# Clutch Vs Clutchless



## Mr. Sharkey (Jul 26, 2007)

The clutch/less question is currently raging in the EVDL, so you can get some answers there. What it boils down to is a matter of opinion. My opinion is that an EV should have a clutch. It's not expensive, it's not difficult, it's expected by every driver of any type of vehicle, and it allows you the option of not using it if you don't want to.

Being locked in a single gear, likewise. I'd much rather have the option of three or four other gears, in addition to reverse.

Of course, I'm biased, my car has a clutch, and a four speed transmission, with reverse, and it wouldn't be possible to drive it at all without all of them.


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## Ioku (Sep 27, 2007)

My question is how do you drive an EV with out a clutch, I know the motor is not always moving like an ICE engine, but wouldn't you still grind gears trying to shift if the car is moving.


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## Alex Everett (Dec 26, 2007)

Best info I can give is, Clutch if you can. The cluch less system is not too difficult to overcome but let someone else drive....HMMMMMM. Floating gears is a term used in the trucking industry. Timing the shift to the R.P.M. of the engine will allow trans shaft and engine to mesh correctly. Get it wrong and you will grind transmission. This is a learned technique and can be done properly with some ammount of shifting experience. Having said that, install a clutch anyhow and learn how to shift without it if you would like. It will make the decision easier to make on your next E/V project.

Hope this helps, Alex


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## John (Sep 11, 2007)

If you fit a clutch surely that means also fitting the flywheel and the heavy clutch pressure plate. All that would mean a fair bit of rotational inertia which could in turn actually make the clutch necessary. Fitting a clutch and not using it won’t give you an idea what a true clutch less setup will drive like due to the polar moment of inertia of all the clutch bits. It’s a question of wether or not the extra inertia of the motor armature and coupling are going to be too much for the synchromesh.


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## BenNelson (Jul 27, 2007)

Is the main idea of NOT having a clutch to loose all that weight and thus the inertia?

Does that mean the weight of the clutch is mostly rotational resistance to accelerating? More amps to accelerate? Is is any more power once you are at speed? Once everything is spinning, inertia helps instead of hurts, right?

I know all weight is negative in general, because it all makes your EV harder to drag around.


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## Alex Everett (Dec 26, 2007)

John said:


> It’s a question of wether or not the extra inertia of the motor armature and coupling are going to be too much for the synchromesh.


Don't believe that would be a problem since the inertia would not be a constant (either electric motor or I.C.E. ) and the interchange actually happens post clutch assembly. With clutch locked, the trans input shaft will turn same rpm as motor regardless of weight of flywheel/plate and disk assembly. I do agree that the added weight of these components will of course need to be properly mounted and ballanced. Now that I have said that, let it be known that I am only a mechanic and do not have the engineering education to be 100% sure of my info but it seems logical.

Thanks to John for making me sit and really think about this. Props to you dude...


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## John (Sep 11, 2007)

I'm not sure how much difference to the performance it makes loosing that bit of rotational inertia but it must have a positive affect on the performance. I'm picking it would become significant if you were building a low voltage EV. Once the speed (revolutions) had reached a steady state the rotational inertia would no longer affect the power requirements. I'm building clutch less due to having cut a slice off the front of the bell housing to create room for my batteries. The bell housing no longer has space for a clutch plus I loose quite a bit of weight off the conversion and simplify the car a bit. I was originally going to retain the clutch as I think it would make the car a little bit easier to drive particularly as I won’t be the only one driving it.


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## Alex Everett (Dec 26, 2007)

DANGER DANGER WILL ROBINSON..... Make sure you did not alter the structural integrity of the bell housing as you do not want a fracture or crack to develop and have everything fly apart at an operational time. Modern floorboards and firewalls are not all that thick and believe me, wheelchair adaptation is not fun, especially if you loose an appendage.

