged the clutch ever so slightly as not to jam the shifts and not slow the tractor down.

Its worth a shot. I was having a thought of using a go kart clutch on my mutant MTD- the one i slapped a 3 speed manual in - i have a belt driven go kart clutch ive never used. Now if i can get out and actually work on stuff sometime soon.....

Ok, so even though a given clutch is rated to grab at , lets say 1700 rpm, it still slips up into higher rpm? I know a golfcart/snowmobile CVT would be the perfect fit but they're in the $300-$400 range new. I haven't had any luck finding anything this winter, people still want $500 for older riding mowers. Like they didn't notice it's the off season.

Im sure the grip is tighter as the clutch revs up higher - otherwise it would slip and loose speed.

A snowmobile clutch is very similar to a MTD variable pulley - the belt rides at different places on the clutch surface , and it also degrees at various tensions- thats why on a snowmobile you can change clutch springs and weigh it to adjust what speed/reaction you want.

Id look for an old snowmobile at the end of the season and use the clutch n driven shiv- heck use the brakes too.

Many years ago i coulda picked up a snowmobile at a moving sale free- i kick myself for that one.

I'm not sure that I'm far enough north to find snomobiles. I'm sure there are some, but they aren't all that popular.

Im surprised- after this winter youd think everyone would be driving em.

Yeah, I think all 50 states saw at least a little snow this year.

oh yea i live in texas and for about a week there it was definitely snowmobile conditions

We saw the cold (went right down to the florida keys) went below 32 more then a few nites - if it was that cold for more then a few days in a row, thered be a ton of water lines a poppin- most arent more then 2 feet down, some even run above the ground.

I dont know if the panhandle got any snow tho- sometimes they do.

how much snow did texas have for that week?

only a couple inches but we were out of school for four days straight because it never got above freezing. iv never seen real snow befor(the white fluffy, soft feelin stuff) until that week. i went out side at like 4 in the mornin and it was snow like iv never seen before... then durin the day it turned to ice

man you shoulda seen my yard a week and a half ago lol there was almost 3 feet, even without a sled i love it and i dont know why lol. now theres only like 8 inches

Will a CVT, snowmobile clutch, work on its side? I'm wondering if it would work properly if ran on a vertical shaft lawnmower and mower transaxle.

iv heard a snowmobile clutch is hard to use on a mower because it needs to be tuned just right or something like that. i dont know much about snowmobiles but thats what i heard over at heymow

i personally dont know if thats true but them guys at heymow, i could see them just saying that so you dont use one or something like that, plus most snowmobiles do rev higher because of 2 stroke and 4 strokes dont so maybe they are right and it doesnt work right because of the rpm's?

Well, I said snowmobile because most people associate that type of transmission with them. They use the same thing on golf carts which run 4-cycle motors, often big horizontal shaft briggs. I was just wondering about what would happen if you flip the whole thing on it's side. Once tension is on the belt it wouldn't matter, but at idle the belt gets loose. When loos normally the belt sits between the two plates on the shaft. With it flipped 90 degrees, the belt would sit on the lower plate. Since I've never seen one setup like that I was curious.

but im defintly no expert on these type of clutches. i just looked up how the work on youtube... lol

i also posted a thread on heymow asking if it would work. but knowing them they wont answer the question.

so do they basically just let u idle and not move? would you use the mechanical clutch to shift still? im just a little bit confused on how and what there used for. do you plan on running a shain to the tranaxle with a sprocket on the input shaft?

i also saw some go cart clutches for $20-40 but deffintly not the same quality as the $200+ ones

this is what i got.. dont kno if its true or not tho.

"I thought about using one on a vertical, but I was told that it would not disengage. The wieght of the belt would let it lay on the rotating surface. If you adjust it to disengage, then it would slip to much to work properly. They do work on horizional engines."

