Torq-A-Verter CVT

218352A - Torq-A-Verter, 3/4" Bore 12 Teeth, #35 Chain Torque Converter

I haven't seen it, no doubt Miles has it on file ...anyway, thought it might be of interest for
some building non frock setups only $180 bucks made in the good ol US of A too notChina haha

KiM

Looks like it might be a similar system to these old DAF cars

http://antholonet.com/EngineersCars/DAF/daf.html

so cheap too

It has come up before:
http://www.endless-sphere.com/forums/search.php?keywords=torq+a+verter&terms=all&author=&sc=1&sf=all&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search

http://www.hoffcocomet.com/EpiphanyWeb/flexpage.aspx?ID=75

They are a heavy & bulky way to only get a 2.7:1 reduction at best ! :?

I belive these were made for go karts etc, as they bolt directly to a Honda or similar industrial engine. Also be warned that comet industries stopped trading for a while & these became unobtainable (there was some talk of production shifting to far east - do not know if this ever happened)
At tick over the belt is just slack, as revs increase the half pulleys engine side grip belt, further speed increses cause a higher ratio, thus at the basic level they are speed rather than torque responsive -meaning you cannot throttle back but stay in a high ratio (eg when cruising on the level) some of the dearer end models have an override in the driven side that means high torque causes the ratio to decline irrespective of engine speed. Would be much improved by a proper centrifugal clutch & also a means of varying the belt ratio under manual control (at least as far as for use on a motorbike / scooter) think this may be also usable on a small electric car but probably a bit of overkill on anything bicycle based

The same thing can be accomplished with a variator system from a scooter or moped. The parts from a Motobecane or puegeot 103 would likely be the best. Both require a pivoting motor mount. Another method would be parts from a Hobbit, Derbi, or Vespa Ciao in which the front variator changes width with RPM and the rear pulley is spring mounted to change width as the belt rides higher on the front pulley.

I have one. It works fine, but as stated above it's big and heavy. I used it on the lead pig emoto I started this adventure with over 3 years ago, and it had no problem lugging me, 2 kids and 600lb pigmoto up a 25% grade from a stop. I took the springs out for immediate engagement after Comet told me the softest they had resulted in a 1krpm engagement. Having no springs made the weights quite rattly, and I wouldn't recommend it.

check this out http://www.pattakon.com/pattakonPatBox.htm

Hugh-Jassman said:

check this out http://www.pattakon.com/pattakonPatBox.htm

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From what I can see on the drawings there ain't nothing special with that variator you are linking to. These type of clutches has been used by snowmobiles for more then 40 years. I can see that they have added a little ball" with hinges" rather then arms and weights. But the principle looks the same except the actuator motor. Might work like a charm but they have added another point of failure with the actuator. And the mechanical variators are well proven and bullet proof.

If you got say a really hi powered hub motor as a mid drive you will get more torque running such a variator. But as others stated that will add weight and also eat away some of the motor power.
If you got heavy loads say in a trailer on your bike or you are doing a trike with large cargo area this can work for you. Then again so can light weight Astro motor(s) in combination with Davinci drive. Add as many motors as you feel you need for crazy power and you can climb so steep traction in tire will brake before you stall motor(s). Or get yourself a Tangendrive. 80:1 reduction and super light weight. There are just too many good arguments why not to use variators on e-bikes. However I will applaud those who thinks different and choose to go that route. Maybe the result will be surprising?

In snowmobiles, those variators make it possible to carry 500 kilo or even1000 kilo on a sled behind the snowmobile, even with a small 300-400 ccm engine less then 40 hp. One of the brilliant things about variators, is that you can tune them to your specific need. Swap primary clutch spring for stiffer spring to increase motor RPM before take off limit is reached. Will make motor run more in higher RPM and give you more torque also, meaning faster acceleration. Expect a little top speed loss. However, top speed loss can be countered by tuning secondary clutch spring, or even the weights and arms in the primary. Today most people drive their snowmobiles standard without playing with their clutches and they are all waisting so much fun by not fine tune it to their specific needs. They will lose hill climbing ability, acceleration and even top speed compared to riders that take the time to tune in variators correctly.

Variators are cheapish, reliable and easy to tune. I know only of one electric motorcycle that uses those clutches, the Sora Lito. How well those clutches work for electric propulsion I don't know. Maybe you can find details test rides of the Lito? One thing is for sure, variators have been topic in many threads here, and I have yet to see any one taking the leap.

Thanks for sharing that bike macribs. Id never seen it before.
I like it. To bad about the price, but such are luxury toys.
Kool that it's made in Montreal. Not too far from me.
Something that I can register here in Canada should I win the lotto.

thanks for the pic, I was not aware of how large these things are. But how 'bout a smaller one made for a 3 HP motor? :

at lang last I have found what I was looking for: a two speed gear for heavy duty use:

http://scooter.wikia.com/wiki/Evo_two_speed_transmission

Hm. Cable operated clutch and plastic lever? Can it handle torque from an electric motor?
If you really need a gearbox why not check for lightweight racing CVT's for tuned up scooters, or go carts? Those are simple mechanically, sturdy as a mule and you can tune it for maximum speed, max acceleration, max hill climb etc. What ever suits your need. And they are cheap, last forever and are widely available. I mean if you are already set on the use of a gearbox, you are OK with the fact that you will loose some efficiency and power, to gain a more useful power delivery that suits your need. If you first are gonna use gearboxes why not use one that will give you the widest choices of tuning?

