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Spaghetti

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Posts posted by Spaghetti

  1. Nylox was MotoGP cam before, I guess GoPro has taken over. I can see one camera mounted on the bike tail and pointing at Dylan's back. Would be curious to see the other mounts and if they processed the footage with a stabilizer. Picture is very stable.

     

    I just finished processing my test clip with iMovie stabilizer at 50%. It does a good job removing the vertical shake but doesn't seem to do as well for horizontal shaking. It's more apparent on the straight before the last turn at 1:50. Still better than the YouTube stabilizer: https://youtu.be/QbsSKWVyXSA.

  2. Looks very good, a few questions:

     

    - How does it work when quickly downshifting the 4 gears at the very end of the straight under heavy braking, before the corner entry? I know the rev-matching is more important at higher speed, but I'm curious to see both scenarios.

    - Which model did you install? There are many advertised on their website.

    - What was the shifter and labour cost?

     

    Also your cam video looks very fluid, what's your setup?

  3. T, actually the youtube stabilizer is not bad at all. The picture above 50mph is much better. There is still shaking at the apex but I guess that's too much to handle for any software. Same clip after correction: https://youtu.be/qWM-MUcb-pc.

     

    BTW, I wonder why I have so much tail shaking in the corners at less than 60mph (and less than 45 degrees angle, I don't remember dragging the knee in any turn during that lap). I guess the gyroscopic forces and acceleration at the same time? Or could it be something with my setup?

  4. Coasting = Maintenance throttle?

    When using maintenance throttle through a corner is that considered coasting?

     

    Coasting is usually described as the absence of throttle and braking inputs. By that definition maintenance and coasting are not the same. Is constant throttle as bad as coasting? No, not always at least. In theory you can trail brake until the apex (and accelerate after), but there are long, slow turns where you travel at an almost constance pace, like carousels, to stabilize the chassis.Chicanes are another case.

     

    Are we able to tell via the rear tire wear pattern, if and how much a rider is coasting?

     

    I wouldn't be able, but the tire side in the picture doesn't have the orange skin peel pattern produced by the asphalt friction while accelarting. You can accelerate a bit more leaving the apex.

  5. I was used to hesitate on negative camber corners because of the added lean angle due to the skewness of the asphalt. My corner speed in turn 10 at Thunderbolt is particularly low (50Mph last time I checked), because of that little negative camber entrance.

     

    Until somebody explained to me that in negative camber turns the inside knee touches the asphalt sooner than on flats, since the inside is elevated relative to center of the track. In other words, using the knee as a reference point will play exactly the same way than on a flat corner, except the whole plane is tilted.

     

    Sounds like a valid point. Yet I've seen a few crashes on negative cambers. How do you ride them?

  6. I observed a few track days coaches and expert riders going very fast while keeping their body almost still, and using lot of lean angle. It gives me the idea of a pendulum swinging from one corner to the other with no other part moving. But they're very fast... I think over a certain speed it becomes harder to correctly shift on the seat, move the upper body to hang off, adjust tighs and knee etc.

     

    Is it something others have noticed? It's one of the things I find hard to work on, as I increase my speed (and mentally rave about my improved lap times) it's easy to leave all those "details" behind.

     

     

  7. I believe the jurispridence that came out of some trial in favor of motorcycles lane splitting was done to offer more safety to riders under heavy traffic. It's easier to dodge cars splitting lanes than standing behind them. Then it became a traffic beater and now apparentley we're down to painting new lanes for scooters.

     

    My guess is that the scooter was not legal to begin with (it should have moved to the center of the lane in absence of traffic, aka regular riding in those conditions) but then, no I don't think you can pass a vehicle within the same lane, even though it wasn't obvious which lane it was occupying.

  8. How can you tell when the bike is about to lose the front/rear? Or more in general something is wrong with your riding. I know, there are many variables, but I've read that tires and chassis are designed to give riders feedback. So how does this famous feedback manifest?