Interesting, thanks for asking over there. I asked on a golf cart site, here's a link to that discussion as well. Found out that using a multi-speed transaxle wouldn't work well with a CVT.

http://www.buggiesgonewild.com/design-center/44694-cvt-clutch-question.html#post525867

lol what a coincidence i saw that buggie forum earlyer today and ment to put wut it said in my last post... not realizing that it was you who posted the question in the first place:)

Haha, that's pretty good. Looks like they have some custom builders on there as well, just have to dig through the tons of stock cart builds. I'm interested in most anything scratch built or cobbled together. Built not bought. Why? Why not.

Coming from a person who knows quite a bit about snowmobiles, I may be able to help you guys out. (probably one of the person who owns a snowmobile on this fourm lol) anyways... I have a friend who has a custom race mower he uses on the gravel roads around here in the country. he has a 14hp v twin briggs and uses that cvt (continous variable transmission) setup. You cannot use a mower tranny or transaxle to shift like a car or dirtbike. You can put it into say gear 1 and stop, then go into 2 depending on where your riding but you will most likely blow the tranny if you "shift on the fly". But he does use his cvt on the verticle shaft motor. works fine for him but as soon as water gets on it it will slip like a S.O.B till it drys off (like a snowmobile). He uses a RAGB (right angle gear box) from a rototiller to convert the vertical to horizontal shafts and runs a chain and sprocket to the live axle. Another thing, Depending on the weights in the clutch, my snowmobile clutch engages at 4600 rpm (enough to blow a mower engine). And i think snowmobile clutches have a splined shaft also. Im sure tractor supply or northern tool (american names, here its princess auto) would have small engine specific cvt designs to engage at lower rpms. My friends hardest challenge with the cvt was to find one with a 1" shaft diameter. Hope I helped

Yamaharules, thanks for the info. I never got back to this idea because I never found another reasonably priced mower. However that might have changed. I was just given a free riding mower of unknown brand or spec, haha. A family that I do odd jobs for got a new rider and decided they wanted me to have the old one. I haven't picked it up yet, no clue on what type, but they don't cheap out on things like that so I'm sure it's in good shape. Only downside is, there's a good chance it's an automatic since an older woman is the one who used it most. Not to say a woman can't drive a manual, but it's less likely. At any rate, if it's a manual I definitely plan to try the centrifugal clutch idea. Also, does anyone know where to get a better price than $180 for a centrifugal clutch for a 1" shaft?

I own a snowmobile - havent drove it in quite a while tho.

Snowmobile clutches and driven shivs arent splined - theyre a press fit like a flywheel on a tractor motor- snowmobile clutches are way more complicated tho then a CVT - different spring rates, weights, shims - same for the driven shivs ( i tore my sled completely apart a few times every year and rebuild it since i was in middle school - before pop and i would go on long distance snowmobile trips up north).

My '79 arctic cat el tigre 5000 has a custom weighted comet clutch and driven shiv , different trans gears- had bigger carbs on it as well - i could crank it up to around 70 with its antique 'fred flinstone' suspension before it got too much to handle .

The snowmobile clutch has more to do with engine balance as well - if its not weighted right- it can over rev and blow up the motor.

Clutches wont be cheep- one for my honda motor was like $80 ( 3/4" shaft)and is supposed to be heavy duty - i bot a pulley type go kart clutch for my murray years ago - that was like $90 ( 1" shaft)- both came from northern tools. A guy i used to buy tractor parts from said he used a go kart clutch on his racing tractor - he welded a large sprocket on it and said hes run it for like 10 years like that.

You can run a twisted belt setup ( my 86GTII does, as well as my 69 simplicity) - but again with a wet belt, slippage can occour - i wouldnt suggest it for higher speeds either- best bet is to do a belt to a RAGB and down to a straight axle.

Thanks, I had completely forgot about Northern Tool. They have much better prices, $120 for the chain drives and $70 for belt. I know you can swap springs for it to engage at different RPM but stock the chain clutches are 2300rpm and the belt clutch is 1800rpm. They all say up to 13hp engines, wonder if they really would handle larger? I may go with the belt clutch to save money and if any give is needed I imagine a belt is more forgiving than chain.