jrock7896
-
Posts
35 -
Joined
-
Last visited
Posts posted by jrock7896
-
-
It is mostly just a feeling after turn and being in the turn thinking to myself "damn I could be going alot faster right now". If I had that feeling I would simply brake a little less for the turn the next time around. I would repeat that process until I felt like went into the turn just a bit to fast. Then try and balance out where my fastest entry speed was from there. I can tell you that applying the brakes even after turn in “trailbraking" helped me a lot with this as I could modulate my entry speed mid turn before apex as well.
You will know if you are entering the turn faster cause you will feel like your going faster.. You don’t need a data logger for that unless your at a very high level of riding on the edge I would think
-
Yes watch the onboard vids... They have close ups and you can clearly see that all motogp riders trailbrake through just about every corner. Its clearly not just them resting their hand on the brake. With the close ups you can download and pay for on motogp.com you can clearly see they are applying and releasing pressure up until apex at which point they roll on throttle. Yes that means trailbraking. Thanks for the link Harinos!
as a side note I dont really care how this applies to my riding either, as I am more interested in why and how this produces the fastest lap times in the world from a technical point of view simply due to of my own curiosity.
-
The braking / throttle graphs on the MotoGP telecasts do not come from actual on-bike data acquisition, but rather from the accelerometers in the TV hardware that is on each bike. Therefore the visual representations shown are merely guidance and at best an approximation of the actual input from the riders.
Interesting. So if the "brake meter" is merely displaying negative forward acceleration, it may be indicating "braking" when, in fact, the rider is merely "slowing" due to being off the gas. Huh.
If you are racing or trying to go around a track fast there really shouldn't be a time your either not on the gas or not on the brakes.... the fact is that these guys brake super deep, you can see their brake lever for christs sake. I dont understand why you guys just dont want to accept that all moto gp guys trailbrake just about every singe corner... accept it and move on.
-
Hey thanks. Thats actually what I started out doing and doesn't feel too awkward, but after watching the pro's (motoGP, AMA ect...) I notice their inside knee is off the tank and out while braking? Or am I mistaken?
As you hang your knee and body off to the inside you can use the inside of your thigh (of your outside leg) and jam it against the tank in order to help prevent you from sliding froward while braking.
-
Here is the basic thing with trail braking, and the area it can be problematic: as the smaller of the 2 tires, and the smaller contact patch, maximum traction cannot be achieved, until the bike is stabilized, correct weight for the contact patch. The normal solution to a front tire pushing (sliding) is to get the gas back on, as there is too much weight on the front.
Does that make sense?
CF
Yep. Bigger contact patch at the rear equals more available traction at the rear, equals more speed when the weight is properly balanced front to back.
No matter how big you make the contact patch at the front, the rear will always be bigger.
Here is my argument against this statement. If this were 100% accurate then trailbraking would not be used at all since keeping the weight on the rear tire would be ideal and one would do everything in their power to ensure that they were on the gas through just about every type of corner. I am no physicist and I am not a very fast rider, however I do like to argue
Here is the main reason why I think trailbraking is the fastest way around the track and why one is better off using the front tire for traction in many corners than they are the rear, which is really what trailbraking is all about. This isnt fact merely a laymen hypothesis as to why it is the fastest way around the track these days. I would love to see a physics professor go nuts with this stuff, it would really be interesting to see some formulas in regards to this. Or even a computer model.
When trailbraking you can put an enormous amount of down force on the front tire. In fact you can put much more force on the front tire with braking than you ever could the back by using the amount of throttle available mid turn (and even if you could the amount of acceleration plus the fact that you are now going faster would push the requirement for more friction or down force past any benefits gained due to the increased need of centripetal force). So when using the brakes (trailbraking) you are putting an enormous amount of down force on the front tire to spread the tire, increase traction and increase speed which will allow for more centripetal force to be applied due to greater friction. As in F1, downforce = good for corner speed, for the same reason. So my theory is that by loading the front tire with down force you are actually making it have more available traction than by using a small amount of acceleration to load the rear. Thus you get more traction while traibraking than you would if using throttle to load the rear. (this applies to many turns not all) My hypothesis is supported by the fact that every single top level rider is using the technique and those that do are most certainly turning faster corner speeds.
