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The last page was a good read in terms of advice, certainly highlighted a couple of aspects of my own riding to work on. Since my last questioning of Z3n, I've put some Techspec on the bike and found it certainly does help. Still need a bit more work keeping my weight off the inside peg though - I think I tend to carry a bit too much weight on the knee slider (weight the tyres should have instead). While we're posting photos, this is from a fun session a few weeks back at one of our smaller tracks:  Going back to the larger track in 10 days time. I need to start making more extensive use of the gearbox and less extensive use of the brakes. I'm fine with leaning the bike over, but I usually tend to brake much more than I need to for a corner, and subsequently end up with miles of extra room on corner exits.
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Dec 10, 2009 15:41
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| # ¿ May 3, 2024 04:36 |
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So, I highsided a couple of days ago. I'm ok but sore (thanks HJC, Knox, and Joe Rocket), and the bike also escaped with surprisingly little damage, owing largely to the sliders on the frame, engine case, and swingarm. My biggest expense by far will be a new helmet. I was accelerating out of a turn, 4th gear maybe 9 or 10k rpm, rolling on the throttle like usual, and a moment later I was airborne. It felt to me like the back end suddenly whipped waaaay out of line, and I barely remember registering this before being flung off. However, it was the first time the rear wheel has ever broken loose on me, so in hindsight it is quite possible that it didn't step out as far as it felt to me, and it's also possible that I wrongly closed the throttle on instinct (though I honestly don't recall doing so, it seemed to happen too quickly for me to have reacted). Basically, does someone with more experience have any pointers as to how to avoid a highside if the rear wheel goes? I know the basic theory is "ignore it and stay on the power", but there must be at least a little more to it. I had been planning on shimming the rear shock ride height in future for better turn-in, but the reading I've done indicates that this would exacerbate any problems with rear wheel traction by reducing weight on the rear, so that's off the list. When I had my suspension dialled in, the guy doing it told me that compression is something he could only have an educated guess at, and that I'd have to adjust it myself later if the bike was doing something I didn't like. The general message I got from him was that too little rear compression would make the rear wheel feel unstable and slip around more easily, whereas too much would make it feel stable but then slip out very suddenly once it did go. If that's right, it seems to me that I need to back the compression damping off a bit. If it's of any use in answering my question, bike is an 02 GSXR 600, stock suspension and stock geometry, new-ish 2CT pilot power front, older regular pilot power rear, wheelbase out near the end of the swingarm as the chain is due for replacement soon. FlyinDoc fucked around with this message at 05:39 on Dec 22, 2009 |
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Dec 22, 2009 05:29
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Pace, unsure really. They run trackdays as 4 groups here (4th being most experienced, and largely made up of racers getting additional practice), and I book for the 2nd group, though I tend to be one of the quicker riders in it, and had been planning on moving up in the near future. It was probably 1pm or 2pm, clear hot sunny day maybe 35-38°C. Tyre pressures were 29psi up front and 31psi rear.