These CVTs are the evil in the world of low-powered bikes, IMO. Although they say they are good for 3-8hp, they really aren't good under 5hp at the very least. There are a few problems in play here:

First off, being a mechanical torque-sensing setup, the CVT upshifts depending on load, and therefore must keep the belt very tight. The driven unit is spring-loaded closed and the driver is progressively GETTING closed by the centrifugal weights spinning out and pushing the cone driver inwards. This introduces a lot of friction.

In fact, a CVT never achieves 100% efficiency. You might get 95% with a fresh belt but expect to see under 75% as the belt wears. And it weighs about 15lbs.

but that's not all. If you have 4hp good luck getting a usable rpm range out of it. First off, the CVT engages at 2200rpm stock and will shift up to 3300rpm, at which point if your motor doesn't have enough power to overcome the belt friction and all, that'll be your max RPM.

I've heard that with higher hp motors the CVT will shift over a range of about 1000rpm, and the motor will continue to pull after that in high gear.

Second thing is, I was unable to get a shift range larger than 1100rpm personally. I tried to get the CVT to engage from a higher rpm and end up at a higher end shift rpm, but what I ended up with was 3100 engagement to 4000 end of shift. This meant that I had to rev up the motor over 1krpm from my idle just to start moving, and the initial movement was very abrupt. I also tried to tighten the driven unit spring to get a later shift, but due to only having 4hp the engine was unable to overcome the new stronger tension in the driven pulley, and the unit did not even shift into direct drive. Not good for a daily driver.

The max speed I was able to attain with the CVT was 34mph or so and with awful hillclimbing. The damn belt smoked when I tried a big hill. Single speed/single JS I achieved 47mph.


There is a thread on oldminibikes that details member Newoldstock's adventures in tuning the CVT.. he even rolled and annealed his own driven pulley springs.

The smaller CVT is a better design, in a way. Definitely better for e-bikes! the belt portion is always engaged, and behind the driver there is a centrifugal shoe/bell clutch like any other, though a bit smaller.

I think this unit is excellent for motors with more than 5hp and for racers looking to drag race. Fuel burning riders can set the stall speed up to 4k or so, set the idle at 3600 and GUN IT to 6000rpm on their 10hp ohvs for some serious speed. And then change belts.

While I've never used one on a electric motor I have used CVT's extensively in high powered off road cars. Starting with the Honda FL350 Oddessy, Honda Pilot and Drakart Formula Cross. Stock clutches, Comet Clutches, Power Bloc and many varieties of driven clutches. Once I really started tuning which starts out looking like Quantum Physics it's really quite intuitive. I had used everything from Heal Clickers, roller bearings and many, many springs of all weights and compounds and found how drastically you change power output. I found the stock Ski-Doo clutch to be the best with 6 setting on ramps. Great for tuning for trail or wide open sand/drag racing. With a specialty item with no after market support, i.e. Springs, arms, belts compounds, your tuning options are slow to make if not impossible for the average Joe.

With a supported product I'd be onboard to build the ultimate bike (in my personal opinion!) and be riding already. For all out racing nothing can touch CVT, nothing. Just can't find a belt to last over 300hp with weights over 750 lbs past a run or three!

Tom

Hm. Today there are Ski-doo's, Yahama's, Arctic Cat's and other sleds that run 1 liter engines with turbo and 300-350 hp. I know of a couple of Yamaha's that are pushing between 240 hp and up to 320 horsepower and they seems to run an entire season on one or two belts.

The belt are kevlar type things and can take insane amount of power and heat. This is for snowmobiles. I can imagine running a 4 wheeled in heavy sand dunes will put a little more strain on the belts but if you look for racing quality belts I am sure you will find something that will work better.

Again these are less than 750 lbs which was the point that they don't work well in larger machines. It's easy to run higher power with less weight or visa versa......less power and more weight.

Tom

litespeed said:

Again these are less than 750 lbs which was the point that they don't work well in larger machines. It's easy to run higher power with less weight or visa versa......less power and more weight.

Tom

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Well today I saw a monster build of side by side ATV. With 1L turbomotor rebuild to put out aprox 250 HP, standard use or a little past 300 in race mode. Guess what, it used a CVT gear. The owner said he had no problems bashing it in steep loose sand with heavy incline, sort of like dune riding style. Can't remember the weight of those side by side ATV's but around 1.000 lbs or more is my guesstimate. And that is before larger intercooler, bigger turbo oversized cylinders, big pipes and what not.

