harnois Posted October 29, 2010 Report Posted October 29, 2010 What I do stand by is that a preloaded brake will allow you to stop quicker with less drama, every time. OK, maybe, but you are also going faster to start with, because if you are trail braking, this certainly must mean you have a faster turn entry speed, otherwise what's the point of continuing to brake into the turn? The guy who slows before the turn, then accelerates gradually through most of the turn, he is going slower at the turn entry, has more time to assess the turn, requires less braking to slow for anything unexpected. The trail-braker on the other hand, at the turn entry, is not only going faster but has a less stable bike due to the braking. Quote
faffi Posted October 29, 2010 Author Report Posted October 29, 2010 See this, look at the section called "Leaning." http://en.wikipedia....ynamics#Turning Note in the formula there, the variables are speed, radius, and gravity. The higher CoG of the adventure bike would not cause it to lean less. Now what might be fun to think about, is how would your lean angle or cornering ability be affected if you were riding on other planets with different levels of gravity? If tyres had zero width, wheel diameter, CoG and wheelbase wouldn't matter. However, since tyres have width, all these things affect how much a bike must lean for a given speed. Wider tyres require more lean than narrower ones. Large diameter wheels require less lean than smaller ones. Long wheelbases require more lean than short wheelbases. And tall bikes (higher CoG) require less lean than lower bikes. Quote
Fajita Dave Posted October 29, 2010 Report Posted October 29, 2010 If tyres had zero width, wheel diameter, CoG and wheelbase wouldn't matter. However, since tyres have width, all these things affect how much a bike must lean for a given speed. Wider tyres require more lean than narrower ones. Large diameter wheels require less lean than smaller ones. Long wheelbases require more lean than short wheelbases. And tall bikes (higher CoG) require less lean than lower bikes. That is completely false. Your lean angle is simply the point where gravity and cornering Gs cancel each other out. Gravity is always pulling us to the earth at 1G so if you make a turn at 1G than your lean angle will be 45 degrees for every single motorcycle with any combination of tires and any wheel base. Read the article that Harnois posted and it will explain it much better than I can. This is also how counter-steering works. If your holding a lean angle to the right and turn the handlebars to the right than what happens? The motorcycle stands up. When you turn the handlebars right your turning sharper, if you turn sharper your corner G is higher and this stands the motorcycle up. You can't defy physics. Quote
faffi Posted October 29, 2010 Author Report Posted October 29, 2010 I cannot see why trailbraking should be an issue. You can safely keep the front brake on all the way to the edge of the tyres, but you need to gently reduce the pressure as you reach more lean. Going faster than I can see is something I still do too often after more than 30 years and despite nearly ending up dead after two very heavy accidents while overriding vision - it's difficult to go slow enough when I'm having fun But trail braking? I see that as added safety, not added risk. Here's the reason why trail braking is dangerous on the street. As I'm sure you know based on your posts and 30 years of riding, if you hit a slippery spot while cornering on the brakes, the front end will step out FAST! You can end up on the pavement before you even knew you were sliding. Now I see in this thread you've addressed that, and say you deal with those issues fine, but what if you don't SEE the slippery spot? I have multiple times had my tires slide out and had no idea what was there to cause it. In some cases I've actually gone back to look at the road to see what it was. Gravel on the road of the same texture and color as the pavement is easy to miss, especially at speed. So lets consider.. Rider #1, who likes to trail brake, he runs over the invisible slippery spot, his front end steps out big time, the bike makes it through the slippery spot still on its wheels and regains traction but the rider is already freaked out, he panics, target fixates on the dump truck in the oncoming lane, game over. Rider #2, also likes to trail brake, but he's more experienced, less prone to target fixation, his front end steps out, but this slippery spot is too big, the bike goes down before it gets back to the better pavement, he slides into the dump truck, game over. Rider #3, hits the slippery spot with no brakes and perfect throttle control. Both the front and rear wheel slip just a tad, but he barely notices, and goes about his day. Which rider do you want to be? Riders 1 and 2 are dead; Rider 3 is a feeling like a bad@ss. First, let me thank you for raising the total number of replies to another level And for adding valuable inputs Some of the issues you bring up are a result of poor explanations on my behalf. Also, writing back and forth instead of discussing across the table brings up shortcoming on their own when it comes to getting nuances out in the open and make sure one is understood. Other issues you raise are highly relevant - no doubt am I stubborn and reluctant to change my ways many times. An