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Dec 22, 2009 05:43
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I understand the relationship between throttle and lean angle, but there is another aspect (though of course, I crashed because of too much lean and throttle in combination, no doubt about that): The corner in question is U-shaped and very heavily cambered towards the exit, allowing you to put down a lot more power on the way out even though your lean angle isn't decreasing that much. In the past I've rolled the power on through there and been WOT by the time I'm roughly 2/3rds around the corner, lap after lap with no problems. This time, I guess I was going a little bit quicker, putting me both at a greater lean angle and higher into the powerband, the combination of which broke the rear tyre loose. I completely understand that a powerslide is slower, and don't mean to intentionally repeat it. I was wondering if there's anything else you can do to help recover a rear wheel slide without crashing, apart from staying on the throttle. Standing the bike up a bit maybe? I'd rather take my chances with running wide versus a highside, at least you have a sporting chance of keeping upright if you stand the bike up and go onto the grass. Unfortunately, as a university student the bike is my sole means of transport, so I currently can't work the logistics of using race slicks, stands, and tyre warmers for the track (yes, some would certainly say I shouldn't be doing trackdays). Even ignoring the warmers problem (i.e. number of heat cycles), the bulk of my riding is on the road, so I can't really justify race tyres, even if some are technically road legal. Same goes for buying a dirtbike or supermoto - I'd love to do it, but lack the money. I guess it just means I keep the trackdays less frequent from now on and my pace a bit more sedate. For the next couple of years anyway. Thanks for the advice Z3n, I'd like to thank you for being a great resource too. FlyinDoc fucked around with this message at 10:29 on Dec 22, 2009 |
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Dec 22, 2009 10:16
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I hadn't considered the camber to be as much of a contributor as it seems to have been now, because yes, I was virtually all the way around before losing it. To further complicate things you exit that corner up a moderately steep hill, though that should help rear traction I suppose. I had been under the impression that even DOT race tyres (I assume that's a term for road legal race tyres like the power one or the pilot race, right?) were only good for a relatively small number of heat cycles, compared to road tyres, before they started to "go off" and lose their stickiness - and that was why warmers were used, so that one trackday was one heat cycle, rather than 6-8 cycles. If that's not really much of a problem though, then I'll be on the look out for some rims. Any comment re: compression damping? I'd always (maybe wrongly) expected it to be the case that the tyres would squirm around a bit when they were pushed, rather than feeling nicely planted and then really letting go quite suddenly. While I'm here and asking questions, what are your thoughts on switching to a Corsa III or similar when the rear tyre needs replacement (assuming I stick with road tyres for the time being)? I remember you mentioning that you ran a stiffer front tyre and a more pliable rear for a while, and was wondering if the more pliable pirelli might help with developing a sense of feel for what the back end is doing. FlyinDoc fucked around with this message at 02:08 on Dec 24, 2009 |
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Dec 24, 2009 01:59
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Z3n posted:Do you have any pictures of the area that you crashed? I can't find any ground level photos (spectating isn't allowed in that area of the track), but I have an aerial one. Entry is on the right, exit on the left. The line drawn on it was a guy on a local forum asking if that proposed line was a good one or not. The second half of that line is fairly accurate, but I start the corner much wider. If you divide the distance between the two yellow markers into 3rds, I think where I crashed was about 1/3rd from the lower marker and 2/3rds from the higher one.  My rear shock is stock unfortunately. The suspension setup was fairly basic, just spent an hour or so setting sags (I don't have the sheet handy right now to check, but I think around 30mm front and 28mm rear?), rebound damping (which apparently isn't quite adequate, but is the highest that the stock shock can be set to without turning it right to the stop), and then the guy had a guess at what my compression damping should be. Just had a check on the bike and the rear compression damping was set 1 turn from softest (with another 1.5 turns to go until hardest). I know I'm not bottoming out the front, as I spread a fine layer of polish on the fork tubes a few months ago (older GSXR right-side-up forks seem to get little rust spots quite readily), and there is still 20mm or so of unused travel where it hasn't been wiped. I'm not sure about the rear, haven't bottomed it as far as I know.
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Dec 24, 2009 09:12
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Thanks for the input. Guess I'll be watching out for an aftermarket shock then.
