Lnewqban

Can Quick Turn Be Overdone?

91 posts in this topic

Unfortunately, I had an interesting lesson in overdoing a quick-turn at Barber the last day of CSS that I think is relevant to this discussion. Unfortunately it resulted in a crash.

 

I was riding hard attempting to catch up to my coach who was chasing another student and had the right side of my tires nice and warm as a result. However, the extreme left edge of my tire was still relatively cold (another of the many lessons from this crash) and I wasn't aware of that. Coming into the final (left) corner prior to the front straight, I quick flicked the bike in at a very high speed (both the flick and the entry speed) and almost immediately lost the front. Fortunately, nobody was hurt and damage was minimal.

 

The quick-turn lesson from this, after much discussion with several coaches, was: the fast rate of steering didn't DIRECTLY cause the crash, it was the cold edge of the tire once I got it there. The tire was able to take the FORCE of the quick-steering just fine, but the reason the quick-flick was an issue was that I didn't get the chance to feel indications that the tire edge was cold in time to stop leaning the bike over. Had I steered the bike more slowly, I would have been able to feel the cues the cold edge would have given me in time to prevent the complete loss of traction. The bigger issue was really my awareness of the cold edge on the less used side of the tire, but since this thread is about quick-turning, I thought the quick-turn lesson would be a good one. This is a big reason you don't quick-turn on cold tires... It's less because they won't take the force while steering, and more about giving yourself a chance to feel where the cold tire traction limit is before you exceed it.

 

Benny

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Unfortunately, I had an interesting lesson in overdoing a quick-turn at Barber the last day of CSS that I think is relevant to this discussion. Unfortunately it resulted in a crash.

 

I was riding hard attempting to catch up to my coach who was chasing another student and had the right side of my tires nice and warm as a result. However, the extreme left edge of my tire was still relatively cold (another of the many lessons from this crash) and I wasn't aware of that. Coming into the final (left) corner prior to the front straight, I quick flicked the bike in at a very high speed (both the flick and the entry speed) and almost immediately lost the front. Fortunately, nobody was hurt and damage was minimal.

 

The quick-turn lesson from this, after much discussion with several coaches, was: the fast rate of steering didn't DIRECTLY cause the crash, it was the cold edge of the tire once I got it there. The tire was able to take the FORCE of the quick-steering just fine, but the reason the quick-flick was an issue was that I didn't get the chance to feel indications that the tire edge was cold in time to stop leaning the bike over. Had I steered the bike more slowly, I would have been able to feel the cues the cold edge would have given me in time to prevent the complete loss of traction. The bigger issue was really my awareness of the cold edge on the less used side of the tire, but since this thread is about quick-turning, I thought the quick-turn lesson would be a good one. This is a big reason you don't quick-turn on cold tires... It's less because they won't take the force while steering, and more about giving yourself a chance to feel where the cold tire traction limit is before you exceed it.

 

Benny

Im interested in the track temp and which tires you are on... mind sharing? :)

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Just out of curiosity, Benny - if you HAD turned the bike more slowly (assuming the same entry speed), do you think you would have made the turn?

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Lnewqban, on 16 Jun 2014 - 3:05 PM, said:

 

Thanks, Tyler!

 

 

That's an awesome article. Thanks for posting the link!

 

Ditto. I particularly like this 'Keith-ism':

 

"You can't steer effectively with the front wheel off the ground ..." :wacko:

 

No argument there ... :D

 

Back to topic: FWIW, I asked Lnewqban's question when I did one of my CSS days. Andy Ibbott's reply was exactly as Tyler's, i.e. "Yes, in theory, no in practice."

 

Craig

 

 

 

 

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Just out of curiosity, Benny - if you HAD turned the bike more slowly (assuming the same entry speed), do you think you would have made the turn?

 

Probably not at that pace. I think I NEEDED the quick-turn given my entry speed and tighter entry line after passing in the previous corner... but I would likely have been UPRIGHT in the runoff area instead of down in it if I had steered more slowly. I put myself in a square corner of HAVING to quick turn but not knowing that I couldn't because the tire edge was cold. Again, though, I think the ROOT CAUSE of this was asking too much of a cold tire, but not being aware that the edge on that side was too cold (the other side held nicely in previous corners at similar pace). But part of what I learned from the whole experience was what I addressed above... one of the reasons not to quick-turn on a cold tire is to give yourself a chance to feel where the traction limit is as the tires warm. Previously, my understanding of why you shouldn't quick-turn on a cold tire was only because you could cause a loss of traction WHILE steering quickly. I hadn't considered not doing so in order to give yourself the chance to feel the traction limit before exceeding it while warming up the tires.