So why did Keith see that in turn one @ willow that the faster rider was on the gas and not the brakes.... Im not exactly sure, but perhaps it has to due wit the turn having a nice bank to it. This would turn some of the centripetal force into down force due to the banking and perhaps this has something to do with it since we know that additional down force would cause friction and friction allows for more centripetal force. Obviously the formula for downforce vs. losing traction vs. braking force, vs. centripetal force would not be proportional, but I think it is a formula that each rider is working out at the very top level of moto gp and AMA each time they enter a turn. Damn their good!!!!!
I pulled this off a website
"Note that the centripetal force is proportional to the square of the velocity, implying that a doubling of speed will require four times the centripetal force to keep the motion in a circle. If the centripetal force must be provided by friction alone on a curve, an increase in speed could lead to an unexpected skid if friction is insufficient."
So with trailbraking you are actually increasing friction with downforce, thus allowing for more centripetal acceleration before a skid happens.... and you might also be lessing the amount of centripetal force (friction) needed since you are slowing the bike down while cornering (due to braking duh). Im positive this effect would also benefit corner speed since with trailbraking you slow as you increase lean angle meaning the need for centripetal force (friction) decreases as you get closer to apex since and your lean angle increases. We know the need for centripetal force (friction) decreases as your speed does.
These two very large benefits are what I hypothesis the benifits of trailbraking are to raers on two wheels and perhaps four as well since it is thier front tires that need the most down force going into a turn as well.
http://www.glenbrook.k12.il.us/gbssci/phys...cles/u6l1c.html
This post took me a shitload of edits to get out of my head right... apologizes to those that read it earlier
-
Awesome job bro!!!!!!!!
-
Its most likely the profile of the tire your using. My brother almost crashed when he changed from Dunlop to michies due to a steeper angle on the front tire. The dunlops where predictable and the michies hit a certain spot and then turned in faster. Look at the profile of your tire on the front end. Is it steep or nice and round?
-
Sense taking the first two levels of CSS I’ve done 2 track days. I can tell I’m improving, but I think I’m missing something. Specifically, during the last track day I wasn’t being passed much in my group but the guys who could get by me went around the corner faster with less lean angle. What gives? I’m trying to follow the widest arc plan (I’ve been reading!), but still these guys went around w/ less lean angle.
Can I make the bike turn tighter without leaning it more? I’m really proud that I can lean the bike over enough to bang the peg on the ground but that doesn’t seem to have anything to do with going fast.
Perhaps I’m overstating it. Say we have a corner that I can do now at 80mph while dragging a peg, the guy going around me is doing the corner 5mph with less lean angle. How? I want to do that! I’ll accept that my 600e is a tank and he’s on a shiny new ZX10, but I don’t think that explains all of it. If that is all it is I just gotta open my check book a viola – passapoolza. Sign me up for the next AMA superbike grid. Not.
So what am I doing wrong? More input on the bars? Get my body further off the bike (I don’t hang off much – no knee down yet)? CSS level 3?
You answered you own question.... Get more weight to the inside of the turn by shifting off the bike. The reason for getting off the bike and putting your weight as far to the inside of the turn as possible is that is allows one not have to lean the bike over as far at the same speed. The more you get off the bike and get your weight to the inside the less lean angle required at the same speed. Since you are at less lean angle your corner speed will increase because this means more contact patch which means more traction which means you can go faster.
-
Right! More guys loose the front by making mistakes (not on the gas, tight on the bars). How about how many guys do you see crashing on the brakes on the way in? Rarely one can loose the front from too little weight. Can happen, but don't it's that common.
How many guys do I see crashing on the brakes on the way in?
Like relative to the frequency of crashes on the gas, ie highside?
From my own memory corner working, far more crashes on the brakes than on the gas.
Your not seeing these crashes because someone isnt employing trailbraking properly, unless you area corner worker for AMA or motoGP. It is because the less skilled rider will freak out and over brake therefore causing their tire to washout so your point doesnt add anything to a discussion on trailbraking and where and when to use it for experienced racers.
