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Discussion Starter #1
I'm sure this has been talked about before, but what would prevent someone from fitting a manual transmission to a snowmobile? I mean, there are offroad vehicles like ATV's and dirtbikes that people have no trouble with, so why not a snowmobile? With all the fiddling and power losses involved with the CVT, why not just go to a clutched manual and be done with it. More efficient and more fun to drive. While they're at it, lose the thumb throttle and go to a twist grip. Other than potential mechanical obstacles, I see no reason why this wouldn't work. Perhaps I'm missing something here.
 

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One issue might be a shifter. Where would you locate it? How would you activate it with those big heavy boots on? Another would be the clutch. There is a lot of resistance getting a sled moving. Might put lots of stress on a clutch pack. It will be interesting to see the RX-1 on snow. Until they are out it is all speculation. ronzx9.
 

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Accually it would not be efficent.  You would lose a lot of acceleration.  A cvt keeps the engine in its powerband at all times and has infinit gear ratio.  with gears the engine goes in and out of the powerband not to mention shift time and your stuck with the gear ration you chose.  

Thats why atvs with CVT are faster then Atv of the same size and power but with gears.

ALso audi cars are starting to use CVT.

Fact is you cant get better gearing then from a CVT.
 

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Discussion Starter #4
Make the shifter a push button deal like the Traxter. Then you have your choice of a clutchless electric shift (good for touring or mountain) or a clutched for trail and drag performance. You'd have to move the brake over to the right bar and your fingers might get a little cold on twisty trails where you'd be on the clutch (or brake if it was there, so it doesn't really matter). As far as getting the thing going from a start, certainly no more wear than that poor belt gets on a current CVT.
 

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Discussion Starter #5
Machzzz,

If a sled gets say, 60% of it's crankshaft power to the snow, what are the proportional losses of the CVT, chain drive and track. I'd imagine that the track is most of it. Maybe the CVT isn't so inefficient after all. I have no experience in this.
 

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Not to sound like a smart a$$ but I read somwhere that years ago when they were first inventing sleds they tried the manual transmission it wouldn't work remember they didn't have nice groomed trails then you had to push a lot of snow, think about it, the drag that is on a sled from snow, sliders, track etc., would stop the forward momentum when you put in the clutch to shift to the next gear thats how the "snowmobile clutch" was invented they needed a drive system that could shift without interrupting the power
 

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Thats right machzzzz1 and formulaman everytime you shift you would be out of the powerband temporarily, just enough to get stuck, miss a shift and your done.
 

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i'd hate to miss a shift in a bush trail and saw down one of mother natures tree's because i was spending more time shifting than paying attention. there is not enough inertia with a sled for gearing to work.
 

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How about automatic transmission, or would that be making a step back?
 

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Like i said before as long as you have set gear ratios you will lose power because the engine move out of the powerband regardles if its manual or automatic.  THE cvt has infinite gear ratios.  It is by far the best method of power delivery for cars sleds, atv.  

You can bet when CVTs make it into cars 0 to 60 times will go right down.  Also cvts dont need to use a rubber belt. They can use a chain or somthing stronger.
 

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Not to get off topic here but i wonder what a CVT would be like in my Ram 2500 4X4 with the cummins turbo diesel.
HMMMMMMMMM??
 

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You will never see manual shift trannys in a snowmobile because of the lose of momentun whenever you have to shift. If you're in mountains plowing tons of snow in front of you you definetly do not want any sort of lag or interuption in power while going up, be it shifting manual or like on the HondaES or Traxter, where they both have momentary lag.
 As for which is more efficient, the automatic or manual in vehicles, take a look in your owners manual under towing for a surprise. The automatic's are rated higher towing capacities than manuals. Usually by 1500lbs per similar vehicles. All heavy equipment, Cat's, Graders, Haul trucks have either auto trannys or electric drive. And you wouldn't want a Cat 797 tranny in your sled! Nor a Komatsu 930E electric drive motor!!!
 But it does raise any interesting scenerio with the rumor of Honda entering the snowmobiling world. The Rubicon uses hydrastatic drive, lightweight and efficient. The new 600, cannot recall its name, uses a full blown automatic. hmmm?
 What would be the chance? Fireblade motor! Oh my. Dream on!
 