 

Benny

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Im interested in the track temp and which tires you are on... mind sharing? :)

 

Dunlop D-211 GPAs, very warm/hot air temp (around 90F) with the sun shining. I didn't measure the track temp. Barber Motorsports Park is mostly right-handers and only a couple of significant lefts so it's challenging to warm up the left edge of the tire.

 

Benny

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Im interested in the track temp and which tires you are on... mind sharing? :)

 

Dunlop D-211 GPAs, very warm/hot air temp (around 90F) with the sun shining. I didn't measure the track temp. Barber Motorsports Park is mostly right-handers and only a couple of significant lefts so it's challenging to warm up the left edge of the tire.

 

Benny

 

 

Thanks so much :)

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Does setting the geometry etc for quicker turn in result in more tire wear?

Not sure this was answered, and I don't know why it would. It would depend a bit on the rider and how he/she rode. With more weight on the front, and if the rider steered quicker, could be back on the gas sooner. If aggressive with the throttle, there would be more rear wear. We had a guy that used to like his bike set up like this, and made it work well.

 

CF

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Im interested in the track temp and which tires you are on... mind sharing? :)

 

Dunlop D-211 GPAs, very warm/hot air temp (around 90F) with the sun shining. I didn't measure the track temp. Barber Motorsports Park is mostly right-handers and only a couple of significant lefts so it's challenging to warm up the left edge of the tire.

 

Benny

 

 

 

Were you running Tire warmers or just taking a few laps to warm up the tires ?

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No warmers. I was on a school bike. I had been following a slower student for a few laps then stopped for a couple minutes before the crash lap.

 

Benny

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Does setting the geometry etc for quicker turn in result in more tire wear?

Not sure this was answered, and I don't know why it would. It would depend a bit on the rider and how he/she rode. With more weight on the front, and if the rider steered quicker, could be back on the gas sooner. If aggressive with the throttle, there would be more rear wear. We had a guy that used to like his bike set up like this, and made it work well.

 

CF

I've lowered the front on every race bike I've had. I like the bike to steer quickly and with less effort. The trade off is the bike is twitchier and less stable.

 

Quick turning the bike seems to me to result in a lot less wear to the front tire compared to turning in slower and on the brakes; trail braking puts a LOT of load on the front tire, and turning slower tends to use more lean angle and/or have you leaned over longer. The most wear I ever put on a front tire was when I was experimenting with trail braking, trying to mimic the style of some of my competitors to see if I could gain anything anywhere by doing so. I really worked the front tire!

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No warmers. I was on a school bike. I had been following a slower student for a few laps then stopped for a couple minutes before the crash lap.

 

Benny

 

 

I though the school bikes were all on Q3's ?? Did you request the upgraded tires ?

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I've lowered the front on every race bike I've had. I like the bike to steer quickly and with less effort. The trade off is the bike is twitchier and less stable.

 

Quick turning the bike seems to me to result in a lot less wear to the front tire compared to turning in slower and on the brakes; trail braking puts a LOT of load on the front tire, and turning slower tends to use more lean angle and/or have you leaned over longer. The most wear I ever put on a front tire was when I was experimenting with trail braking, trying to mimic the style of some of my competitors to see if I could gain anything anywhere by doing so. I really worked the front tire!

 

 

Although I am not qualified to comment in any way... I'll still do it :D

 

I have, up until recently, been braking late and turning with the front brake trailing, using more of a V-corner style, standing the bike up before accelerating out. If I overshot, I would brake all the way through a corner. I have not had any issues with front tyre wear or grip in general. My brother has always done most of his braking upright, turned in hard and been back on the throttle early. He has always had issues with front tyre wear and often lost the front. This is with street riding in mind.

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I've lowered the front on every race bike I've had. I like the bike to steer quickly and with less effort. The trade off is the bike is twitchier and less stable.

 

Quick turning the bike seems to me to result in a lot less wear to the front tire compared to turning in slower and on the brakes; trail braking puts a LOT of load on the front tire, and turning slower tends to use more lean angle and/or have you leaned over longer. The most wear I ever put on a front tire was when I was experimenting with trail braking, trying to mimic the style of some of my competitors to see if I could gain anything anywhere by doing so. I really worked the front tire!