He had experienced axle that snapped, but the belt or CVT had no problem handling the weight and power. I will try to remember to ask him about more info next time I see him. Like what CVT he uses, belt etc.

beginner01 said:

These CVTs are the evil in the world of low-powered bikes, IMO. Although they say they are good for 3-8hp, they really aren't good under 5hp at the very least. There are a few problems in play here:.......

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There are so many choices of CVT today so if you choose the right one for your need there will be no problems, even if you run a 10K RPM motor. In addition to the spring in primary clutch there are weights/rollers that you can swap, file, grind etc to meet your criteria. Have a high RPM motor? No problem. Tune the CVT to set take off/engage RPM higher RPM ie 3000 RPM and use the right combination spring/weight/rollers to let motor spin up to max RPM. Snowmobiles with high power can stay "forever" with 8000 crank RPM without any problems for CVT. So adding 2K more RPM's should be a cake walk.

First off, being a mechanical torque-sensing setup, the CVT upshifts depending on load, and therefore must keep the belt very tight. The driven unit is spring-loaded closed and the driver is progressively GETTING closed by the centrifugal weights spinning out and pushing the cone driver inwards. This introduces a lot of friction.

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Friction? Well yes on the belt the same way a chain hugs the cogs/sprockets, but the hug is sideways. But the friction does not eat up or tear up todays high quality kevlar belts.

If you have 4hp good luck getting a usable rpm range out of it. First off, the CVT engages at 2200rpm stock and will shift up to 3300rpm, at which point if your motor doesn't have enough power to overcome the belt friction and all, that'll be your max RPM.

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Agreed, if you have low powered motor, wasting motor power into any sort of mechanical gearbox is not your best choice.
A CVT can't do magic. If you got a lazy RC motor with low peak power you can't expect insane power, thrilling hill climbs, mad acceleration and scary top speed.
But if you have a semi powerful or powerful motor the correct tuning of CVT will give you a much wider RPM band. For instance engage at 4000 RPM and top out at 8-10.000 RPM. I would think one (or more ) Astro 3220 would work well with a CVT. Or those crazy Joby motors. Or even a mid mounted powerful hub motor with a much more narrow RPM band but with more torque could benefit from CVT. But those DD hubs add weight too, so on second thought that was a moot point. The combined weight of DD hub and CVT would be too much for e-bike use.

In fact, a CVT never achieves 100% efficiency. You might get 95% with a fresh belt but expect to see under 75% as the belt wears. And it weighs about 15lbs.

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If you have the right motor to begin with 95% might be acceptable.
Remember that any gear reduction will take away from motor efficiency. If you use a two step reduction that too will reduce motor output power before the power hits the wheel. Again, belt wear is minimal even on high powered motors so I would not worry about belt wear for an e-bike due to the light weight and overall low rolling resistance. When you notice loss of power just change the belt, you wouldn't ride a normal bike until chain it starts skipping teeth's on the sprockets. I do agree about the weight. Those CVT's add weight.

The max speed I was able to attain with the CVT was 34mph or so and with awful hillclimbing. The damn belt smoked when I tried a big hill. Single speed/single JS I achieved 47mph.

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Well seems you did something wrong. Either you chose the wrong CVT to begin with, had too little power in your motor, or messed up when tuning primary and secondary clutch springs/weights/rollers or a combination of all this. Smoking CVT belts are from the past, you should not have any problems with smoking belts with the right setup.

Tuning a CVT can be very difficult if you have not done it before, and even when you think you have optimal tuning you might find that changing the ration between front sprocket and rear sprocket might make a big different in end result. So can wheel size etc.

I am not saying CVT rules for e-bikes, but for some people with special needs or special usage a CVT is one way of achieving desired goal of performance. A drop in efficiency might be tolerable for some, other will just not even consider a CVT or any other mechanical gearbox for e-bike use.

macribs, my reply was about the CVT linked to in the original post, the $100-180 GTC/COMET/Clone CVTs for minibikes and go karts.

My setup was 8:1, 26". One day my driver unit exploded 3mi from home because I didn't use a long enough crankshaft bolt. I locked the bike in the bushes behind a school field and came back the next day to swap it over to single speed and ride home. On my first ride getting past 20mph it was a great feeling! I immediately gained 15mph just by going to a cent clutch. I ordered the parts I'd lost and more for tuning. I never could make it go faster than about 38 downhill nor make it to the top of that hill. Yes, even going downhill, the CVT slowed me down.

I ended up building a 2-speed transmission using dual cent clutches, freewheel, 4 chains and two jackshafts. This setup took me over 50mph and powered up that same steep hill while accelerating in first gear (see signature link).

2-speed vs TAV2 from another guy who's had both. See post #4: "I dont know why but [the cvt] didnt work real good on the steep incline around the top. (i give this one to the 2 speed)"
http://www.oldminibikes.com/forum/mini-bike-discussion/511-2-speed-jackshaft-torqueconverter.html