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Pucture at 200k's

Discussion in 'New Riders and Riding Tips' started by raven, Jan 28, 2006.

  1. Last wednesday, I was off on a 4 day ride, and on a country road just short of Maffra I came upon a loooong straight stretch and decided to take the bike up to higher speeds to see how it sat on the road and felt.
    I got to 200kph and sat there for a little while, pretty impressed with the way things felt so I took it up a little more...at 210, I decided "nyah, this is too fast on a regular road - back off and get back to normal riding"...

    So I let the bike ease down, but at about 160-170, I felt an odd force, like the bike tyre was following a groove in the road or something....at that speed I just relaxed on the bar and just go with the flow....it disappeared.

    By now I'm down to about 120ks, when I feel the back tyre become a little "oozy", and want to drift a little....I added some throttle gently to stabilize things, and noted that the rear-end was feeling squirrely...O-ohhh...I'm thinking I have a rear tyre deflation, and I know that as I reduce speed the rear will get veeeery lose....at about 80k's I am barely feathering the throttles to get a feel for what the bike is going to do, as I allow the speed to come off as slowly as I can without shifting weight from throttle shut down etc....

    Finally the bike starts to get very loose at the rear-end and sends me into a slight drift across the road into the other lane...gently tip-towing the bars, I regain the right ballance and at about 40k's I know I am slow enough not to get too injured if I'm tossed off...down to 20k's and it was to slide all over the place, but with adding some steady throttle to keep a little power going to the back wheel, she steadies and I am able to stop from there.

    Luckily for me...it was a rear tyre!...It looked like I may have picked up a nail or something, which then threw out of the tyre when I took it up to high speed, causing the unexpected deflation.

    With the rear tyre deflated at speed, it was similar to riding on a very slippery surface...you just have to make gentle inputs until you can get things slowed down enough, where injuries will be minimized. Stabilize things with a gentle throttle and ease down slowly.
    Fortunately for me, I was on a long straight stretch of road, and was able to work it down safely...had it happened in the twistier areas, I might not have been so lucky.
    It's also worth noting that I had to ride with the rear tyre flat as a tack for about 22k's into Maffra. I was amazed actually, at how the tyre stayed on the rim, and allowed me to crawl along at about 20k's, but VERY watchful of the rear-end sliding out. Be especially careful of road camber...at one point I was riding pretty much sideways until I could get over to the centre of the road and ride the high spot...veeeery gentle throttle inputs, and using alot of "seat of the pants" to feel the bike along the road.

    Ultimately - no damage to the bike or the rim - a new tyre, and away I go a few hours later.

    Just in case my experience might be of some benefit to someone else.


  2. Pffft... when I had a rear tyre go pop at 200+, it was nighttime, I was two-up and setting up for a third gear left-right S-bend with a concrete divider around the outside.
  3. Thanks for the indepth description jgm, I have yet to have the unfortunate experience of having a tyre go down while riding and always wondered what would happen to the feel of the bike if it did.
  4. man someone is looking after you mate
  5. Are you sure it was a nail, or could it have just delaminated because of the speed you were doing? I guess by the time you rode it another 20kms with no air, you wouldn't have been able to diagnose the cause anyway.

    Still, a good outcome, and obviously, since you're still with us, good riding.....

    And IK, what's the rest of the story, man, you can't leave it hanging like that.....?
  6. Nice one. Good to hear to managed to pull the bike up without throwing it away.

    I had this attraction to nails for a while, picked one up within 1500km of riding on a new tyre.
  7. This was on north end of the Captain Cook Bridge, in Sans Souci, in Sydney.

    There was surprisingly little drama about it, actually; the way there usually is when things go wrong at speed and you react before you figure out you should probably panic.

    Tipped in, the bike did its best to keep heading for the concrete divider, countersteered more, made it round and lost enough speed in the process to limp over to the kerb.

    Like I say, surprisingly little drama. Limping the 35km home to Da Valley with the arse end going flop-flop-flop was a lot scarier, what with westies in Toranas leaning out of windows and yelling shit.

    Got the bike (B-model ZX-9R) home, up on the race stand, realise the entire rim is about as hot as the muffler. Just from the heat transmitted by the mangled tyre.

    When the tyre came off at a bikeshop the next day, inside it were about five or six fistfulls of rubber, ground to a consistency like printer toner by the action of the rim grinding the sidewall into the tread.

    Think I might still have the tyre somewhere...
  8. erk, I know that road very well, and it's 90kph across the top heading north and even though it drops to 70 in the middle of the left-hander, no-one ever does :grin:
  9. Yeah...after the incident I could'nt find anything wrong...was even thinking that the sidewall did something wierd....I had that spray foam in a can, and started to re-inflate it, when it all started squirting out a hole between the tread. (The hole was too big for that stuff to plug, so it just squirted out till the tyre was flat again (groan)...

    By the time I got to Maffra, the tyre was still in one piece thankfully, but it had taken a hammering and was too far gone to fix. But I was impressed that it got me that far!. And thankful that it did it's job in protecting the rim. :)
  10. At my recent PI session 6 days ago, I flicked into Turn 1 at ~180kph, and the bike handled dreafully and almost fell on its side without a LOT of effort on the inside bar to hold it up and on line.

    Pulled in off the track at Honda corner and went in to see what the deal was. Measured the front tyre pressure. 0psi!!! The front air valve was opening by the cetrifugal force of hitting >250kph down the main straight, and had totally deflated the front tyre by the time I had reached the end of the straight.

    I was thanking my lucky stars that the tyre didn't peel itself off the rim as will typically happen in such a scenario.
  11. Bewdie...that's the only reason I posted - just in case it might help someone else ahead of time. :)
    All circumstances are different of course...let's hope that when it finally happens to you, it's not too bad.
  12. It would be more helpful if you passed on a bit of info on how the bike reacted when the tyre deflated, what you did to control it etc...
    ie, how did you avoid the tail from sliding out?

  13. he did tell the story, further up, John.
  14. Wew!...lucky indeed...and good job for keeping it upright!!
    Thanks for reporting what it felt like...might help someone.
  15. Oops...yes, I see it ...sorry IK. :oops:

    Like you, I did'nt immediately realize what had happened...Had my brain screamed "Tyre flat - big trouble" I could easily have ditched it with by over-reacting.

  16. Yeh, I'll remember that too...next time I take the SR185 to those sorts of speeds!
  17. Ok you can't do this in a corner, or probably not in heavy traffic, but with a rear going flat, wouldn't braking hard with the front brake only minimize the effect the rear tyre had on handling?
  18. I wondered about that afterwards, but I think that the transfer of weight forward without any grip on the rear, would cause it to drift out and put you in a tailslide??...unless perhaps if you were dead straight on a very flat surface. Even the camber of the road might be enough to spin you around - tyre peel off - rim dig in - and pitch you off...

    Seems to me to be a real seat of the pants affair....if it feels ok it probably is...in my specific case...allowing a little drive on the rear axle but not enough to prevent me slowing down, kept things under fairly good control. Of course...I had the room ahead of me.

  19. Many years ago, actually I was 16. I was riding my old Triumph speed twin. It had what was called a Mk 3 sprung hub suspension. Had the mate on tha back. Doin say 120 k, We went over the jion in an old bridge. The old triumph started doin big snakies from the rear. When I stopped, the mate got off & said, F#@k look at that. The spoke wheel had completely disintegrated.
    When you look back, many times we are just bloody lucky hey.
  20. You need to transfer the weight forward, like a stoppie. With no (or little) weight on the rear, the rear tyre would have less stress, and therefore would be more stable, me thinks.
    Also has the benefit of protecting the rim.