# Clutch Vs Clutchless



## sailfish11 (Sep 15, 2007)

Thanks for this great explanation! I have a question though -- are there any special issues with an AC system going clutchless? Would it affect regen?


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## DVR (Apr 10, 2008)

In short, no, there's no difference between AC & DC as far as clutchless goes and it should not affect regen at all.


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## EVfun (Mar 14, 2010)

sailfish11 said:


> Thanks for this great explanation! I have a question though -- are there any special issues with an AC system going clutchless? Would it affect regen?


If you have off-throttle regen (often included to simulate engine braking) it needs to be turned off when you want to shift. If even mild regen is happening the syncros will not be able to do their job and it should be difficult (and damaging) to pull the transmission out of gear.


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## locoo (May 6, 2010)

Hm that is wery bad Now a Q? I will use Altrax *AXE **7245 what kind of regen dhoes it has ?

Tanx 
*


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## dtbaker (Jan 5, 2008)

The other consideration that is rarely mentioned is that retaining the clutch allows small amounts of misalignment without damage. 

A completely solid coupler, the slightest misalignment will cause tiny flex with each revolution and eventually break something... especially if you have welded something together and not hardened it afterward.

If you go clutchless, SOME couplers have spirals, or plates, or rubber bumpers designed to handle some mis-alignment. The rubber ones are generally bad news at high torque. The metal plates work well, but add back almost as much weight as you take out with the clutch.


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## EVfun (Mar 14, 2010)

Some clutchless couplers are built from the sprung center of a clutch disc. These will allow slight motion, essentially like the stock clutch assembly. 

On most transmissions and transaxles the pilot bearing part of the input shaft should still be supported. A pilot bushing is not required because it will not rotate relative to the motor shaft, but often the transmission depends on that support for alignment. The spline fit is not tight enough to provide the proper support.


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## Earthwindwater (May 2, 2011)

Great Info! This should be a sticky!


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## cruisin (Jun 3, 2009)

After many years of designing both clutch and clutchless adapters it has to be the choice of the builder. Some car tranny's work better than others as a clutcless. Having said that, I find that a clutchless design is better with a coupler as small as possible in diameter to avoid a out of balance as some shafts vary a little in diameter. About 2 3/4" is ideal without the clutch springs. Most splines have enough slop for a very very small alignment problem. Here is a few pictures of a coupler for the VW.


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## cruisin (Jun 3, 2009)

here is a coupler for a clutchless VW using the disk springs (not recommended). Too much weight and mass for a motor that may spin up to 8000rpm like the AC-50.


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## m38mike (Dec 27, 2008)

I started my Electro-Willys as a clutchless car. The direct connector matched the motor output shaft directly with the splined input shaft for the transmission. That lasted about 6 months before it broke the output shaft for the motor. I'm not sure what the problem was, but it was an expensive repair. Then I went back to the clutch. Yes it added more weight to the vehicle. But the reduced stress on the transmission by allowing "normal" shifting was worth it. And by putting the clutch plate back in the mix, I reduced the chance of damage to either the transmission or the motor from something being out of balance or out of allignment. I've been running this arrangement for almost 2 years now and so far so good.


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## pluggedin (Sep 20, 2011)

m38mike said:


> I started my Electro-Willys as a clutchless car. The direct connector matched the motor output shaft directly with the splined input shaft for the transmission. That lasted about 6 months before it broke the output shaft for the motor. I'm not sure what the problem was, but it was an expensive repair. Then I went back to the clutch. Yes it added more weight to the vehicle. But the reduced stress on the transmission by allowing "normal" shifting was worth it. And by putting the clutch plate back in the mix, I reduced the chance of damage to either the transmission or the motor from something being out of balance or out of allignment. I've been running this arrangement for almost 2 years now and so far so good.


Mike,

The Willys, I got to see it man. Any kind of media anywhere on the forum? I have built a couple as wheelchair accessible vehicles so I would love to see what you have come up with. Hit me up if you have anywhere I can take a look.


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## dtbaker (Jan 5, 2008)

besides a little more wiggle room for possible mis-alignment, you have another method to disconnect the drive if you get stuck in a 'welded shut with full power on' situation.

Direct coupling of 80+ peak horsepower with lots of stops/starts is pretty tough on any solid coupling.