often unfortunate human reaction. One thing to remember is that I ride for fun and not to win races. Also, I'm more concerned about feeling fast then being fast. There are fast bikes that feels slow and slow bikes that feels fast. I prefer to ride the latter because they are more satisfying. Also, having fun on slow bikes enhance the safety as well. Having fun is also why I prefer to use more lean that I need to. If this was a major concern for my safety I should have gone down a lot more often, although I will admit that I have been saved by reflexes and luck many times when I leaned enough to lift the wheels off the ground. This has happened around hairpins, meaning low speed, and didn't use to worry me. Now, I don't push as hard. Over the years, my riding has changed. For instance, I am now comfortable slowing before corners and accelerating once I can see where the road is going. And I use it at times. But I still prefer to turn on the brakes for the reasons stated. I don't know when the preference was laid, if it was when bicycling as a kid or riding motorcycles early on, but even riding on ice and in deep snow I prefer the front brake. Here I want to bring up an issue that interests me; my brother. Or rather, his riding. He rides far more according to the principles advocated here than I do. For instance, he brakes early and accelerates early. He leans into the corners a bit, keeping he shoulders "square". Generally, he leans over less than me. Yet he has always had issues with the front letting go to a lesser or greater degree. I do not have front end grip issues. And I tend to lean a litte outward while cornering and usually brake much later. As mentioned before, when in front I am often still braking when my brother sitting several bike lengths behind is already on the throttle. Now to your comment about trail braking being dangerous on the street - the trick, I believe, is being smooth. Since I rarely have tyres sliding at all - and if they do slide, it's usually very gentle and very smooth and caused by tarmac with unexpectedly little grip - and leave enough margin to change my line, I do not agree. Of coruse, changing the line (if required) will mess up the exit, but that matters little as long as the bike is upright If the road is slick, be that gravel or from rain, I ride slower and smoother and will either use engine braking only or just a hint of front and/or rear brake depending on the situation (strangely, although I do not regularly use the rear brake, I somehow automatically find it if I need it for emergency stops or just to tighten my cornering line without thinking about it). I have survived several winters riding street motorcycles on standard tyres without trouble, despite regularly leaving cars on studded tyres behind. I doubt I could do that over time purely on luck, or? As to your 3 riders - it is not my experience that the front end will step out big time. Even locking the front (while upright) on black ice is easy to control as long as you let up again. Sure, if you are braking hard while leaned over when hitting a slick spot, you will slide. But it's highly unusual to hit them on dry tarmac, especially big enough to let the slide cause a crash and still being invicible. What I have found of great value from participating on this site is a new awareness of my riding. Even if I opt to keep doing the "wrong" thing, it is good to know why and how. Also, I am now really focussing on staying relaxed, which have enhanced my ability to deal with the unexpected and already has saved my hide once when we rode over a big slick patch stretching over almost 100 yards. Finally, over the past month I have slowed down dramatically. For whatever reason, coming home safely has become more important than throwing sparks. Whether I'm growing old or the inputs from this board is reaching too me is difficult to say, but I think it's a very, very good thing that I'm now having fun without riding like a moron I better stop now before I start repeating my own repeats and end up writing a book nobody wants to read Quote
faffi Posted October 29, 2010 Author Report Posted October 29, 2010 If tyres had zero width, wheel diameter, CoG and wheelbase wouldn't matter. However, since tyres have width, all these things affect how much a bike must lean for a given speed. Wider tyres require more lean than narrower ones. Large diameter wheels require less lean than smaller ones. Long wheelbases require more lean than short wheelbases. And tall bikes (higher CoG) require less lean than lower bikes. That is completely false. Your lean angle is simply the point where gravity and cornering Gs cancel each other out. Gravity is always pulling us to the earth at 1G so if you make a turn at 1G than your lean angle will be 45 degrees for every single motorcycle with any combination of tires and any wheel base. Read the article that Harnois posted and it will explain it much better than I can. This is also how counter-steering works. If your holding a lean angle to the right and turn the handlebars to the right than what happens? The motorcycle stands up. When you turn the handlebars right your turning sharper, if you turn sharper your corner G is higher and this stands the motorcycle up. You can't defy physics. Whatever Quote
