Observed trials bike designing

General Discussion about large electric scooters and motorcycles and other things with no pedals.
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DanGT86   10 kW

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Re: Observed trials bike designing

Post by DanGT86 » Dec 31 2021 10:27am

Tech is always evolving. This all just further demonstrates how its a spectrum and you could draw your line arbitrarily at any point and say any technology past this point is cheating.

The other day I was reading about honda's CR series of mx bikes in the 90s. Apparently they implemented a primitive form of traction control using the ignition system back in the mid 90s. It had the unintended result of making the bikes sluggish and taking the edge of the burst of power commonly found in 2 strokes. I could see some guy who rides a 25 year old bike telling a guy on a new bike that he is "Cheating" and "back in my day we didn't have traction control"

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speedmd   1 GW

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Re: Observed trials bike designing

Post by speedmd » Dec 31 2021 10:52am

I think most of us welcome honest improvements in design. The mapping choices are a interesting option on a race bike. Nice to have the WFO option when you can take advantage of it. Nice saddle and hand grip setup also. Quick shift also nice for keeping the tranny from added abuse.

For a trials bike, the cockpit mapping options may be of some use. A multi disk flywheel that can be separated or connected by operator on the fly may be something that could help. I would like to experiment a bit with either -both. Also a shock "damper" bypass- release would allow much easier hopping, much like a pogo stick when you need it.

Not finding much info on the traction control setup - operation. Only words I find is that it works to smooth out - limit rpm spikes. Sort of an electronic flywheel. May be more of the type of mapping that may be at work at the higher rpm ranges in the power plot up the page a bit of the more current trials motor.

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Re: Observed trials bike designing

Post by speedmd » Jan 13 2022 11:59am


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DanGT86   10 kW

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Re: Observed trials bike designing

Post by DanGT86 » Jan 14 2022 10:10am

Very cool bikes! wish I had the money to get one.

It looks like they have included some of the control options and strategies that we have been talking about. I love the tick-over/idle feature. I bet that was hard for the designers of the bike to tune for the right feel.

The regen lever is a cool idea. If I were designing a bike I would try to include a foot shift lever that has a different regen strengths much like the engine braking in a gas bike. Some habits are hard to break.

I'm pretty impressed with the execution here by EM. This bike includes something for everyone whether they are a new rider learning only in the electric environment or a seasoned pro gas rider. Other than a slight weight penalty for including a clutch there is really no reason not to have one. If you don't need it don't use it.

Is the swing arm and frame sections carbon or are those just covers? I kinda missed that in the vids. I'm a bit worried about repeatedly dropping carbon on rocks and logs.

Now I just need to cook up a plan to get a bunch of money.

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speedmd   1 GW

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Re: Observed trials bike designing

Post by speedmd » Jan 14 2022 10:38am

The carbon look is cool. Some sections (fork covers) appear to be carbon or carbon wrapped plastic. The frame sections are plastic tape with carbon or carbon look facing. Frame is near identical setup to gassers. Looks like they set the bar for folks to follow. Word is that the other major brands are all working on releasing their electric versions.

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Re: Observed trials bike designing

Post by bikerpete » Jan 14 2022 8:16pm

All the carbon is aftermarket add-on covers.

EM currently use the Silixcon controller which is very flexible from what I've seen, but I'm not sure it's really capable of the sort of control and logic that might be ideal for trials. Once the likes of KTM make a serious push into electric GasGas trials bikes I expect we'll start to see controllers with software designed with the task in mind from the outset. Or maybe an innovative company like Vertigo might take the leap into e-trial, although they seem to be so head down, tail up developing their ICE bikes that they perhaps don't see that they're developing semaphore while the world moves on to radio.

I'm not sure why EM wouldn't put the regen control on the existing brake levers? Either foot or hand or both. The first little bit of movement would be regen, then the hydraulic would come in. Exactly as electric cars currently do. I don't see why you'd muck about with a third brake lever. You might still keep the ability to set the underlying "engine braking" setting so the bike doesn't just freewheel when the throttle is cut, but regen braking is just braking - use the controls you've already got. Trying to juggle one finger clutch, then over to the regen lever, then back to the clutch - what a nuisance.

I wouldn't have thought the idle setting would have taken much tuning - just gradually increase idle RPM until it feels about right, basically similar RPM to an ICE bike with a little tweaking to cater to the different gearing.

The other downside to the EM clutch is $$$$. You get what you pay for.

I agree that I'd love to have the spare cash to get hold of one. Even though I think they're still a fair way off being as capable as the ICE trials bikes, I'm not as capable as the ICE bikes either!

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DanGT86   10 kW

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Re: Observed trials bike designing

Post by DanGT86 » Jan 14 2022 10:42pm

For this style of riding the braking needs to be too precise for it to be combined with the hydro levers. The chain slack would also be a problem compared to caliper braking at the wheel. Sometimes the rider needs to slip the clutch to keep the chain loaded while the wheel is stopped on an edge. There are too many situations where a rider is quickly transitioning between brake and throttle or even using them simultaneously. Imagine trying to rev your engine for a clutch dump while holding the brake to keep you in place. It wouldnt work if the lever is engaging regen.

