I ride every saturday with a bunch of sportbike riders. I do a descent enough job of keeping up on my GS but I am concerned with exactly how much I can lean the bike before i start losing traction with the tires. Can anyone provide some input or better yet, some pictures?
Greater than 47 degrees (this I know). Probably 50.
Hokierower... hokie! Do you go to Tech?!
Yea, graduated this May. Missing VT football something terrible.
I've leaned to the pegs hit... startling... felt like it would go more. I hang my toe off a little now to warn me before the peg drags...
Like any bike, a GS will lean over until it falls over.
Its going to depend on your tyres, the road surface, the camber, how much you hang off the seat, your grandma's shoe size.....etc etc.
How long is a piece of string? :thumb:
^^ +1 to that
I look at it this way the GS will go over as far as your comfortable with, I haven't scrapped the pegs yet on mine but pretty sure I have gotten close (at least going left around one of the curves I take every day ....) but alot depends on tire and road conditions, there are other factors of course as the mole point out.
Personally, I don't like going over any further than when my boot scrapes as seen when sitting on the bike normally. Of course, if I have my toes on the pegs then... well... how far over I go is anyone's guess. Not to the new boot position, but further than normal. See. Accurate as.
Just ride to a lean you feel comfortable with. And any Lean Preference for a certain side - left lean or right lean - will diminish over time.
Michael
I guess the reason I ask is that I've gone around corners and my boot/peg has scraped and everything has been solid, but I've gone around others where my front end gets squirrely and the back seems to slide out.
I guess that's more road condition than anything but I'd rather not find out by low-siding the bike.
(http://farm5.static.flickr.com/4120/4743358710_f2cf886905_b.jpg)
It will go at least that far.
(Notice: Above motorcycle is not on stock suspension, or tires. Professional rider, closed circuit. Please do not attempt to reproduce.)
Seriously... You are the limitation, not the bike. Most crashes are caused by the rider exceeding their own abilities, rather than riders exceeding the limits of the bike.
It depends on what parts you don't want scratched from dragging. I usually stop when I can smell the oil on the ground.
I didn't get it as far as burning did, but I got her over pretty far. I wasn't hanging off at all and the pegs were scraping...I don't think you have anything to worry about because even after the far over leans there is almost always that little chicken strip.
Theroy is sometimes different than actual practice....
But in THEORY, a motorcycle with "standard" tires on "standard" asphault could take a side load of .7 g.
This works out to only about 35 degrees off vertical.........( 1 g downward, and .7g sideward....inverse TAN (1/.7)
But.....the angle of the centerline of the bike is different than the actual angle of the center of gravity to the edge of the tire......(we ride on the SIDE of the tire during lean in the turn)
This effect will give a few more degrees of lean on the bike, and still keep under .7 g.........
Now it also depends on the tires.........some tires are capable of more than .7 g......
Racing tires are somtimes around 1.0 g and even 1.2 g........so more lean is possible with good tires...
Then there is the road surface coeficeint of friction..........an then there is non-level road........
Cookie
Quote from: the mole on October 07, 2010, 03:09:59 AM
your grandma's shoe size.....etc etc.
How long is a piece of string? :thumb:
err.. twice its folded length aint it? :icon_mrgreen:
Actually,
Typical street tires should be good for 1G lateral acceleration. Good racing tires are capable of upwards of 1.5G. I wouldn't trust those CoF calculations for anything.
Quote from: burning1 on October 08, 2010, 10:07:45 AM
Actually,
Typical street tires should be good for 1G lateral acceleration. Good racing tires are capable of upwards of 1.5G. I wouldn't trust those CoF calculations for anything.
1 g seems high to me, but I'll take your word for that...................
That would give a lean angle of 45 degrees from the machine's center of gravity to the contact spot of the tire (side wall)
So you figure the same for braking? 1G ? That would give some pretty short stopping distances...........
I have seen some test results for cars.......for braking.....and the .7 number seems about average....Seems like really good street tires do better, and racing tires go over 1G............
Cookie
I recently put a fresh set of Bridgestone BT090s on stock rims on my GS and they feel like there's no traction limit, wet or dry, for street riding. The front tire chicken strip on the left side is like 1/2" wide, larger on the right side since there are no U turns to the right over here. The rear tire chicken strips are even smaller, 1/4" perhaps. They are way smaller than with the old tires. However I've never scraped the pegs. I recommend these BT090s, despite they (mine) use tubes, but can be found tubeless type. Before these tires I had a front Avon Viper, which seemed to be such a great tire, but the rear was just a Metzeler Z2 that didn't perform accordingly. Since asphalt coefficient of friction may vary from block to block the best bet is a good set of tires, and proper rider's gear.
