faffi

Wow - is that even mathematically possible

As long as you know what you are doing, sliding the tyres will make you faster. Top rank riders use sliding to quicken the steering and whatever, they gain several seconds per lap from it. Actually, to be absolutely correct, you cannot accelerate or decelerate without slip. And slip is sliding. And steering needs acceleration of some sorts. So what we are talking about here is the transition between controlled slip and a complete lock-up. Also, I suppose a tyre can be locked up in one direction and rolling in another, which would be sideways sliding under speed. BTW, I followed and read the link you pasted, and it - to me - failed to give any new answers to what's been discussed under this topic.

We at the school are kinda all about using logic to break stuff like this down to specifics. That's kinda the point of this thread. Might not always work, but if we can find something that will work a large percentage of the time I think it is a worth while discussion. Sorry if it sounded like I was implying otherwise - I was more hinting that the theories are flawed in actual life for some reason or the other in that even the best of the best cannot always adhere to them. Probably because we as humans aren't sensitive enough to put them to use under all conditions. A bit like knowing how all robbers look like, but since nobody can cover 360 degrees 24/7, you can still get robbed

Interviewed by Soup about the old Honda Superbike based upon the CB750F, Haney said: Yeah, just what I do

Welcome! I'll second that about the snow! Hope you'll enjoy your Beemer - personally, I lack sufficient self preserving sense to ride good handling fast machines on the road

Considering your occupation and who you work for, the answer is with all probability that yes, you can put it into words It still doesn't prevent even the best of the best to get caught out, so obviously the transition from grip to slip can at times be very abrupt and the line too narrow for even riders like Pedrosa or Stoner or Rossi etc. to be able to react at all before they are down. In my opinion, this suggests that you cannot just use logic or break it down to specifics and always make it work. Apparently - and this fit with my own experiences - various tyres have different characteristics. Some may have a very wide window between where they start to slide until they actually let go completely, others will have a razor edge and hence be far more demanding to reach the limit on. Then you have tyres that doesn't act consistently, which must be the worst. Personally, I feel that the tyres feel vague when they start to let go, a sensation as if they are slightly floating over the road surface. It's not a feeling I enjoy much, and the faster I go, the less I like it.

Perhaps you just got a bad GoPro camera? One wouldn't imagine a product could become the highest seller if it didn't work as a rule?

That's the very reason, khp, why I always make the corner as wide as possible. Not only can I see much further around the corner, but it also keeps my head as far out of harms way as possible. Turning in the opposite direction, I will sit closer to the oncoming traffic, but this is more than outweighed by the improved visibility ahead. And should the oncoming traffic be too close for comfort, I can tighten my line. Surprisingly often, that oncoming traffic is a rider crowding the centre line and leaned into my lane.

Do you really know for sure before you fall down When braking in a straight line, you can safely lock the front momentarily to find the absolute limit, but willingly locking up in a corner takes far more skill than I have. For me, it's about feel, I cannot put it down to science. Just before locking up, the front feels alsmost like it's skating and I "know" I do not have any grip left for steering or turning. Most tyres will also howl a little at this stage, but it depends on the tyre and the road surface. Since I don't race but stick to road riding, I prefer to err on the side of safety. Hence I will try to avoid maximum braking - that's for stopping for a deer etc. - and ease off the brake as I reach more and more lean. Since my built-in tiltometer usually cry uncle before I run out of cornering grip, I can leave a little bit of brake pressure on throughout the corner if I want/need. Again, it's just a feel thing for me and as mentioned, I do not willingly go on search for the limits during cornering. As long as the front end isn't unloaded from running out of cornering clearance, in my experience lesser tyres will tend to gently slip-grip and make me run a little wide if I get close to the traction threshold. It has happened, but I do not like it on the road. Then again, what seems to me as the very limit will probably just mean it's time to shift some body weight etc. to regain traction for an expert because compared to Rossi & Co I do not have a clue about what's going on. Not a clue.