acebobby Posted October 30, 2010 Report Posted October 30, 2010 It seems a shame for people like harnois going to the trouble of writing so much, and putting his opinion to a thread just to have the OP change and contradict what he has previously written rather than admitting he was wrong. Its not the first time someone has come along and tried to contradict the techniques taught at the school yet without ever attending in the first place, At the end of the day what we have here is a dude that thinks its cool to trail brake and drag hard parts on the road, but has so much experience that his way is right and everyone else is wrong! I cant argue with any of it as I only have 17 years experience, but then I am also open to learning and improving my riding as much as possible! Quote
ozfireblade Posted October 30, 2010 Report Posted October 30, 2010 Cut and paste, Over this thread Quote
faffi Posted October 30, 2010 Author Report Posted October 30, 2010 As I said, this is the trouble you often see when discussing over the net. Basically, acebobby, it seems that you believe harnois is giving his opinions that are supposed to be considered gospel whereas my opinions are automatically dismissed and I should just bend over and take it. I do not think that is how the world is brought forward. I highly appreciate harnois taking the time to reply as well and as in depth as he actually did. First, I gave him right in that he had several points that were right and where I'm just stubborn, but I must admit I cannot see where I altered what harnois wrote or that I failed to generally give him right. For instance, I cannot argue against the fact that it is safer to use less lean rather than more lean around bends. However, experience have thought me that I can do OK with using additional lean even if it isn't ideal. Yes, it would be more sensible to use less lean. Yes, I can do it. But I won't because it detracts from my riding experience. Do you only do sensible things in your life? No smoking? No alcohol? No speeding? No fatty acids? No sugar? Probably not. However much I'd love a rational world, fact is we are not rational beeings. When it comes to trail braking, we can probably argue to the end of time. Is it best to set your cornering speed early and corner on more or less steady throttle, or is it better to stay on the brakes a little until you know the road is clear? You have your opinion and I have mine. I stand by that having the front suspension and brakes already preloaded will reduced the stopping distance. I do not believe anybody can argue otherwise and nobody can prove otherwise - it does take time for the brakes to bite and for the suspenion to settle, and time equals distance when you are moving. So the only thing to debate is really if this benefit is lesser or greater than keeping the bike balanced 40/60. Or maybe, just maybe, there are more than one way leading to Rome? In the end I will repeat that I did not and do not want to express any disrespect towards harnois. Nor am I going to say that I have all the answers or that he is wrong. I appreciate him taking his time to reply and I can only hope he managed to better understand what I tried to get across than some did. If not, I'll have to start over again. Nah, I think I'll save you that Quote
acebobby Posted October 30, 2010 Report Posted October 30, 2010 For instance, I cannot argue against the fact that it is safer to use less lean rather than more lean around bends. However, experience have thought me that I can do OK with using additional lean even if it isn't ideal. Yes, it would be more sensible to use less lean. Yes, I can do it. But I won't because it detracts from my riding experience. Cmon, detracts from your riding experience, really? Your opinions are welcome Erlik, all I am saying is for such an active member on this forum I dont understand why you dont want to try to learn or even try the techniques, but instead argue against them with some titbit from your massive riding experience! From every skill and technique I have learned from the school none of them have ever taken anything from my riding experience, actually It is much more enjoyable! Or maybe I'm just a boring person for not dragging hard parts on the street! Bobby Quote
ozfireblade Posted October 30, 2010 Report Posted October 30, 2010 Eirik, I would put it to you to at least do level 1 and see if you actually learn anything, then you can see what we (the forum) are on about. I've only been riding since I was 5, so I dont have as much riding experience as you do; However, I always learn something new every time I'm on a bike whether road or track because I try to implement all the techniques that I have learned from Level 1&2. No matter how good you are you will always learn something...unless your Rossi . I've had mates who used to like dragging hard parts in fast out slow etc etc.... but not many of them are around because situations on the windy, tight, slippery roads beat them. I just wish they had had a chance to learnt some of the schools techniques. I suppose that if you don't want to detract from your riding experience and like lots of lean angle you could always find a roundabout Quote
