Cornering: Street vs dirt bike, why different?

[BSer]

I'm a lifelong dirtbike guy who recently bought a CBR600F4i sportbike to use commuting to work.

Cornering on a dirtbike without a berm is like: weight outside peg, body perpendicular to the ground, leg out for balance.

Cornering on a sportbike is like: never stick your leg out, buns off the seat to the inside of the corner, body off the to inside of the corner in an attempt to "kiss the mirror".

The streetbike guys do it this way because leaning the body means you don't have to lean the bike. This is good because it keeps lean angles from getting too great and assumably keeps momentum loss to a minimum.

So, now when I ride my motocross bike I'm confused on which way to lean? When there is no berm doesn't it make more sense to lean your body and keep the bike as perpendicular to the ground as possible like a streetbike?

...and SuperMotard really baffles me. Wouldn't those guys be faster if they rode like Nicky Hayden instead of McGrath on the pavement, or is it the other way around?

Can somebody explain all this?

 

[Anssi]

Well, supermoto here in Europe has evolved to the point where the cornering is decidedly more RR like than it was a couple of years ago. I suspect the style can be contributed to the geometry of the bikes and the speeds they race at. The tracks in the World Championship have gotten faster with less dirt and the jumps are not very big (so the bikes can have less suspension travel and be adapted to something more suitable for the paved sections).

 

[FruDaddy]

I'd have to say that traction and weight are the biggest issues. The rr guy have much better traction, and just need to get the weight down low. Moto guys have to add weight to the outside and front wheel to gain enough traction on the dirt, especially on flat or off camber turns.
The supermoto guys have to ride motocross style in the dirt, I would venture to gues it's a case of do what you know how to do. Flat trackers do it this way too.

 

[BSer]

So when I put my ice tires on with a few thousand kold kutter ice screws there is pretty much unlimited traction. Then which way should I lean? I have always tried to keep my body perpendicular to the ground but is this really the best way in this case?

 

[FlyingPika]

You stick your foot up so you dont twist ur knee, or ankle, get it twist in a rut, ridden over, flapped or bounced about on the dirt etc.