Вот еще сериальчик интересный

http://www.youtube.com/user/TheOffroadfanatic#p/u/26/B30F2dvGE9w

хотелось бы сделать такой же, может кто нить подскажет ньюансы(размеры и прочее), и есть ли вообще смысл в данном "мероприятии"?

Там же написано - 11 метров.
Быстрые гонцы такой циркуль накапывают за одну тренировку на ровном поле без спецтехники.

брод виноват

Volume #3 - How to Master Wheelies, Logs, Rocks, and River Crossings
Come join Shane Watts, legendary Offroad racer and renowned skills instructor, as he gives you an in-depth analysis of how to master wheelies, logs, rocks, and river crossings. Wattsy will take you across the world in search of some of the most fantastic riding areas where he will increase your knowledge and skills on how to conquer each of these specific obstacles and difficult trail situations.
Get the full DVD series at www.shanewatts.com.


Volume #4 - How to Master Hills, Ravines, Switchbacks, and Off-Camber Trails 
In the fourth and final volume of the DirtWise In-Depth Instructional DVD Series, Wattsy will continue to take your learning a step further by teaching you precisely how to implement many important skills techniques into your riding and training when attempting hills, gullies, ravines and off-camber trails. Filmed in some gnarly trail situations in an effort to bring you the best skills demonstrations possible, this DVD will also provide plenty of spectacular action that you are sure to enjoy along the way! 
Get the full DVD at www.shanewatts.com

в свободном доступе не нашел. надеюсь появится когда-нибудь.