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Overlay Of Two Riders


mazur
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I did a track day yesterday at Arizona Motorsports Park, and as I scrolled through the event pics, I noticed that there were two good shots of my friend and I where I could overlay them. So I did.

 

What I find is interesting. Though we both have nearly identical lean angles and are fairly square to the bike, my friend (GSXR 600) is in a much more aggressive position.

 

My question would be is one more right than the other? We both talked about it, but neither is quite sure. Will he have more ultimate traction on exit due to lower CG, or do I have more control and save energy by not getting too low?

 

Interestingly, we also run nearly identical lap times. I corner faster and get on the gas sooner on exit, so he never gets a good run on me on my SV650.

 

 

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Mazur;

Interesting comparison and amazing that you and your friend could find the exact same spot on the track AND the photographer caught these images - but that's beside the point. If you are running near exact lap times it would suggest to me that it's riders preference. I have been told by Cobie among others that I get too far off the bike when I corner (much like your friend does in these pics) but I found I could see thru the turn better by getting lower. Hopefully one of the coaches will chime in here.

 

Kevin

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OK, first let me just say, that is a REALLY COOL idea and great job with the overlay, it's terrific!! And you pose a great question, too.

 

There are many factors that come into play here - the two of you are on different bikes, for one thing, so the ergonomics of each bike (and probably the weight) are different. What are some possible disadvantages of trying to hang off that much on your own bike? Why is the weight of the bike potentially a factor when making this comparison?

 

From the appearance of this photo, you are not running out of lean angle or ground clearance. Assuming good traction conditions, good suspension and tires, and good throttle control, I wouldn't think an SV650 would be running out of traction on the rear wheel at the shown lean angle. So what COULD be a benefit of using a more aggressive body position, in this case and in this corner? What about in other corners?

 

What about if traction was NOT very good, or your tires were getting worn out?

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Any other forum members want to jump in on this discussion? What advantages do you see for hanging off more, or less, in the situation shown?

 

What could the rider that is hanging off LESS gain if he were to hang off MORE?

What are some possible negative effects of hanging off more?

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THIS IS SUCH A COOL TOPIC, I can't believe there is no discussion going on - no one has any opinions on this stuff? Anyone ever made any decisions about how much to hang off? What data or experiences did you use to decide? Do you hang off the same amount in every corner, or vary it by corner or your particular pace on that lap? Speak up, this is a great topic to kick around!

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All things reasonably equal, you say you carry more speed at the apex so maybe you turn in later, and need your additional body reach to counter the extra speed. One question for clarity. What occurs immediately after the picture, smooth track out, quick right, etc?

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I don't have any good images but this is the latest I have. My understanding is that hanging off more allows for more speed with less lean angle. The flip side is that it usually requires more effort. Some will say not to waste the effort if it is not needed. I just make sure I am fit because I'd rather have the available option of more lean than to be without it. Really, I am not sure where I actually am in the spectrum of on the bike or leaning all the way off but I feel like I found a good balance.

 

I tend to vary how much I hang off depending on the corner and speed. Also, I feel more comfortable leaning left and was shocked I had a decent image of myself leaning right. I'd love to say I am consistant but I still have some work to do there.

 

post-25537-0-57664600-1459356690_thumb.jpg

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It appears to me that even though both bikes are in the same spot on the track, they are not on the same line, the position of the front and rear wheels is different, one has both contact patches almost perfectly inline, while the other has the front contact patch shifted to the riders left a few inches. this would suggest that the one rider has the bike turned more and is holding a tighter line through the corner. If this is the case, he could stand the bike up sooner and get considerably more drive out of the corner, something that is demonstrated exceptionally well by Dani Pedrosa's riding style.

 

It's also possible that you both have considerably different turn points and lines through the corner and just happened to be in the same spot on the track

 

 

Similar lap times doesn't necessarily reflect similar performance through a single corner, one rider could be losing a few seconds through this corner and make it back up later in a different section.

 

 

His more aggressive body position has a number of advantages, but if he isn't utilizing a good pickup technique and continues to carry the lean angle longer than needed he's cutting himself short and losing out on considerable drive out of the corner.

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I did a track day yesterday at Arizona Motorsports Park, and as I scrolled through the event pics, I noticed that there were two good shots of my friend and I where I could overlay them. So I did.

 

What I find is interesting. Though we both have nearly identical lean angles and are fairly square to the bike, my friend (GSXR 600) is in a much more aggressive position.

 

 

Respect to a vertical line, the lean angle is measured from the line formed between the combined center of mass or CG and the horizontal line connecting both contact patches.

That combined center of mass is located at a point over the line that connects the CG of the bike (about the valve train of the engine) and the CG of the rider (about the belly button).

That point is closer to the CG of the bike because the bike is much heavier than the rider.

 

http://forums.superbikeschool.com/index.php?showtopic=3303&page=2#entry26514

 

That lean angle depends on only two things: speed of the bike and radius of the trajectory on the curve (radius of turn).

The higher the speed of the bike, the greater the lean angle.

The smaller the radius of turn, the greater the lean angle.

 

If, as you stated, the speeds of the bikes were comparable, then the [bike+rider] carrying more lean angle must have been describing a tighter turn (inside the curve rather that outside).

Therefore, both bikes could not have been at the same spatial point, like the overlapped picture may suggest to some readers.

 

I have aligned the background (grass + electric cable) of each individual picture, just to show the actual trajectory of each bike.

 

Based on all above, the [GSXR 600+rider] in the picture was at a lesser lean angle than the [sV650+rider].

 

post-23333-0-48935100-1460085800_thumb.jpg

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