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Ratgin
Posted on Saturday, June 05, 2010 - 01:33 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Happened as couple times now and im not certain why.

Maybe someone who races can help answer


Leaving working at 10:30pm, bike is warm, tires are warmish

on a big right hand sweeping on ramp to freeway.. road sign reads 50kph (30mph) and im doing >80kpm second gear holding throttle,

counter steering and at a decent(ish) lean angle and rear tire "kicks out? slides out?" to the left.

I just hold my line and bike grips again and away we go but wth am i doing to cause this read kick/slide out?

Near had this happen before this bike but i likely didnt corner as quickly either.
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Craiga
Posted on Saturday, June 05, 2010 - 01:43 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Tar strips (aka tar snakes) on the road???
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Ratgin
Posted on Saturday, June 05, 2010 - 01:44 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

nope,, nice clean pavement

im baffled as to what im doing wrong
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Drawkward
Posted on Saturday, June 05, 2010 - 02:38 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

What tires and what pressures?
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Bitey83
Posted on Saturday, June 05, 2010 - 03:48 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Maybe you're getting on the gas too early, try taking the corner in 3rd so your not unloading as much torque on minimal contact patch. My corsa 3s started doing that after 2500miles and 2 trackdays, i have read thats they tend to lose edge grip quickly.
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Bartimus
Posted on Saturday, June 05, 2010 - 03:56 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

"tires are warmish"
Not letting your tires get up to operating temp, will allow them to slip.
they will not have maximum traction until they are up to temp...
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Brumbear
Posted on Saturday, June 05, 2010 - 08:07 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Nine do it as well but not till they are pretty worn after about 1500 miles it started happening to me and on the corsa 3 thats pretty worn for them. I got 2200 miles out of my last set I think and edges were gone and cords were showing
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Ratgin
Posted on Saturday, June 05, 2010 - 10:16 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Tires are max pressure as im a heavyweight.

Ramp is about 5 kms from where bike started and tires seem warm, its the road so theres no warm up lap so hard to be sure. OEM tires with about 1.5k miles

holding steady rpms in second , speed is about double the recommended but not stupid fast as im too old for that now.

Always slides the rear at the same spot on ramp which makes me think its my riding and not the equipment,

will post a poor drawing




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Drawkward
Posted on Saturday, June 05, 2010 - 10:53 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

What is max pressure???

I'd be willing to bet that having that much air in the tire is contributing. If you're getting on the gas real hard at the "slip" point you can definitely easily break it loose with high pressures.
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Ratgin
Posted on Saturday, June 05, 2010 - 10:56 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

no im holding the same speed threw corner not rolling anything on yet when it slips.

max is 41 iirc
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Craiga
Posted on Saturday, June 05, 2010 - 10:56 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

the high tire pressure may be making your "traction patch" much smaller than it should be.
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Usanigel
Posted on Saturday, June 05, 2010 - 11:05 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Same area every time? That's the road surface, could be "polished" in that area. If it were you then it would happen in different places. ie Sooner one day and maybe later the next.
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Duphuckincati
Posted on Saturday, June 05, 2010 - 11:20 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I never trust the traction at on/off ramps. Cars are either on the gas or on the brakes and dealing with centrifugal forces and all that will make various fluids (brake, tranny, water, steering, oil, etc.) drop onto the roadway. You may not see this stuff but it is absolutely there. And what is the road surface made of? Concrete or blacktop? Take it easy there. Crashing sucks. Period.
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Drawkward
Posted on Saturday, June 05, 2010 - 12:42 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

41psi is going to give you a MUCH smaller contact patch than say, 35 or 36. For reference, when I ride the track my cold pressures are 28/27 front/rear with maybe .5psi difference. Hot pressure is around 31/30. Obviously that's not ideal for the street and I don't ride with those pressures, but I'm a big guy too and I don't go above 35 or 36 psi for every day riding.

