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Thread: THE Wheel & Tire Thread

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  1. #1
    Senior Member Xusia's Avatar
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    Ahh. I see the disconnect. You are associating my statements about limits and getting a preconceived notion of how I will drive. You don't really know me, so I think your impression is likely inaccurate. Not pushing the limits doesn't mean a Sunday stroll! LOL. It just means keeping a margin of safety (i.e. for the uncontrolled environment and such), which is below the car's limits and within my own personal limits (This is how I ride motorcycles too). I do plan to drive it aggressively on back roads and such, just with an appropriate margin of safety.

    As far as my avatar goes, I had to laugh a bit when I read your comments. Bragging isn't my style, so I don't ramble on about how good I am or what my experience is, etc. As a result, you seem to have formulated an incorrect assumption as well as underestimated my riding skill (not surprising since we only know each other through this NON-motorcycle forum!): I'm not even close to pushing it in that pic (that was only at about 65 and I take that corner at 85 when I decide to ride closer to the limit). Seriously, I could taken a hand off the handlebar, turned my body completely around, waved to the guy behind me, and taken a sip of tea (if that were possible with a helmet on). I'm not even leaned over far enough to get my knee down. The only reason I'm even leaning off the bike is because it's fun. The photographer was a friend who wanted some action shots in his portfolio, so I thought I'd have a bit of fun while we were out and was just screwing around as I took various runs through the corner. That one just turned out to be a really good pic, so I use it as my avatar.

    Not really related, but I thought I'd clarify something you stated incorrectly. I don't mean or want to offend you; I only want to ensure accurate information is presented in case there are other motorcycle riders reading this: Letting off the throttle doesn't push you wide. The front fork compression caused by using the front brake changes the bike's geometry and results in the bike wanting to "stand up" (the more forceful the braking, the more pronounced the effect). If you LET it stand up, THAT can cause you to go wide. If you maintain lean, however, you actually drop into the corner more, tightening your line. This can be dangerous, however, because braking while actively maintaining (or increasing) lean consumes additional front traction. And you don't want to exceed your finite amount of traction! That puts you on the ground and ends your fun.

    Letting off the throttle causes engine braking which primarily affects the rear tire and shock. The front forks and overall geometry are not appreciably affected. So as long as the engine braking isn't enough to compromise rear traction, letting off the throttle causes you to drop into the corner more, tightening your line with minimal impact on traction.

    Lastly, leaning more AND using the throttle is a bad idea in an emergency avoidance maneuver because it has a much greater likelihood of overcoming available traction than other options. Leaning/steering and accelerating both consume traction, so if you do more of them, you are in effect consuming more of your precious, finite traction (both front and rear). If you encounter an emergency situation and you need to tighten your line, the best response is to let off the throttle (but avoid excessive engine braking) and push on the inside bar until the you have achieved the necessary tighter line. This consumes the least amount of additional traction.

    The following was taken from Sport Rider Magazine (link):

    Your bike's trajectory or curved path through a corner is primarily determined by two factors: your speed and your lean angle. Increasing lean angle quite obviously tightens your cornering line while increasing your speed has the opposite effect. In other words, once you've set your lean angle you can tighten your line by simply reducing your speed or widen your cornering arc by increasing it; without ever changing your lean angle. Keeping your engine rpm between 60 and 80 percent of redline also enhances its throttle response, though the higher rpm also demands greater smoothness.

    While I'm not as experienced with high performance driving as I am with riding, I am a sharp guy and quick study. And based on what Wayne said, the car is well mannered when being driven at less than the limit. So, I think I got this!
    Last edited by Xusia; 06-28-2013 at 01:45 AM.

  2. #2
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    Quote Originally Posted by Xusia View Post
    While I'm not as experienced with high performance driving as I am with riding, I am a sharp guy and quick study. And based on what Wayne said, the car is well mannered when being driven at less than the limit. So, I think I got this!
    I understand, and I didn't mean for this to become a war of words. It's just a simple fact that the car will handle differently and be more prone to oversteer if you decide to run the same size tires front and rear. Wayne's comments about the 818 throughout this forum apply only to the setups he has driven and track tested. If you take an 818 and start messing with the setup, everything goes out the window. It's simple enough to turn an 818 into a handling mess if things aren't approached the right way. Running equal size tires front and rear is step one towards making it a mess.

  3. #3
    Senior Member DodgyTim's Avatar
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    The analogy with the sportbike and a 818 is a good one, they are both going to be too fast to have genuine fun with on public roads. Too many cops and distracted drivers for me. For $120 I can go to the track and pretend to be Valentino or Sebastan for the day!

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    Senior Member wleehendrick's Avatar
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    Quote Originally Posted by Xusia View Post
    And you don't want to exceed your finite amount of traction! That puts you on the ground and ends your fun.
    Been there, done that, front wheel washed out... four broken vertabrae.

    I have no memory of several minutes before/after my accident, but looking at the scene afterwards, it was clear that I exceeded the traction limit of the front tire and I low-sided. I slid for a while, which would have been fine since I was in full gear, but then there's the guardrail. I always try to leave a significant safety margin on the street, but having no memory, I can't say what was responsible... did I come in too hot? possible. There was gravel in the corner that I may not have seen. I just don't know.

    That experience is why I want my 818 to be as well balanced with as predictable handling as possible.

  5. #5
    Senior Member Xusia's Avatar
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    Quote Originally Posted by wleehendrick View Post
    ...I always try to leave a significant safety margin on the street...
    That experience is why I want my 818 to be as well balanced with as predictable handling as possible.
    I hear ya and agree. I'm sorry to hear that happened to you. I had a similar experience in the past that has also shaped my thinking and behaviors. I wasn't injured, but the distinct potential of death was undeniable (had things gone another way, which they easily could have).

    I think it's been forgotten, but my intent IS to run as wide a tire as possible on the rear, AND a narrower tire on the front. I understand that's the desired set up and what is best for handling. I would only run wider fronts IF I HAVE TO. Hopefully, I won't have to.

  6. #6
    Senior Member wleehendrick's Avatar
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    Quote Originally Posted by Xusia View Post
    I hear ya and agree. I'm sorry to hear that happened to you. I had a similar experience in the past that has also shaped my thinking and behaviors. I wasn't injured, but the distinct potential of death was undeniable (had things gone another way, which they easily could have).
    Thanks... I'm fine now, but it does change your perspective.

    Quote Originally Posted by Xusia View Post
    my intent IS to run as wide a tire as possible on the rear, AND a narrower tire on the front.
    That's my thought as well... just don't take it to an extreme, or you end up with this:

    deltawing-takes-off-inline-turns-photo-460519-s-original.jpg

    http://www.caranddriver.com/features...ce-car-feature

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