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## wessss77 (Jan 4, 2013)

okay so you really wouldn't wnt to go clutchless on the AC 35 or AC50 then since they are both regen also unless you disable the regen...correct?? Also, in many of the older cars are the synchro's not almost all fouled up?? Thanks


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## Zappo (Sep 1, 2011)

wessss77 said:


> ... Also, in many of the older cars are the synchro's not almost all fouled up?? Thanks


I don't know about most older cars but I'm sure glad I kept the clutch in my '96 Ford Ranger. I've driven a lot of clutch vehicles without using the clutch. It usually isn't that hard. This thing is miserable trying to run it without the clutch. I realize the weight of the clutch changes how it would feel as opposed to going clutchless but I don't think it would help enough. And this body only has about 100,000 miles on it.


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## poprock (Apr 29, 2010)

Reply to Locoo. The AXE7245 depends on the letter after the 5 .The code is on the alltrax website if not in the enclosed manual. Plug braking is available but not sure about regen,


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## trukr (Mar 17, 2013)

wessss77 said:


> okay so you really wouldn't wnt to go clutchless on the AC 35 or AC50 then since they are both regen also unless you disable the regen...correct?? Also, in many of the older cars are the synchro's not almost all fouled up?? Thanks


I'm guessing you could always keep the clutch pedal to act as a kill switch for the regen. Or convert an old domestic high beam low beam foot switch to do the same job. It might be a good idea to do this regardless since allowing the motor to spin during a shift might extend the life of the clutch somewhat. Wouldn't regen without a load just stop the motor completely?


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## CyO (Mar 23, 2013)

cruisin said:


> here is a coupler for a clutchless VW using the disk springs (not recommended). Too much weight and mass for a motor that may spin up to 8000rpm like the AC-50.


Sorry, but is this saying that clutch-less is fine but not with the spring center plate of a clutch?


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## favguy (May 2, 2008)

I wouldn't worry too much about the opinions of cruisin, there's a reason he got banned!

Assuming you've decided to go clutchless, there is nothing wrong with using the torque damper from a clutch pressure plate in your coupling design, it gives some damping effect and properly engineered adds little additional rotational mass. Other advantages are it can allow for very slight misalignment due to the "floating" nature of its centre component.


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## johnsiddle (Jun 22, 2011)

This is my effort at a clutch coupler, there are four bolt holding it together although only two are shown in the photo.
The small spider that is the spline part has a bit of spring load slop built into it as standard and this takes care of a small bit of mis-alignment.

http://www.diyelectriccar.com/forums/showthread.php/converting-my-2001-volvo-v40-75026p4.html


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## TEV (Nov 25, 2011)

And this is mine :

http://www.diyelectriccar.com/forums/showpost.php?p=315820&postcount=3

Also you can't see the 16 bolts because the middle piece was not drilled and tap at the time of the picture.


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## favguy (May 2, 2008)

Another example of a Coupler build:

http://www.diyelectriccar.com/forums/showthread.php/my-project-favelec-58958p4.html


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## Bern (Apr 28, 2013)

What about removing the whole gearbox to save weight? As I understand the electric motor gives 100% torque from standstill, so if the ratio allows it to get to top speed without exceeding max RPM it would just be a heat dissipation issue at low speeds right? Would it not be possible to make a simple cooling system using the existing radiator and some copper pipe wrapped around the motor?


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## TEV (Nov 25, 2011)

Bern said:


> What about removing the whole gearbox to save weight? As I understand the electric motor gives 100% torque from standstill, so if the ratio allows it to get to top speed without exceeding max RPM it would just be a heat dissipation issue at low speeds right? Would it not be possible to make a simple cooling system using the existing radiator and some copper pipe wrapped around the motor?


We name that a "direct drive"(of the differential), it was discussed allready, you can use the "Search" 
http://www.diyelectriccar.com/forums/showthread.php?t=83046&highlight=direct+drive


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## CyO (Mar 23, 2013)

Bern said:


> What about removing the whole gearbox to save weight? As I understand the electric motor gives 100% torque from standstill, so if the ratio allows it to get to top speed without exceeding max RPM it would just be a heat dissipation issue at low speeds right? Would it not be possible to make a simple cooling system using the existing radiator and some copper pipe wrapped around the motor?


Well that would certainly help with my load problems. It has been a very cold winter here and I am still struggling to understand how to get heat into the cab without reducing the distance traveled. I will also have to think about the new connection element, any opinions?


