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Catching A Slide With Your Knee


GregGorman
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The theory: the front (usually) or the rear starts sliding with your kneed down. To keep from crashing you push down with your knee and hold the bike up until it regains traction.

 

Is it possible? Is it really what is causing the bike to regain traction?

 

Yeah, I saw Colin Edwards and Nicky Hayden at Jerez. My theory is the bike simply slowed down enough for the front to regain traction and/or they rolled on the gas a bit and that's what saved it.

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Tried to be colin the other week using knee and elbow but didnt help me get the bike back up....just a nice little slide at a constant speed along the road was my end result.

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Really, this would be one to test on the Lean Bike - see what the real deal is.

 

Personally, I know I'm not going to be holding a bike up with my knee or elbow. I mean, lay on your side and try to lift your body off the ground. I don't know about you but I can't move much at all just pushing straight down with my knee and elbow.

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I dont think it would be possible to lift a 400 lb bike with your knee and elbow, but if you think whats happening if you dig your elbow into the road you would also be pulling on the inside bar while you did this, if the front regained traction even for a moment that could be enough to counter steer the bike back up! What would you be doing with throttle control though, Colins save looked like it was off the throttle to me, or maybe he just chopped it after he saved it!

 

Bobby

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Chopping the throttle may be the answer combined with knee and elbow push, the bike should try to stand itself up with the chopping of the throttle/ I think the lean bike is the best way to test it, so if you want me to give it a go and dod some testing some plane tickets and accommodation would be nice

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Hi,

I had to reply here as I have done this myself. Many years ago when I was a whippersnapper, me and a mate had an old yamaha DT 50 MX. We used it for winter, I learnt more riding on snow, ice, greasy and wet roads on tghat bike than anything since.

Anyway, messing about late one night in a car park, trying the one cheek on one cheek off knee down method, I decided to try both cheeks on for a laugh. The front let go before I got the knee down but reaction made me slide off the bike the knee dug in and the bike was saved, both myself and mate who witnessed it, couldn't believe it.

As I said I learnt more riding that than any other bike. We loosened the brake levers, handlebars took indicators off, put a road tyre on the back instead of a trail tyre.

It was a crash bike, 54mph downhill with the clutch in, 44 on the flat.

Knee down in the wet with one cheek on, 2 up knee down but rear slid spitting passenger(me) off. super motard riding, both feet on pegs inside foot got stuck. Pegs down with normal riding, it was the best thing I have ever done. I would advise everybody to buy a small M-bike just for that, messing about, something you don't worry about if you crash, also you aren't going fast enough to cause any major damage too yourself.

Sorry bout the log winded blurb but yes you can save a slide with your n=knee even as a novice

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I've been trying this on one corner in particular. It's a bumpy section that I'm real comfortable on. I haven't gotten to slide the tire out yet, but I'm wearing pucks trying to do it. I want to kick the back out, but my problem, even at school, is throttle control. I've read that you can predict slide, and have your knee down ahead of time and keep the bike up while sliding.

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That's the same thing that happened to Edwards. I think they are picking up the bikes and giving the tires time to stick. They all push that outside leg out. I'll almost bet he was open to the possibility of that happen when he went through the detergent.

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There's no way in hell that rider is holding the bike up. Holding himself up, maybe. But not the bike.

 

He goes through the detergent losses it, knee comes off the ground than knee goes back down. It looks like he's holdin everthing up. I've been watching this thing over and over again, and just noticed that you can see the front wheel wobbling back and forth and then chattering right before he get's it back up. While the tire is searching for traction, he's keeping the bike from crashing. That's why I think he's holdin the bike up, but it's though to tell.

 

That's Thomas Luthi, we'll just have to have Andy ask him. :)

 

Hmmmmm. That would be pretty cool to get a first hand answer. Especially with some detail, like a play by play.

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You're telling me, while practically falling off the bike, having only his thigh on bike as a contact point, he can push hard enough with his knee to do anything other than keep himself from falling off completely, if that?

 

Maybe that's what "save it on the knee" really means. It should really be said, "You see my outside foot came off when the bike slid away from me suddenly. I practically fell to the ground but I just pushed on my inside knee hard enough to keep from falling off while the bike continued to slide. I was just being dragged along with it! Man, I thought it was GONE! Then the bike regained traction somehow and I was pushed into the seat hard enough by G-forces to pull myself back on the bike. Talk about rider input man! I was GRABBING on to the bars and anything else I could!"

 

Yeah, that was too long winded. "I saved it on my knee," is much better. :D

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I think if you watch the end of that footage, as he's riding off into the sunset, was him sayiing holy snapping ducksh?t did that really just happen and im still riding!!? If keith or someonoe can ask the likes of luthi edwards and the rest what went through their heads as it was happening that would be cool. But at this point in time Im agreeing with greg!!!

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You're telling me, while practically falling off the bike, having only his thigh on bike as a contact point, he can push hard enough with his knee to do anything other than keep himself from falling off completely, if that?

 

Maybe that's what "save it on the knee" really means. It should really be said, "You see my outside foot came off when the bike slid away from me suddenly. I practically fell to the ground but I just pushed on my inside knee hard enough to keep from falling off while the bike continued to slide. I was just being dragged along with it! Man, I thought it was GONE! Then the bike regained traction somehow and I was pushed into the seat hard enough by G-forces to pull myself back on the bike. Talk about rider input man! I was GRABBING on to the bars and anything else I could!"

 

Yeah, that was too long winded. "I saved it on my knee," is much better. :D

 

That long winded response kinda helped with the mental picture of what's happening. I wasn't really sure either way. But now thinking about what you've said it makes sense that he's just keeping himself up an on the bike while the bike is just doin it's thing.

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I have some experience of this.