Happy riding and peg scratching.
Quote from: TR on October 08, 2010, 05:45:54 PM
I recently put a fresh set of Bridgestone BT090s on stock rims on my GS and they feel like there's no traction limit, wet or dry, for street riding. The front tire chicken strip on the left side is like 1/2" wide, larger on the right side since there are no U turns to the right over here. The rear tire chicken strips are even smaller, 1/4" perhaps. They are way smaller than with the old tires. However I've never scraped the pegs. I recommend these BT090s, despite they (mine) use tubes, but can be found tubeless type. Before these tires I had a front Avon Viper, which seemed to be such a great tire, but the rear was just a Metzeler Z2 that didn't perform accordingly. Since asphalt coefficient of friction may vary from block to block the best bet is a good set of tires, and proper rider's gear.
Happy riding and peg scratching.
Tires are everything when it comes to performance!
Cookie
Quote from: twocool on October 08, 2010, 02:49:22 PM1 g seems high to me, but I'll take your word for that...................
That would give a lean angle of 45 degrees from the machine's center of gravity to the contact spot of the tire (side wall)
So you figure the same for braking? 1G ? That would give some pretty short stopping distances...........
I have seen some test results for cars.......for braking.....and the .7 number seems about average....Seems like really good street tires do better, and racing tires go over 1G............
Cookie
Hi Cookie, yes, exactly... 45 degrees. Most bikes are capable of that, even on sport touring tires. That's with the rider on the centerline of the bike, obviously. The bike may lean more or less than 45 degrees at 1g, depending on the tire profile, CoG height, and the rider's body position.
Cars generate most of their grip from elastec restoration forces, the so-called slip-angle. Motorcycles make cornering force both from elastic restoration forces, and from camber thrust. In fact, camber thrust alone produces so much cornering force that at mild lean angles, many tires are actually running at a negative slip angle. Your typical motorcycle will out corner a car, despite what intuition would tell you about contact patch size.
Braking is limited more by the wheelbase of the bike and the CoG than it is by traction. There are some exceptions though: My GT is limited by tire traction. It'll also stop awfully fast; 1G is attainable.
Also keep in mind, that the traction circle is actually more of an oval than a circle. Moto tires create much more lateral cornering force than straightline force.
For what it's worth, in the above pic I was WOT, and no where near the cornering limits of this bike. I've slid the bike due to abrupt inputs, improper body position, and poor use of the throttle. Even at those lean angles, I've never found the limits of traction.
Quote from: burning1 on October 08, 2010, 06:28:10 PM
Quote from: twocool on October 08, 2010, 02:49:22 PM1 g seems high to me, but I'll take your word for that...................
That would give a lean angle of 45 degrees from the machine's center of gravity to the contact spot of the tire (side wall)
So you figure the same for braking? 1G ? That would give some pretty short stopping distances...........
I have seen some test results for cars.......for braking.....and the .7 number seems about average....Seems like really good street tires do better, and racing tires go over 1G............
Cookie
Hi Cookie, yes, exactly... 45 degrees. Most bikes are capable of that, even on sport touring tires. That's with the rider on the centerline of the bike, obviously. The bike may lean more or less than 45 degrees at 1g, depending on the tire profile, CoG height, and the rider's body position.
Cars generate most of their grip from elastec restoration forces, the so-called slip-angle. Motorcycles make cornering force both from elastic restoration forces, and from camber thrust. In fact, camber thrust alone produces so much cornering force that at mild lean angles, many tires are actually running at a negative slip angle. Your typical motorcycle will out corner a car, despite what intuition would tell you about contact patch size.
Braking is limited more by the wheelbase of the bike and the CoG than it is by traction. There are some exceptions though: My GT is limited by tire traction. It'll also stop awfully fast; 1G is attainable.
Also keep in mind, that the traction circle is actually more of an oval than a circle. Moto tires create much more lateral cornering force than straightline force.
OK some interesting concepts.......I get what you mean about braking.....bike wil lift the rear tire off the ground before the front wheel is at max braking....
But this camber thrust.....Yes I understand how that works and how it turns a bike dirrerent than a car turns...but I am not convinced about that the general statement "your typical bike will outcorner a car".....IMHO it depends on what bike and what car..........for example cars with downthrust, like say F1....will develop way more than 1g or even more than 1.5g in turns......
You are not suggesting that camber thrust somehow creates better cornering than the coefecient of friction would normally allow?
