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Hotfoot

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Everything posted by Hotfoot

  1. Wow, cool pic! I bet that tire would feel pretty scary tipping it into a corner the first few times...
  2. So let's explore this skinny tire versus wide tire question. WHY do high horsepower 1000cc bikes use a wider rear tire than low horsepower bikes? We know friction is NOT dependent on surface area, so who can offer up some reasons the tire needs to be wider on an S1000rr, for example, compared to, say, an SV650? Or a roadracing bicycle?
  3. How many total trackdays and commuting miles do you have on the tires now? And what type of bike are you riding? Riding aggressively on the track on a 1000cc bike, if you have done three track days your rear tire may be done. That could be why it is feeling squirmy. It's pretty common to change the rear tire (on a 1000cc bike) after two track days, and the front after about 3 days. The high horsepower bikes eat rear tires.
  4. How far back from the tank are you? It's very hard to tell from the photo, but I am wondering if you have enough distance from the tank to allow you to rotate your hips into the turn, so you can get your chest down without having to twist your lower back to do it. Sometimes scooting back in the seat a little can make it a lot easier to rotate your pelvis into the turn so your back is more in alignment, plus is helps push your outside knee more into the tank.
  5. There is an absolutely perfect description on Twist II that discusses quite specifically both side of this issue, see Chapter 5 Throttle Control, the first section "Street Lazy" followed by Off-Gas Results, it talks about why riders coast, where and for how long, and the exact effects.
  6. Hey BikeSpeedman, PM me with your name, school date (if you remember) and the track where you rode and I'll check to see if it is still possible to get the laptimes.
  7. Oh yes, hi! What a fun day, we were very fortunate to have such nice weather, it was originally looking like it would be very hot but ended up great, with a nice breeze. You did look good through 3-4-5, I followed you through there multiple times and really liked the line you were choosing. I had a lot of fun coaching you at Streets, it was great to watch you getting more and more comfortable on the track on that big bike, I really enjoyed watching you ride it. I thought you rode it REALLY well, especially since you were adjusting from riding a different bike the prior day.
  8. Yes to the above. The turnpoints marked will give you a good line, but as I'm sure was mentioned in the classroom, there is no "ideal line" that is the absolute perfect line for every rider. Riders will tend to choose their preferred lines based on their particular skillset, bike characteristics and riding preferences. For example on my little Moriwaki, which weighs only 180 lbs, I can carry far more corner speed than a heavier bike, and with very low horsepower, maintaining momentum is critical. My lines on the that are not quite the same as the ones I'd take on the BMW; for example, I might use all the track on the exit on the BMW because I am driving hard and the rapidly increasing speed widens the arc and forces me outward. That doesn't happen on the Moriwaki, it can't accelerate that fast so if the next corner was turning the same direction I might not go out so far on the exit, why cover the extra distance if I don't have to? I also, personally, tend to choose relatively late turn points (on the BMW) because I LOVE to quickturn the bike, whereas another rider that likes to trailbrake heavily might choose an earlier or more inside line to better complement their strengths. The turn points at the school are there for learning purposes and students are encouraged to experiment with them, turning before and after, inside and outside, to see what happens. In fact, one of the targets for the TP drill is to go out and do that exact thing, turn before and after the mark, etc. Most novice riders are inclined to turn in early (due to SRs firing off) so those turnpoint marks help get the riders to actually GO to an area that might otherwise never even try. Another aspect is visibility - riding on the road, using a turn point that is later and more to the outside gives you better visibility through the corner. On a familiar track if you have good references (like the rider in the video), that might not be a consideration but for street riding it can be very useful. Do you remember how you determine, after you go through a corner, whether the line you chose was a good line?
  9. Reading Twist II and/or watching the DVD can help keep skills fresh in your mind, and often after attending a school you can re-read the book and find stuff that you missed before or things that mean more to you now than they did before. Every time I re-read it, I am at a different place in my personal riding and some info is more useful to me or comes across in a different way, due to my new skillset, pace or perspective. Doing some trackdays can be enlightening, as you can use your new skills and see if you find that your pace has changed, and I think it is also useful to observe errors OTHER riders make and see what effects those errors have. Turning in early, turning slowly, and poor body position resulting in excess lean angle are some of the more obvious ones you can see - what other errors do you think you could readily observe in other riders?
