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khp

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Posts posted by khp

  1. The Difference Between Bridgestone And Michelin In Motogp

    in School Questions/General Discussion

    Posted

    Kevin,

     

    My life is a bit hectic atm. I was 33,000' above Silverstone at the time of the race this weekend, and only got to watch it on my itsy-bitsy-teeny-weeny laptop monitor* Tuesday evening.

     

    But seven different winners in seven consecutive races is a mouthful. I would have expected this in the beginning of the season, but not now. Why now?

    Mav totally deserved that victory btw. MM clearly went into "win it or bin it mode" but it was a great battle for them and us as spectators.

     

    *) Nope, it's neither yellow nor dotted.

  2. Race Bike Maintenance

    in School Questions/General Discussion

    Posted

     

     

    I used to think it was much safer and smarter to "leave it to the professionals" but now I am not so sure. :/

     

     

    I came to the same conclusion (the closest Ducati dealership was more than 2 hours away). Once you get comfortable repairing your own bike, it takes a BIG issue (blown motor) to pay someone else to fix it.

     

    Ah, more that have discovered the old adage: "If you want something done right, you gotta do it yourself!"

     

    Applies to a lot of things beyond motorcycle maintenance.

  6. Gifting Bike To Wife- Suspension Question

    in School Questions/General Discussion

    Posted

     

    I just got a response from Ohlins. It turns out that the stock spring (which I have) works well for her goal weight numbers, She's just 5lbs shy of the recommended range.

     

    It sounds like her losing 5+ lbs and THEN changing the springs is the ideal solution.

     

    We haven't attempted to set sag, which I know is the correct order of operations to know for sure if the spring needs to be changed out. I figure they usually get you in a good ballpark with math calculations on spring selection which makes setting preload a breeze.

     

    I have two suggestions:

    1) You should NOT, under any circumstances, suggest to her that she ought to lose 5 lbs. :)

     

    Hotfoot, you just made my day there.

    Your advice is very well dispensed, and to my knowledge covers all women that walk this earth.

    It's like trying to say that a woman is older than 29 years old :)

     

    More seriously, what I'd recommend you to do is to have the shock serviced by an Ohlins technician (new oil and Nitrogen gas, checking if any gaskets etc needs replacement. Fairly inexpensive stuff). I don't ride competitively on the track, so I keep my service interval to every 2 years (both for the roadbike and the racebike) - otherwise I would be looking at once a year.

  9. The Difference Between Bridgestone And Michelin In Motogp

    in School Questions/General Discussion

    Posted

    MCN posted an interview with Andrea Dovizioso about the transition from Bridgestone to Michelin tyres. Dovi posted a pic of the 2 pages on twitter here.

     

    Since it's pretty hard to read, I transcribed here for everyone's reading interest:

     

     

    IF THE FIRST pre-season test at Valencia in November confirmed one thing, it was that Michelin's new tyres would require a different style of riding as well as quite a different set-up. As stacks of cracked carbon fibre amassed in pit garages, riders were still beginning to understand just what was needed to extract the maximum from the new tyres.

     

    At the end of 2015, there was a clear contrast between Michelin's new batch of tyres and the Bridgestones that had gone before. The Michelin front was found wanting where the Bridgestone excelled, while the French firm's rear had plenty of grip - the opposite of the Bridgestone.

    Michelin's front and rear tyres have since gone through several evolutions, ensuring the differences are now less marked, but a slightly different riding style is still necessary. Ducati's Andrea Dovizioso explained - with the aid of a felt pen - to MCN Sport.

    "The first point is that with the Bridgestones everybody had to brake hard" says Dovizioso. "It was the way to go fast. The set-up and the line was made for the braking."

    "The second point is that the rear grup with the Bridgestone was never the best so you had to create your own grip. With the Michelins the base of the grip is better so the line has to be more flowing, smooth and wide because you have the grip to do that. With the Bridgestones you didn't have the grip, so you had to cut [square] the corner off. When you have grip you can spend more time with the bike leant over.