Trailbraking does allow for faster around the track period. By placing more Gs on the front tire you are adding grip and also contact patch. Like Collin Edwards says the front tire actually spreads under load and provides more contact patch and in turn greater grip and in turn greater corner speed. Like Stuman says this thread isnt addressing the question of whether trailbraking is faster, as that question is already answered for us in every top level race. This is addressing where and when to employ the technique. There doesnt seem to be an easy formula for this as there are sooo many variables to consider, however I think it is a very intersting discussion and one that a very experienced smart racer could add much insight to.
Racer you made this statment
"The effect of "adding traction" (to gain speed) with trailbraking decreases proportionally with lean angle until the bike reaches 45° of lean angle. After that, more brake equals less traction, period. (No matter how fast you are going or how good you are.)"
Where in the world did you come up with this? It doesn't decrease proportionally, for reasons I explained above. If it did there would be no need to trail brake because you wouldnt gain anything. How in the hell did you come up with 45 degree angle as a point where more brakes equal less t reaction?
-
Thanks for the input... Yes thats me on my bike. I bang down a gear and give some brakes very lightly through turn one.. I find the turn in is just as fast or faster when on the brake a bit due to the geometry change it gives me as the front end compresses a bit.
-
Thanks for the thoughts stu, perhaps I am over doing it....
-
The bottom line is that every fast racer trailbrakes!!! Trailbraking IS the fastest way around the track period, otherwise the fastest racers wouldnt do it. Read some articles on this speciifc subject or talk to very fast racers, they all do it...
and speaking of generalities. No one is questioning whether or not racers trail brake, most do in SOME corners. I think what Wisquared was asking is why does it seem like at some tracks they do it more frequently then others. Most will agree that it is not a technique that is used in every corner, the question was why do it in some corners or some tracks and not as much in others.
Also, Wisquared is not one to toot his own horn but understand he is not some noob asking for advice, Just FYI he is the current WSMC #1 plate holder.
I was making a generality for argument sakes and of course you are correct that not every corner requires trail braking to be fastest, but many do. It just seems that some on this forum will not come to grips with the importance of usign this technique to be competitive at any level, yes even WERA novice, which where I am. So the question is why in some corners and why not in others? Perhaps both you and Wisquared can help answer that question. List out some tracks and what braking methods you use at each turn. Once listed perhaps the reasons will become more apperant. Ill start even though im slow and a noob compared to you guys.
Take two tracks that I have rode a few times
Fontana... I have ridden this track probably 10 times and my best lap time is a high 1:37 (lol dont bag) Look here for a track map http://www.fastrackriders.com/tracks/cal-800.html
Corner #1 coming into the chicane of the front straight (left)
I usually trail brake this corner just until the point i have to start transitioning to the right hander #2
Corner #2 (right)
I am totally off the brakes here since I completed my trail braking in turn 1 during the transition into this corner as stated above
Corner #3 (left)
I trail brake very minimally here since I approach this turn very fast and since the turn is so sharp and coming off of such a fast straight that most of my braking is done after getting the bike upright after having the knee down and close to the infeild. If I was a better rider though I bet I would trailbrake deeper into this turn, im just not comy with that yet.
Corner #4 (right)
No trail braking here as this is a fast transition to the right aftter a slower corner so there would be no reason to be on the brakes, this corner is maintenance throttle or more
Corner #5 and 6 (double apex left)
This corner I trail brake heavily into all the way until the first apex or corner 5 then its onto maintenance throttle through until I accerate out of the second apex of corner 6
Corner 7 and 8 (left right chicane)
I trailbrake into this corner up until the point I have to start transitioning for turn 8
Corner 9 (right decreasing raduis)
I trailbrake deep into this corner all the way until apex
Corner 10 and 11
This isnt even really a chicane and itss full throttle straight thorugh
Corner 12
I trailbrake deep into this corner until apex
Corner 13
I lightly trailbrake into this corner as I am still going kind of slow from turn 12 and havent built much speed since that turn so its a very light and note deep trail brake
Corner 14 and 15
no braking since you are accelerating through these corners since 13 slowed you up so much
corner 16 (left)
Deep trailbraking into this corner until apex
corner 16, 17, 18,19,20
These are corners
Maybe just a slight bit of trailbraking into corner 19 but usually you can make one big sweeping left out of the corners and be on maintenance throttle or accelerating a bit.
