Jumping

[nitro5185]

I had a small fall not to long ago on my CR125. So that made my ego down down pretty good. I was jumping a small wooden ramp, which was probably not the greatest idea. When going up a jump, do u stand up or sit down? Also, is preloading the suspension needed all the time or does it depend on the situation? Any other tips/suggestions?

Thankx, Nick

 

[Anssi]

Originally posted by nitro5185
When going up a jump, do u stand up or sit down? Also, is preloading the suspension needed all the time or does it depend on the situation? Any other tips/suggestions?

Until you get to a lot more advanced jumping (I haven't, and I jump 60 foot tabletops), you'd better stand up and just go with the flow without any special preloading.

 

[High Lord Gomer]

Anssi's being uncharacteristically modest, :scream:, and as usual, he's right.

Preloading the suspension on a jump is done to get even more rebound out of it in order to get more height. It adds several more variables into the equation. Preload too early and you actually unload the suspension for the jump. Attempt to preload too late and you might be jumping off the bike.

Another thing is that a small, wooden ramp is one of the hardest things you could jump for several reasons.

Unlike a dirt jump, there is no smooth transition from flat ground to angled ramp, but rather an abrupt transition that jars both you and the bike and makes control difficult.

In order for a jump to be predictable, it should have (in addition to a smooth transition) a long enough ramp that both wheels are on the ramp at the same time and travelling in the same updward direction. With a short jump the front tire is often already in the air by the time the rear hits the ramp. This kicks the rear upward and the front down violently (but I probably don't need to tell you that, do I? :) ).

 

[Mephisto]

i thought to preload all you did was sit on the seat on the way up the jump?

 

[96717]

thats when you have a small runway to the jump and you need all the height & distance you can get.

 

[Anssi]

Originally posted by Mephisto
i thought to preload all you did was sit on the seat on the way up the jump?

That's another sort of preloading, and if you JUST do that, you'll be on your head pretty soon.

 

[TerrorFirma]

I am soooo far from being an expert. However, being a noob and just starting the "hucking-my-body" thing I thought I'd give u my 2Cents.
I'm jumping a wood ramp also 9'long & 5' high [I would think jumping anything smaller would be dangerous] into a 4' dirt transition and it'll throw you up and out about 30'. We only have a 30' run to the ramp after going through a little hairpin turn so I'm shifting into 2nd - 2-3ft before the ramp.
litely power up the ramp and let off the throttle just close to the top. Look for the landing and cover the rear brake & throttle. I'm sure you've heard or read it 1000 times, if your front ends coming down too fast "pin it" or if the rears sinking too fast tap the back brake. I'm not exactly sure when, but somewhere up the ramp im standing up [cause i'm sitting before the ramp and standing when im in the air].
You're gonna "case" so get used to it. Keep practicing, build up the height and distance when you feel comfortably and try not to "think" too much... it'll screw up the flow.
Hope I helped.

 

[High Lord Gomer]

In a "normal" situation, you approach the jump in a semi-crouched position and when you actually hit the takeoff ramp, the bike's suspension compresses some in response. Your body's suspension (knees and ankles) compresses some as well. As you leave the jump, the bike's suspension rebounds some, as does yours.

If you are sitting, then the bike's suspension has to do all of the compressing and therefore rebounds more than if your body had helped. Most people refer to this as "seat bouncing" or "seat jumping".

What most people refer to as "preloading" involves trying to force the bike more into the face of the jump in order to increase the compression, and therefore increase the rebounding action of the bike's suspension.

 

[High Lord Gomer]

Originally posted by TerrorFirma
...  let off the throttle just close to the top ...

I wouldn't suggest that part of it.  (At our level) Most jumps are much more predictable and safer if you maintain constant (even if only slight) acceleration all the way up the face and don't let off until your back tire is in the air.  If doing this seems to cause your front end to get too high, move your body farther forward to compensate, but don't back off the throttle.

 

[Menace]

I usually stand up for a jump. And most of the time i preload the suspension. I ride a 125 so 1/2 the jumps I take are difficult to clear without preload.

 

[jovy]

yes i no this is porbally posted some where else on the site but what is preload and when do you need to do it or why would you need to preload

 

[High Lord Gomer]

You won't have to look far ... I think all of that has already been covered in this thread right here.

 

[tedkxkdx]

Since I have my own SX dirt track in the back yard I would like to comment.
I find that only if you are worried about your tire slipping under acceleration you should seat jump but you gotta be sure your gonna make it and not case. ie better to roll it if unsure.
I have tested the result of standing and sitting and when using the same throttle and accel to approach and go thru the ramp, the sitting position puts you up (3-5 more feet on a 40' double with a ramp angle of 25 degrees) due to the rebounding action. Also the less dampening you have on you suspension will cause you to go higher, i tested full in damp and half. BIG difference. I would not set jump anything over 15 mph. It is just too risky since as speed increases the throttle and body position increases as well. So when do u need to seat jump. Well I cannot start from a dead stop and stand 20 or 15 feet away from a 25 or 30 foot jump and make it. But seated I can.

I would say that people first learning this technique should find a jump where they can launch but instead of it being a flat table top it is humped up. If you get it wrong than the distance to you and the ground are very reduced. Also once you do clear the say 20feet with gentle slope landing, you should try that standing and realise that you cannot get as high up in the air as seated and will land sooner. Roll up to the jump and work your way back. So roll in first and then power on at 5 feet from the ramp. once you have that than go back in 2 or 5 ft increments. The ramp should be 1.5 times the length of your bike as measured where the rubber meets terrafirma. Ramp angle should be between 10-20 degrees, remember 30 degrees is very steep and the most any dirt ramp should be in order to be safe.