when clearing trail logs...
Posted 07 March 2012 - 10:35 AM
Posted 07 March 2012 - 05:51 PM
Posted 12 March 2012 - 06:10 AM
Not the same... the elevated smaller log is like a much larger log on the ground because the middle of the log is higher off the ground. In your example above, the 16" elevated log has a center 12 inches above the ground while the 20" log is at 10 or less. Getting your rear tire initial contact of the log ABOVE that center point of the log is key to a smooth jump. Contact above that point will at least deflect the tire up while.. Below that point and the log tends to trap the rear tire.
Most really big logs tend to bury themselves into the ground a little so at some point, the diameter of the log is large enough that BOTH tires can be on the log at the same time and the skid plate will not touch.. The smaller ones are more likely to catch your skid plate or the front of the tire at the swing arm as you experienced.
The whole secret to good log jumping is to learn how to use the front tire impact along with body input to launch the REAR tire off the ground BEFORE it gets to the log. If you loft the front clear of the log, it will be more difficult to hop the rear tire off the ground. If the log is smaller in diameter than your rear wheel, your tire will most likely bounce up and over. As the log approaches the diameter of your wheel, that gets much more difficult with a more violent bounce and then when larger than your wheel, it traps the tire and the bounce of the tire is BACK and then the skid plate comes crashing down on the log.... You can see this in one of the videos I've posted before... Here it is again along with an even more extreme successful log jump with an elevated log. Watch closely... in the second video, I make comments about some of the jumps..
Pay special attention to the amount of body input he uses in these jumps!
Jumping a 36" diameter log on the ground is difficult, but a 6" log with the top of it at 36" above the ground is WAY more difficult.
Edited by 2PLY, 12 March 2012 - 06:20 AM.
Posted 12 March 2012 - 06:37 AM
It's an 'S' turn approach and finish. You crowd the drop-off side of the trail. As you loft the front tire, you turn toward the uphill side of the log.. contact the log with the front tire at an angle... Then as you unload the rear tire with your body jump, you don't let the front tire climb any higher than the tag on the log.... And as the rear tire is unloading at about the time that your skid plate is over the log, you tip the bike over for the finishing turn back to the center of the trail. This tipping turn lifts the uphill side of your skid plate and foot peg clear of the log.
When you jump this way, the diagonal track over the log makes the log fill in more of the space between the front and rear tires and allows you to finish with the bike leaned over for the turn to keep the peg and skid plate clear.. ALSO, if there is any tendency for the rear tire to slip along the log, it will slide uphill in the direction that you want to put you back in line with the trail. It doesn't take much of a turn to make this work, and the slower you can approach it, the more angle you can add to that turn.. This is an advanced move for sure, but one that will have you grinning from ear to ear and your friends will NOT believe how you got over so slick if they weren't watching close enough.
If you try to jump one of these straight on, there is a good chance that you will catch the uphill side of the skid plate or foot peg and the will toss you downhill and off the trail. OUCH!
Edited by 2PLY, 12 March 2012 - 06:42 AM.
Posted 12 March 2012 - 04:07 PM