 

On a road (NS400R) a pedistrain stepped out in front of me, the front tucked and the bike was going over.

In a split second I managed to kick the floor with the ball of my foot and the bike popped back up.

Was quite odd.

 

Second to that I was at a very wet race at Silverstone and a rider came off in front of me, his bike was over and about to hit when he took the bang on knee and body and came off. Bike picked itself up and carried on once the weight was off it. carried on for a good 300 yards before gently stopping on the tyre wall minus its owner.

 

All I could conclude is that a dramatic weight reduction at the inside foot peg, or a push back at that point must be able to re-traction a bike.

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I have some experience of this.

 

On a road (NS400R) a pedistrain stepped out in front of me, the front tucked and the bike was going over.

In a split second I managed to kick the floor with the ball of my foot and the bike popped back up.

Was quite odd.

 

Second to that I was at a very wet race at Silverstone and a rider came off in front of me, his bike was over and about to hit when he took the bang on knee and body and came off. Bike picked itself up and carried on once the weight was off it. carried on for a good 300 yards before gently stopping on the tyre wall minus its owner.

 

All I could conclude is that a dramatic weight reduction at the inside foot peg, or a push back at that point must be able to re-traction a bike.

 

And the rider no longer fighting it :)

 

CF

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Cool topic! It would seem that a bike could get far enough over that the tires would no longer contact the ground... if the rider could then push it up far enough for the tires to regain contact it might improve the chance of a recovery?

I think this is one of those situations where an ounce of prevention is worth a pound of cure though, hahah.

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I'm skeptical that anyone can really save it on the knee. Even if the rider in the vid perceives to have done it, I'm skeptical. The forces and inertia involved are way to high to be overcome by our muscles pushing at awkward angles.

 

Once a bike truly loses traction it travels in a straight line - think of a bike tumbling off the outside of a turn into the sand trap - straight line! The bike in that video travels in a steadily curved path, and doesn't look to me to necessarily reach any particularly unusual lean angle by Moto GP standards.

 

You can see the front wheel turn in, and the rear wheel slide out, at the moment he rolls over the detergent, but from there, it oscillates a few times with each oscillation getting smaller as the bike regains its stability, which in my experience and observation is the normal behavior of a motorcycle recovering form an instability IF there is traction to work with.

 

It's amazing that he stayed on the bike, stayed on the track, and apparently in the midst of all that also maintained decent throttle control! So I'm not at say'n it's not an awesome save!

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Harnois,

 

Didn't see the vid yet, but I have for sure had coaches save the bike on their knee. Only really happened to me once at Laguna: went into T-3, the tire was a very old hard front (real old slick), and never hooked up. I had a little pressure on my knee, the front went, I didn't do anything else (except think I was down), then it came back.

 

CF

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I keep thinking about how hard it is to hold up a bike when stopped if it gets leaned over too far, or how hard it is to pick up after a fall - it takes everything bit of muscle I've got plus a bit of technique to lift up a sportbike, and I can't do it while straddling the bike. So if a bike truly loses traction in a turn enough to cause a fall, that's what the rider would be faced with, 400 pounds of bike, and holding that up with their knee in an awkward position with no leverage? I'm still very skeptical, but maybe it's just something one has to experience to believe. Why couldn't it just be a temporary loss of traction, due to some surface or tire irregularity, and the traction comes back later because the surface or tire improves, or due to a throttle change, but the rider thinks they've done it with their knee? For example in the video, the detergent is there, then it's not, and the bike recovers, what's so unusual about that?

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I've watched this therad with some great interest over the last couple of weeks, deliberately not chiming in, waiting to see what came of it, people's opinion. It's been really, very interesting, great input from everyone.

 

So, what's my view and experience? Well, I've "saved" a bike a couple of times from low siding on the front, and I'll be really, really honest, it was total luck, every time. In all occasions it's happened, I've been on the gas, and the only way I personally think it's come back, is that I've been locked on the bike well, kept stable, i've kept with good throttle control, and the tyre has managed to re-gain traction all by itself. Sure, I attempted to dig my knee in harder, did it help? I don't know, but I didn't fall off.

 

On all the occasions I've lowsided on the front, and there are a few :blink: , I've either trail braked or been later back to gas, or ran into the turn a little hot and had late throttle application, and the front's folded. On these instances, I've tried to carry the bike, but it's just gone to quickly and folded me onto my arse!

 

So there, thats my twopenneth, I think it's possible, but good throttle, being stable and having an element of good luck and fortune that the front will regain traction serve as to contributing much more heavily than pushing it up off the floor.

 

Bullet

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I keep thinking about how hard it is to hold up a bike when stopped if it gets leaned over too far, or how hard it is to pick up after a fall - it takes everything bit of muscle I've got plus a bit of technique to lift up a sportbike, and I can't do it while straddling the bike. So if a bike truly loses traction in a turn enough to cause a fall, that's what the rider would be faced with, 400 pounds of bike, and holding that up with their knee in an awkward position with no leverage? I'm still very skeptical, but maybe it's just something one has to experience to believe. Why couldn't it just be a temporary loss of traction, due to some surface or tire irregularity, and the traction comes back later because the surface or tire improves, or due to a throttle change, but the rider thinks they've done it with their knee? For example in the video, the detergent is there, then it's not, and the bike recovers, what's so unusual about that?

 

H,

 

It isn't the full 400+ lbs of weight that one has to hold. We are talking the times a rider has saved it, when it has just gone over the edge of traction, but the tires are still in contact with the ground. How much does one have to "hold" a correctly set up bike, when it is in the turn, and the bike is moving? AND let's not forget no lean angle change (otherwise the rider would have some pressure on the bars).

 

Any of the physics guys up here have a an idea of how to calculate this?

 

CF

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