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Army Tanks are automatic, they used to be manual but they would loose all their speed ever time they shifted from gear to gear. A snowmobile might be lighter but it would do the same. When I was a kid they use to sell sled kits for motorcycles, this thing changed youir cb750 into a sled by adding a track where the rear wheel was and a ski that replaced the front wheel.  I remember my father having a chat with a fellow who had one of these, he said it was hell to drive and that it was underpowerd. I thought it looked pretty cool myself.
 

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As far as the automatic Ac tried that way back when and it was too much of a problem child you have clutch pack seals thay don't want to seal when it gets cold plus the trans runns to hot so they went back to the cvt.as far as the magnum and sportsman deal yes the magnum was faster but that is on the gravel or packet dirt if you put them in the mud the sports man is faster as is the magnum with the cvt as you don't have to shift to keep it in the power and the manual you have to shift or you are over reving or bogging and at the moment that you shift you lose power to the wheels and this is when you get stuck even if you were to shift it fast enough you would fall bellow the power band and bog so you have to leave it in a lower gear and just go slower and overrev the motor.most snowmobiles have a power band that is only 7 to 900 rpm wide this is not a great distanceand if you go too far above the power band you will lose hp..Also the reason the Expidition(manual/magnum) is faster than the sportsman is that 5th gear is an overdrive for smoth packed surfaces.
 

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When my family sold Polarises that was the only selling point of the expediton that it had a true overdrive but in the dealer team tips this gear was only recomended for packed trails or roads. having driven them I know first hand that the auto is faster in the loose stuff even the auto magnum but on the packed stuff the manuel was faster top speed but the auto was quicker getting there.but neither can beat a explorer 400 which is a 2 stroke and it will wheelie pretty much on demand.this is why polaris put the 500ho motor in the scrambler 500 as the scrambler 400 was faster and less money.
 

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I've been contemplating the pros/cons of a manual tranny in a snowmobile for some time...
it would be fun for short trips, etc, but imo, it would get really old having to shift all the time on the trails. it would be neerly impossable to do any off-trail riding because of all the drag that is on the sled in the powder.

also, where to put the clutch and shifter? my best conclusion was put the clutch on the left handle bar, along with the brake so that the the clutch handle was farther forward than the brake handle. ie, if you wrap your hand around everything and pull, you have to pull the clutch in to hit the brake. still havent figured out where to put the shifter yet


- jason
 

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You missed the point.read again. auto is faster in the loose stuff even the auto magnum but on the packed stuff the manuel was faster top speed but the auto was quicker getting there.and as far as the auto in a diesle and less power this is because the motor puts out less power because no manufacturer and build a hydromatic trans that can handle what these motors will pull so they are down tuned a little so you will know when you are overworking it.Being a mech in the auto business for most my life I know this.and to prove this go get a yamaha banshie and put a track kit and skis on it and run it in the powder or take it through a mud hole and you will see that you will have to down shift a few times to stay in the power and you will notice this because you will have bogged down and stopped and now you are stuck this is why mud racing trucks use an auto trans also.
 

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Lots of good info on the pros ov CVT transmissions.  Nobody has hit the achilles heel of a CVT.  They are not good at transferring torque.  Look into the automotive world and look at the final drive ratios of CVT equipped autos.  They are typically given VERY short final drive ratios, and the capacity for ultra high OD ratios is used to make up for this.  I've driven four CVT equipped cars.  First was a Subaru Justy.  The CVT utilized an elecromagnetically acutated clutch to connect the engine to tranny.  This thing made an otherwise underpowered little car rather fun to drive.  Too bad they had so many problems with them.  Honda was next in line with the Civic HX CVT.  They used a viscous coupling on the output side of the tranny.  This seemed to exasperate the torque transfer deficiency.  The car felt as if it labored to pull its own weight.  Next was a Honda Insight.  They seemed to have fixed the early problem of power transfer with the Civic.  The little insight was downright sporty in its acceleration and handling.  Honda has seemed to have gotten the reliability engineered into them as well.  A co-worker purchased a Toyota Prius.  I've gotten the chance to spend quite a bit of time behind the wheel of that car.  Excellent package that seems to anticipate what you want it to do - untill you floor it.  Then the rubber band syndrome kicks in some.

CVT's are not a new concept in automotive applications.  AS for snowmobiles, what others have posted make perfect sense.  Simple, lightweight, and able to keep a small engine in its peak at all times to push through the snow.  The CVT's weakness is not a problem in this application, and is hands down the best possible option on a sled.
 

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how be when a stupid subject like this comes up we don't pay attention.
 
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