The same reason for why motorcycles or bicycles lean into turns. Roller coaster tracks are designed in such way that the ride always leans into the turns. Even NASCAR tracks are inclined on corners.
SMOOTH & FAST
The wheels are 101 millimeters big and made out of urethane. Having big wheels allows it to go faster and easily over any terrain, giving it a smooth ride without compromising the ground clearance. It will get you around town a little faster.
LOW CENTER OF GRAVITY
This longboard is lower to the ground which makes it perfect for cruising and carving purposes. It also gives you better handling and stability and gives you more confidence to make those quick sharp turns. The system of parallelogram linkage trucks move jointly at specific angles, Allowing the wheels to lean into the turns so you can make really quick carves. These trucks are spring loaded so you get a constant force. It's very consistent the whole time which makes it very responsive.
STANDARD PARTS & FULLY CUSTOMIZABLE
The lean trucks have the same screw hole location attachment as the regular standard trucks so it is easier to attach it to any other board. Also, the wheels have the exact same 8-millimeter bearings as the regular wheel bearings so you can use these wheels on your trucks if you like.
Ryan Farmer explains LeanBoard technology
Jasper The Skate Dog is Cooler Than You, And He Prefers A LeanBoard Longboard
Braille Skateboards Review
Just got my for the weekend had some fun on a hard pack dirt road and yes it rolled fine doesn't work in high cut grass but that was nice to bail into...- Mark Hazard
Had my new f*ing awesome leanboard delivered last week. and i've had a blast. the waiting and waiting and getting frustrated for not receiving any updates are very much worth it! for people that want to buy this board in the future:- do it! the board is amazing and i think you will have an amazing time; the product is amazing.- Jurre Spoor
Great product. Loved it !!! Would like to buy couple more.- Sahil S. Khirid
Excellent updates and customer service these guys really care about their product. Can't wait to receive my Lean board.- David Biggs
Awesome longboard..test tried today and it was fast, smooth, and fun.- Praveen G D'Souza