4

When I need to clear a missing pothole or a slippery section of the trail, I try to make the hop as long-distance as possible. The result is that, unlike when hopping onto something elevated, now I push the bike forward while in the air in order to "place" it as far as possible forward. The drawback is that I am getting closer to falling off the back of the bike.

Is this smart? What other techniques exist for jumping the furthest at fixed approach speed?

  • 2
    The distance you jump is determined by how high you jump and your speed. So, how high are you currently jumping? – andy256 Aug 24 '15 at 4:53
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Some points.

  • If you bunny hop by getting both wheels to leave the ground at the same, the rear wheel has to jump the length of the obstacle plus the length of the bike to clear the obstacle.

  • A more modern, trialsy and BMX-y bunny hop is what is what is sometimes called an 'American bunnyhop'. In this, the front is hauled up first, then the back as the front is being pushed down (tutorials are available on youtube, other video sharing sites are available). This means the back wheel can leave the ground later, and so doesn't have to jump as far as in the point above.

  • Your time in the air is determined by your height, your distance traveled in that time is determined by your speed. So jump higher while riding faster and you'll go further. (And, potentially, crash harder. Every silver lining has a cloud.)

  • When mountain biking, simply "unweighting" can often be enough to help an already rugged and quite probably suspended bike better cope with rough patches. And if all else fails - just get the damn front up and over!

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    I have always understood the term "bunny hop" to refer to the technique you referenced as an "American bunnyhop," with a "hop" referring to both wheels leave/land at the same time. It is interesting how terms differ across the world. – Rider_X Aug 26 '15 at 18:09
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Answer: Watch a few Ballet videos on youtube, and duplicate the Grand Jette manoever.

Bear with me on this...

Watch this

at around 15 seconds. Notice the dancer seems to hang in the air for a second.

http://capa.phys.dal.ca/dalphysicslib/Graphics/Gtype15/p0767a.gif

So the body doesn't need to move up as much as the bike does, but the bike is blocked by the rider's body.

Here's a method:

  1. Approach the obstacle at decent speed and straight on, in a place with runout room on either side and a landing zone beyond.
  2. at a distance of 4 seconds from the obstacle, stop pedalling and level the cranks.
  3. immediately lower yourself on the bike. Chest and head should be down and backside should be off the seat.
  4. about 0.5-1 seconds before the obstacle, push your bike down into the road using even pressure between your arms and legs. Net effect is your body will rise up but with a flattish posture. Your Center of Mass is now taking on a parabolic arc.
  5. right at the edge of the obstacle your body should be moving upwards, and your bike is relatively unweighted. Right now you need to lift your toes and rotate your wrists to lift the bike. Your center of mass will continue in its parabolic arc, but your body will fly level for a bit. It should feel like pulling the bike up into your torso.
  6. the pothole or obstacle should be passing clean under you right now.
  7. Landing time - you can simply ride the bike onto the ground like an aeroplane hitting a runway, or you can reverse the step5 process and lower the bike smoothly, which looks better and is safer.
  8. resume pedalling and ride on.

Personally I find step 3 works better if my hands are on the drops rather than the hoods, but you may not have time for that.

Step 5 might be all you need to do to get over many obstacles. This is called Unweighting the bike and it will only be exerting ~10-20 kilos of pressure on the ground compared to your full mass+bike mass.

Step 5 is a lot easier with clips or clipless pedals. With flats you're going to have to try and push the bike down so the tyre springs you up somehow. (this is a gap in my knowledge.)

Step 7 can be a bad time if you're not going fast enough. Horizontal distance is a result of how high you jumped, and how fast you're going. That's all. If you're coming down short, you need to avoid smashing a rim into the corner of a pothole cos that risks punch flats, cuts, and a dinged rim, assuming you stay on the bike!

So back to ballet - you're maintaining the arc of your center of mass over the jump by sacrificing head/body height in favour of lifting the bike.


Practice idea - find a large open flat concrete area with no traffic, and lay out some lines with pavement chalk. Try and jump them, and the chalk should show exactly how far you got. Practice.

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Perhaps a light weight bike and a pedal like this might help you :) AFAIK a best way to make a bunny hope is to start with a correct procedure. Low your breast on the handlebars, then push it upwards and when the time to make the rear fly arrives, link your feet on your pedals (with the teeth on it) as strong as you can and push them back. Your legs should bring on hair the bike, but your feet should be linked to the pedals as strongest as possible (I don't know if my English dress well the concept :P)

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Since you mention fixed speed, your remaining options are:

  1. higher bunnyhop
  2. late bunnyhop (as late as possible)
  3. land with the bike pushed (as you mention)

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