Electric Trials

[wherry]

OK I haven't ever had anything to do with electric vehicles or bikes so how does the transmission on these things work? Is the motor hooked up pretty much direct to the driven wheel(s)? And if so is it a fancy controller that allows the power to be fed in and out?

The reason that I ask is that this topic has had me thinking about an electric bike and what it would take for it to appeal to me. It seems to me that to replicate the characteristics of a petrol bike it would need to have a clutch and/or a gearbox maybe (or maybe not - I don't know the torque characteristics of electric motors). Stating the bleedin' obvious - A lot of modern riding is done on the clutch with that controlling the power applied almost instead of the throttle so I think you'd need to have something that replicates that to appeal to a broad spectrum of dyed-in-the-wool petrol-heads. If it was significantly different you'd have to develop a new riding style that I suspect a lot of people would baulk at, particularly if the petrol bikes are still around at the time.

[grahamjayzee]

OK I haven't ever had anything to do with electric vehicles or bikes so how does the transmission on these things work? Is the motor hooked up pretty much direct to the driven wheel(s)? And if so is it a fancy controller that allows the power to be fed in and out?

The reason that I ask is that this topic has had me thinking about an electric bike and what it would take for it to appeal to me. It seems to me that to replicate the characteristics of a petrol bike it would need to have a clutch and/or a gearbox maybe (or maybe not - I don't know the torque characteristics of electric motors). Stating the bleedin' obvious - A lot of modern riding is done on the clutch with that controlling the power applied almost instead of the throttle so I think you'd need to have something that replicates that to appeal to a broad spectrum of dyed-in-the-wool petrol-heads. If it was significantly different you'd have to develop a new riding style that I suspect a lot of people would baulk at, particularly if the petrol bikes are still around at the time.

Completely agree Wherry! I am presently working on an electronic replication of an IC powered bike! It has to have some similarities with a gas bike if it is to gain acceptance.

I'll keep you posted

Graham

[atomant]

I have great hopes for electric trials bikes of the future. Remember that a lot of 4 - 6 year olds riding oset's will make the transition to bigger bikes quite easy so if they are available, they will be buying them - 10 years or less I reckon

[jonathan collier]

The scorpa Etricks looks like its going at at between 2000euros and 3000euros depending on model. I bet a trials version would be similarly priced.

[reddawgst]

I built the initial Electric Trials bike version in 2006 (the Lewisport writeup). That was powered by 4 14Ah 12V (48 volt) motorcycle batteries. Good for about 30 minutes of riding, usually enough to get around the Saturday events. Charging time was about 30 minutes. At its inaugural debut at Hollister Hills in 2007, I ended up doing a lot of pushing

I started building Lithium-Ion packs in towards the middle of 2007, building a gigantic 40Ah battery for the last event of the year at Hollister. This battery got me around the loop without pushing, but I didn't have enough time to recharge it, so I revamped my whole battery approach. Nonetheless I got 2nd place in the Modern Bike 2 line on the electric bike. I rode the gas 315R to a second in the Sr Sportsman class.

For 2008 I was building my own custom Lithium-Ion battery packs using A123 cells from DeWalt 36V battery packs in 6Ah and 11Ah configurations. In 2008 I rode the electric bike exclusively, both days events. I managed a 1st in Saturday's Modern Bike 2 line, and a 2nd in Sunday's Sr Sportsman. I am now building a slightly smaller 11Ah 66V packs that I plan to mount lower in the frame after we complete frame modifications to allow it. Next weekend is my nemesis, the Cowpile Trial in Marin County. I have not yet completed a single loop on Sunday without having to push or at least walk the bike. This year, the plan is to use two 11Ah packs, wish me luck.

I use a jack shaft so I don't need a gigantic rear sprocket. Top speed with current gearing and throttle map is about 25mph. Roughly equivalent to between 2nd and third gear on the gas bike. I typically cruise around the loop around 15 mph to conserve energy. Going flat out takes way to much energy. The motor can deliver around 26 HP, but with the low gearing, I never get that sort of demand, so even going up a steep hill I use less than 10 HP. But from a stop, wick on the throttle where there is good traction and you cannot keep the front wheel on the ground. In fact, when I ride any other trials bike, from a slow speed just twisting the throttle, they all feel fairly gutless. At high speed, this a completely different story, so for blasting down the trails, this is not the ticket.

You can read more about the bike and see some videos from 2007 at www.ecotrials.com.

Last year I didn't post any new video, and so far this year I have been concentrating on new bits and tweaks. The motor has been shrouded since I started competing on it, to keep out the mud etc. I have been working with the power delivery, making some progress. Without a clutch, you are totally dependent on a smooth right wrist.

This is probably the most powerful trials bike in existence. Adrian Lewis commented after riding it late last year when he was trying to come to grips with the power of the Beta 4 stroke "I thought the Beta had too much power, that thing would kill me." But tons of power doesn't translate to easy to ride, in fact quite the opposite. So I have been trying to reach a smooth output, but with enough power to easily manage a wheelie as required. Last year, I got the crawling speed dialed in, but then didn't have enough power to lift the front wheel. I finally got a new throttle map which helped, but there was a definite surge just past slow that was spinning the rear wheel at inopportune moments. This year I have a slightly better setup.

So after the frame mods, probably next up is a clutch, a major undertaking at a time of limited funding, so that might take a year or two. Until that time, the bike really isn't suitable for accomplished riders.

Depending on terrain, the bike is usually good for about 30-40 minutes of actual riding, and roughly five miles. I have multipple packs and swap after each loop. Until the cost of batteries comes down, probably not viable in the market place. I'd say in another 5 years or so to be competitive with petrol/gas bikes. If we can triple the power to weight/size, probaly a real winner.

And no, the bike isn't silent. You hear a definite "ZZZZZZZ" from the primary chain. But it is tons of fun, amazing traction at crawling speeds, no fives for killed motors, and maintenance, what maintenance? I wash the bike, lube the chains and levers, and of course, recharge the batteries. The brushes in the motor are supposed to be good for 3000 hours. I probably ride the bike on average 2 hours a week, (actual riding time), so call it 100 hours a year. Assuming the bike maintains that level of activity, I guess my heirs will have to change the brushes in 2037! Well, with all the new bikes available by then, maybe it'll be the curators at the Smithsonian

Hope that answers some questions for everyone, Paul

[atomant]

Thanks for that info Paul. I found it very interesting.

Cheers

Ian

[reddawgst]

Here is another perspective, this from Frank Raines Park in California at the 2009 season opener.

http://www.youtube.com/watch?v=z5H7kHQfm_M