And like some other have said, NEVER trust the on and off ramps.
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Rsh
Posted on Saturday, June 05, 2010 - 02:11 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

The tire pressure is to high, even the manual says at max GVWR the tire pressure is still listed at 34psi front, 36psi rear.
Unless you and all your stuff weigh more than 395 lbs you should be at least using the tire pressure in the manual.
With the tire pressure that high, it will amplify any road irregularities, and may not let the tire get up to a decent temperature.
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Slaughter
Posted on Saturday, June 05, 2010 - 03:49 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

41 psi for ANY riding other than upright slab riding is waaaay too much. Like riding on a surface of marbles.

The recommended pressures are for rubber life and NOT handling! Depending on what brand and design, you really want to be MUCH LOWER if you're doing any turning at all.

Many folks are shocked at how low the recommended pressures are for "spirited riding."

GENERALLY sportbike tires do well starting at about 30psi cold.

I doubt that in just 10 miles in the city that you'll get any heat into them - and for SURE if you're running 41 psi, the carcass is not really flexing enough to help in the heat-up either.
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Ezblast
Posted on Saturday, June 05, 2010 - 06:28 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

34PSI front and rear works for me warmed up, and if I was to do a day of twisties, I'd take it down to 32 hot, but for everyday its usually at 34. Believe me I fit into your category - lol
EZ
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Usanigel
Posted on Saturday, June 05, 2010 - 08:26 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

When I attended a Continental tire training session a little while ago, they told me to expect a 10% increase in pressure from cold for the best starting point for the right air pressure. Its always worked for me.
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Ratgin
Posted on Saturday, June 05, 2010 - 08:39 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Ok will double check the pressure cause its possible im off on the reading.

Maybe that ramp has a spot that is polished.


Just figured it was my riding style that was off since bike is a hoot to corner and couldn't see it being the issue.
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Drawkward
Posted on Saturday, June 05, 2010 - 09:17 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Usanigel: Last trackday I went from 27psi to 34psi in my rear tire (Rosso Corsa), lol.

Ratgin: Def check your pressures...they are a very important and integral part of how the bike will handle. Usually it's the simplest things. Let us know how it turns out.
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Nattyx1
Posted on Monday, June 07, 2010 - 01:08 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

And if you can rule out the tire (do what everyone says here, run em lower - I like 32 front/34 rear in warm weather. 30 front 32 rear in cold weather), then look at suspension. Is there too much damping in the rear?
Maybe there's a bump that skitters the rear tire that you aren't noticing?

Is your spring set too soft? That could be the cause as well, because there could be a wallow triggered by a wave in the pavement and your tire would track it calmly if your suspension was set up right.
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Ratgin
Posted on Monday, June 07, 2010 - 01:23 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

im leaning toward something with pavement or my tires are still cold.

The kick out isn't unnerving just kinda a humm whats that all about moment, almost like rear is sliding sideways about 4 inches,

never felt like i was gonna low side or tank slap when it hooked up.. just a slip that causes me to run a little wider then line i picked.

since i work afternoons i haven't taken it during daylight to check out the ram better
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Andros
Posted on Monday, June 07, 2010 - 01:58 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

so slaughter, whats a good pressure for cold tires very spirited driving you think?
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Andros
Posted on Monday, June 07, 2010 - 03:33 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

And i dont care about how long the tire lasts as long as i can blast through the corners feeling safe.
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Ezblast
Posted on Monday, June 07, 2010 - 03:46 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

32/32 - LOL
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Andros
Posted on Monday, June 07, 2010 - 04:52 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

fanx =)
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Jaimec
Posted on Monday, June 07, 2010 - 06:08 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Do a search. I've posted many times how to calculate your proper tire pressure. I'm feeling too lazy to retype it at this point.
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Chessm
Posted on Monday, June 07, 2010 - 06:38 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

to the op...an easy test that you can do to rule out tire temp is to change up your routine so you get to that same spot with warmer tires. maybe add a small loop to your route where you can add a few hard stops and accelerate hard a few times. then go to the turn and try to replicate the issue.

if it happens again they you've ruled out tire temp.
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