  10. I second that, I was there, too and I really enjoyed the track, I liked the chicanes and that long right hand fast sweeper! I also got a lot of practice figuring out how to find a line on an unfamiliar, blind turn where you can't see the exit. Glad to hear you liked the facility. Did you bring your own bike or ride a school bike?
  11. At least two are steering, and the third could be also, since being able to carry more entry speed has a lot to do with being able to steer the bike quickly! You mentioned earlier that you had the idea that you needed to be on the brakes to compress the forks to steer the bike - did (or does) that misconception create the entry speed problem and the mid-corner adjustment problem you are trying to fix? Can you (personally) steer the bike more quickly (and carry more entry speed) if you are not also trying to brake hard enough to compress the forks? It is certainly less to worry about, easier to gauge entry speed, and easier to control the steering action, if you are not trying to brake hard at the same time. To be clear, compressing the forks CAN tighten up the steering by compressing the forks (this steepening the steering angle) but it can also make the bike harder to steer (more effort) and I have been in at least one back-and-forth debate with Cobie about which is the greater effect. Personally I almost never use the front brake for the sole purpose of compressing the front end - if I don't need the brakes to slow down, I don't use them. One exception that I can think of is a VERY fast chicane where I have difficulty getting the bike steered fast enough (only at my max pace), and I am driving going into the chicane. In that one case I do SOMETIMES us the front brake a little to help me get the quick direction change, because otherwise the forks are extended coming into it, because I am accelerating coming into it, and the combination of speed, momentum, and fork extension makes the direction change difficult in that tight chicane. A touch on the brakes helps to get it flicked over from one side to the other, but it is a bit tricky to do and I need a lot of free attention to get it right.
  12. Not necessarily - I wasn't attempting to evaluate the rider's technique overall, I was just looking at his lines based on your post. I'd have to watch again to have any opinion on his general technique. I didn't have the sound on, so I didn't hear his throttle control, and there is very limited info available with a camera view like that. All I can say is that his lines looked reasonable and I didn't notice anything particularly sketchy (like abrupt slides), and he seemed pretty consistent. He seemed to pass effectively which indicates that he was not getting "stuck" visually on the rider in front of him, probably he has a good wide view, which is of course a huge key to overall speed. What sort of maneuvering did you see that you wish you could do?
  13. In watching the video, it looks to me like he does straighten out the corners, except for where he is dealing with traffic and has to take a different line to pass. He consistently comes in tight to the apexes and uses all of the track on the exits, except where it doesn't make sense because there are connected corners and he is setting up the next turn point. In fact at one point I noticed he was passing and had to hold a tighter line on the exit and as a result he couldn't get on the gas as hard as normal and the guy he was trying to pass passed him back, on the outside. What specifically do you observe that makes you say it looks like he doesn't care about straightening the corners?
  14. I'll also add that I'm not sure about other brands, but I have ridden on some Dunlop slicks that had cords starting to show through on the rear tire and they still had good grip. I was only running a medium pace but they felt fine. It's certainly not something I'd recommend doing and I'd not do it on my own bike, ever, but it seems like as long as there is rubber left - even if thin - there is still some grip, as long as the tire is able to get, and stay, warm enough. I'm not sure whether that would be true for other brands or for street tires, and when you factor in actual AGE that is a different conversation, since the rubber can get dried out over time and lose grip. In regards to profiling, I rode on someone else's worn front tire and the profile had changed enough that I felt a huge difference in handling, particularly in one direction versus the other, I felt REALLY uncomfortable riding on that tire. I've also ridden on a street tire that had a ton of freeway miles on it and was squared off (flat in the middle) and I found that quite disconcerting, too, it was hard to turn initially then dropped rather suddenly into the lean and I didn't feel like I had good control of my lean angle.