As for the idle, I can see where it would be tricky to program. If you tell an electric motor controller to maintain 600rpm it will do it. If you start to apply load it will just apply more current to maintain your 600rpm. So then you have a trials bike that wont stall. Thats great but would feel very unnatural. If you tell it to apply a minimum current at all times for idle then its going to continue to rev higher just sitting there. Its a delicate balancing act that just kinda comes free with the analog nature of an ICE motor. Trying to explain it to a computer is a challenging prospect.

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Re: Observed trials bike designing

Post by bikerpete » Jan 15 2022 1:42am

You have a point about using throttle, clutch and brake simultaneously. That does make it a bit tricky. Maybe a pushbutton switch on the brake lever itself so you move your finger over a centimeter or so to engage regen or not, then regen varies according to the first part of the lever movement or force? Certainly needs a bit of consideration.

I don't think it would matter in the least if the controller was changing current to maintain 500 rpm against a slipping clutch - you're controlling the torque to the wheel via the slipping clutch anyway, so it matters not one jot if the motor is reacting to the load or indeed varying revs - you regularly vary revs against clutch without moving the bike at all on an ICE.
Once a friction device is fully slipping the rate of slip has far less consequence to the resultant friction than the force applied to the friction surfaces. Kinetic friction does not depend on the sliding velocity.
In fact I suspect it might be a good thing if it did maintain constant RPM, it would probably make it slightly easier to balance against the clutch if anything.
Holding pressure (balancing on the rear wheel) on an obstacle while building revs for a zap across a gap is an example of almost complete separation of engine rpm/power and control of torque to the wheel. It's no big deal, just requires skill development.
I don't think the EM's do stall either - there's an argument going on in some parts of the world saying that makes it unfair against ICE bikes. Now that's a pointless argument - electric is coming, get over it!

Gotta get myself a ride on a recent EM so I can get some real world knowledge!

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Re: Observed trials bike designing

Post by speedmd » Jan 15 2022 10:55am

The regen lever looks like a afterthought imo. May make marketing sence, but agree, it should be incorporated into the existing controls. Looking for the first one to come in with a variable flywheel mass control. Separating that from idle speed, would allow tremendous amount of variety to impulse potential. Agree, may be time spend a bit of ride time on one just to see if any of the skills improve or better see what direction things should go. The electronic shock damper control has me quite interested at the moment. Somethirng like the pedal on a piano does to keep the felt off the strings, it could be activated momentarily to allow added pogo as needed.

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DanGT86   10 kW

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Re: Observed trials bike designing

Post by DanGT86 » Jan 15 2022 11:08am

I was at a trials competition recently and I asked the riders about the rules regarding electric bikes. They said in some sanctioning bodies an electric bike in the group gives all the riders an opportunity to restart their bikes without a any points.

As for the idle stuff. I'm sure its nothing for engineers and programmers to work out. I just always like to try and wrap my head around the concepts and what it would take to make them work as a a diy builder. In the videos you can hear the motor "bogging" as the rider works the clutch. So it does seem to simulate the behavior of the ICE motors riders are used to.

What I do think is really cool about all of this is that you can electrically simulate any type of gas bike. 2strokes and 4 strokes have different engine braking and power curve behaviors. Different flywheels weights have different behavior. All of that can be mimicked by electric motor control programming. So its conceivable that an e-trials manufacturer could custom tailor a perfect feeling bike for any rider.

I would also have a noise vs silent switch. If you are going to rev up and dump the clutch then the rpm motor noise would be pretty important. If you were someone who learned in a clutchless EV format then you might not want or need the noise.

Exciting times we live in.

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Re: Observed trials bike designing

Post by bikerpete » Jan 15 2022 9:57pm

Indeed.
That's funny about being able to restart if there's an e-trials in the class! Certainly doesn't happen that way here in Australia, nor in Germany from what I hear from a friend over there.

I'm still not quite convinced that, " All of that can be mimicked by electric motor control programming."
Perhaps it's just that it can't yet be mimicked because the controller hasn't been designed that can replicate a flywheel. There are huge issues to overcome to achieve that, so I'm not sure anyone is going to bother for a while yet. Not least is how big does your motor need to be in order to give the short high power impulse that is available from a smaller motor/flywheel combination? You'd need to be able to supply all the power a flywheel can store without a significant weight penalty.

I should soon be receiving my first shipment of a new flywheel/clutched, brushless e-trials bike, claimed peak 10kw, around 42kg. Really looking forward to getting them and having a play. I've got a Nucular 12F here that I'll put in one if the factory controller isn't flexible enough for me to play with.

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Re: Observed trials bike designing

Post by DEHiCKA » Jan 17 2022 4:30am

bikerpete wrote:
Jan 15 2022 9:57pm
Indeed.
I should soon be receiving my first shipment of a new flywheel/clutched, brushless e-trials bike, claimed peak 10kw, around 42kg.
Interesting, is it a new company? do you have a link?
I would assume it does not have the standard trials 21"/18" wheels+tires, shock and fork, or 42kg would not be possible.
Trials 49KG middrive on stainless LMX frame
QS2000 + custom 8T/62T #420, Kelly KEB 10kW 450A Peak.
Michelin X-Lite trials tires on 21"/18" Jitsie moto trials wheels

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