     

    For example, I've learnt to read a Q3 cold tire using these indications:

     

    - Accelerate to a speed above 30/40 mph (no feedback in the pit lane or low speed)

    - Signal comes mostly from the rear tire, not the front

    - Sit forward to avoid loading the rear tire for better feedback

    - On a straight, feeling of slight sideways tire movements. It's very subtle, but definetely readable

    - At approx 30/40 degrees lean angle the twitching is a bit more obvious

    - Rear feels lighter than usual

     

    Of course, this won't work for any bike/tire/track but I'll be happy to learn signs for any configuration you might have :)

    So what are the specific indications you're about to lose the front and/or rear? I'll attempt one: as you push on the handle bar through the corner, you feel resistance coming back at you (again this can be very subtle but I did notice it a few times).

  9. My advice? Ease into it and see what the bike does when the front end gets light. If it's still stable increase your speed as long as you remain comfortable. If you aren't comfortable don't do it. It's costing you attention. There's plenty of other places on the track to make up that time.

     

    Thanks, sounds good, but this "feel comfortable" needs to be digged in further. I have another thread ready to go... :D

  10. Causing the front wheel to lift should not itself cause a crash (although it could contribute to running wide, due to decreased traction with less tire surface on the road),

     

    Good point! I never thought about the increased arc due to the loss of front tire traction.

     

     

     

    (One specific warning - pay attention to throttle and lean angle. Some riders, when they feel the bike get light over a crest, unconsciously lean the bike over MORE to try to keep it from running wide. The combination of rolling on, increasing lean, and decreased traction over the crest can exceed traction limits quickly and with little or no warning. Be careful not to add throttle AND lean angle simultaneously.)

     

     

     

    Good warning! Perfect example of why riding on track without the right knowledge can do bad. It's easy to rush to put down the front in this case.

     

    Regarding the comment about throttle control rule #1, keep in mind that a primary purpose of the throttle control rule is to optimize handling by maximizing traction and keeping the suspension in its best operating range. You are looking for an ideal weight balance of 40% front, 60% rear; would rolling on hard enough to launch the front wheel in the air over the crest and top out the suspension accomplish that goal?

     

     

    OK, but then what about the wheelies I see professionals do all the time on straight hills. The front lifts off the ground often in races. Where's the 60/40 balance there? Not even close. My guess is that rear tire traction is higher than 60% anyway, so it's better to maximize acceleration/speed vs. front grip?

  11. So what I'm gathering so far is --throttle control! make sure the front adhere to the asphalt to maximize traction--

    That's fine, but let's brake it down further:

     

    - Why in the next turn 3 at NJMP (after the chicane), many expert/racers wheely there? Where is the throttle control and traction there?

    - Assuming best is to keep the front tire in contact with the asphalt, how do you know when you have reached the optimal balance between acceleration/speed and traction? When the front feels "very light" just before lifting or when the front feels a "little bit" light? Or when it's down solid to grip the asphalt, pressuring the suspension?

     

    In other words how do you balance acceleration and grip to optimize speed on a crest apex corner? What about straight crest? And where is the acceleration crash point, assuming line/exit room is not an issue here?

  12. I've asked this question various times to expert riders but I always get evasive answers of the kind "stay light on the handle bars" or "the bike is designed to handle it". I know I shouldn't front load the bars, what I want to understand is how the bike is going to react and some physics explaining it. Crest apexes are thorny because the front becomes very light right after the top of the hill. The fear is that, with enough speed, the front could lift off the ground while still at max lean (different than straight hills where a wheelie is a lot more manageable). Can the bike crash in this situation? Should I cut the throttle enough to insure the front sticks to the ground?

    Turn 2 at NJMP Thunderbolt is the best example I have, followed by turn 1 at NJMP Lightning. I've seen other tracks with this kind of turns (NYST, Laguna...), just can't remember exactly which turn number. Looks like track designer love to put at least one blind/crest apex at each track.

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