  15. When tire is very worn and the rubber is thin it is much harder to heat up the tire and keep it warm, that is the biggest thing I notice on a very worn race tire, or in some cases the tire profile is changed through wear which can change handling.
  16. Where do you want it posted? I can move it for you.
  17. I think he is talking about just the bar end, the crash protection slider (also sometimes a weight for reducing vibration) which is just screwed in the end of the bar.
  18. Oh, this is hilarious, for two reasons - one, I meant to type RACING story but apparently the typing app on my phone (I use Swype) decided I meant 'teaching' and two, red velvet furniture and a sexologist, OMG. I think I was at that Laguna school. My husband and I spent most of the free time huddled in our little cargo trailer trying to keep warm!!
  19. FOSSILFUEL!! Welcome back, my old friend, so great to have in here again. I think you should start us out with a teaching story, got a fun one to share? I have a question for you, as another rider who has raced a lot of different types of bikes: what bike or race class has been the MOST fun for you?
  20. Riding a curved on-ramp at the speed limit with a cop behind you.
  21. This sounded a little odd to me so I watched the video. Here is what jumped out at me: The title of the video is: Ninja 300 shock causes tire wear. The first thing he says is that the bike has a stock shock, and that he is suggested this riding change as a way to compensate for that stock shock. My interpretation of that is that you could manage the problem temporarily by adjusting your riding but what you should REALLY do is check your suspension settings (or possibly the geometry) to FIX the problem, by setting it up so that the tire is not so unloaded or bouncing at corner entries. I'd also verify your tire pressure, as I suspect that tire pressure too high could aggravate the problem. I'm not a suspension expert and you should ask someone who is - but from what Dave Moss said, it sounded like the shock was not keeping the tire planted so maybe slower rebound, and possibly softer on compression, might help to keep the rear tire from bouncing up and down. Have you had the sag set properly on your bike for your weight? Have you checked the spring rate to see if your weight is within the recommended range for it? It seems like a better plan to fix the mechanical issue rather than changing your riding style to compensate - unless, of course, you are just trying to get through a race or practice day like the rider in the video. Also... there is a WORLD of difference between throttle at 30% on a Ninja 300 and throttle at 30% on an S1000rr! 40hp versus 200hp and the BMW only weights about 60 lbs more than the Ninja. I don't think I'd assume that piece of advice would apply the same from that bike to yours, you might get a different effect. For the sake of discussion, what sort of effects do you think you would notice on your bike's handling if you put the throttle on 30% entering a turn?
  22. Bashir, I think we should move this question to the Tech/tires section so our Dunlop tire expert can take a look at it. Would it be all right with you if I moved it your post?
  23. Have you tried working with a coach or friend, or looking at photos, to compare your left vs right body position to see what you are doing differently? Or is there a strength issue on that side? In the absence of any other info I'd look at how you are holding the throttle, as rolling on the gas as the biggest difference between lefts and rights. Are you doing something awkward with your arm, shoulder, or body to give yourself room to twist the throttle? Have you tried the "screwdriver" grip on the throttle to help prevent your wrist getting bound up when trying to roll on hard?
  24. Laptimes are mainly used for students who want them, to see evidence of their improvement through the day. Or sometimes to compare to their buddy's times, for bragging rights. It happens that as techniques improve, especially visual skills, the rider can feel like they are going slower - less rushed, less frantic, less fearful, sometimes using less lean angle- yet they are actually going a lot faster. Laptimes really help make that real to the student. It is rare for coaches to use the lap time data for coaching, unless a student knows/races that particular track and has a specific lap time goal in mind. We have better tools than a laptimer for L4 students, like video or the BMW datalogger, which collects WAYYYY more info, if a rider is specifically focused on improving laptimes. It's a lot more effective to use video to find areas of improvement. I think we do have records of prior laptimes but don't know that they are used for anything; Trevor has an incredible memory for returning students and can usually say whether someone is riding faster than they have before, or whoever coached the student before usually knows too.
  25. You should start rolling in the throttle after you have completed your steering action (reached your desired lean angle) AND the bike is pointed in the direction you want to go. Can you roll on TOO soon? If you did, what would happen to your line?
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