View Full Version : How do you jump?
Without getting thrown out of the seat?
Jump? On a motorbike?
My understanding is you use the 34" shockabsorbers that are your legs :D Thats from dirtjumping on a bike though rather than motorbike though.
Same principle i guess
Bend both legs & straighten them quickly...
Wait... on the bike...
Normally, I'm stood up before both wheels are even in the air.
HTH.
Blue_SV650S
14-05-08, 06:24 PM
ratchet straps?!? :)
Sorry, thought 'Bikes - talk & issues' would explain what I meant. & Yes on the road, this being SV650 'n all.
just get your @rse off the seat, but keep your knees slightly bent
philbut
14-05-08, 06:54 PM
Grip the tank and side of the bike with your knees and lower legs - works in MX so I assume the same is true for all bikes. If you don't, not only will you fly off the bike on the way up, but you will have a rather nasty crotch to tank moment when you decend - I speakfrom experience!
http://uk.youtube.com/watch?v=0_Y36ef6dRU
just get your @rse off the seat, but keep your knees slightly bent
No, still got thrown further off the bike.
Is it important to accelerate through the jump? or can you just hit it at high speed.
Warthog
15-05-08, 11:03 AM
Ok I know what you mean. I went over a humpback bridge at speed and nearly got thrown off the bike because I assumed the bike would jump with me. This is wrong. Listen to Phil, he has done a lot of motorcross. You HAVE to grip the tank with your legs and knees. Also for the high flying motocross stuff I think you need to keep on the throttle for a gyroscopic effect or else the bike does a front somersault. HTH.
Blue_SV650S
15-05-08, 11:03 AM
No, still got thrown further off the bike.
Is it important to accelerate through the jump? or can you just hit it at high speed.
You use the throttle to keep the bike level ... if the nose drops, hit the accelerator, if the nose rises, kill the throttle/use rear brake.
You think of the spinning mass in the rear wheel, and the 'moment' forces involved in spinning it up and slowing it down, you are using that as a control mechanism 8)
Best thing to do is watch MX videos, you will see them using this technique all the time 8)
Warthog
15-05-08, 11:10 AM
You use the throttle to keep the bike level ... if the nose drops, hit the accelerator, if the nose rises, kill the throttle/use rear brake.
You think of the spinning mass in the rear wheel, and the 'moment' forces involved in spinning it up and slowing it down, you are using that as a control mechanism 8)
Best thing to do is watch MX videos, you will see them using this technique all the time 8)
yep, also check out travis pastrana who absolutely revs the nuts off his bike doing the double backflip! http://www.youtube.com/watch?v=VngJrAIzFNE
You use the throttle to keep the bike level ... if the nose drops, hit the accelerator, if the nose rises, kill the throttle/use rear brake.
You think of the spinning mass in the rear wheel, and the 'moment' forces involved in spinning it up and slowing it down, you are using that as a control mechanism 8)
Best thing to do is watch MX videos, you will see them using this technique all the time 8)
I really don't think you should be airborne long enough on a road bike for that to come in to play, especially considering how much heavier the road bike is and the way that will reduce this effect significantly, I wouldn't want to rely on it :)
I think later I'll go find a nice canal bridge and try a superman-to-no-hander-landing.
You use the throttle to keep the bike level ... if the nose drops, hit the accelerator, if the nose rises, kill the throttle/use rear brake.
I understand all that would work as described with a wheelie. But do you mean it also works when the rear wheel is in the air? :shock: So does a spinning wheel have the effect of making it heavier? :???:
You think of the spinning mass in the rear wheel, and the 'moment' forces involved in spinning it up and slowing it down, you are using that as a control mechanism 8)
Best thing to do is watch MX videos, you will see them using this technique all the time 8)
I'm more talking about trying to get the rear wheel at least, oooh 2 inches of the ground? without being thrown 12 inches higher than the bike. :D
So I'm not sure I can learn form MX?
Blue_SV650S
15-05-08, 11:30 AM
I really don't think you should be airborne long enough on a road bike for that to come in to play, especially considering how much heavier the road bike is and the way that will reduce this effect significantly, I wouldn't want to rely on it :)
I think later I'll go find a nice canal bridge and try a superman-to-no-hander-landing.
