Hotfoot
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Posts posted by Hotfoot
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If the bike "slows down severely", what does that tell you about the weight balance between the front and rear tires? Which tire do you think is handling the majority of the weight?
How about your arms - when you roll off and the bike slows severely, is there any weight transfer onto your arms?
If it happened in the same place each time, could there be a change in he surface? Something slick, or does the camber change? Or does the uphill get steeper right there?
A front end tuck usually IS an indication of loss of traction - just as you describe, the bars turn in, the bike leans more, and then... well, it either regains traction on its own when it hits better pavement (crossing over a wet pavement snake can feel like this), or you get on the throttle and shift some weight off the front tire, or it keeps sliding and you can lowside.
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Awesome! I asked Keith about this over a year ago and I've been anxiously waiting ever since
Me too! The eBook is a good motivator for me to re-read A Twist of the Wrist, it was the first motorcycle instructional book I read. I've spent a lot of time reading and re-reading Twist II, and now I'm looking forward to going back to Twist I, its been a while.
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Sounds excellent! Hottie, do you know if it's just Twist-I or is it all three books that will be released now as ebooks?
Kai
Right now it's just Twist-1, but I imagine the others will come along after, especially if Twist-1 proves to be a popular eBook. I'm sure Twist II would be the next project in line.
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Well, it's that time of year - what are your tips and secrets for keeping warm and comfy while riding in chilly weather? If you do track days, how do you dress or prepare to keep warm in the pits? What about handling drizzle, wind or rain?
Something in particular I'd like to know - have you found gloves thin enough to work in (set tire pressures, for example) but still a help against cold numb fingers?
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Sounds like a terrific experience, and and excellent opportunity for you both to spend some time having fun together! I love what you said about sharing some experiences while you have such a good chance to do so.
To attend CSS, your son would need to be comfortable operating the motorcycle - being able to ride and shift gears and generally control the bike without that, in itself, being a big distraction or occupying all of his attention. Actual street riding experience is not a requirement; dirt bike riding can be good preparation, as well as the track experiences you mention above. As far as an age requirement, that will depend on the particular track, they have varying age requirements (I think Streets of Willow is 14 years, for example), so you should call the office and talk to them about what tracks would be options for him - (800) 530-3350.
A Ninja 250 is a good option, a versatile bike that is relatively easy to ride and inexpensive to operate and can also be a street bike if desired, and there are race classes available for them, too. It is acceptable as a student bike at CSS. The older (Gen 1) Ninja 250s have a lower seat height and can be bought quite inexpensively, but the Gen 2 bikes have better handling and brakes. If you check some racing forums (the WERA forum, for example) you can often find Ninja 250s already set up as full track/race bikes, and a WEALTH of info about them.
Another option would be to look for "minimoto" or youth roadracing clubs near you. These are generally aimed at younger kids but they operate at go-kart tracks on smaller bikes and can be a great way to get started on smaller, closer tracks in a very friendly environment, and sometimes you can find open track days on go-kart tracks that will allow bikes like NSR50, RS125 and sometimes even up to 450cc supermoto bikes.
There are a variety of small roadrace bikes available, plus a lot of supermoto options, that might be worth considering - especially if future racing is an ambition - but IMHO it's hard to beat the Ninja 250 for cost, availability, reliability, ease of ownership, easy resale, and generally usability. However, a supermoto bike might give you the option of riding local go-kart tracks and/or making it convertible for use on dirt, street or track.
As far as gear goes, if he's gonna be on a racetrack, get him in leathers - safety is important! If he's not big enough to wear adult leathers, check youth roadracing organizations like USGPRU for used youth leathers, or try two-piece zip together jacket/pants, sometimes it's easier to get a fit with those. There are a surprising number of shops that will make custom leathers to fit based on measurements and the cost is really not much higher than off the shelf leathers. (Another possiblity, if he doesn't wear adult men's sizes, is to look at womens' gear - it is available in much smaller sizes, and I can tell you from experience it is often cut exactly the same as men's gear <frown>, can be found in straight black, and also sometimes costs significantly less or is being dumped on clearance sales.)
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As long as they zip securely together, 2 piece leathers are fine.
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I just learned that "A Twist of the Wrist" is going to be released soon, in eBook format! I'm excited about that, because that means I'll be able to get it for my Kindle. And THAT means I can also read it on the Kindle app on my iPhone, so I can have it easily at hand anytime I want, like at track or race days when I want to look something up... or just need inspiration!
I love my Kindle reader and I've been hoping for a while that Keith Code's books would become available electronically, so I'm really happy to hear about this. Ooh, and I just realized this means I'll be able to use the Search function, too.... this is going to be great!
