weelie problem, I can't accelerate full power!

[bzhwindtalker]

Hello all,
I just finished a build on a full susp 20 wheels alloy frame. The bike uses a conshimotor 750w rated motor on 40v, nothing special here.
I have on the bike a 120mm travel fork, that makes the bike more uprigth than normal, It's a child bike
now the problem is that if I sit on the bike and put some power, the front wheel is imediately in the air! I need to accelerate verry slowely to keep the wheel down, wich ain't fun 8) If I lean forward, it's a bit better, but even when I'm almost over the bars, full power is risky.

I guess a good solution would be to incrase wheelbase and move the COG forward?
Another problem is that happens with stock controller

 

[Drunkskunk]

wheely bars, like the drag racers use.

Seriously. that much weight, that far back over the rear wheel, with that much power.... are you complaining or bragging?

 

[biohazardman]

With your front end so high all your body weight is right over your rear axle so it doesn't take much to bring the front end up. If you bring the front end down or bend your seat post forward things should be a quite a bit better. Some battery weight in the front might help also. Batteries in a backpack would make it worse. Good luck

 

[Thud]

"Wheelie problem" is an oxymoron

 

[Seriousknot]

Looks to me like you could easily 'stretch' the swingarm at the two mounting points. I might try something like 2 inches at lower mount and 1 1/2 inches at the top.

 

[bzhwindtalker]

haha
Seems like I have a quick fix, I changed the side of the seat, I got 10cm forward.
Another problem is the 5KG battery in backpack. If I put It on the top tube, may be better for COG!
Do you think that pedals would be better than pegs for handling?
Will try to get a video of it tomorow!

 

[SilverSurfer]

Bring it over, we'll take it for a test ride, see how bad the problem is!

 

[gwhy!]

haha
Seems like I have a quick fix, I changed the side of the seat, I got 10cm forward.
Another problem is the 5KG battery in backpack. If I put It on the top tube, may be better for COG!
Do you think that pedals would be better than pegs for handling?
Will try to get a video of it tomorow!

pegs are always better for handling.

 

[John in CR]

Is the swingarm steel or AL? If steel, add some wheelbase easily. If AL, don't ride it again until you get some torque arms on that motor.

 

[AussieJester]

Bring it over, we'll take it for a test ride, see how bad the problem is!

IIRC you neighbor Seth Enslow, i am sure he and his Crusty Demon buddies will give it a good workout

KiM

 

[liveforphysics]

Learn to embrace the wheelie and love it.

When you want to accelerate hard, throw your upper body out way over the bars.

This is essentially how riding a 1000cc sportbike or a good dirtbike works. At any speed under 50mph (if you're in the right gear), cracking the throttle should result in the tire lifting.

It's how things should be.

 

[mdd0127]

It's also a highly under rated tool for getting over obstacles....even better combined with momentum.

Check out Danny McAskill(sp?) on you tube.

Wheelie good.



If you got some triple crown forks you could move the crowns down and maybe get a little more stability and a little better steering though.

Oh yeah....get video.

 

[dogman dan]

I built a bike like that a couple summers ago. 24" no suspension frame with rear 24" 5304. Then I put a shock fork and 26" wheel up front. Nicads were mounted in the frame, and on a rear rack. Wheelie mobile. Pretty much lifted the front wheel with any throttle imput. It was fun as hell to ride in loose sand roads. Get er up to speed carefully, then let the front float around the corners. Steering with just the rear tire is fun!

But it was pretty sketch, so I moved one set of the nicads to the handlebars, and rode it dirt for the summer. It was ok, you could still wheelie at will, but really, on a technical dirt singletrack it sucked to have such poor handling. But as a dirt drifter, it was pretty fun till you'd lose it and ride straight into a thorn bush.

 

[bzhwindtalker]

Hey all, I got some video of the second run with frame mounted battery and seat moved front. Not impresive really I ordered some video sunglass, to make videos of my tracks, they are really beautifull ! I need to up the current limit as well
[youtube]xF3ME3aMU2A[/youtube]
now that I'm getting used to the bike, I should be able to ride it harder

 

[AussieJester]

Cool vid...bike looks to be about 17 times to small for you though haha...can't you dig up a bigger frame perhaps?
Heck, with your skills you should be making a solo frame to match that neat trike you are building!

KiM

 

[TPA]

Your first lesson should be gaining enough confidence to keep your feet on the pegs. As you get better, putting your foot down will be useless...and dangerous.

Learn to corner and slide without worrying.

 

[RWP]

This issue of eWheelies has been on my mind lately.

What I see with gassers is a lot of control and my thoughts go to the fact that with a gasser you can let off a bit and control the wheelie attitude with getting on and rolling off the throttle.
With electrics I think one only has getting on the throttle as it freewheels when one rolls off the throttle.

Is this an issue?

What I see on YouTube is a lot of wheel lifting but not with any real sense of control. Have I been watching the wrong vids?