I have hit the rear brake before now after going over a hump-back ... my mistake as to 'give it large' right at the crest ... that gave the nose a tendency to rise ... even in a little hop like that, you'll be surprised what a difference it makes .. I'm just glad I watched MX when I was a kid and realised what they were doing and how dramatic effect it had on attitude of the bike!! ;)
remember that a wheel spinning at say 50 mph has quite a bit of energy in it, you try stopping that with your hand ;) Its certainly going to be enough to change the trajectory of the bike ;)
Warthog
15-05-08, 11:31 AM
I understand all that would work as described with a wheelie. But do you mean it also works when the rear wheel is in the air? :shock: So does a spinning wheel have the effect of making it heavier? :???:
I'm more talking about trying to get the rear wheel at least, oooh 2 inches of the ground? without being thrown 12 inches higher than the bike. :D
So I'm not sure I can learn form MX?
Wow, ignore all the other posts then! Go on. Ignore them. Especially the bit about grabbing on to the tank with your knees like in MX.
I understand all that would work as described with a wheelie. But do you mean it also works when the rear wheel is in the air? :shock: So does a spinning wheel have the effect of making it heavier? :???:
I'm more talking about trying to get the rear wheel at least, oooh 2 inches of the ground? without being thrown 12 inches higher than the bike. :D
So I'm not sure I can learn form MX?
Just lift yourself off the seat but keep your knees bent. The important thing is that your feet stay firmly on the pegs.
The technique blue mentions does work. It's the equal and opposite reaction thing. If you spin something one way, then the object spinning it will be pushed in the opposite direction. If you imagine the bike weighed no more than the wheel- when you hit the throttle in mid air, the bike would obviously try to rotate around the spindle in the opposite direction to the wheel rotation. Only because the weight of the bike and rider is so much greater than that of the wheel is this effect diminished so greatly.
Blue_SV650S
15-05-08, 11:35 AM
I understand all that would work as described with a wheelie. But do you mean it also works when the rear wheel is in the air? :shock:
Ok, the rear wheel is spinning ... to stop it from spinning you need to apply a force right? if you think about the direction of the force, it is rotational about the rear wheel spindle. Stop that force dead, the rotational force is transfered form the wheel to the chassis. The chassis does weight a great deal more, so it won't rotate at the same speed as the wheel was, but never the less it will have a downward rotational force.
I have hit the rear brake before now after going over a hump-back ... my mistake as to 'give it large' right at the crest ... that gave the nose a tendency to rise ... even in a little hop like that, you'll be surprised what a difference it makes .. I'm just glad I watched MX when I was a kid and realised what they were doing and how dramatic effect it had on attitude of the bike!! ;)
remember that a wheel spinning at say 50 mph has quite a bit of energy in it, you try stopping that with your hand ;) Its certainly going to be enough to change the trajectory of the bike ;)
I bet your rear wheel was still on the ground :)
j/k but it can't come close to motox bike "adjustability"
Blue_SV650S
15-05-08, 11:42 AM
j/k but it can't come close to motox bike "adjustability"
Agreed, but you have to agree with me (or more importantly Mr Newton ;)) that it WILL have the desired effect to some degree! ;)
The technique blue mentions does work. It's the equal and opposite reaction thing. If you spin something one way, then the object spinning it will be pushed in the opposite direction. If you imagine the bike weighed no more than the wheel- when you hit the throttle in mid air, the bike would obviously try to rotate around the spindle in the opposite direction to the wheel rotation. Only because the weight of the bike and rider is so much greater than that of the wheel is this effect diminished so greatly.
Ah, that explanation is great! I can understand that (nothing to do with weight) (but like a helicopter with the tail rotor broken - instead of the helicopter spinning the main rotor, the main rotor spins the helicopter in the opposite direction):D
Blue_SV650S
15-05-08, 11:51 AM
Ah, that explanation is great! I can understand that (nothing to do with weight) (but like a helicopter with the tail rotor broken - instead of the helicopter spinning the main rotor, the main rotor spins the helicopter in the opposite direction):D
Yeah, you get the idea now!! 8) Nice analogy/example of the concept with the choppa too :)
p.s. what was wrong with my explanation I wrote/posted at the same time!?!? :rolleyes: :D
So I'm not sure I can learn form MX?Wow, ignore all the other posts then! Go on. Ignore them. Especially the bit about grabbing on to the tank with your knees like in MX.
I presume that's the specific bit you are referring to :D
In the situation I'm talking about, it's all over in a split second so I was never asking about how to trim the attitude in mid flight :D
I'm not sure what Motocross is, but I'm thinking it the one where they jump from crest to crest. What with the helpful video posted by pmap I think this was going a bit off topic.