Since you must go clutchless, shifting will be something that is just simply learned. No way to describe how to do it other than get in and do it (like swimming) once you are proficient at it, you will wonder how you lived without the knowlege.

Anything I can do to help, please let me know as I will be asking tons of questions here as well


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## John (Sep 11, 2007)

I had the alloy plate welded in the hole to restore the integrity of the bell housing.


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## Alex Everett (Dec 26, 2007)

Excellent good thinking.


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## SkylineUSA (Dec 27, 2007)

When you guys are talking clutchless, does that mean you shift without a clutch, or you start off in a 1:1 gear?


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## John (Sep 11, 2007)

Shifting gears without a clutch. There is less rotational inertia in a motor armature than a crankshaft and flywheel so it won’t be like trying to drive an ICE car with a busted clutch cable. From what I'm told shifting gears just takes a bit longer to accomplish. Like 2 to 3 seconds long. A blip on the accelerator could probably shorten the shift time. I have rev limiting on my controller so doing this wont over spin the motor. I guess I'll find out how it all works when I finish my EV.


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## SkylineUSA (Dec 27, 2007)

Won't there be issues from moving from a dead stop? Also I see stop and go traffic not being too fun either?


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## Alex Everett (Dec 26, 2007)

Absolutely no issues with dead stop or stop & go. Put it in gear ,leave it in gear let off accelerator pedal, electric motor will stop rotating. This may sound strange but that is way easier than clutching first gear in and out.


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## John (Sep 11, 2007)

Because of the electric motors high starting torque it won’t need as many gear changes as an ICE would. I'm picking that in stop and go traffic it would just stay in second gear. When I come to a complete stop I won't need to bump it out of gear. The electric motor will sit there turned off until I need to move again.


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## SkylineUSA (Dec 27, 2007)

I keep thinking in ICE terms. That makes perfect sense. Thanks guys.


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## MARTY (Dec 16, 2007)

Hi;
I have Just driven my Electric 1971 VW Bug, which we just finished convering, it was built as a 72 volt system, and later everything was taken out.. And I helped Put in a 96 Volt system... And so It was finished just a little while ago and Driven for the first Time by me.... It has NO Clutch and I didn't have any trouble shifting between the Gears.... I Just take mt foot OFF of the Accelerator and then I shift,,, No Problem at ALL !!!!! 
THANK YOU Marty


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## Alex Everett (Dec 26, 2007)

how much differance was there in the 72 volt vs new 96 volt system. More power, faster take off, higher top speed DETAILS, DETAILS......

I sure hope you like it better. I originally was thinking 48volt, located a better (and cheaper) 72 volt motor. So far I seem to be stuck there.

I of course will go with clutch because I will not be the final owner of my first e/v project


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## MARTY (Dec 16, 2007)

Hi Alex;
I Don't know ,, since everything was taken out of the car, before I came to get it,, and help with the conversion... I have NEVER driven any Electric before I drove this one, this afternoon... And I didn't have a chance to drive the other Car that does have a 72 Volt system... I just ran out of time...
THANKS Marty


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## Alex Everett (Dec 26, 2007)

No problem. I have never driven an E/V either. I just want to check and see from someone who has/had a 72 volt for referance in building an inner city (MAX 45 mph) vehicle.


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## MARTY (Dec 16, 2007)

Hi Alex;
Check with the Guys at Wilderness EV, They have BEEN A GREAT Help, and they are ALL Great Guys.. The Sport Bug is a 72 Volt system, and they are converting another Bug to 96 Volts, for another Customer. They might be able to Compare the TWO Bugs, and get some Data or information to you, once they have the 96 volt system up and Running, Which will be as Soon as they Get a Motor for it. (it is on order) The Motor for My machine came in on Friday, but the Motor for theirs hasn't come in yet.. (Both were 144 Volt Motors, but because of the limitations of the battery weight that a Bug can carry, I chose 96 volts, and that is what they are using also)  
THANK YOU Marty


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