 

[bzhwindtalker]

thank for advices! will try that, fiting a rear brake could be a good idea to control the bike too :?
for now the bike has more to give than my skills show, time to learn
And yeah kim I planned a custom build inspired by a motoped frame, but this one was too tempting at 50$ delivered I plan to rework the rear part of that frame to make it more power-capable (longer), and maybe put the frok out of the wheel, don't like the weigth in the rear wheel, makes jumps horrible!
[youtube]uvZd2ChhCYo[/youtube]

 

[Drunkskunk]

This issue of eWheelies has been on my mind lately.

What I see with gassers is a lot of control and my thoughts go to the fact that with a gasser you can let off a bit and control the wheelie attitude with getting on and rolling off the throttle.
With electrics I think one only has getting on the throttle as it freewheels when one rolls off the throttle.

yeah. with a gasser, you have compression braking when you let off the throttle. with an electric, it has nearly zero resistance by comparison with the throttle off. Balancing a wheely would be a lot more of a pain in the @ss. I can pull a wheely, but I can't ride it very far on an electric. I've never been able to master the balance needed or get coordinated enough to use the brake and throttle that way.


But that leads to an awesome idea. Why not put regen or plug braking on the throttle, were they react like compression braking. let off the throttle a little, and the motor drags down your speed. you could even add a "clutch" that would turn off the braking effect when you just wanted to coast.

 

[gwhy!]

This issue of eWheelies has been on my mind lately.

What I see with gassers is a lot of control and my thoughts go to the fact that with a gasser you can let off a bit and control the wheelie attitude with getting on and rolling off the throttle.
With electrics I think one only has getting on the throttle as it freewheels when one rolls off the throttle.

yeah. with a gasser, you have compression braking when you let off the throttle. with an electric, it has nearly zero resistance by comparison with the throttle off. Balancing a wheely would be a lot more of a pain in the @ss. I can pull a wheely, but I can't ride it very far on an electric. I've never been able to master the balance needed or get coordinated enough to use the brake and throttle that way.


But that leads to an awesome idea. Why not put regen or plug braking on the throttle, were they react like compression braking. let off the throttle a little, and the motor drags down your speed. you could even add a "clutch" that would turn off the braking effect when you just wanted to coast.

Could always feather the back brake, The other issue with pulling a wheelie on a pushbike is peg pressure is non-existent, costing ( manual wheelies ) are ( I think ) a lot more difficult than if you are peddling, on gassers its also so much easier sitting than standing and the same applies even more so on a cycle. Im rubbish at low speed wheelies ( but reasonable at high speed wheelies) a lot of my mates have tried to teach me, I think if you can master a wheelie going no faster than walking pace ( as some of my mates can do ) then you got it nailed the faster your travelling the easier it is to maintain a wheelie .

 

[AussieJester]

But that leads to an awesome idea. Why not put regen or plug braking on the throttle, were they react like compression braking. let off the throttle a little, and the motor drags down your speed. you could even add a "clutch" that would turn off the braking effect when you just wanted to coast.

Something i bought up a while back more related to getting on the throttle at the apex of a turn, with the freewheel there is a 'gap' between turning throttle and anything happening...I Suggested to do away with the freewheels to GWhy for his trials bike to get the benefit of the electric motors cogging also, would be similar to compression lock up on a ICE bike...I agree, wheelies on a bike setup with a freewheel would be harder than on a ICE bike, when you let the throttle off the engine brings the front down, on an electric the freewheel stops this, i would imagine alot of rear brake is necessary on an e-bike to hold a decent wheelie IF you have a freewheel in the mix...then again, poppin wheelies on a 'manual' pedal bike is piece of piss and there is freewheel in the mix there...

KiM

 

[beast775]

aaaahhhhh my speakers,i had my system cranked up haha thanks... bad rake and trail on that machine.

 

[John in CR]

But that leads to an awesome idea. Why not put regen or plug braking on the throttle, were they react like compression braking. let off the throttle a little, and the motor drags down your speed. you could even add a "clutch" that would turn off the braking effect when you just wanted to coast.

I use throttle regen with my Lyen controller, so your "awesome idea" is what I use on a daily basis. When I let off the throttle, regen braking comes on at the point where throttle would be just coasting. The amount of braking force increases to full force as I back the throttle to zero. The regen braking cuts off below about 10kph, so now I only use by brakes for stronger stopping or to come to a complete stop.

John

 

[RWP]

I use throttle regen with my Lyen controller, so your "awesome idea" is what I use on a daily basis. When I let off the throttle, regen braking comes on at the point where throttle would be just coasting. The amount of braking force increases to full force as I back the throttle to zero. The regen braking cuts off below about 10kph, so now I only use by brakes for stronger stopping or to come to a complete stop.

Sensored controller I presume...

 

[The Mighty Volt]

"Wheelie problem" is an oxymoron

This. If you are popping W's then you have it down.

That's another contradiction.