It seems that the more grip a tyre can give when in its ideal operating range, the less grip it has when cold. More touring oriented tyres seems generally to grip fine from the first corner. That said, I cannot fault the grip from the several years old Bridgestone BT001 type 4 (softest compound) front even around the first roundabout 300 yards up the road even on very cool days. It has more grip than I have nerve under all conditions. The rubber is so soft, that sharp stones up to 4 mm across will cut the rubber and create permanent marks, yet it still doesn't seem to wear any quicker than most tyres. Not bad for a tyre I got for free

I only saw one rider go down? Anyway, it's almost impossible to believe how easy it is to perform a highsider. Sometimes, you even see top rank world class racers falling off at ridiculously low speeds - and usually they do not even understand what happened. So far, such incidents have eluded me, knock wood.

Also, if it was due to braking, it was a panick reaction and not controlled. I can do that

If that's you in that picture, mate, I'd be highly surprised if any road legal tyre didn't slip a little every now and then

BTW, after watching your link, the next video that was suggested was this one: Can anybody explain what went wrong here? Neither pace nor the amount of lean suggest to me that they were anywhere near the limit

Then it starts to make sense

I'll freely admit I have trouble following your posts, RW. I don't use my feet/legs a lot while riding. If I let go of the handlebars, I use my upper body a lot to make the bike steer, although that does move some of the forces down to my feet. By grabbing the fuel tank hard with my knees, the lower parts of my legs are less involved and the bike feels more stable to me. Just stepping on the pegs with various weight doesn't, to me, seem to have the same amount of influence on the machine. When riding normally, as in holding the handlebars, it seems to me that whether I pull only or push only, the force hardly bypass by arse. I use a very quick "snap" on the bars - I usually pull some and push more - and this doesn't seem to overpower the friction between my leathers and the seat. For racing, it obviously makes a lot of sense to stand on the pegs and use the whole body to force the machine into submission, but it sounds like a tiring way to ride for 3-400 miles in a day on the road. In my experience, you can make the bike turn very quickly with very little effort. Use the power of the torso by stiffening the shoulder and arm for a quick strong flick while pulling on the other side simulataneously seems to me like a much better way to stay fresh and alert during long street rides. But opinions may - and will - vary, no doubt

Since you brought up push/pull - do most of you push with one arm, or pull with the other - or both at once to initiate a turn?

It's funnier to write stories about things that went wrong but here is my contribution: This was way back in 1980, and didn't have a lot of riding experience. I was riding a narrow backroad lined with old, large fir trees - and farms. Most exit roads came out of the trees, causing horrible visibility. I was doing maybe 45 mph when suddenly this huge tractor shovel appeared right in front of my helmet. There was no time to swerve or stop; I just managed to throw myself flat on the fuel tank. I didn't hear the shovel scrape the backside of my helmet - I guess I was too stressed to hear anything - but I did notice the scratches when I got home. That's as close as I've ever been at becoming decapitated without even coming to any harm. Then there was the time, a bit earlier, when I spent a bit too long admiring my own reflection in a shop window and as a result failed to notice that the car in front had stopped to let some kids cross the road. I got a glimpse of red lights at the corner of my eye sitting much to close for comfort and pulled a handfull of front brake that nearly threw me over the handlebards. That wasn't the worst of it; when I pulled the clutch I realized that I hadn't had time to close the throttle before I pulled the brakes. So I came to a stop just inches from the car's bumber with the engine screaming its tits off. Just what was needed to draw attention to myself...

