Dirt/supermoto vs sport bikes (road)

[UDRider]

Hopefully I can phrase it correctly. For purposes of this discussion assume track/closed course.
For sport bikes the idea is to hang off which lowers CG and reduces effective lean angle.

For dirt/supermoto we want as much pressure on outside peg as possible. So riding position is more upright and we almost "seat" on that outside peg.

What is missing is why you ride one way over the other.

I am guessing geometry factors in to it, but also what we are trying to achieve. On street bikes corners are not as sharp and more traction is available. So we try to reduce lean angle to minimize lateral forces for given speed and go through turn on bigger/smoother arc and as fast as possible.

On dirt traction just not there (compared to asphalt). So we want to control that slide. Thus we don't care as much about lean angle and more about putting weight over the tires for maximum control, and increased downward force. Also the corner is sharper so it's more of a "point and shoot" then on sport bikes. Go in to the corner, start braking, turn in and let the rear step out tightening the turn.

Similar is supermoto. Corners are sharper so we need rear to step out to make it.

Am I on a right track?

Second part of the question. What about "standard" bikes. For example KTM Duke it kind of looks like supermoto, but people ride it more like a street bike then supermoto. Why? I am guessing it's geometry related?

Thank You.

 

[Maddevill]

One of the reasons we ride dirt with weight over the outside peg is to force the tire down into the dirt and offsetting the tendency to slide. Especially important on off camber hillsides. People like Stoner and Doohan also used this technique to increase drive out of turns. They'd wear out a pair of boots every race meeting.

 

[westie]

Yes and no. The idea is how to get the bike to turn. A 400lb. streetbike is harder to turn than a 250lb. sumo or dirtbike. But riding styles for either do cross over. Take for instance Rossi's leg off catamaran style. Taken from dirtbiking but used to get a moto gp machine to tip into the turn. Think of the bike as a gyroscope thats sits straight up and doesn't want to lean. The heavier the bike, the heavier the force to make it lean.

 

[HeatXfer]

Go out in the dirt and ride a dirt bike like a road bike. It should be very clear after a few turns what feels natural in a turn: weight roughly centered over the bike. Ever have the back tire step out unexpectedly on a twisty road? What did you instinctively do? You stood up, you weighted the pegs, you moved your center of gravity from somewhere above the seat, inside the corner, to over the center of the bike (approx).

 

[Donelop]

This is stupid. Ones size of testicles is inversely proportional to the number of cyllinders you have, greatly lowering the center of gravity on motards.

 

[UDRider]

Yes and no. The idea is how to get the bike to turn. A 400lb. streetbike is harder to turn than a 250lb. sumo or dirtbike. But riding styles for either do cross over. Take for instance Rossi's leg off catamaran style. Taken from dirtbiking but used to get a moto gp machine to tip into the turn. Think of the bike as a gyroscope thats sits straight up and doesn't want to lean. The heavier the bike, the heavier the force to make it lean.

Not sure I follow.

Go out in the dirt and ride a dirt bike like a road bike. It should be very clear after a few turns what feels natural in a turn: weight roughly centered over the bike. Ever have the back tire step out unexpectedly on a twisty road? What did you instinctively do? You stood up, you weighted the pegs, you moved your center of gravity from somewhere above the seat, inside the corner, to over the center of the bike (approx).

No I understand that, so why are we not riding street bikes like that?
Then of course there are bikes like duke kind of looks like supermoto, but it's ridden more like a sport bike then supermoto.

 

[UDRider]

This is stupid. Ones size of testicles is inversely proportional to the number of cyllinders you have, greatly lowering the center of gravity on motards.

Well I ride a thumper so...

 

[atomicOp]

Assuming #2 and #3 are looking like street photo and dirt photo respectively, your CG's are incorrect. #2 should be moved off center line to the left and #3 should be moved off center line to the right.

 

[UDRider]

Assuming #2 and #3 are looking like street photo and dirt photo respectively, your CG's are incorrect. #2 should be moved off center line to the left and #3 should be moved off center line to the right.

Not my illustration, something I found on adv rider.

 

[redtail]

It is an interesting question, and there are no absolute answers since as you see, you can ride either way and still be fast.

I personally ride my Sumo and dirt bike (no longer have) differently than my sport bike or road bikes. I grew up riding dirt bikes so I have the habit of throwing a dirt/sumo bike down into a corner. YMMV

 

[NTron3000]

No I understand that, so why are we not riding street bikes like that?
Then of course there are bikes like duke kind of looks like supermoto, but it's ridden more like a sport bike then supermoto.

Traction. On a dirt bike you are expecting to slide around every corner especially when pushing it, you are controlling the slide by putting your weight where you have optimal options over a sliding object. On a street bike you are doing everything to prevent a slide and maintain traction - barring bleeding edge performance but even that is minute and more linear compared to dirt.

Sumo is a fucked up chimera so people pick their poison.

As for the duke it is more of an upright naked sport bike - chassis/suspension/tires-wise - than a proper sumo though I've seen people treat it like a sumo. When I test rode one I had no inclination to push it down but I think I just like traction on street. I'm daffy like that.

 

[jwb]

I always ride exactly like Rich Oliver regardless of equipment or conditions.

 

[UDRider]

Traction. On a dirt bike you are expecting to slide around every corner especially when pushing it, you are controlling the slide by putting your weight where you have optimal options over a sliding object. On a street bike you are doing everything to prevent a slide and maintain traction - barring bleeding edge performance but even that is minute and more linear compared to dirt.

Sumo is a fucked up chimera so people pick their poison.

As for the duke it is more of an upright naked sport bike - chassis/suspension/tires-wise - than a proper sumo though I've seen people treat it like a sumo. When I test rode one I had no inclination to push it down but I think I just like traction on street. I'm daffy like that.

So would you ride sumo like a dirt bike or sport bike?

 

[russ69]

Are we taking street riding? If we are, just plant your ass in the seat and ride, there is no need for gymnastics on the street.

 

[Sharky]

Traction. On a dirt bike you are expecting to slide around every corner especially when pushing it, you are controlling the slide by putting your weight where you have optimal options over a sliding object. On a street bike you are doing everything to prevent a slide and maintain traction - barring bleeding edge performance but even that is minute and more linear compared to dirt.

Sumo is a fucked up chimera so people pick their poison.

As for the duke it is more of an upright naked sport bike - chassis/suspension/tires-wise - than a proper sumo though I've seen people treat it like a sumo. When I test rode one I had no inclination to push it down but I think I just like traction on street. I'm daffy like that.

That depends on which Duke you are talking about.

 

[redtail]

So would you ride sumo like a dirt bike or sport bike?

Like a Sumo.

(ride it like a dirt bike, much cooler)

 

[Karbon]

Are we taking street riding? If we are, just plant your ass in the seat and ride, there is no need for gymnastics on the street.

yeah, but that's not as fun on asphalt roads full of leaves, silt and general funk.

 

[corndog67]

Who is Rick Oliver?

Anyway, ride however you feel comfortable riding. I've been riding dirt bikes for 43 years, and street bikes for about 37 years. I'm pretty comfortable riding either way. Kind of depends on what I'm riding.

 

[louemc]

yeah, but that's not as fun on asphalt roads full of leaves, silt and general funk.

And those asphalt roads with a layer of hailstones are a real hoot..

 

[UDRider]

Are we taking street riding? If we are, just plant your ass in the seat and ride, there is no need for gymnastics on the street.

Track. But frankly doesn't matter. This is more about general differences more then "how should I ride on the steet vs track". That will just muddy the discussion.

For purposes of this discussion assume track/closed course.