faffi Posted October 30, 2010 Author Report Posted October 30, 2010 No doubt would I learn a lot by taking a class. I also try out several of the issues that has been brought up here and also in TWOT 2, the book. Most of them, in fact. I find it highly interesting and educational, although there are a few things I question - or maybe believe there could be optional solutions to - and a few things I refuse to incorporate despite better knowledge. Like using lean Still, I could undoubtedly persist a bit more before discarding some of the principles as of little interest to implement permanently into the way I ride. Although my riding has undoubtedly improved from what I have inmplemented from the CSS principles. And it's also good to know what actually is the reason for issues that pop up during riding. It's a pity I'm considered as someone who constantly argue against the techniques preached on this board. That's probably my bad from not managing to express myself properly. What I try to do, is challenge you to think outside the box or to try and see things from a different perspective in order to get some discussions going. If we all just sit around and agree, we risk stagnation. After all, the whole principle about CSS is questioning the established "truths". In conclusion, I do not try to stand out like a prikk, but maybe as a little buzz to keep you on your toes Quote
faffi Posted October 30, 2010 Author Report Posted October 30, 2010 Somewhat related... I made an interesting (for me) observation while riding today. As I've mentioned some time ago on this forum, I have up until recently just acted upon instincts. And when riding slowly in slippery conditions, this has still held true. On today's ride, it was a mix of wet, drying and dry roads. In addition, dead leaf could be seen rotting on the tarmac in abundance. To top it off, tractors had scattered dirt and even manure in liberal amounts several places. In other words, treacherous conditions. Now to the observation; I decided to actually pay attention to my riding, not just ride on "auto-pilot". An lo and behold, I found myself braking early and gently. The more uncertain the conditions - or certainly slippery - the earlier I slowed and the earlier I was off the throttle. If I knew or expected the road to be dirty and hence slippery, I was already on the throttle to steady the bike at the point of turn-in. The bike was held in this fairly neutral position (no deceleration and little or no acceleration) until the corner opened and lean reduced. This wasn't anything special but how I've always ridden in slick conditions. So without knowing it, I apparently have applied some CSS-similar principles for the past 3 decades Quote
Fajita Dave Posted October 30, 2010 Report Posted October 30, 2010 In slippery conditions you need to be using some of what CSS teaches otherwise you probably would have been falling fairly often. Explaining things can be difficult. I especially suck at it, something might seem so simple in my head but I would need to write a book to put it in words. I think what CSS teaches is how to optimize the use of the motorcycle. Motorcycles are all designed the same basic way and there are riding techniques that use that design to its full potential which is what Keith teaches. By using the riding style that you have you'll lose control long before you ever reach the true potential of the motorcycle your riding. Modern technology (especially tires) lets us get away with doing almost anything we want without crashing but that doesn't mean you are using everything it has to offer. Quote
faffi Posted October 30, 2010 Author Report Posted October 30, 2010 that doesn't mean you are using everything it has to offer. That I will definitely subscribe to - it boggles the mind to think how fast the really fast blokes can ride a motorcycle. Quote
harnois Posted October 30, 2010 Report Posted October 30, 2010 See this, look at the section called "Leaning." http://en.wikipedia....ynamics#Turning Note in the formula there, the variables are speed, radius, and gravity. The higher CoG of the adventure bike would not cause it to lean less. Now what might be fun to think about, is how would your lean angle or cornering ability be affected if you were riding on other planets with different levels of gravity? If tyres had zero width, wheel diameter, CoG and wheelbase wouldn't matter. However, since tyres have width, all these things affect how much a bike must lean for a given speed. Wider tyres require more lean than narrower ones. Large diameter wheels require less lean than smaller ones. Long wheelbases require more lean than short wheelbases. And tall bikes (higher CoG) require less lean than lower bikes. There's a thread here discussing this topic, with a nice graphic showing how the tire width affects things: http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=312 The differences caused by the tire width are so minuscule as to be basically academic. In your original post you seemed to be implying that this had something to do with why you were dragging parts and the Africa Twin rider wasn't. This tire width and CoG thing you bring up does not make enough difference to be even worth mentioning. The reason you were dragging parts and he wasn't, is either because your bike does not have good ground clearance, or you have bad body position (leaning the bike more than your body), or you are not on the throttle, or some combination thereof. Quote