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## Bern (Apr 28, 2013)

CyO said:


> Well that would certainly help with my load problems. It has been a very cold winter here and I am still struggling to understand how to get heat into the cab without reducing the distance traveled. I will also have to think about the new connection element, any opinions?


My thought is you can either piggyback the existing system or add a valve to send the coolant either to the interior radiator in winter or the main one in front during summer for cooling the motor. The question is will the motor produce enough heat to warrant the effort?


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## CyO (Mar 23, 2013)

Bern said:


> My thought is you can either piggyback the existing system or add a valve to send the coolant either to the interior radiator in winter or the main one in front during summer for cooling the motor. The question is will the motor produce enough heat to warrant the effort?


A previous member in response to the use of the heat suggested "It would be utterly negligible to be of any use for heating the cabin of the car, it just vents to outside the box". So? Unless I got this wrong, it is a no-goer.
CyO


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## Ziggythewiz (May 16, 2010)

CyO said:


> It has been a very cold winter here and I am still struggling to understand how to get heat into the cab without reducing the distance traveled.


If you have access to a plug you can heat from the grid. Most EVs don't travel far enough to get that cold if they start out warm.

Not only is there not much heat to recover, doing so is counterproductive. If you're cooling the motor or controller you're going to want the source to be as cool as possible. If you're heating the interior you want the opposite. You can't efficiently have both.


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## CyO (Mar 23, 2013)

Ziggythewiz said:


> If you have access to a plug you can heat from the grid. Most EVs don't travel far enough to get that cold if they start out warm.
> 
> Not only is there not much heat to recover, doing so is counterproductive. If you're cooling the motor or controller you're going to want the source to be as cool as possible. If you're heating the interior you want the opposite. You can't efficiently have both.


I like that very much, many thanks,
CyO


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## Canadian Electric Vehicle (May 20, 2010)

Here is an explanation of my take on this from our web site page.
http://www.canev.com/adapters.php

*Reasons why we built clutch-type adapters:*
1. Safety disconnect. If the motor were to lock up you can disconnect it from the rear axle and avoid locking up the rear wheels.
2. If the controller were to fail full ON (and they do) you can disconnect the motor so your not rocketing through a stop sign.
3. Have your tried to shift without a clutch? Yes you can get on to it but we like to build vehicles that anyone can jump into and drive without having to learn the "tricks" of shifting without the  clutch.
4. We have built vehicles with both systems and find no noticeable difference that the extra flywheel weight makes. Yes there is a theoretical difference but I have never been able to tell by driving both systems in the same vehicle.
5. Most clutchless adapters are the same cost as our clutch adapters so no savings on cost.
6.There is no modification to the clutch to work with our adapters. We make the drive end of the motor "look" like the back end of the gas engine so the flywheel bolts on just like stock.


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## CyO (Mar 23, 2013)

Sound reasoning from my perspective. I can still see values in not having a clutch, but yes, some family or friend getting in to drive without time to explain what is different, worrying!
However, I am still thinking the thing through, but more than likely I will draw the same conclusions as you.
Many thanks.
CyO


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## dtbaker (Jan 5, 2008)

Canadian Electric Vehicle said:


> Here is an explanation of my take on this from our web site page.
> http://www.canev.com/adapters.php
> 
> *Reasons why we built clutch-type adapters:*
> ...



the other thing that a good clutch-type adapter does for you is absorb minor misalignments, and shock loads..... solid couplers tend to crack or break something upstream or downstream.....


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## CyO (Mar 23, 2013)

dtbaker said:


> the other thing that a good clutch-type adapter does for you is absorb minor misalignments, and shock loads..... solid couplers tend to crack or break something upstream or downstream.....


Hi,
Yes, it makes more sense to me.
Looking at your list of plates and Canadian car models, I would imagine that your range of plates would possible be similar to European models. Are there any tables to compare say a Toyota Corolla with what you have?