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Dec 27, 2009 14:12
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After looking around and considering options, I've found these: Forks - Elka do a piston kit for $145 USD http://www.elkasuspension.com/?q=node/46 I've contacted one of the local suspension guys to ask if it's something he could install and set up, still waiting to hear his opinion on it. Shock - Reading gixxer.com, there is a suspension guy who sells reworked versions of the 04/05 GSXR600/750 shock, which is supposed to be the only year that gixxers got a decent shock. I can get one, reworked and sprung for my weight, and shipped over here, for around $390 USD. This link goes into detail about what he does with them: http://shop.ebay.com/110448493907 Any thoughts on whether this is a reasonable plan of action for a trackday rider on a budget? FlyinDoc fucked around with this message at 07:38 on Dec 30, 2009 |
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Dec 30, 2009 07:29
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Congrats on picking up a bulletproof trackbike. I was going to recommend a stator cover slider plate, but it looks like yours has an aftermarket stator cover on it, which will be built to take a slide. On a less positive note, gently caress anti-competitive import agreements, seriously. Elka won't sell anything to me, because they have an agreement to do everything via a single Australian distributor, who apparently puts a 200% markup on their prices compared to what Elka charge. On top of that, I'd be paying for shipping from the other side of the country anyway. As a further kick in the ribs, Elka Canada currently have a single slightly used 01-03 GSXR600 shock in their clearance section for $300  I never understand why companies enter into self-defeating agreements like that, as it most likely means I'll just buy a fork kit from another company like Racetech or GP suspension who do business in a less retarded manner. They cost a little more from the beginning, but end up far cheaper after the ridiculous markup on the Elka kits. FlyinDoc fucked around with this message at 11:57 on Jan 4, 2010 |
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Jan 4, 2010 11:44
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That would be awesome. I'm fairly sure they do ship to the US, as there's a North American ordering phone number on their site, and they list all prices in USD. Their contact form is at http://www.elkasuspension.com/?q=contact Just ask them what it would cost to get that clearance GSXR shock (second page on the pdf at http://www.elkasuspension.com/?q=clearout) set up (for a 150lb rider doing trackdays on a 2002 GSXR 600) and shipped to you. Before you go through with anything I can paypal you that cost, plus whatever it will cost you to reship it, plus whatever it will cost you for a few beers. FlyinDoc fucked around with this message at 01:28 on Jan 5, 2010 |
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Jan 5, 2010 01:14
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I have no upgrades on my account, so can't do PMs, and I'm getting an error message saying that an administrator has disabled the email function. If you email me at madscientist2003 (at) "that free microsoft high-temperature email provider"(.com) then I can send you my address and such.
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Jan 5, 2010 03:33
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Suspension isn't really something you can set from other's recommendations, and you want to have your sags (i.e. preload) set in the ballpark before you play with damping settings. Measure the sags (distance with wheel off the ground, minus distance with you sitting on the bike in full gear), and set the preload to give you somewhere in the region of 25-35mm sag at each end, tending toward less sag if it's primarily for track, and more sag if primarily for street. Then, record the values in case you wish to adjust them later based on how the bike behaves. The same goes for all suspension changes, make a record of everything you do, and change one thing at a time. Then set rebound by turning the adjuster to the "softest" (i.e. least damped) setting, having a friend hold the bike upright, and pulling momentarily upward on the bars before shoving them downward as far as you can. Increase rebound damping gradually until the suspension returns only to its original height (i.e. without any subsequent bounces up or down). Repeat same steps for the rear shock as well. Compression can't really be guessed at with the bike stationary like the other settings can, so either stick with the recommended settings, or do the following: Remove all compression damping, go for a gentle ride and see how the bike feels. Max out the compression damping, go for a gentle ride and see how the bike feels. Find a happy medium between the two where the bike feels settled over bumps. The aim of compression damping is to make the suspension compress at just the right rate over bumps, so that the wheel not only remains in contact with the road, but also with as much weight remaining on it as possible. If the suspension compresses too quickly, the upward momentum of the wheel (over a bump) will be trying to continue compressing the suspension and lift the wheel off the ground, despite the bike itself not moving much. If it compresses too slowly, the wheel won't be moving enough, forcing the whole bike upward and again trying to lift the wheel away from the ground. Setting it all is basically some educated guesswork and then trial and error from there. FlyinDoc fucked around with this message at 11:40 on Jun 19, 2010 |
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Jun 19, 2010 09:30
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520 Drag Knee Every Day Got a couple of hours of track time in recently, for the first time in much too long. Still not even close to as quick as I was before highsiding last year, but smoothness, baby steps and all that... Track days are indeed the best days 
FlyinDoc fucked around with this message at 12:31 on Aug 10, 2010 |
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Aug 10, 2010 12:21
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| # ¿ May 3, 2024 04:36 |
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That front looks fine, what you see is just blobs of rubber scrubbed off from other bikes tyres that your tyre has then run over and picked up. If it feels wierd on hard braking though, check you aren't bottoming out the forks. A ziptie is good for this.
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Aug 17, 2010 05:02
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