 

 

Although I am not qualified to comment in any way... I'll still do it :D

 

I have, up until recently, been braking late and turning with the front brake trailing, using more of a V-corner style, standing the bike up before accelerating out. If I overshot, I would brake all the way through a corner. I have not had any issues with front tyre wear or grip in general. My brother has always done most of his braking upright, turned in hard and been back on the throttle early. He has always had issues with front tyre wear and often lost the front. This is with street riding in mind.

 

 

Tell me you are still on soggy suspension and street tires :ph34r:

 

Had a turn on one of the shops really messed up scooters , no way in hell im gonna quick flip it, it just doesnt feel planted at all to the ground , its like .... its on ice for a lack of a better term to describe it :blink:

 

Back to topic :

 

Im sure the S1000RR 's longer wheelbase and slightly relaxed rake/trail + TC makes quick turn almost impossible (to be overdone *EDITED) 'cept when tires are not warmed up properly and with TC set to really really low or off

(I presume in racing, its off/ set to low?) .

 

But having one of the highest output of all the 1L engine streetbike sure sets some of the above off; its a see-saw of balancing how much stability you can trade off for more speed without having an accident ,

does that count as experience ?

 

newer GSX-R 1000's for a lack of a better term, because of the short wheelbase +no TC , makes it a weapon in the right hands( WSBK grade rider) and right racetracks (smaller /tighter turns)

 

but lethal to less talented/educated/experienced riders as what hotfoot said for a bike with a "lower" front ,more instability and twitch at some speeds/conditions (No TC= one less safety net)

 

 

 

 

 

info: 2014 GSXR 1000 1405 MM wheelbase , 2014 S1000RR 1432 MM wheelbase

 

Do note that the 2014 GSXR 1000 has an electronic steering damper to iron out some instability/twitch (what speeds and conditions I dont know) while the S1000rr has TC + longer wheelbase.

 

Im sure COG has some influence here but just cant find a pattern here atm...

 

 

Edit:

 

this is PURELY theoretical and not trying to be sexist but if COG has a formularic pattern,

then it could explain why riders who are more top heavy (esp women) prefer lowered front bikes, it offsets a part of their COG on the stock settings, how much im not sure.

 

Im sure Im taller than hotfoot but with a lanky light build , i actually prefer a slightly taller front end , maybe my COMBINED COG of a similar bike+rider might be actually the same as hotfoots lowered front build.

 

there almost certainly can only have one "Sweet spot" range in a formula governed with constants like gravity and mostly fixed variables (wheelbase,power output,tire sizing) imho

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Tell me you are still on soggy suspension and street tires :ph34r:

 

Yup. The situation has been like that since we began riding 30+ years ago on virtually every bike we've had. BTW, the only bike I've had regular issues with regarding front end grip was with the CB400SF on Dunlop Motard radials, and by than I had altered my riding to more mimic that of my brother; brake early and turn in after getting off the brakes. Very disconcerting. Now I'm comfortable with late, medium and early braking, and the old style diagonal tyres on my old Z650 stick fine from the first meter. Which I like. Ultimate grip isn't great, but I do not push events any longer, so I have no issues. Track oriented tyres, from my limited experience, do not stick well when cold and when temps get close to freezing they offer about the same kind of grip as 10 year old touring tyres. For my mild mannered riding, I prefer predictable tyres that offer similar grip from from start to finish, from cool to warm days. And I have never been able to break traction no matter how hard I work the handlebars to change directions.

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Tell me you are still on soggy suspension and street tires :ph34r:

 

Yup. The situation has been like that since we began riding 30+ years ago on virtually every bike we've had. BTW, the only bike I've had regular issues with regarding front end grip was with the CB400SF on Dunlop Motard radials, and by than I had altered my riding to more mimic that of my brother; brake early and turn in after getting off the brakes. Very disconcerting. Now I'm comfortable with late, medium and early braking, and the old style diagonal tyres on my old Z650 stick fine from the first meter. Which I like. Ultimate grip isn't great, but I do not push events any longer, so I have no issues. Track oriented tyres, from my limited experience, do not stick well when cold and when temps get close to freezing they offer about the same kind of grip as 10 year old touring tyres. For my mild mannered riding, I prefer predictable tyres that offer similar grip from from start to finish, from cool to warm days. And I have never been able to break traction no matter how hard I work the handlebars to change directions.

 

 

I did a search on the Z650... mind if i ask if the wheels are spoked or forged ?

 

If its spoked.... the suspension is gonna take one hell of a beating from modern race oriented rubbers esp with the carbon sidewall Q3's imho.