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A bad setup, such as too-soft rear suspension, especially if it has a lot of rebound damping that can cause it to 'pack' down, can result in a bike that squats and wants to run wide. Weird geometry could cause it, too - that "triangle" mentioned above is a real factor in what happens and a bad swing arm angle could cause squatting. Per your "friend's" comments above, if rider weight was way heavier than what the bike was set up for, the rear spring could be overweighted and I would classify that as a "bad setup".
The CSS material is intended to educate riders who have the misconception (as many do) that the rear suspension will compress under acceleration on a sportbike and that is generally not true. Sportbikes are built with anti squat properties and generally rise (both ends) under acceleration, increasing ground clearance - which is the part that is important to know for throttle control in a corner!
There may be a perception issue, also - most people don't really notice the feeling of the rear end rising, the writer above may think the bike is squatting when it is really rising - telemetry would be the way to find out for sure! The bike running wide does not necessarily prove that it is squatting - other things can cause that, like tension in the rider's arms.
Tony Foale or Dave Moss are good resources to explore all the nuances of geometry and suspension, there is a lot to learn and an apparent infinity of adjustments that can be made to change the handling of bikes.
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I am looking at the Miller MP class in 2013. I am assuming I must provide a bike since I see only 1 price. Thanks for any info.
It's the opposite, actually - it is a 2 day camp which means the bike will be provided for you. And we'll be using the new 2013 S1000rrs by then.
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Turn the bike, get it to lean angle you want, then roll-on, pick up the bike when appropriate, all is well. If you roll-on at the same time you are steering the bike (adding throttle and adding lean simultaneously) then you're taking a bigger risk. Adding throttle and picking up the bike generally is ok.
Roll-on before the apex shouldn't have any effect on lean angle. If you have the bike at desired lean, regardless of where the apex is, and you start your roll-on, then you shouldn't generate more lean angle unless you also add pressure to the inside bar.
That's not true is it?
Imagine going round a roundabout.
you start going round, gently accelerate, your knee touches down, you continue to increase speed and your lean angle increases, boot touches down, peg etc.
Basically the faster you go the more lean angle you need to hold a constant radius turn.
In long, constant radius turns to follow the throttle rule you will end up with more lean angle than when you started the corner.
In your example, if you increase your speed on the circle without adding any steering input, your circle will get larger. You have to actively steer the bike to keep the radius constant. On a properly set up sportbike, rolling on the throttle will not change your lean angle.
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Yes, do levels 1 and 2. You'll have a blast.
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The 2013 schedule is being finalized now and should be posted in a few days. If you have questions about anything (including about his age) you can call the office at 800-530-3350. That is the US school, and they can give you contact info for other schools if you like, and answer any questions you might have.
If he is comfortable riding that bike, it will be fine for taking the school; the techniques taught apply to any type of bike. If he's got a race license I imagine he has enough hours on a bike to do just fine at the school, actual street riding experience is not necessary.
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pardon me for asking this question, im stumped for a few weeks now that :
If i want to hold the best line and provide the maximum stability for the bike for some corners ...
I go way above the speed limit imposed on that turn (eg the SL is 50KM/H and I usually exit at near 70KM/H...)
and if I go on the legal limit... I dont feel safe because everything is unoptimized and unstable (brake points,entry speed, quick turn,bike feels less stable etc)
I dont like to speed for safety and financial reasons ; Im a law abiding citizen when possible
But
This "problem" have me in a dilemma for a few weeks now...
(i dont feel safer at slower speeds for that corner)Anyone has a familiar problem like mine and solutions?
I wonder if a much lower horsepower bike with lower gearing would help with that. I have a cool little YSR50; at 45 mph I am in 5th gear. I have no trouble getting a good throttle roll-on even on regular public streets, and the speed limits hardly seem like an imposition on that thing. If you can get it up to 65mph it feels like you're going 100mph.
By comparison riding the 1000cc bike on the street feels like a lot of work; feels like I'm in first or second gear all the time, it's hard to keep from speeding and it's basically like riding a racehorse in a small pen - all that potential energy and nowhere to let it run.
Regarding Rishi's comment about posted speed signs - I do use those on blind unfamiliar mountain roads as a guide - if the normal limit is 50mph and a curve speed sign says 15mph, at least I have been warned that I better slow down a whole lot - especially if the conditions are slippery. Also sometimes those speed limit signs are there for reasons you wouldn't otherwise know - the presence of children or wildlife, blind driveways or construction, etc. - so I do respect them and I save my speeding for the racetrack.
