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Edited Date/Time
10/26/2014 1:25pm
Currently sitting here watching the moto gp series in Malaysia. Watching these mad bastards through the corners, there cornering technique is pretty much complete opposite as dirt.
So looking at flat corners, in mx we lean the bike over, and the sit upright and weighting the outside. Moto go, they are hanging as far off the side as possible in the direction they are turning.
Anyone got a simple explanation on the differences?
So looking at flat corners, in mx we lean the bike over, and the sit upright and weighting the outside. Moto go, they are hanging as far off the side as possible in the direction they are turning.
Anyone got a simple explanation on the differences?
In case you thing I'm mad check out the way supermoto cornering has changed from it's early days till now.
The Shop
Why not on dirt?
My theories:
1. On dirt the chances of sliding are more. If you had your weight to the inside, like MotoGP, and the bike slid, it would slide out away from you and you would have little chance to catch it. In MX it first slides underneath you, not away from you.
2. In MX there are ruts and berms. Leaning with or slightly away from the direction of the turn allows you to move your body inside and outside to better use body English to steer the bike and keep it following the berm or rut.
The best person to ask would be a MotoGP rider who also rides mx. Do they change their technique when they get on a motocross bike?
I bet JMB would know!
Ben Spies is a friend of my buddy. I have been at the MX track with him a few times. He rides just like every other MX'er out there. (And he looks as fast as any local Pro too)
i would also say it does boils down to grip, completely changes the way you ride the motorcycle, and the motorcycles are night and day different too. It is amazing what a modern day sportbike is capable of, much less one of those motogp bikes
If you had a long silky smooth rut or wall berm with no bumps coming into it and no bumps on the way out, you might be able to "hang off" a dirt bike, but that is just not the way it is in mx
The most awkward i have ever felt on dirtbike was when i rode my sportbike to the mx track, it took a while for the dirtbike to feel right again and get up to speed.
That being said, they are both motorcycles, so many skills do cross over, like throttle control, brake control, shifting (although usually an opposite pattern), balance, feeling the tires grip (or lack thereof), etc. Take a top motocrosser and put him on the asphalt and he will pick it up pretty quick. Also, i would say the learning curve is much steeper going if you were going from asphalt only to dirt.
Oh ya, and both of em are fun as heck!!!!!!!!!!!!!!!!!!!!!!!!!!
Dirt tires are made to lean,soft terrain knobby h a s a row on the sidewall that cuts like a hoe in a tabacky patch. A hard pack knobby is rounded over on the sides and creates about the same patch no matter lean angle.
MotoGP bikes have traction control that works with lean angle,more lean,less power,and they have a control on the bar to dial in how much wheelspin they want.
On a really tight track you would be better of with a supermotard than a motogp machine imo
In Moto GP the extreme grip causes the CG to move out thus the rider hangs well to the inside. Moving the riders mass to the inside is to keep the movement of the CG from moving out and causing a massive high side. Since the is only so much room for the rider between the bike and inside the lean angle has to stay more upright. The MotoGP style has been progressing much differently then MX.
The same theory applies to dirt, only the variables (dirt conditions! speed, traction, ruts berms............speed) that affect the CG transition are constantly changing way more than MotoGP.
MX and street bikes corner completely differently. It is more than just the level of grip, it is the VARIABILITY of grip that is key.
MX bikes are designed so you can corner having broken traction, specially in the rear (relative sliding between the surface and the tire). Street bikes work on slip angle (the drift is from tire carcass flex as loads move across the contact patch) with both wheels tracking. If a road racer regularly breaks rear traction, he will not have tires for long. If you dont know what slip angle is, then go read Milliken (Race Car Vehicle Dynamics). While is is focused on cars, there is a proper description of how road tires really work.
On an MX bike, the body position is focused on recovery, because you invariably break traction and are having to recover. The flat corner "overlean" position allows you to maintain a higher average speed, because you are able to continuously recover from when you break traction. Consider that when you do not have this problem (a rut) you do not over lean. You lean in line with the bike, and your position is mainly dictated by the rut forcing your leg up, etc. You can also watch flat trackers and super moto guys. With a more consistent surface, you can get your body more to the inside, and lower, because the the variability in grip is less.
On a street bike, the surface is more dramatically more consistent, and you can push up to this constant limit without out going over as often. This limit is higher, but the limit is also much more consistent. The goal is focused on the other end of the spectrum, and that is maximizing grip at the limit. You do not have to worry about recovery as much, because exceeding the limit is a continuous state, not a super short duration event, like hitting a patch of soft dirt over hard.
So, to put it simply, on an MX bike you go fast by continuously saving it. Your position is not focused on the upper limit of grip, but the lower limit of grip, which can be dramatically different. Again...the variability is what dictates your position. If you try to ride a flat rough dirt corner like a road racer, you will end up low siding it every time. The position is too aggressive, and too unforgiving. There is not enough margin for error and the position does not allow recovery when you hit a patch with dramatically less grip.
On a road bike, you go fast by going right up to a more consistent limit. If you try to ride a street bike like a MX bike, you will be slow, because you are compromising your ultimate limit (CG too high, etc) to allow for a margin of error you do not need.
Essentially, road cornering is much more refined and optimized. MX cornering is a more robust technique, allowing for variance in grip.
The high speed of a road bike thru turns means the centrifugal force is great and pushing on the bike towards the ouside of the turn. The high grip plants all this force on the tires, which only increases the grip, which only increases the speed, which only increases the force, which only increases the grip, etc. This force (paired with the low CG) means the rider can get way off the bike towards the inside without upsetting the balance of the bike, to help steer it and, I guess, to get low for better aero.
Obviously too if the bike weren't leaned over far the G's would high side it and you make it so you can't make turns unless you're going under 30.
Pit Row
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