 

the load capabilities are just off the charts compared to 10 yr old touring tyres ... Kinda like bow and arrow VS a magpul ACR tech wise .

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this is PURELY theoretical and not trying to be sexist but if COG has a formularic pattern,

then it could explain why riders who are more top heavy (esp women) prefer lowered front bikes, it offsets a part of their COG on the stock settings, how much im not sure.

 

Im sure Im taller than hotfoot but with a lanky light build , i actually prefer a slightly taller front end , maybe my COMBINED COG of a similar bike+rider might be actually the same as hotfoots lowered front build.

there almost certainly can only have one "Sweet spot" range in a formula governed with constants like gravity and mostly fixed variables (wheelbase,power output,tire sizing) imho

 

Ha ha, I WISH I was top heavy. :) I'm sure those who know me are giggling at the image...

The center of gravity is usually lower on women than men, actually, and women are often shorter and lighter, which makes shifting weight by hanging off more challenging for women in general. But, we have the advantage of light weight, flexibility, and being a lot smarter overall... (hee hee) :D

 

Regarding lowering the front, I think it is just preference on how stable you want the bike to feel in corners and how much effort you want it to take to turn the bike. I started OUT lowering the front as much as possible mainly just to get the bike as low as possible because I am so short. But I also learned that I liked the way they handled with a low front. My husband hates riding my bikes, they feel wobbly and nervous to him. To me, his bikes feel totally planted in corners and more stable under braking but I have to push a lot harder on the bars to turn them and I can't get them turned as quick.

 

Interesting comments on wheelbase - on my SuperSingle we just shortened the wheelbase significantly by moving the rear wheel forward, and lowered the front an additional 5mm (I had already lowered it 5mm), and the net result was much sharper handling. We tried lowering the front ANOTHER 5mm but at that point it started to wobble on corner entries.

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Im sure the S1000RR 's longer wheelbase and slightly relaxed rake/trail + TC makes quick turn almost impossible 'cept when tires are not warmed up properly and with TC set to really really low or off

(I presume in racing, its off/ set to low?) .

 

But having one of the highest output of all the 1L engine streetbike sure sets some of the above off; its a see-saw of balancing how much stability you can trade off for more speed without having an accident ,

does that count as experience ?

 

 

The more I learn about the S1000RR the more I'm absolutely amazed by it. Here's a video I recently ran into.

 

 

The Race Calibration kit allows you to adapt the bike down to VERY granular levels of detail to suit your needs on specific tracks.

 

If I was racing the S1000RR turning off the TC would probably be one of the very last things I would consider doing. With the ability to adjust it any way you see fit gives you options that until recently were only available to well funded factory race teams.

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We are staring to play with this on ours now, it is SO cool what you can do!!! It is pretty amazing to be able to ride a session and then look at ALL the data that is available - like seeing exactly how much the tires slip in each corner, and where and how much EXACTLY the TC intervenes, and you can see throttle position, and lean angle, and ALL kinds of cool stuff.

 

I can't believe how much this thing does - I thought you'd have to spend $100K to get this kind of data setup.

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Yeah. It's pretty amazing to be honest. It's scary how serious BMW is about this bike. :)

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ktk_ace, I have never had race rubber on my wire wheel 650, but I had on my Daytona. Bridgestone BT001 in the softest edition.

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Back to topic :

 

Im sure the S1000RR 's longer wheelbase and slightly relaxed rake/trail + TC makes quick turn almost impossible 'cept when tires are not warmed up properly and with TC set to really really low or off

(I presume in racing, its off/ set to low?) .

 

 

 

The way you've phrased this makes it sound like you perceive Quick Turn as a all or nothing kind of technique, which I don't think it is, as Dylan stated previous in the thread the technique is to steer as quickly as possible for the conditions, you can always turn the bike quickly, and quicker steering action always has benefits on your line, you cannot however steer the bike as quickly at 150 mph as you can at 15 mph, the massive increase in gyroscopic force to be overcome means no matter how strong your upper body strength you cannot throw the bike down as fast as you would be able to at a much slower speed, A raked out chopper might not steer as quickly as a Moto 3 bike, but you can still use the quick turn technique to steer "As Quickly As Possible" and carve a tighter line that someone who steers the same bike at a much slower rate.

 

I assure you, after watching Joe Roberts and School Coach James come through the 4,5,6 sequence at Streets of Willow at full tilt, the S1000RR quick turns just fine

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How does the Aprilia RSV Factory compare to the S1000RR in terms of such adjustability....any ideas?

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