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I am the WERA races this week and I know someone here running a supermoto, so I asked. He said sliding the rear tire is FUN, and it scares the hell out of anyone that is trying to pass him (and I can personally attest to that!), but he gets around faster if he doesn't slide the back tire like that. He also said that it feels dramatically different from riding a regular sport bike, in a variety of ways. Light weight, high center of gravity, relatively low top speed, etc etc.
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Z Custom makes custom gloves. Boots, too. They are in Huntington Beach.
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Here's another little tip I wish someone had given me sooner:
If you get a new chain, MAKE SURE you clean that nasty white packing grease off it before you ride the bike, so it doesn't get flung all over everything. Shops don't always bother to do this.
If you DO forget... WD40 does a GREAT job cleaning off the accumulated grease and dirt that ends up all over your bike.
Hey, I noticed that Plexus (a great bike cleaner) has skyrocketed in price to something like $21 per can. Anybody know of a more reasonable alternative that works just as well, on paint, windshields and helmet shields?
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I thought CSS did not teach trail braking? Or are you talking about another school? Come to think of it I can't recall any school/coaching that has claimed to teach trail braking...? But I would say it's one of those things that can't actually be "taught", there are just techniques and a method to follow - the rest depends upon the student and how well they can execute the technique,
I don't know if the higher CSS levels or CODErace courses teach trail-braking, but I would be shocked if CODErace doesn't.
CSS covers trail braking in Level 3 and also in CodeRace. Here is a thread with a great post from Keith about it:
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I was thinking the other day about some neat tips I have gotten from experienced riders or coaches in the last few years, some of them things I wish I had learned MUCH SOONER.
Aside from the awesome riding technology we get from Keith's books and the school (because we ALL wish we could have learned all THAT sooner!), what are some cool little tips that you wish you had known sooner?
Here's a few that I can think of:
For races, write your grid position on a piece of duct tape and stick it on the tank of your bike, to help you remember where to go at the grid.
If your bike ever has a violent headshake, remember to check your front brakes - you may have to pump the lever a few times to get them to work again.
Put StompGrip on your bike's gas tank to help you hold on with your legs.
If your helmet sits so low on your head that you can't see well when you get low on the bike, you can add some foam in the top to raise it up.
If your gloves have a big wrinkle in the palm, it can make it hard to fully release the throttle when you are braking hard.
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I didn't think about being too tight on the bars, when I can't see the persons body positioning I just subconsciously assume that they have proper body positioning. He would have to have quite the death grip to give off that much chatter right? I know with more speed everything is amplified but that still seems like a lot....would you say it's more mechanical or rider error?
Did you notice that the chatter got progressively worse as the race went on? And that the chatter was inconsistent, sometimes really bad and sometimes mild - even on the exact same parts of the track?
What "suspension component" is most likely to be the cause of inconsistency in the bike's handling?
In fact I did notice it wasn't consistent but I thought maybe it had something to do with variance in speed, track pavement or lean angle. I didn't notice they were different on the same parts of the track though so that part I did miss!
If were talking suspension only I would have to venture the rear shock because the rear tire is more likely to slide or slip causing the rear swingarm to raise. If by quotation you actually mean throttle control and proper manipulation of the throttle would be the most likely cause.
The most likely cause of inconsistency in the bike's handling is something the rider is doing. Actual suspension parts don't change from lap to lap, but rider behavior can change at any moment! You can see the variations in throttle control on the video, as you mention above, and it is also highly likely that the rider gets progressively more fatigued throughout the race and begins to hang onto the bars to support himself, and/or as Eirik pointed out, stiffens up due to anxiety.
It is possible that the rider is pushing himself beyond his comfort zone and firing off SRs, causing a variety of errors - hanging on the brake too long, slow turn-in, late throttle action, etc., and all the scary feedback from the front end was probably creating some tension, too!
You asked how stiff arms can cause chatter: see Chapter 8 in Twist of the Wrist II for a detailed explanantion with good illustrations. In short, the handlebars need to move to absorb irregularities in the pavement; if the rider is stiff and prevents that movement, the tire can be forced to slide or skip across those bumps. Additionally those stiff arms will transmit that chattering and shaking to the rider and the rest of the bike, which can cause the GoPro to rattle around and screw up the video.
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I didn't think about being too tight on the bars, when I can't see the persons body positioning I just subconsciously assume that they have proper body positioning. He would have to have quite the death grip to give off that much chatter right? I know with more speed everything is amplified but that still seems like a lot....would you say it's more mechanical or rider error?
Did you notice that the chatter got progressively worse as the race went on? And that the chatter was inconsistent, sometimes really bad and sometimes mild - even on the exact same parts of the track?
What "suspension component" is most likely to be the cause of inconsistency in the bike's handling?
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lol yea man you are way late!
I was too rushed to read the whole darn thing.