harnois Posted October 30, 2010 Report Posted October 30, 2010 Eirik, I think your point about having the brakes preloaded is an interesting one. Although I still think it's obvious that whatever benefit you get from that is offset multiple times over by many other added risks. The general feel I get from your posts at this point is that you agree that the textbook superbike school method (slow in and smooth throttle through the turn) is actually optimal, but you prefer to do it in a less optimal way because you think it is more fun. I can't really relate to that, but to each their own. If you idea of fun is looking for the least optimal way to ride, why not just swerve all over the place all the time for no reason? Or like, aim for cars just to see what happens? Or like, hang way off the wrong side of you bike to see how fast you can wear your foot pegs off. I mean where does that end? This is entertaining. And the point I've tried to make and will make again, is that the only reason you think the less optimal way is more fun is because you haven't given yourself the proper chance and made a proper effort to get comfortable with the most optimal method. When you are flicking from side to side with speed and smoothness and accuracy, and nailing the lines and keeping your bike super stable, you can fly through the turns and practically ignore all the debris and whatever that's on the road, and it's an awesome feeling to get it right. I do understand though what you mean about slow bikes. I have a gsxr750 for the track, but the only street legal bike I have at this point is KLR650. It is by far the slowest bike I've ever owned, and I have knobbies on it which reduce cornering traction on paved roads, so it's a lot easier to challenge myself with it without getting into the "go to jail" portion of the speedometer. But when riding, I'm still challenging myself to find the most optimal way to ride that bike. Riding it on gravel roads, this throttle control thing we are discussing becomes a much bigger deal. Quote
harnois Posted October 30, 2010 Report Posted October 30, 2010 Now to your comment about trail braking being dangerous on the street - the trick, I believe, is being smooth. Since I rarely have tyres sliding at all - and if they do slide, it's usually very gentle and very smooth and caused by tarmac with unexpectedly little grip - and leave enough margin to change my line, I do not agree. I also certainly occasionally enjoy the feeling of braking hard into a downhill reducing radius turn, so it's not like I think it's so dangerous that I never do it. Just because we are good enough riders to get away with it does not mean there is no added risk. It is definitely riskier. Aside from the higher likelihood of a traction issues, the technique is pointless unless you are charging into the turn at a fairly high speed, and at that higher entry speed, and already braking, there is less allowance for the unexpected. Quote
harnois Posted October 31, 2010 Report Posted October 31, 2010 Here I want to bring up an issue that interests me; my brother. Or rather, his riding. He rides far more according to the principles advocated here than I do. For instance, he brakes early and accelerates early. He leans into the corners a bit, keeping he shoulders "square". Generally, he leans over less than me. Yet he has always had issues with the front letting go to a lesser or greater degree. I do not have front end grip issues. And I tend to lean a litte outward while cornering and usually brake much later. As mentioned before, when in front I am often still braking when my brother sitting several bike lengths behind is already on the throttle. Just because A happens at the same time as B, doesn't mean that A caused B. The superbike school would no doubt help your brother fix his front wheel sliding issue. I have never had front wheel sliding issues except when off-throttle or on the brakes. I'll tell ya story bout my own brother... I was riding in front on a 2-lane backroad, mov'n at a pretty fun pace, as I crested a hill I see an unexpected left curve with a big swath of gravel all over it. So I brake before the turn, lean in quickly, get on the throttle early and kept it on throughout the turn - basically the same way I take any turn. The wheels slid somewhat on the gravel but from experience I knew it would work out fine, and the bike stayed stable through the whole thing. My brother on the other hand, equally surprised by this predicament no doubt, but less experienced, rolled over the gravel off-throttle, his front end stepped out, his SR's fired off and he ran into the ditch, totalled his bike, and spent 3 days in the hospital with a deflated lung, broken shoulder, and bruises all over. Another incedent, all my own, on the track, heavy down pour, I was just trying to get back to the pits but it was dumping like mad. In a downhill section I was off-throttle leaned over, not even trying to go fast, hit a dip and a slick spot of rubber on the track, next thing I know I'm trying to figure out why I am looking at my own bike sliding across the pavement, and then realizing that I was sliding the across the pavement too! Hey Wait! Am I crashing? When did this start? Reacting to this slide was out of the question. Now I think I get the gist of what you are saying, that your method of braking into the turn isn't that dangerous for you because you know what you are doing. Like you said, after 30 years you are still here, and that can't be just luck. And yeah, with good pavement and good tires and smooth riding, of course you can get away with it. And yeah, with your experience you can usually adjust to the things that would make you crash if you see them ahead of time. And yeah, those invisible slick spots are rare and most won't be big enough to make you crash. But despite your 30 years of experience, and my 200,000 miles of experience, either one of us could make a mistake or just have some bad luck and bite the bullet on our next ride. Keeping the bike stable throughout the turn is just sensible risk management, and for most people I think, it also improves the fun of riding. Quote