    "How the front Michelin absorbs the stress and the movement is not as good as the Bridgestone. So all the movement you create has to be softer and smoother because if you move quickly, you loose grip. It can be more sensitive to bumps too, and when you release the brake or touch the throttle, it has to be more smooth.

    "You are braking a little bit sooner with the Michelin mainly because of the line [see doodle]. With the Bridgestone you never really had a problem with the front locking whereas sometimes, yes, there is some with Michelins.

    "Another point is that you can use the rear grip to stop the bike, while with Bridgestone it wasn't possible because it didn't have the same grip on the rear. So my style is to use the rear grip quite a lot because it has the grip, to slow down the bike."

    From a crew chief's perspective setting up a MotoGP machine in 2016 is different too. Christophe Bourguignon, crew chief to Cal Crutchlow says:

    "With Bridgestone you could really set up your bike to do the hard braking. Ok, you were lacking rear grip but you could say, 'Forget that. We're going to gain some tenths on braking in every corner. Let's make the bike as stable as possible' You showed your rider you could make the time up and then you focused on doing that. We cannot do that with the Michelin. The margin for error is smaller, meaning you will crash.

    "We're not setting up the bike like it's a hard braking bike. We're setting it up so they can brake more in a straight line and release the brake so they have a little bit more corner speed to get a good exit. Befure we would set the bike up to do a 'V' line. That suited the Honda really well: late braking, off throttle as long as possible, turn the bike, pick up the bike and drive out of the corner.

    "Most of the riders have understood that and changed their style. Probably some have a better bike for the Michelins. The Suzuki, for example, was already like a floating, good handing bike. Their riders didn't have t change their riding style a lot. Neither did the Yamahas. The Honda bike was built for hard braking, a 'V' line and exit."

    "In fast corners and changes of direction the line is the same. The only difference is that with Bridgestone you could cut across the white line through the curve much easier with no scary consequences. You had to cut it because most of the time the white line and the kerb gave you better grip. With the Michelins you can't use the white line at most of the tracks. The line is the same with both tyres. The only point is that when you cut the kerb, you could be very aggressive with the Bridgestone. This year some tracks is was possible but not like before [because the grip is different].

     

    Enjoy!

     

    /Kai

  13. Why 1000Cc Vs. 600Cc On Training On The Track?

    in School Questions/General Discussion

    Posted

    The F800 isn't a 600cc sportsbike. It's something else - say a city commuter or roadster. Turns good, but when you take it to the track you'll start to find the limits of it (a friend and fellow CSS student of mine has it).

     

    For me, one of the key components of a 'real' sportsbike is a fully adjustable suspension, and the only thing you can do to the OEM fork is change the oil and give it stiffer springs. The rear shock has preload and rebound, but not compression.

     

    Don't get me wrong: the F800 is a nice bike, but it just isn't a sportsbike.

  15. Why 1000Cc Vs. 600Cc On Training On The Track?

    in School Questions/General Discussion

    Posted

    What's interesting to consider as well is the way that many larger race teams use traction control. An interesting video where they interviewed Mat Mladin regarding his views on traction control. They use it to conserve tire life and to be able to make their tires last an entire race.

     

     

    Right, I remember watching that interview with Mladin.

     

    Interesting counter-point to MotoGP today - 10 years later, where it's Rossis' superior hand throttle-control (avoiding the electronic TC) that make him save his tires and get better acceleration out of the corners than, say, Lorenzo.

  17. How Do You Read Traction?

    in Cornering and Techniques

    Posted

    Trying to weigh these factors against each other during a ride is impossible so it’s more a question of feel versus mentally tracking an infinite number of variables.

     

    The clue to sensing traction lies in the fact that tires are always slipping when you corner.

     

    [snip]

     

    The rider also notices that the bars have slightly less tension in them--they feel “light” in the hands. This would be a dead giveaway that the slip angle in that instance is greater than usual.

