Getting a big traillie airborne

[jarl]

Had a little bit of fun earlier today with my tranny (see youtube vid) but whenever I try to take off, the front wheel really doesn't want to, so the back goes high and the front slams down and it's really not smooth at all. How can I keep the front high and land smoothly? I managed to keep it smooth a couple of times, but I have no idea what I did whilst in the air to land her both wheels at the same time.



Also, can the TA take this kinda work, or should I stop before I break something?

Cheers

[AlanH]

Keep the power on as you take off otherwise the bike will nose dive and the rear will kick up. Keep trying and you'll get there. It took me a while to get the hang of it on my old RD04.

[Kjell Lindberg]

Stand on your footpegs and lean backwards a bit, when jumping.

[jarl]

Pleased to say staying on the throttle works

Apparently a dab of the front brake also makes the bike go back a bit more. Heard this from the kids with the dedicated 2 stroke crossers (that they couldn't get to start, hehe) but didn't get a chance to try it because I had to get home so only had a chance to do a couple of jumps. I think I need some stiffer springs, they're so easy to get in the air! Would have got a vid but the kids with the crossers probably would have nicked it

[Ashley M]

If you watch motocross riders they can control the bike in the air with the throttle slow the back wheel down ie use the rear brake and the front wheel will drop, use the throttle to spin the back wheel faster the front wheel will lift, it will also help to move your weight back and pull up on your bars when you take off the bike is more then likely front end heavy and take off under power, but start small and build up

[AlanH]

Apparently a dab of the front brake also makes the bike go back a bit more

It's actually the opposite effect so they were talking bowlacks. I won't bore you with the physics but basically speaking when you apply the front brake, the momentum of the wheel is transferred to the bike chassis which tries to pivot the bike in the direction the wheel was travelling. It pitches the bike forwards.

The brake dab is used if the front has come up too much and you need to level the bike out. It's usually the back brake that is used (clutch in first so you don't stall). A dab on either brake will have a tendency to bring the front down - useful if your take-off wasn't quite right and you're starting to look skywards. As Ashley M says, throttling on or off mid-air also affects the attitude of the bike and is the way to go.

Personally I stay well clear of the front brake when I'm in the air.

Oh, and stand up too as Kjell says. You can't move your body around properly if you're sat down

[jarl]

It's actually the opposite effect so they were talking bowlacks. I won't bore you with the physics but basically speaking when you apply the front brake, the momentum of the wheel is transferred to the bike chassis which tries to pivot the bike in the direction the wheel was travelling. It pitches the bike forwards.

Ahh, that's what the physics is, I was trying to figure it out but couldn't.

So now I have to ask, if that's true then how come staying on the throttle keeps the bike level? Surely if you stay on the throttle in the air the rear wheel speeds up and the bike will pitch forwards?

[AlanH]

Staying on the throttle doesn't automatically keep the bike level.

Your throttle position on takeoff is the start point. If your throttle position causes the rear wheel and motor to spin faster it in the air, it will have the effect of bringing the front end up not down. Open throttle = front up, close throttle = front down. However, all that depends on how the bike took off and can only serve to modify the movement it had when it left the ground.

If you leave the ground with not enough throttle, the back kicks up and the front dives. With no further input, the bike will continue pitching forwards. You need to minimise the chance of landing on the front wheel and going over the bars. To reduce the overall forward pitching open the throttle wider spinning up the engine and the rear wheel. The reaction reduces the tendency to dive forwards.

If you give it a big handful coming off the ramp the front will be lifting as you leave the ground and the bike will continue to rotate in the air pitching backwards. To minimise the chance of going over backwards, you can throttle off or, if it's a real panic, throttle off, grab the clutch and dab the back brake.

These are all techniques for recovering from a flawed take-off. Get the takeoff right and you should be fine just shifting your body weight around and using the action of the throttle - unless you are doing massive jumps (which would break a TA).

[btbloke]

all down to practice an ability


listen at the end,you'll hear him give it some gas to bring the front up to level the landing because the @ is a bit front heavy.

[jarl]

ace, this is all making sense now, especially since I just went down to my garage and spun some wheel on my pedal bike and applied the brakes. Weird, but cool. I might go out and practice a bit more on the tranny now...

It just seemed a bit counter-intuitive to stay on the throttle when doing a jump, IMO, hene why I was nose diving all over the place! Cheers guys, hopefully have a slightly more respectable youtube vid in a few days