I would like to hear from some of the instructors or the chief himself if this is an absolute or if there are several ways to Rome. As mentioned, I prefer to sit on the front brake - naturally easing off as I lean more - because I'm very comfortable with this. I also find it easier to catch a sliding front that a sliding rear. Perhaps this is from years of riding through winters, through deep snow and on black ice, any winter condition you can think off. Always used regular "summer" tyres, always kept me feet on the footpegs and have always relied on the front brake. I still regularly lock up the front on purpose (in a straight line) in both dry and wet conditions just to retain the feel for it. The only bike on which that was a bit interesting, was the Intruder 1400 I once had, where locking the front at 60 mph had the handlebars/front wheel turning instantly and the bike was quickly going over on its side, requiring a quick release of the brake to prevent a crash. But most street bikes will allow a momentarily locked front tyre without any drama whatsoever. I have also many times had the front end slide out around hairpins after dragging hard parts (old style bikes, not speaking race reps here by any definition of the word) and a quick stab with the inner leg will instantly kick the bike back on track. I wouldn't recommend this at high speeds, but I think my foot would still slip off the peg by instinct - only to break on impact, most likely. Again, it would be interesting to learn if this is by definition the wrong way (to rely on the front) of if it's just a different way.

Interesting. I find clutchless downshifts something I can do, but I always get a hint of acceleration with each shift. Also, I find them difficult to perform with high rpm while at the same time braking and observing the road ahead etc. You do not see many top level racers omitting the clutch on downshifts, either - although that in itself is no guarantee that using the clutch is the best way, of course. Personally, I find that a quick, partial dip with the clutch and a blip with the throttle is easy to perform without wasting what limited brain capacity I have on this matter, spending it instead on braking and steering. Perhaps I'm just not willing to practice sans clutch until it becomes second nature...

Very interesting read! I know this is an old post, but being new here, I'm going through a lot of things not recent because there are always things to learn. Just before I began reading this article, I was thinking that the most important thing about riding is to stay alert and focussed. Not scared or stressed, just fully aware of what's going on. So you can say I was more than a little surprised that an article titled Race Face would basically discuss the very same thing! During my 30 years of street riding, I have found that the most dangerous thing to do (for me) is to go a little fast, but not fast enough to concentrate. It took me many, many years to grasp this simple fact. Riding in dense traffic has never daunted me (unless I start to act daft and hurry things beyond my ability to observe and process what's going on). By looking well ahead, constantly checking mirrors and surroundings, looking out for indecisive or erratic drivers and so on, even the densest and craziest city traffic can unfold in slow motion. It's the same with the open road; be aware, have a reserve plan, keep your mind from wandering, and much has been gained. My biggest issue is myself; I enjoy the corners so much, I often go in to and through them faster than I know is sensible. Not because me or my bike struggle with the pace, but because I do not leave as much in reserve for the unexpected as I should. Still, it's a risk I know about, understand and accept because - at that moment - the risk is worth it for the joy of living 100%. Even at an elevated pace, you are likely to get away with it as long as you are totally focussed on your riding. I find that the stupid mistakes are usually made when my mind starts to wander and I don't slow enough to compensate. In this case, slow enough can actually mean come to a complete stop. Sorry for the rant - and thanks again for an enlightning article

This is getting interesting! I do have a tendency to act as if I have the answers even when I don't, but I have found that it speeds up my learning process and enhance the chance of replies that either correct my statements or confirm them. So here goes my .02: Again, the tendency to stand up under braking is an effect of the tyres having width. The wider the tyre, the further away the patch of contact between rubber and road moved away from the bike's centre line, giving more leverage to affect the bike negatively. However, there apparently are ways to, if not eliminate, at least greatly reduce the tendency for a bike to stand up under braking during. Some bikes are more affected than others, and also different tyres can have a huge influence. For instance, on the CB1100 I once had, the standing up thing went from pretty bad with a Metzeler ME11 front to quite mild with a Micheling A49 rubber. For me, the worst bike in this regards was my CX500 back around 1980. But I have also had bikes were the tendency to stand up under braking was virtually unnoticeable, even when hitting the brakes mid-corner. For me it comes down mostly to comfort; I feel so much more secure when turning in with the brakes on, but I don't think much about the power required. I have also found that turning with the power on - as you would accelerating through a set of widening esses - seems to make the bike want to stand up and resist change of direction noticeably, though, just to bring in another element in the discussion

The physical explanation is probably that you lower the CoG and reduce rake and trail during braking, all contributing to reduced steering effort. But since I'm a person of way too many words, simplistic explanations are hard to present