Seems to me that in cornering you have to have some unbalanced lateral force (toward the center of the circle), in order to produce the acceleration..........now matter how this force is produced or created, it still is going to require the tire/road friction to hold it.........I could see that modern sport bike tires could give up to 1g or so........
Interesting to look at other "things" that use "lean" to turn.........Some boats, skier, ice skater, airplanes, human running, etc.......
Airplane is another hobby of mine............you would think that air is kind of "slippery" with little coeffecient of friction....yet 2 g turns in a plane is commonplace..........in fact up to 80 degree bank is still do-able at around 6g.
Only limit is the structrual strength of the airframe to hold up to that g loading, and the plane's ability to fly fast enough........
Fill me in on what I still missing about motorcycle turns!
Cookie
On the road, the limit is nearly always road surface conditions. What you can do on a nice clean track that you know is clean and clear ahead (since there are cornerworkers to warn you) and what you can do on a public road that may have gravel, oil, antifreeze, cow poop, leaves, water, small children, RV's stopped to take pictures of the foliage, or deer just out of sight ahead of you is perhaps somewhat different, unless you act like it isn't, until it is...
Under good conditions, the whole reason the footpegs are hinged is so that they will start to fold up and warn you that you are getting there as you lean. If you have something that sticks out farther than the footpegs that does not fold, it can pry you right off the tires in an instant (been there, done that, removed the poorly designed accessory, couldn't sit down for weeks, bought leather pants.) If you keep leaning until the footpegs run out of fold room or something else touches, same thing can happen.
If you fattened your rear tire, you can end up with odd effects as you lean way over and end up riding the sharp edge of a too-fat tire, with less rubber on the road than a stock tire.
But you can also be barely leaned over, hit a patch of gravel, and lowside on the ball-bearing effect. Wet leaves are about as slippery as ice.
Hanging off (various degrees of leaning you into the corner more than the bike is leaned) can help reduce the lean angle of the bike.
Far to many variables to be specific, just keep practising, you will soon find the bike`s (and your) limits for the situation.
Here is a tip.....When you get on your bike and before you put your gloves on hold out your right arm with your hand open and palm upwards in the horizontal. If after 20 or so seconds it becomes noticably wet......its safe to assume its raining and therefore banking in turns should be kept to the absolute minimum :thumb:
Cookie, it's not really fair to bring down-force into this conversation. :) Most consumer cars don't make appreciable down-force, and you're absolutely right that things start to change drastically as down-force comes into play.
If you're interested in the subject of Motorcycle traction, pick up a copy of Motorcycle Dynamics by Vittore Cossalter. My comments are based upon empirical testing described in that book... And the subject matter is covered at a depth I couldn't possible do justice to, here.
Quote from: burning1 on October 11, 2010, 11:58:20 AM
Cookie, it's not really fair to bring down-force into this conversation. :) Most consumer cars don't make appreciable down-force, and you're absolutely right that things start to change drastically as down-force comes into play.
If you're interested in the subject of Motorcycle traction, pick up a copy of Motorcycle Dynamics by Vittore Cossalter. My comments are based upon empirical testing described in that book... And the subject matter is covered at a depth I couldn't possible do justice to, here.
Thanks for the book recommendation.....
You're right about it being a complicated subject........If you search the internet all you get is simple physics explainations of the individual concepts.......never the whole complex deal at once.
Inquiring minds want to know....
Cookie
...Never-mind the amount of misinformation out there... You wouldn't believe how often I've debated the topic of motorcycle stability, counter steering in general, and low speed counter steering.
Motorcycle Suspension and Chassis Design by Tony Foale is also very good, BTW. :)
I believe it was Cossalter who described a motorcycle as a collection of simple components that interact in an incredibly complex way.
Interesting head-to-head from years ago: http://jsdproducts.com/Bike_Talk/References/Articles/Smackdown/smackdown.html
Quote from: burning1 on October 07, 2010, 06:24:57 PM
Seriously... You are the limitation, not the bike. Most crashes are caused by the rider exceeding their own abilities, rather than riders exceeding the limits of the bike.
Nailed it.
Is there a chicken strip thread with pics around here? I know that with a 130 rear tire, this bike will produce wear marks right off the lip of the tire in "normal" :D riding conditions. I'll get some picks later.
I'm well off the edges of the rear, and about .5 millimetres from the edges of the front tire. To be honest, I feel like kind of a panzy out there. I'm pretty sure I could get an elbow down on my GS.
A vid for you here - http://gstwins.com/gsboard/index.php?topic=54250.msg611470#msg611470