E Pure Questions

[al_orange]

I've always loved the thought of an electric trials bike but said that I'd wait until it had a proper clutch. Now, with being on lockdown, I've had a little ride in the garden (on my petrol bike) and it's underlined how awesome it would be to have an electric bike. 
 

But, I've got a couple of questions/musings that I wonder if people have experience enough to answer:

1. Gears.. they exist for a reason - before the coronavirus hit, I was doing a fair bit of practice in mud. I learned quite quickly how important it is to use the gears to maintain grip. Using 3rd when I might be in 1st in the dry, and using 4th (with clutch) for big climbs for example. Now, with an electric bike with one gear, how do you go faster without increasing the torque/power relatively? In general, how do they ride in the slippery clay/mud we have in the south? Having a bike that has max torque all the way through the revs makes it sound like hard work. Gears effectively change the relationship between the torque the engine is producing and what is delivered to the rear wheel.

2. Static/slow speed balance - I'm sure expert riders wouldn't notice a difference but I've been doing engine off balancing for a while and have just started doing engine off hops (mostly because I don't want to annoy the neighbours). Now we know how much easier it is to balance with the engine running, but I didn't realise how much easier front end hops are with the engine on (even without using the clutch at all). With the e-pure, presumably, you don't get any increase in static stability at all? In fact, what is the gyroscopic force of the engine like?

[micm]

If you want gears you will have to wait for another manufacture to actually market one with a box, both the Gasser and the Mecatecno prototypes had gears. I'm sure a proper clutch (and flywheel) on the E Pure Race single speeder is a good idea.  

[al_orange]

27 minutes ago, micm said:

If you want gears you will have to wait for another manufacture to actually market one with a box, both the Gasser and the Mecatecno prototypes had gears. I'm sure a proper clutch (and flywheel) on the E Pure Race single speeder is a good idea.  

I don't necessarily want gears as such, I'd be more than happy with one gear as it makes life is bit easier! What I wondered is if by having only one gear then does it compromise the bike in typical British conditions? 

[motovita]

Bonjour,

 

First of all, I hope that you and your family are safe and secured during this very difficult period.

 

At EM company, we have decided to organize a LIVE INSTAGRAM SESSION on SUNDAY, APRIL 5th.

 

1 session in French with Léo Finiels at 5pm (French time)

1 session in English with me at 6pm (French time)

 

We will present the EM range and answer to all your questions during this LIVE.

 

Feel free to share this information on your social media or invite all your friends that would be interested (see visual below).

 

EM instagram link >> https://www.instagram.com/electricmotion_officiel/

 

Looking forward to hearing from you on sunday,

Best regards,

 

 

[nhuskys]

6 hours ago, al_orange said:

I don't necessarily want gears as such, I'd be more than happy with one gear as it makes life is bit easier! What I wondered is if by having only one gear then does it compromise the bike in typical British conditions? 

 3 different power modes help with that according to this vid.    

?

Edited April 4, 2020 by nhuskys

[micm]

17 hours ago, nhuskys said:

On 4/3/2020 at 7:05 PM, al_orange said:

 

 3 different power modes help with that according to this vid.    

With all due respect to the excellent and well informed team at Inch Perfect, on the 2019 EM I ride (with only the electronic PELS disconnecting clutch) the lowest of the three modes (green, blue, red) the green one, is gutless, the other two blue and red (red the most potent) are fine and noticeably different. It may be the 2020 has a different lowest (ie the green) map. On the 2019, with standard gearing, green was only useable on the flat (11 stone rider) any gradient at all would stop it. Also in my experience you need a very very delicate hand on the throttle to stop the engine spinning up if you loose traction. For example when you get stuck at an obstacle or loose way on a camber. I have not ridden in very muddy conditions so I can't make a comment about that. However a 'real' clutch (and it's flywheel) must help to maintain grip used with the engine momentum. In the dry the bike has fantastic acceleration. Ok these are critical comments, but I'm still saving up for the 'Race,' riding these well designed bikes is a different and enjoyable experience. 

[bikerpet]

I really can't comment on the EM with any authority as I've never ridden one and only seen one older one in the flesh. However I am in the midst of designing and building my own lightweight electric trials bike and have been learning a lot about electric bikes generally.

The older EM's used a very common Kelly controller that should be pretty simple to alter settings to whatever you want. There's a limit to what these generic controllers can control, the big one in my mind being exactly what micm mentions - there's really no useful way to prevent the motor accelerating if the wheel loses grip with any throttle at all on. The contoller basically controls torque, so if load is less than torque, the motor spins up until load equals torque, or max rpm is reached. Not great in mud I expect.