This is a minefield, so I better not be too bombastic If you look at racing, you will find that there are several lines and ways to take a corner that will be more or less equally fast - there are several individual styles. And someone like Rossi can make so many different styles and lines work it ain't funny, which is why he can pass his competitors as if they weren't even there. WARNING: The following is based on what I have read. I do not have the skill or knowledge to verify any of it - which is why Keith Code and his instructors make sense So please do not take it as gospel, just as a base for further discussions (if anything). Kenny Roberts Sr. was the man who perfected hanging off in the modern tradition. He also did something unusual in that he went in fairly slowly (for top level racing) and then accelerated early while spinning the rear tyre. This made cornering safer and by hanging out the rear end he effectively made the cornering phase shorter. In addition, beginning the acceleration earlier meant higher speeds down all of the next straight. Previously, racers typically relied more on the front end and by keeping a more consitant high cornering speed for longer, like Hailwood or Agostini. Even Barry Sheene relied mostly on the front end and would wait much longer than Roberts before getting back on the throttle hard. Then came Spencer, in my opinion the most naturally talented racer the world has ever seen. Which was probably also his downfall since he relied mostly on talent and confidence and hadn't spent much time on his mental training, so he suffered when times got tough. Anyway, he introduced something entirely new to the sport. While retaining Roberts' early-on-the-gas style, he combined it with very late braking. Later than anybody before him. So late that he slid the front wheel and, just as he was about to crash, saved it by feeding on the throttle to ease to load on the front end, allowing it to grip. It goes without saying you need lots of confidence to that corner after corner, lap after lap. A few years later, Rainey came to the same conclusion, saying that he didn't know why it was so effective, but that the moment he began to slide the front going into corners, his lap times fell dramatically. Anyway, the result was a point-and-squirt riding style with quite low apex speed and where the bikes where either braking or accelerating and spending as little time as possible leaned over. Today, it seems like it is the norm to slide both tyres quite a bit, but with the 800 class in MotoGP it also looks to me like they are also back more to a classic style with high cornering speed carried for quite some time, although mixed with a fairly late cornering entry and early throttle appliance. The tyres seems to slide more due to absolute cornering forces than from heavy brake- or throttle use. The difference from earlier in the GP class seems, to my untrained eye, to be that they brake for longer but gentler and accelerate earlier but gentler, but I could be totally wrong. *** FWIW, personally, I have always turned in with the brakes on. I don't even mind hitting the brakes mid-corner if something forces me to slow down. Usually, I manage to keep the front wheel on the verge of locking up/sliding out easily (I failed once in 30 years when I found the road blocked by two oncoming cars side by side and apparently locked the front and fell down, although I have no recollection of that...) and it's like second nature. I feel very secure when braking through a corner, even all the way around if I went in too hot - although that isn't a very effective way to make time. Only a few years ago, after riding for more than 25 years, did I try to set my cornering speed early and then accelerate hard the moment I had clear visibility ahead. It wasn't as difficult as I had imagined, although I need to think about it because it isn't natural for me to brake this early. I find that I use a combination today, depending on road conditions and my mood. For road use, setting cornering speed early seems a little safer, gives a bit more margin for errors, even though it isn't as natural. I haven't discovered any appreciable speed difference getting from A to B regardless of method, but then again I'm just a wobbler without much skill.

Actually, a lower CoG requires more lean for any given cornering speed, not less. Wider tyres, lower CoG and longer wheelbase all demand more lean. Using narrow tyres, a short wheelbase and a high CoG will significantly reduce the required amount of lean compared to a long and low cruiser riding on wide rubber. If we could have tyres with zero width, wheelbase and CoG would no longer matter - the required lean would be consistent. At least that's what has been mathematically proved by people far brighter than me What makes the bike require less lean when you're hanging off is that you move the collective CoG of you and your machine inwards. Hence the balance point to counter the centrifugal forces will allow the bike to stay more upright because you are leaning more to compensate.