I never said I would ignore the advice of gripping the tank & I have stomp grips for that :D
p.s. what was wrong with my explanation I wrote/posted at the same time!?!? :rolleyes: :D
Just he got there first! :D
Your reply wasn't there when I started replying or I just dealt with it as I was reading down.
I like a nice choppa ! :D
Absorb the bump with your **** off the seat. However, it's harder to keep the throttle steady doing this.
either that or grip like buggery with your knees.
Blue_SV650S
15-05-08, 12:30 PM
This is a good opportunity for me to post one of my vids really ... I have been trying not to as people must get a bit fed up!! :oops: :D
Anyway this is Cadwell mountain, which is effectively a 'jump' ... if you watch it closely (~17s in), you'll notice I raise myself out of the seat slightly just before the crest, that way, when the bike rises/the suspension unloads, the bike simply comes towards my botty, rather than resulting in it spitting me up 8) I am using my legs as shock absorbers ... you will also notice I roll off the throttle to help maintain an more level attitude ... it is so easy to end up wheelieing the whole of that bit after the mountain if you don't ;) Or worse still flip it :shock:
http://www.youtube.com/watch?v=Hjl-a2Zgp-Y
Agreed, but you have to agree with me (or more importantly Mr Newton ;)) that it WILL have the desired effect to some degree! ;)
Never!
:)
Nice vid btw. Lots of crashes there aren't there. Leon Camier's leg break (last season?) was nasty.
http://www.youtube.com/watch?v=8e-vgQSqNtA&feature=related
:-dd
Tim in Belgium
15-05-08, 01:21 PM
either that or grip like buggery with your knees.
I never grip with my knees during buggery, it spoils the whole occassion.
As for the term you're looking for I think you'll find it's the conservation of angular momentum.
How do you jump?
1:28 in.
http://uk.youtube.com/watch?v=DuaXn4-gasE
stuartyboy
15-05-08, 06:31 PM
Stu...
Are you coming on the Ecosse rideout? If so then wait till the Duke's pass section. There's a straight about 2 miles long with 5 jumps. Keep a steady throttle at 70 and grip with the tank with your knees - you will definitely experience air. (Ask any of the SV eccose posse).
If you sit off the seat with bent knees then trust me you're gonna get sore nads when you come down.
I assume non of those arguing about throttle/brake use in the air have watched off road RC racing?
In RC racing, the drivers often blanace the throttle very delicately, for the exact reason that gyroscopic affect does alter the trajectory of the RC car. Think about the weight's involved in an RC car, and the amount of force you'd need to apply whilst it's in the air (bare in mind these things move at 40mph easily).
Now apply the same logic to an MX bike. Also 125cc road bikes used in fields (hey! I was young, ok?!?).
An SV is no different. Once you're up, alter pitch of the bike using the throttle, then pull the clutch in to land (just to be safe - you can try & balance revs to road speed on landing if you want to really show off).
fizzwheel
15-05-08, 06:43 PM
Step 1 :
Dont really pay attention to Amarko when he says "road we are going on has a jump on it and you can't really see it"
Step 2 :
Approach said jump with to much speed, watch Scoobs go over it out of the seat and dont slow down enough
Step 3 :
go over said jump with throttle open not realising its bigger than Amarko described, come right out of the seat, grip tank with knees just about and and land rather un-comfortably thinking "oh feck"
Step 4 :
Watch Dr Rich aka the white rabbitt in your mirror do exactly the same, except he comes right out the seat and his feet come off the pegs to.
Step 5 :
Search for b*ll*x
HTH
When I did the off road day ages ago, they told us, stand up, grip tank with knees and dont shut the throttle when you are airborne, seemed to work out OK, you defiantely want to avoid front wheel first touch down. I found keeping the throttle open meant that I always touch the back wheel down first.
you defiantely want to avoid front wheel first touch down.
I did that once as a kid. :lol:
In a field, I went off a ~ 4ft vertical drop from one flat field to another. At approx 65mph, closed the throttle just before I went off the lip.
The front touched down fine, then the rear did, and the suspension compressed, then kicked back. The result was me somersaulting forwards, and the bike going over the top of me. :shock: :oops:
No lid on, and I landed on the back of my neck, and luckily just kept rolling with the momentum. Approx 5 forward rolls later I dizzily stand up.
The chain had come off the bike, but that was about it. Awesome... lets try that again, but properly...
Don't let the front touch down first on the road folks. Mind, no-one here is proposing to jump on the public road are they? :lol: Still, private road interfaces hurt just as much...
stuartyboy
15-05-08, 07:11 PM
you defiantely want to avoid front wheel first touch down.