There's another controller mode, Speed mode, where the throttle signals a desired RPM, not a desired torque. These seem to be pretty brutal on a bike as they effectively give full power until the requested RPM is achieved, then back off to hold it there. The Kelly controllers (and a few others) do have a hybrid Torque/Speed mode where the throttle setting calls for a particular speed, but how far the throttle has been moved determines the torque that's delivered to get there. This might be a better mode in poor traction, but from what I've read it doesn't really feel natural or smooth for anyone coming off petrol bikes. A few people use it, but most seem to end up on torque mode. It might be worth a try for really slippery conditions. I don't know if the Kelly lets you change control modes on the fly, or just the settings within the current control mode.

I can't recall which controller the Pure series use, I believe they changed to a different brand, but still pretty generic. It certainly can also be altered in a myriad of ways to get the response you want, within it's limits.

Currently I don't believe there is a production controller available that can replicate what our flywheels do - particularly that you can get some momentum up, cut the throttle and let the flywheel carry the bike - the key with that, as we all know, is that the back wheel can't break loose and spin up, it's always slowing down so is much more likely to retain or recover grip.

The Race with it's "real" clutch and adjustable flywheel has got to be a vastly different beast to the older ones with the pseudo clutch and less significant flywheel. Sadly they're well out of my budget so hi-ho it's DIY we go.

My build is based around a dual suspension Fat Bike MTB with a KX65 clutch grafted onto the electric motor, and a flywheel fitted inside the motor housing. Lots to do before it sees the light of day!

I'd really like to find out more about how the Race is constructed - is the clutch on the motor shaft or a jackshaft? Which controller do they use? How heavy and large is the flywheel? how heavy are the adjustment weights (I'm guessing they have weights as the advertising mentions adjutable flywheel or some such). 

[drca]

On 4/3/2020 at 1:51 AM, al_orange said:

1. Gears.. they exist for a reason - before the coronavirus hit, I was doing a fair bit of practice in mud. I learned quite quickly how important it is to use the gears to maintain grip. Using 3rd when I might be in 1st in the dry, and using 4th (with clutch) for big climbs for example. Now, with an electric bike with one gear, how do you go faster without increasing the torque/power relatively? In general, how do they ride in the slippery clay/mud we have in the south? Having a bike that has max torque all the way through the revs makes it sound like hard work. Gears effectively change the relationship between the torque the engine is producing and what is delivered to the rear wheel.

2. Static/slow speed balance - I'm sure expert riders wouldn't notice a difference but I've been doing engine off balancing for a while and have just started doing engine off hops (mostly because I don't want to annoy the neighbours). Now we know how much easier it is to balance with the engine running, but I didn't realise how much easier front end hops are with the engine on (even without using the clutch at all). With the e-pure, presumably, you don't get any increase in static stability at all? In fact, what is the gyroscopic force of the engine like?

Theoretically with the constant torque of the electric motor, you really don't need gears.  Now in practice the motor has a max RPM, so not having gears is a compromise between torque at the rear wheel and maximum speed on the trails.  Alta had a motor that could spin up to 14,000 RPM (if I remember correctly) while delivering a very healthy amount of torque, so you could really have both torque (acceleration) at the rear wheel and good top speed.  That's not the case on the EM, but in my experience the top speed is plenty enough.  One issue tho is when you are close or at the max speed and want to pull a power wheelie over something...  That's not going to happen.  On the positive side, not gearbox = lighter weight, less maintenance, less failures!

As far as muddy climbs are concerned, not much experience here in California, but plenty of very dry and slippery hills and the EM is pure magic on these.  More torque than needed to go up most hills (you'll probably loop the bike or loose traction before you run our of torque), no need to worry about having the slip the clutch to avoid stalling, just constant rear wheel torque with a direct link to the throttle. And you can hear what your rear tire is doing and dial the throttle accordingly.  The one thing I haven't been able to do as well on the EM as I can do on the Gas Gas is to synchronize weighing the rear suspension (to get traction) while blipping the throttle.  But I am sure that if I work on it for a day that'll come.

Balance - I am not that great at static balancing, but I haven't seen much difference between the Gas Gas and the EM.

Hope this helps.

 

[lotus54]

This is from another thread- but shows the real clutch on the epure race.

 I believe the motor shaft has a gear on it that drives the clutch, much like a ‘traditional’ bike.  I don’t know how much the flywheel weighs are, but it appears three different options?

Edited June 10, 2020 by lotus54