faffi Posted October 31, 2010 Author Report Posted October 31, 2010 Well, I continue to disagree. Recently, on this forum, someone posted pictures that showed the effect of CoG, where a rider sitting bolt upright needed the same amount of lean for a given speed around a given corner as a rider hanging off and keeping his torso very low and to the inside of the bike. A rider sitting upright with his torso while hanging off needed a lot less lean. I have, for your benefit , made a drawing that shows the differences between wide and narrow tyres as well as where you place the CoG. As you move the contact patch further and further away from the bike's centreline, you create more and more leverage, or torque if you like. This has to be countered with extra lean. In the drawing, you will see the thick line indicating the actual amount of lean forces. With a wide tyre and a low CoG, you can see that the forces created are a lot less than the amount the bike is leaned over. Hence you have to lean significantly more than 45 degrees to reach the required 1G speed. Quote
faffi Posted October 31, 2010 Author Report Posted October 31, 2010 Sorry, I didn't realise you'd made several replies - my former answer was to your first. I'll come back with answers to your further points, I'll just make sure they're well funded. You may be surprised, even Quote
faffi Posted October 31, 2010 Author Report Posted October 31, 2010 After riding yesterday and discovering how I rode instead of just riding, I have been thinking quite a bit. For instance, I have already adjusted to the early braking method and found it to work. So why not now? This is something I wrote on June 7, 2005, on another forum. My bike at the time was a Suzuki GSX600F Katana. I know I have been a fond supporter of the late braking thing, using the binders at least to apex level. However, I also discovered that middleaged men can not only absorb information, but also process it and put it into good use. I think it's called learning Hence I have been working to move my braking points up the road, which wasn't as hard as I thought. On the 5-day trip I found myself accelerating from the corner entrance quite often, sometimes hard at maximum (for me) lean. I would rush towards a corner but instead of putting off the braking stuff until the very last minute, I made sure it was all over just where the corner began or slightly beyond. When going into a given corner, I just drop the bike as quickly as possible onto its side as far as needed and open the throttle. If I felt comfortable I would use more lean and more throttle, feeling the rear tyre struggling for traction, rapidly cycling between grip and small slides. That is not spinning, you tiny jumps towards the outside of the corner. I found this "new" way of riding to quickly become natural. In fact, I was soon experiencing being sucked deep into corners by the two cruiser riders - and it annoyed me because it messed up things and made slower speeds feel faster. I don't think I'm any faster from A to B this way, at least not yet, but I now have a much larger margin for errors. Now I must work on looking far ahead to slow things even more, but it's hard to do when the road is littered with dips and bumps and cowdung... Obviously, someting has changed. The bikes. So what could it be in a bike that changes the way I ride? Confidence! Now I was getting somewhere, and I knew it was going to hurt. I began be determining where and when I actually trailbrake. Mostly, entering hairpins. That means cornering speed at the apex will be slow and there will be more time to read the road. Also, the harder I charge, the more I'm inclined to trailbrake. I used to think this was because quite often on public, unknown roads, you do not have to brake even when it looks like it, giving me an advantage since I could comfortably hit the brakes very late and get away with it. Now, with a confidence-inspiring motorcycle, that probably is reasonably true. But there is another reason I often trailbrake; fear. Ouch! How embarrassing And the more reluctant the bike is to follow my commands and the more unpredictable it behaves - like my current machine - the more likely I am to succomb to fear. I think that fear has finally gotten the better of me with this bike, which is why for the past month I haven't been pushing at all. The bike is fine braking into hairpins and cornering around slow bends, but once things gets a bit hectic, it really isn't to my liking. So instead of relying on the bike, I hit the stoppers. Because it generally misbehaves more on the throttle, perhaps; just changing gears under hard acceleration in a straight line can make the bike wobble badly - relaxing the grip on the bars settles it quickly, but ideally it should have remained stable. All my other bikes have I doubt I'll ever completely stop trailbraking into hairpins. And I will probably still have the front brake covered with a gentle pressure around blind corners in case I have to stop for that big tractor blocking the road, but ideally with the reduced speed I know to be correct - I still believe in the benefits, but prolly not at break-neck speeds. But in general, it is time to A) fix my bike so it becomes predictable and go back to what I learned to work 5 years ago. Thanks for bearing with me through this and for bothering to persist in debating with me until this bleedin' stubborn old clown could admit to his mistakes PS! I will NOT budge on the CoG/tyre width topic, however Quote
