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Full-Sized E-Trials


juanroberts
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Pretty much the same. This has a more developed battery quick swapping system. Also, 1.2 kWh of capacity. I am using a 500 amp peak controller but in practice it rarely pulls more than 200 amps, even on steep inclines or wheelies. Weighs just 60 kilos (134#). The biggest change really is the chassis, which now has a 4 bar linkage on the rear Olle shock and awesome formula forks and brakes. I'm planing on entering an event this weekend and see how it (and me) holds up.

Cool , try and get some video if you can I would like to see it in action..

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Wow. I don't see how they can do that. IF I take mine to market, which I am still not so sure of doing, it was going to be closer to $10k.

I rode mine at Dallesport COTA event this weekend. My first trials event ever so I entered novice at the request of the marshal (yeah, I know, trail riding). But I got to see how the events are structured and had a blast. I did a few intermediate sections and the bike performed really well. Plenty of power for everything in that class, no problem. My wife took a bunch of nice family photos and videos (I let my son ride the first beater prototype), but nothing worth a posting really.

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OK just saw the $9k USD, which sounds more realistic.

It really comes down to how many you can build / sell. The more you make the cheaper they get of course. And it looks like they have geared up for some volume. I would love to ride theirs. It sounds like kinda low power but electric specs can be very misleading, ie, continuous vs peak, etc. We Americans always lie on the high side.....they are probably using honest numbers (go figure!) I expect its a torquey bike..... Its hard to make an electric that isn't!

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Yes the specs of this bike is not very impressive for the a price of $9k but having said that its about the same spec as a EM5.7 and the E-gasgas which is around $7k. At least yours is up there with the power of a 250 and not a 125 :-)

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It looks like it may be a bit rear heavy from the pix, but I hate being a critic without any beef to back it up. On mine, its about 2% rear heavy, theirs looks like about 8 to 10%, which might be weird. But again, I hate to bash something without anything but a pic to reference.

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First off this is a great post. That because gwhy , no stroke and jojo started a great conversation as partners bouncing ideas and I am in awe of your knowledge. I am in awe of you all participating in unproven technology in its original form. Not too often you get to see pioneers in action.

Having built a few solar cars and diagosing hybrid technology for a good part of my professional life I have a few questions for you folks. I can tell you that the automotive world focuses on torque curve and its optimization. Most of them do this digitally from a fly by wire input processed. That's complicated right? It can be done mechanically thou. If your going to stick with mechanical throttle response linear with electric it isn't going to react like the IC engine is it? My suggestion would be to study torque curves and create a mechanical assembly to mimic that of the ic engine. Using worm tracks on a lever actuator or diverse cams on a cable actuator might be a way.

Here's a trick we have used with cable cams. Get a worst case cam, connect your oscope, and use tooth pics to adjust the profile. Match that to a profile you have studdied. Glue them with spray tac from the craft store to hold in place if needed. mimic the off idle profile of the ic engine and i think you will have most of the trials community covered. Most of us recover with an off idle profile.

Those curves may not be available for trials bikes but I think its hi time I get some speed sensors on my throttle with tach on my bike. Maybe I can even turn that into some dyno time. I'm surrounded by nerds.... let's see what happens.

Tc community, who else can help capture data? This cause is worth investigating and pursuing.

--Biff

Edited by biffsgasgas
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I think you may be over-thinking it, biff. Having played with darned near everything you have mentioned, weird cams, logarithmic pots, and microprocessor based programmable ramps...my favorite is a nearly linear crisp predictable (OK, analog!) ramp. On my bike, I expand the pot travel via cable to a linkage that provides about 90 degrees of mechanical rotation, instead of the more typical 45 degrees. On a gas bike, the throttle cable needs to pull exactly the same linear distance as the carb bore (~30mm), so you have to use different twist throttle cams to affect a change in sensitivity. But with a pot (rotary, hall or resistive), you can make the arm or quadrant however you want, relative to the twist grip cam. Wow, now it sounds like I am over thinking it.

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I would add that this is all very subjective stuff. I think the jury is still out as to what best provides good control of a trials bike, certainly electric motor based torque response. Personally, I feel that the clutch emulator is an added distraction, but I think most experienced riders would do better with that system, But I don't like it. I have been riding hot rod electric bikes for a long time, probably twenty years (I'm waay crusty).

That said, I am pretty sure of one thing...to get a pro level electric bike to leap like a gas bike, controllably, it will need a mechanical clutch. There just isn't enough torque available to simulate a spinning (gas bike ) flywheel launch. And I also think at those high levels, you would need to quickly de-couple ANY motor connected to it, gas or electric, to get the snappy response required on say a double blip. And that's what mechanical clutches do really well.

This is not to say that a 'smart' closed loop servo control is out of the question, but I think you would have to take the control inputs largely away from the rider, which is kinda scary, in a autonomous drone / Segway fashion,...and what fun would that be?

Edited by nostroke
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I agree with nostroke about the throttle ramps, on electric its not really necessary as the power delivery is linear unlike a gas motor, ramps on gas motors iron out the non-linear power curve or can also be used to put the use-able power into a certain spot on the throttle. But having said that its no big deal to incorporate throttle ramps on electric and may be of some use to some, but more for tuning the throttle resolution through out its range.

Me and nostroke will have to agree to disagree about a e-clutch :-), but it do depend on how a e-clutch is implemented within the control system to how much benefit it brings. As long as a electric bike has enough torque to throw the rear wheel up into the air after throwing the rider off the back then there is enough torque to do what every a gas bike can do and then it just becomes a matter of controlling that torque in a usable way.

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I think the Theory is very interesting, but much more impressive is what you can do with the bikes which are currently for sale like the EM 5.7. I rode the EM for the first time in a competition and I rode far better than with my old 4 stroke bike, despite I haven't had any training with the EM before!

Now I have sold the "old" EM 5.7 and I am waiting for the 2014 Model with Belt and Homologation Kit, and better electronic clutch.

Sunny regards from Germany

Jojo

Edited by jojo
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Yea after looking at my post i think you are right. I am probably overthinking it.

I will leave you with this. I am still pro clutch for this. There have been countless times where I need to have a neutral situation for the rear tire. If you have ever ridden a gas bike with a dragging clutch it totally messes with you for the whole day. I don't think you can get the reaction time out of a throttle that you would with a pull of a lever.

Thanks guys and keep it up!

--Biff

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  • 4 weeks later...

The Kuberg Trex is now on Kickstarter for $4999 free US shipping.. You cannot beat that price. Please back the kickstarter so I can get my bike. Only 18 days left and they need more orders. Remember if the Kickstarter is not successful. You don't pay. The only downside is it won't be delivered until 2015.

https://www.kickstarter.com/projects/1511813482/kuberg-free-rider?ref=search

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