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khp

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Posts posted by khp

  1. Dunlop Sportsmart2: 190/50 Vs 190/55 Profile?

    in School Questions/General Discussion

    Posted

    A new year has come, and Ye Olde R1 (nee 2003) needs a new set of shoes this year. The old shoes are Dunlop SportSmarts that I have loved to pieces (literally), so it is an easy decision to just go for the newer SportSmart2.

     

    In the 190 size, they come in two profiles: 50 and 55. Obviously, the 55 profile is slighty higher (9,5mm if I got that right), which should give a more pointed profile, less rubber in the middle for the straightaways but more rubber when leaned over to the edge. Not that I've lacked edge grip on the SportSmart - I've run my knee into the tarmac on the outlap at a CSS course in Sweden, without any troubles.

     

    Do anyone have any experience with 50 vs 55 profile?

     

    Thanks,

     

    Kai

  3. Engine Oil

    in School Questions/General Discussion

    Posted

    Discussing engine oils between motorcycle enthusiasts can get you into a fist fight, so be warned!

     

    My father is a petrochemical engineer by trade and worked in the lubrication industry all his (working) life. His recommendations to people whenever they ask him is simple: Choose an oil that has the same specs (API, SAE, etc) as what the manufacturer prescribes in the manual.

     

    That's it. Forget about brand X is better than brand Y. It's BS.

     

    The reason the "brand war" is BS is that they all use identical base oils etc to get to those specifications. If they didn't, it would show up as a spec difference.

     

    For your racebike, I would still use the same engine oil, but change it more frequently.

     

    Kai

  5. Health Insurance Coverage

    in School Questions/General Discussion

    Posted

    Caveat emptor: I'm in Denmark. My private accident insurance policy states that if I partake in "risk-prone activities" (invariably including anything that doesn't happen above or under ground-level and motorsports), my insurance sum gets halved. You can get specific insurances for racing (that's part of what you pay for in RR license), but it's cheaper to simply buy an insurance with 2x the coverage. Then you also get 2x payout, should something happen to you when you aren't taking part in a "risk-prone activity".

     

    YMMV.

  7. Track Day Friendly Insurance Companies?

    in School Questions/General Discussion

    Posted

    I believe that liability = third party insurance. Mandatory here too.

     

    What happens if you ride your car/bike without registration? You get to pay full tax + a fine equal to the tax. That'll teach 'ya.

    And if you're living in Denmark, you are not allowed to ride a foreign registered car/bike (there are some very narrow exceptions).

     

    I like to test my bike on a dyno or at a trackday for that reason.

  10. An Article I Wrote

    in School Questions/General Discussion

    Posted

    @rchase congratulations on a really well written article. I sure can relate to your descriptions even though I never have gone 2-up with a racer. In fact, it's been many years since I last was on the back of a bike.

     

    14 seconds faster is beyond massive, it's a gargantuan leap! But it does make me wonder what your previous speed at this track was. How many seconds or percent slower were you than the track record?

     

    At my "home" track I'm around 12 seconds back of the 58s50 record (my personal best from 2011 is 1m08s86)

     

    Thanks for the inspiration

     

    Kai

  17. Suspension And Rear Tire Under Braking

    in School Questions/General Discussion

    Posted

    Hotfoot, great to have you to inject some knowledge in this exchange of guesses :)

     

    My personal experience with braking is that stiff arms are much more harmful than sitting upright. I should know, because at 6'6" I can sit with an almost vertical back and still have bent arms. Of course, having the forks to bottom out is a very effective way of ensuring a stoppie (DAMHIK). But that shouldn't be your problem. It's the braking force vs rake/trail/CoG that's making the problem for you.

     

    In my 6 years as an instructor at a MSF-like course, I've worked on braking with more students than I can count and letting your arms loosen up worked for all, regardless of bike types (from Harleys to Ducatis) and rider body size.

  19. Suspension And Rear Tire Under Braking

    in School Questions/General Discussion

    Posted

    Also in chatting with Keith about it, he asked if I could get lower on the bike to get the COG lower, which was a really good point; I can definitely keep my upper body lower in the hard braking zones and that should help reduce the tendency for the rear wheel to lift. That's an easy thing to change so I'll definitely do that.

     

    I should know better than arguing with Keith, but if you lower your upper body to lower the CoG, you will also bring the CoG forward. I don't know which effect will have the biggest impact on the braking stability, but as you're pointing out, it's an easy thing to change and test out so by all means do it and see what it does. And please do report back here on your findings :)

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