Actually this isn't strictly true Fizz. There are certain times when you want the front wheel to land marginally before the rear - ie a downward slope landing.
I competed for years in mountain biking and moto cross. We even have a moto cross jump course on the farm.
On a downward slope landing you want both wheels to land at the same time or the front marginally first. If you land rear wheel first on a downward slope and slam then front down then you can kick yourself over the bars when the rear rebounds out and the front is at full compression.
Additionally if the jump with downward slope has a turn at the end of it then the last thing you want to do is land on the rear then slam the front end down then try to steer round the bend.
Different jumps need different techniques and you should always try to have the suspension as settled as much as poss.
fizzwheel
15-05-08, 07:15 PM
everytime I've had the bike off the ground on the road and the landings were always level so I've never done it in those circumtances.
I just remember the extreme fuel tank to testicles interplay when I've accidently messed it up and put the front wheel down first and its not an experience I'm keen to repeat :cyclopsani:
I always find when I get it right I never slam the front down, but most of the time I know the road that I'm on so I know theres no corner coming at me so I have time to get the bike setup right before and after the jump.
I assume non of those arguing about throttle/brake use in the air have watched off road RC racing?
In RC racing, the drivers often blanace the throttle very delicately, for the exact reason that gyroscopic affect does alter the trajectory of the RC car. Think about the weight's involved in an RC car, and the amount of force you'd need to apply whilst it's in the air (bare in mind these things move at 40mph easily).
Now apply the same logic to an MX bike. Also 125cc road bikes used in fields (hey! I was young, ok?!?).
An SV is no different. Once you're up, alter pitch of the bike using the throttle, then pull the clutch in to land (just to be safe - you can try & balance revs to road speed on landing if you want to really show off).
Have you ever actually jumped your sv for long enough for that to make any real difference? Obviously the pitch of the bike is affected much much much more by the way you leave the "ramp", whether the bike is accelerating or decelerating or on a trailing throttle at a constant rpm.
You have to be airborne for a significant amount of time to be able to adjust the pitch to any meaningful degree using throttle or brake. It's fairly plain to see why an SV650 is nowhere near as adjustable as an r/c car or motox bike.
Have you ever actually jumped your sv for long enough for that to make any real difference?
Nope, can't say I have had the SV in the air for any real length of time.
Still, same rules of physics apply, and it certainly feels like it makes a positive difference to me. Though I admit I may be speeding up/slowing down just prior to take-off (thereby unsettling suspension as well).
Stu...
Are you coming on the Ecosse rideout? If so then wait till the Duke's pass section. There's a straight about 2 miles long with 5 jumps. Keep a steady throttle at 70 and grip with the tank with your knees - you will definitely experience air. (Ask any of the SV eccose posse).
If you sit off the seat with bent knees then trust me you're gonna get sore nads when you come down.
Can't wait :D
so just to be clear, are you saying stay in the seat? and it's just the gripping with your knees that stops you flying higher than your bike does?
Once you happy with jumping Stu,
you realise we are going to need some pictures!!!
:D
walkaboutandy
16-05-08, 09:20 PM
I don't think this guy gave it enough throttle and defo didn't grip with his knees!
http://www.youtube.com/watch?v=PEib3Op3Hdk&feature=related
Blue_SV650S
17-05-08, 12:34 AM
Can't wait :D
so just to be clear, are you saying stay in the seat? and it's just the gripping with your knees that stops you flying higher than your bike does?
That is such bad advice, you wouldn't believe!! :D
Theres a nice little bridge down Ripley lane to practice on Stu.
I'm sure that would go down well in the company I tend to keep down there :lol:
DanAbnormal
17-05-08, 12:36 PM
Why would you want to jump a road bike?
:confused:
Red Herring
18-05-08, 06:46 AM
You wouldn't, it's just a consequence of not wanting to slow down...!
Red Herring
18-05-08, 06:55 AM
If you go to this website there are a few snaps from the Liege Rally last year including a few of a small jump. It's only a little one but you can see the different styles (and different bikes, especially the old boy on the R80). Note the front wheel landing from the guy on the Aprilia. What made this jump fun was that it was in the middle of a bend, approach was flat out but slightly up hill so about 100mph and the brave boys didn't roll off.....
http://www.wheelspinphotography.co.uk/liege%202007-Bikes.htm
I'm sure that would go down well in the company I tend to keep down there :lol:
:lol: :lol: Just tell them its part of the course training - the new revised edition to get rid of the pipe and slippers image...
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