Willow http://www.fastrackriders.com/tracks/willow-track.html
Turn 1 (left)
I trail brake deep into this corner almost until apex
Turn 2
I trail brake into this corner just until I reach a comfortable maintenance speed then is on to maintenance throttle since its such a long corner.
Turn 3
Deep trail braking until apex
Turn 4
A bit of trail braking but again its a long turn so once reach desired speed its on to maintenance
Turn 5
Super deep trail braking up until apex... I dont think you can afford not to trail brake this turn especially with the downhill aspect involved.
turn 6,7
No braking on gas
turn 8
Minimal trail braking since its such a fast long turn
Turn 9
Couple of downshifts and very minimal trailbraking
I would love to hear from the more experienced riders... thanks for the great discussion
-
Sorry I didnt see this post sooner! Good job bro a 1:27 downright fing hauling ass!!!!!!!
-
The bottom line is that every fast racer trailbrakes!!! Trailbraking IS the fastest way around the track period, otherwise the fastest racers wouldnt do it. Read some articles on this speciifc subject or talk to very fast racers, they all do it. Back in the day when tires didnt have the grip levels they do now it wasnt a technique used as liberally as it is these days. Trailing the brakes is exactly that... Keith points out it isnt an on off thing to brake in truns... Of course it isint, its called trailbraking because as you near the apex you are trailing off the brakes, in other words applying less and less braking force. Riders actually use trailbraking to apply additional load to the front tire to help it spread out and grip the track (See Interview with Collin Edwards in Road Racing world) for more on this. Not using this method is an old school way of riding and racing. Jason Curtis and I spoke in depth about this out at Willow not too long ago and he said that even racers that he has argued with about this trailbrake and they swear they don't. Then he actually watches them and there they are using the technique without even knowing it.
Keith also points out that the most common reason for top level crashes now is overuse of the front breaks while turning and I would agree with this. THis is because that is really where much of the flirting with disaster takes place these days. The rider is one the edge of lean angle and front braking pressure and really has to "feel" where the edge is. This is very very hard to do and is one reason why they need such great feel in their front ends these days as well.
-
You are hearing the skid? there really is no possible way the front tire would skid due to down shifting alone. There is no resistance on the tire at this time to cause a skid only the back tire would have resitance... Plus you wouldn't hear it you would feel it.
-
Of course its not snake oil..... and hes talking about this
http://www.motorcycle-usa.com/Article_Page...3207&Page=1
-
Thanks for sharing the links Ulrich.... The writings of the reverse rotating rotor inventor have summed up just about everything I ever needed to know about counter steering and the effects of precession have on the front wheel on the bike. Wonderful information.
Thanks again
-
OK, are there times you would want to be done with the breaking and have the throttle coming on well before the apex?
CF
absolutley there are turns such as this, but since you are on a racetrack the turns are predicatble and as such one would not be hard on the brakes and then realize.. Oh no i forgot this turn was the one where i need to complete braking first and get on throttle. Agian this is barring an emegency situation or aviodance needed for some reason. Sine the track is predicatible I dont see why trailbraking would cause any delay of getting back on the throttle, unless your in an unprecitable situation, which is more the eception when on a track.
-
To understand precession you can get a bicycle wheel and an axle. Hold the axle horizontal while the wheel is spinning in a forward direction. Try to rotate the wheel to the right holding the axle horizontal. The wheel will LEAN to the left same as if you were pushing on the left handlebar.
This is not just a theory, but a law of physics.
I understand that... I wasnt questioning you I was questioning Woody.... Se the quote above my post, that is what I was questioning.
-
Why would trail braking cause you to delay rolling on throttle? If I am trail braking and I fell like I want to roll on throttle i just roll on at the same time I am letting of the brake.... There is no additional time penalty for having two fingers on the brake lever and easing the pressure on those while at the same time rolling on throttle. Am I crazy or do I just have large hands?
