Full-Sized E-Trials

[gwhy]

I dont use off the shelf e-throttle anymore as I have never found a reliable/consistent one so I now use a regular trials cable throttle with a interface to move magnets either side of a hall sensor, this picture do not have the mags or the hall sensor installed and this was a prototype so now its a bit neater,slimmer and fits nice into a very small box inline with the cable.

[gwhy]

Been a while since I visited Trials Central. I now have an EM 5.7. Rode a trial early this month. Some video here http://www.electricmotioncanada.ca

Rode with my son on his OSET 16. Trial was 4 1/2 hours, plus folks tried it out afterwards for about an hour. Didn't have time for any recharge during the day, still operating with the same amount of power at the end. What I like - smoooooth, simple - no clutch, no stall. What I didn't like - just a little bit heavier than my Ossa 280i Replica and top speed is limited (about 4th gear OSSA is tops). My riding style has had to change slightly, no flywheel effect means you have to roll the throttle back slowly rather than shut off completely when finishing a climb. Stop on a climb and you don't have a stalled gas engine locking the back wheel, if you don't hold a little power it freewheels backwards - it only happens once, then you learn!! The power profile is so configurable, when it came it was set up with a slow throttle, I changed that through the computer to a fast throttle and took power to 80% of available on the fast map. I tried 90% but it was like a drag bike, too scary. It has a clutch but it seems just a throttle working backwards, I agree with other comments - to get the big power bang, you need a mechanical clutch to build up the energy and dump it. I've don't bother using the clutch, and stopped looking for the kickstart and gear lever to - although I do sometimes look for neutral - doh.

yes riding a electric is a whole new ball game but just as fun, Im still not convinced about the mechanical clutch , I think I need to test ride a 5.7 as the setup on my bike works very similar to if it had a mechanical clutch even down to holding the bike still with the clutch lever on a hill

[nostroke]

I have a funny thing going on with my GasGas conversion..it has a low speed misfire! It acts like a dirty carb or half fouled plug. I am pretty sure its just a dirty potentiometer wiper in the Magura twist throttle, but it adds an element of gas realism that I think is cool, in a twisted sort of way. Its not a distraction because its very minor and just at one distinct throttle position.

Anyways, I have had a few people complain of wrist issues using this throttle so I am curious to see if the cable pull pot setup improves things. Because I have no E-Clutch (anti-throttle, whatever), the throttle is crucial to good bike control. The Magura trhottle, with no cable (the pot is internal, in the twist grip assy), its probably too smooth. In other words, there is no friction feedback which I think may actually be a unintended but useful fault in a cable system. That smoothness, combined with a very sensitive quick throttle (about 45 degrees of rotation) can be very fatiguing, requiring too much focus on the throttle.

Edited May 15, 2013 by nostroke

[gwhy]

I am building a new electric trials bike here at my shop and am interested in how that throttle/ anti-throttle clutch setup works for you. On my GasGas conversion here, I am using a Magura twist throttle and its making me sore! Its only a 45 to 60 degree turn and, while it offers great power delivery, its just too hyper. So I have ordered a Magura 120 degree and a Domino 90 degree that I will use to spin a remote mounted pot with a cable.

(BTW I have NO clutch / anti throttle set up)

sorry mate i only just seen this post... the clutch setup works very well and I would not go back to throttle only. I didnt get on very well at all with the magura pot throttle and any pot will wear and generate noise so I opteded for a hall sensor setup that is 100% better

[nostroke]

Well, I built up the cable pot system using a 45 degree pot from a Curtis potbox and the Magura 313 Trials Throttle and designed it for 32mm of cable pull, almost a half twist to full throttle. I like it. You have to be more aggressive with it but control is much better. I mounted it on the fork, behind the front number plate, so the cable doesn't have to contend with any steering movement.

[axulsuv]

I haven't really been following this thread , but I was quite impressed watching the spanish guys play with the electric gas gas at the world round in TN.

From what I saw , it definitely works ....

[betarambo]

Gwhy I just wanted to thank you for the pioneering on the e-clutch design. I am starting on building my version of a full size e-trials bike. I am starting with a 20" Oset. Phase 1 is just Lipos and a big steering neck to get the bars up so it fits me better. That should be enough to get me competing in a lower class. Phase 2 is 26" wheels. After that I suspect that phase 3 will be some welding to get the geometry right for the wheels. Along the way somewhere though I think I am going to need the e-clutch in order to control the power more smoothly. My dad is all about this project. He was an electrical engineer back in the day so I kind of volunteered him to go through your schematic and build me a prototype. We'll see how it goes but I wanted to say thanks for posting all the details.

My goal is to start competing on it in October and to be back up to Expert sometime next year. The darn kids adapt to electric so quickly, but us more experienced types might need a bit longer to catch on. I think it is cool that none of my current plans include finding more power. The darn thing has plenty of that!

[gwhy]

Thanks Betarambo for the shout out...

Your plan sounds good to me, but I think once you go do a bigger wheel the power may not be quite enough from the standard motor/controller , but this is something you will need to try to know for sure. If you are going to use bicycle rims then 24" with 3" tyres are a comparable size with standard gas bike wheels/tyres. Drop me a pm If there is any questions that you would liked answered about the e-clutch, good luck and keep the board informed of progress :-).

[betarambo]

I came across something called a Throttle Tamer over on Endless Sphere. http://endless-sphere.com/forums/viewtopic.php?f=31&t=51460

I thought I might try it out. In general it gives you some adjustable pots and makes the throttle react to the speed at which you twist it. Go straight to WOT and you get full power. Take a second to get there on the throttle and the bikes maybe takes two seconds to get to full power. Its worth a try and might prove pretty interesting in confunction with the throttle response pot already on the 20.

You make a good point about the big wheel and the loss of power. I was thinking that I could probably have sproket specialists make me a sproket to return it to stock gearing, but we will see. I may also end up running a regular trials rear wheel so I can get some soft rubber and a 4" tire under her. That would probably give me more sproket options, but with the big goal being weight I want to try the bicycle wheel first.

Today I ordered (4) 24 Ah batteries from EarthX. All 4 together is still under 10 pounds. They will be a little tricky to mount as they will probably end up stacked two high, but I should be able to break out the ABS and the heat gun again and make a decent enough battery box. With 15C Zippy's disapearing these things are not a ton more expensive than HK Lipos and the built in BMS makes for a bit less maintenance (my dealer discount doesn't hurt either).

I will dig around on 24" wheels. I picked 26" because I think it is the most common size so I figured I would have better tire options than 24". Also, if I understand bike trials right I think they pretty much only come in either 20" or 26". I'll certainly do some homework when I get to that phase. Luckily I have a pretty good bike shop who is supportive of my projects so I will run down there and get educated.

[nostroke]

Have you looked at the Monty trials rims and tires? I built a few electric bikes for small kids about 10 years ago using them and they are awesome. If you use 24" bicycle rims there are a few wide 3.0" downhill tires like Nokian Gazzalodi. But nothing works as well as a gummy 4.00 x 18 m/c tire, although the scale is a bit out of whack on a smaller rig.

Regarding the throttle pot...if you can find a 1" travel slide pot with an audio taper and cable operate it, it has a great feel but its not very durable as most of the pots are crappy (at Radio Shack).

Edited July 24, 2013 by nostroke

[nostroke]

Just finished a new bike.This is the dash 3 version. New and improved! I got forks and brakes from Formula, wheels from FABA and made pretty much everything else.

[purkyuk]

Mint!

[gwhy]

very nice

[gwhy]

did you use the same setup for the electrics as your other one?

[nostroke]

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.