     

    Great read, Dylan. I think you could evolve this further to a section or chapter in a Twist-3 book.

     

    The key take-away for me here is the point that as a rider I cannot - and should not - try to track those infinite number of variables that impact the available traction, but track my feeling of traction; the tire slippage.

     

    However, the feeling of a front tire slipping is different from the feeling of a rear tire slipping.

     

    The 'light' bars (or even a gentle rocking) is a dead giveaway for a slipping front tire.

    For the rear tire, how would you describe the feeling when the tire starts to slip more than usual? - just this Sunday, I doing a trackday with a worn rear and in the last session, the rear felt as it was 'gliding' slightly outwards through a RHS turn (the final turn out on the front straight, so you're feeding the throttle). This was a gentle gliding sensation throughout the first part of the turn (until I could stand up the bike enough to get away from the worn-out part), not a "let go & grip" feeling.

  18. Why 1000Cc Vs. 600Cc On Training On The Track?

    in School Questions/General Discussion

    Posted

    Denmark is an outlier, but here the R6 is 200K DKK and the R1 is 300K DKK (the R1M is 370K). The RR is 268K DKK for the base model.

     

    All of this explains why I still have "Madame Blue" - my 13yo R1.

     

    I think the reason why BMW doesn't get into the 600cc market and that you don't see new models coming out can be destilled down to three words: The Financial Crisis. Motorcycles are discretionary/luxury spending, and a lot of that got cut back on a world-wide scale from mid/late 2008, and it hasn't recovered yet. Companies may make a lot of money on the bottom line, but make people are not seeing an upturn in the personal finances.

     

    Sorry, I'm getting OT here.

  19. Why 1000Cc Vs. 600Cc On Training On The Track?

    in School Questions/General Discussion

    Posted

    I'm fine with riding 1k or 6 on the track (think 6 would be my preference but wondered why CCS chose to go with a 1000cc machine to train vs. a 600cc machine?

     

    IANAC, but the 1000cc bikes come with all the electronic gadgets and have seen a major evolution over the last 10 years, whereas several of the 600cc models are basically the same model as in 2008, only with "bold new graphics".

     

    Cobie (and Kieth) have told that with the rain/street/track/race driving modes have actually helped half the number of falls per student from the older bikes (the advanced TC didn't prevent me from loosing the front when hitting a bump during CodeRACE a few years ago, but I'll admit fault for that).

  20. Assen

    in School Questions/General Discussion

    Posted

    Kevin,

     

    I drove off at 4.30pm local time and were home at 1.30am this morning - 8 hours of driving and 1 hour for pitshops (and bordershopping - the Europeans/Scandinavians will related to this).

     

    I have still to re-watch the races, after catching up on all the QPs today.

     

    I think the original decision to stop the race was correct, as we got the real down-pour shortly after (btw those who claimed that it was a "tropical level rainstorm" clearly haven't lived in a tropical area). I think Race Direction and the Marshalls could have been better at assessing the track condition (and maybe waiting just another 5 minutes) before deciding on the 2.55pm re-start time.

     

    Valentino clearly admitted that he pushed too hard and the crash was his mistake, but all credit to #JackAssen for pushing when he had nothing to loose.

    But in the end it's still a pity to see so many crashes (in fact, everyone in the MotoGP field crashed at least once during the weekend), and it will inevitably impact the championship. It's all but gone for Valentino, I'm afraid.

     

    Edit: I also have about 1800 photos to sort and grade from the first two days :blink:

  25. Catalunya & Mugello

    in School Questions/General Discussion

    Posted

    Kevin,

     

    From what I hear, HRC is very much "The Great Japanese Engineers At Headquarters Are Right". They had a pretty unridable bike last year, and they haven't made the problems smaller this year. Engine far too aggressive so they can't get any edge grip, can't get the tires to hook up and get the bike to go. All five Honda riders are having problems.

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