I'd heard there was a thread that guys were worried about transmissions and clutches while doing clutchless down shifting...was this is?
CF
Yes - that was discussed in some detail and also there are some different viewpoints on how quickly/reliably folks could shift clutchless, versus using the clutch, versus just pulling the clutch partway in ("feathering" it).
So, we would love to hear your viewpoint on the whole thing - do you downshift without the clutch and why? Any worries about potential damage to the transmission?
One person also had asked why they don't see pro racers shifting without the clutch - is it true that they don't, and if so, why?
I know you shift without the clutch, both up and down - what are your reasons for doing so?
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Suspension certainly could be a problem here - lack of rebound damping and springs/compression too stiff - but there are things the rider could have done to improve the situation. It appears that he is really asking a lot of the front tire; getting on the throttle sooner would shift some weight rearward, turning the bike quicker would have allowed him to carry less lean angle, and relaxed arms would make a big difference on the load on the front tire.
It seemed like the chatter was worst when he was leaned over, crossing a bumpy part of the track, and off the gas. It also appeared he went wide on his turn exits compared to the other bikes, which could be because of stiff arms and also made worse by lack of rebound damping.
My husband watched this with me and also suggested possibly low tire pressure, with the tire getting overheated making the problem progressively worse. (But the FIRST thing he noticed was that the guy is really "on his front tire a lot")
Here's a question : when he crashed, was he ON or OFF the gas? Could better throttle control have prevented that crash?
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I think your missing a post here......
I didn't miss the post or the quote.
Sorry, I simply cannot see the blip anywhere in the video, just the simultaneous roll-off / shift that Hotfoot explained as the first step to practice the technique.
I would like to learn how and when the throttle blip should be.
WHEN: The blip happens simultaneously with the shift. If you do it too early, you will feel the bike surge forward, if you do it too late the bike won't shift.
HOW: Blip right when you shift, and just enough to match the RPM to where it would be in the lower gear. You will have to experiment with it to get it right for your bike. Too MUCH blip will make the bike accelerate (not desirable if you are TRYING to slow down for an upcoming turn) and it may not shift.
If you don't blip enough, it just won't shift.
(Finer point: if you blip a little too much, the RPMs go a little too high, but the bike might still shift, if you catch the sweet spot as the RPMs are going up or going down. So if you get the downshift but the bike jerks forward a little AFTERWARDS, the blip was a bit too much and probably a little late compared to your throttle action.)
When you shift without the clutch the RPMs don't have time to fall very far like they do when you pull in the clutch. So It doesn't take much of a blip to get it to shift, when you are cruising along at a relatively low RPM - just enough to take the load off the gears. However, if you have the bike wound up to a high RPM AND you are braking hard and decelerating rapidly, the RPMs are already going down quickly, the load on the gears is much higher, and it takes a more significant blip to match the RPM on the downshift. In the CSS demo videos, Will is riding faster and braking harder so you can really hear the blip.
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I am sure this is common when practicing this but I REALLY have to focus when doing this, if I were to race tomorrow I certainly wouldn't be using this technique because it would make me a lot slower because I would feel so rushed to brake and still do it correctly. However with plenty of practice and working my way up I feel like this is a great technique and honestly for me personally I feel that it's easier to rev match without using the clutch vs using the clutch because like you said you lose so much RPM. Once you get the feeling for how hard you have to blip the throttle in each gear it will make you a lot smoother.
I did have a couple jerky ones but that was because I didn't have the blip quite right. This is only my second time out practicing this so I am still learning for sure! The other thing I started doing was I would set a marker for myself and once I got to that marker I would downshift to help get me in that on demand mindset rather then whenever I feel comfortable.
Sounds like you've got it figured out! The ones on the video sounded good, and yes it takes some practice to coordinate it, it's definitely a bit of reprogramming. Great job getting out there and trying it out, and thanks for posting up the video!
(i dont feel safer at slower speeds for that corner)
Lateral G's In Relation To Lean Angle And Speeds
in Cornering and Techniques
Posted
I think he already answered his own question! He has made some good observations. In particular, finding that the amount of G force changes more dramatically at higher lean angles AND that rider position has a greater influence at higher lean angles, supports the idea that it will be nearly impossible to pin a specific number. Too much will depend on the rider and the particular bike setup and the conditions of the tire, track, etc. You'd probably just have to look at measurements from top racers and find a range of data.
I get interested in the physics side but I only find it useful up to a point - there are SO MANY variables (rider, suspension, tire compound, temperature, etc.) that the calculations quickly become overwhelmingly complex - or you end up oversimplifying and ignoring so many factors that the solutions are unrealistic and not useful. Data acquisition is so much simpler...