harnois Posted October 31, 2010 Report Posted October 31, 2010 Well, I continue to disagree. Recently, on this forum, someone posted pictures that showed the effect of CoG, where a rider sitting bolt upright needed the same amount of lean for a given speed around a given corner as a rider hanging off and keeping his torso very low and to the inside of the bike. A rider sitting upright with his torso while hanging off needed a lot less lean. I have, for your benefit , made a drawing that shows the differences between wide and narrow tyres as well as where you place the CoG. As you move the contact patch further and further away from the bike's centreline, you create more and more leverage, or torque if you like. This has to be countered with extra lean. In the drawing, you will see the thick line indicating the actual amount of lean forces. With a wide tyre and a low CoG, you can see that the forces created are a lot less than the amount the bike is leaned over. Hence you have to lean significantly more than 45 degrees to reach the required 1G speed. Nice drawing. I do understand the concept. Your drawing is similar to the one posted here that I mentioned earlier. http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=312 I don't dispute that the difference exist, I was just saying it's not enough difference to be worth mentioning. In your drawing, it appears to me that you dramatically exaggerated the difference in tire width and CoG location, which is fine because it makes the concept more clear. But in reality, the difference in CoG and tire width between a sportbike and an adventure bike is not that great. I own one of each. Yeah my KLR looks tall when jacked up on it's center stand, but after the suspension sags 3 or 4 inches under its own weight and my weight, it's not that much higher than the sportbike. I would bet at most 2 to 4 inches difference in CoG between the 2 bikes, but I have no way to measure it. But I did measure the tires, and there's only like about a 25-35% difference in how far the contact is offset from the center line at 45 degrees. Your drawing shows like a 100% difference. If you redrew your drawing to scale it would probably be hard to even see the difference in the angle of the thick line. If comparing a low-rided cruiser with one of those 300mm rear tires vs Dakar racing bike, then maybe it'd be enough to matter. Quote
faffi Posted October 31, 2010 Author Report Posted October 31, 2010 Yes, I know I exaggerated, but the difference could easily be around 5 degrees between the A-T and my Daybird, and even if it was only 3 degrees it could have been the difference between throwing spark and not. The Honda is not nearly as softly sprung as your KLR and my bike sit noticeably lower than stock. Still, the amount of lean wasn't my main criteria of the post and how much difference there was is something we'll probably never know except that it must have been somewhere between 0 and 50 degrees, one way or the other But as you mentioned for the majority of current motorcycles riding on radials , there will not be enough difference to matter for road use. Quote
abhoy Posted November 19, 2010 Report Posted November 19, 2010 You may be correct. You are no doubt much faster and also more skilled than me, what with all your theoretical and practical background. As such, I'm in no position to argue. I have absolutely no doubt whatsoever that you can ride faster than me with a greater level of safety because of your skills. What I do stand by is that a preloaded brake will allow you to stop quicker with less drama, every time. Other than that, my arguments could probably be ripped apart and proven wrong in every respect. However, from 30 years of experience, I can say that when things have gone wrong, it has either been from lack of attention or going too fast for the conditions. My physical way of handling a motorcycle, my style so to speak, have never caused any sort of drama. The times I've messed up, be that ending up with an accident or narrowly avoiding one, has come from taking silly chances or because I didn't concentrate. The former is reducing with time and age, the latter has virtually been eradicated over the past couple of decades. Again, I am never going to say what I do is perfect or the best for anybody else. But I am very aware of when I take (unneeded) risks and what they are and fully understand how I need to ride to return safely, cocky as that may sound Quote
abhoy Posted November 19, 2010 Report Posted November 19, 2010 Cornering master = posts a lot. Trailbraking is used when appropriate. Not all corners require braking. Quote
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