Brain sends signal to hand to roll on throttle, hand rolls on
at the same time brain sends message to fingers to ease pressure to zero on brake lever. My brain sends multiple messages to its appendages, am I special
btw not being a smartass just trying to understand.There may be some overlap to the two actions, but any effect of this would be negligible. By that I mean that the throttle could be cracked at the same time a tad bit of braking is still being applied (before fingers release completely), it would be so little braking at this point it wouldn’t detract but maybe a few HP.
The above statement also makes one important assumption. That you are toward the end of trailing the brake, in other words close to APEX and not on the brakes hard. I cant think of a time (barring severe emergency) you would really be trailing braking with a large amount of force and then realize you needed to roll on throttle. THis applies to the race track only and as said baring a crash or other emergency avoidance.
-
So, to initiate the turn the bike must first be leant over. Turn the bars to the right and the bike starts to turn right, this tips the bike onto it's left hand side. Once the pressure is released on the bars the steering geometry pulls the front wheel back around so that it is pointing into the corner and the bike starts to turn left.
Woody
I dont belive the need to be released to start the turing, otherwise there is no way I could make it through some really tight chicanes at the speed I do... THe bike turns as you are countersteering, you dont have to let off the bars to allow for the turn. In fact I can think of one chicane where I am using countersteering the entire time through and never allowing the bars to rest.
HOw does your theroy explain this?
-
Your response is greatly appreciated Keith.. Thanks
It is interesting what you say about trailbraking used to compensate for poor entry speed judgment. THis is for sure why I started trail braking in the first place. At my home track Cali speedway I would constantly haul ass, brake and then turn in... Once turned in I would be thinking to myself "I could have been going much faster when I turned in." Once I started gaining confidence in trail braking I also gained confiednce in being able to carry more entry speed. Having the confidence to be able to use the brakes at turn in and beyond helped me carry much greater corner speeds. I knew if I misjudged and had to much speed I could continue to scrub speed up until apex. I havent been riding for too long and it seems I am still using trail braking to compensate for poor entry speed judgment, but I belive the ability to know that I can trailbrake and with confidence, will no doubt speed up the process of being able to proplery judge correct entry speeds.
-
I loved your article bro... I thought the video you threw in there as the best example of countersteering I have ever seen in slow and on a track. nice work
-
Hey jrock,
The simple answer to your first question is that you don't see every single motogp rider trailbrake into corners under normal circumstances. It might be difficult to see that from a TV screen.
I've only attended or worked for a handful of riding or racing schools but I can tell you that, in twenty years of riding or racing, none of the schools I have seen taught that trailbraking was an advanced technique to get around the track faster.
It might be that trailbraking is discussed as part of the passing or pass prevention technique I mentioned in my previous post, but, that is a very specific situation and is about getting in front of another rider, not about being fast. A rider who charges into corners or engages in braking duels will post slower laptimes.
R
I do not thik your post is accurate..... Read some quotes out there of fast races in AMA and motoGP.. almost all of them talk of trailbraking. In fact receltny I read an ardicle where Randy Mamola was giving a F1 drivier a ride around the racetrack on the Ducati two seater GP bike. THe F1 driver said "My god that was insane, I mean we trailbrake in F1, but I cant belive how much these guys trail brake" Mamola wasnt just doing it to be impressive, its a technique he used in racing as well and not just to stuff and block.
Pro's And Cornering
in Cornering and Techniques
Posted
I have been watching this same phenomenon for a few years now.. I think that the foot acts like a monkeys tails as in a counter balance. When hard on the front brakes the rear wheel wants to lift off the ground and we all know this is no good for a stable turn in... I think that by placing the foot off of the peg it goes lower and further towards the rear of the bike that the weight of the foot and leg act as a counter balance and help to settle the rear end back down and or allow for just a hair of harder front braking without the rear picking up or getting as light. This is purely speculation though.. but you can see that when they are battling and someone has gone in really hot and deep the further out and back they will throw the foot and leg.