Regards,
CyO


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## Pete1961 (Apr 11, 2014)

Hi,
I have driven non syncro gearboxes & shifting down is much harder than up, I had the idea of a clutch less coupling but with a freewheel or one way bearing built into it. This would mean that the syncro's do not have to handle the motor rotor mass, & so we are back to about the clutch friction plate mass position as originally designed. This does have drawbacks, as no regen would be possible, & if any engine braking is present from an elec motor it would be lost. I am pre supposing that reverse is selected from the mech gear box - hence the motor only ever runs one way. Basically the motor drives the clutch plate, but this plate is free to escape from the motor when being speeded up by the syncro's


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## dtbaker (Jan 5, 2008)

Pete1961 said:


> Hi,
> ... so we are back to about the clutch friction plate mass position as originally designed. This does have drawbacks, as no regen would be possible, & if any engine braking is present from an elec motor it would be lost.



huh?
whether there is a clutch or not has NOTHING to do with regen. regen is depending only on whether motor is DC(impractical), or AC (possible).

having clutch makes downshifting way easier whether you have syncro or not. in both cases it helps to 'rev a little' in neutral to bring motor revs close to what they need to be for the downshift.... in the old days without syncro you had to do this 'double-clutching'.


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## miev 1 (Jan 22, 2015)

> If you have access to a plug you can heat from the grid. Most EVs don't travel far enough to get that cold if they start out warm.


At present, this works the best. Had some very cold mornings and needed the range to get to and from a meeting in burbs. The car does have a remote that allows heating for 30 min. prior to departure. This really, really helps. Gets the cold out without using batteries.

However, 15-20 min. into the ride, the wind starts making footwell cold. I tried a plug-in heater which did not reduce range, but was useless. So cycled the heat on and off so that it was not constant. Had only few miles left at end of day.


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## MaxP (Apr 24, 2015)

Canadian Electric Vehicle said:


> Here is an explanation of my take on this from our web site page.
> http://www.canev.com/adapters.php
> 
> *Reasons why we built clutch-type adapters:*
> ...


Hi Canadian Electric Vehicle,

Do you typically use the stock flywheels of the car when you use the clutch adapters, or do you get a reduced weight flywheel? I was looking into using a clutch adapter, and I was wondering whether it would be worth the extra cost of getting an aluminum flywheel (the type that is used for racing). I imagine the reduced weight would help improve acceleration when using an electric motor.

It's not that I want my car to have particularly high acceleration, I'm just concerned that by using the stock flywheel, the car might be quite "sluggish" when accelerating.

Obviously it's very dependent on the type of car, but I think stock flywheels would typically be in the region of 18 lbs, while aluminum racing flywheels might be more like 8 lbs.

Thanks,
Max.


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## dtbaker (Jan 5, 2008)

MaxP said:


> Do you typically use the stock flywheels of the car when you use the clutch adapters, or do you get a reduced weight flywheel?
> Max.



unless you are drag racing, looking for that last .1 sec, you'll never notice the difference.


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## MaxP (Apr 24, 2015)

Haha, no, I won't be doing any drag racing. I'm just looking to be able to get to work and back every day. Thanks dtbaker! In that case, I think I'll stick with using a clutch.


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## Duncan (Dec 8, 2008)

If you stick with a normal flywheel then you will need a clutch
If you biff the flywheel you don't need a clutch

All a clutch does is uncouple the engine so that the syncro's can match speeds inside the gearbox when changing
The reason you want to uncouple the engine is it's rotational inertia - which makes the matching of speeds too slow

90% of the rotational inertia of a engine is the flywheel - losing the flywheel means that you don't need to reduce the rotational inertia - so you don't need a clutch


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## Moltenmetal (Mar 20, 2014)

Others here have done successful clutchless arrangements, even with AC motors and regen. You need a defeat switch for the regen and to remove the flywheel as already mentioned. 

I kept my clutch in my AC50/Curtis arrangement because it made the conversion process dead easy- just buy a mounting plate and hub from CanEV or others, bolt on the old flywheel, clutch and pressure plate, and bolt the assembly to the end of the transmission. I think it took me about 1/2 h our total. Building the motor mounting bracket took longer! And then the car requires no training for anyone who is used to a car with a manual transmission except of course that you don't have to "burn" the clutch to start off- you just press your foot on the accelerator and go! I can start off without using the clutch in 1st, 2nd or even (gently) in 3rd gear as long as I watch my ammeter. In fact I don't even need to watch the ammeter- the Curtis limits the current for me. In town, I more or less drive the car in 2nd and don't bother to shift or use the clutch.


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## brian_ (Feb 7, 2017)

If the initial post in a Wiki thread like this is supposed to be the informative article - with the rest as discussion - then someone who understands how a synchromesh transmission works should re-write the synchro part of that post. The way a synchro works is relevant to whether or not a clutch is desirable.


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