rchase
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Posts posted by rchase
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Great article. One of the biggest problems I have had is being able to wrap my head around the properties of adhesion. This article puts me a bit closer to that understanding.
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Something I have recently figured out is lever adjustment can help a LOT with this.
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Impressive. Especially at those speeds where one teeny mistake and you lose control completely.
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I suppose that's one unique incentive to get on the gas early.
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Sorry for going off tangent with the data. So here's an interesting observation that might be wrong due to my point of view (a non racer).
If you are seeing front end push would you not be then "charging" the turns and sacrificing your exit speed as a result?
I'll agree that some level of sliding is probably needed when everyone else is doing it (you need to keep up). Some sliding though to me seems like it's slowing you down rather than giving you the speed you are looking for. Is front end sliding useful in the grand scheme of things for going fast? That's an actual question rather than one to make a point.
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The 2d system that is on my BMW's provides front and rear wheel speeds independently in two seperate data channels. The Slip Rate metric is a percentage calculated by the difference in speed from the two wheel sensors. I'm pretty sure if the front starts sliding it will change speed and get lumped into the slip rate metric. In addition to that you could observe the data trend in speed between the wheel speed channels independently to see them "letting loose".
you could be right, but in my mind the challenge in measuring front wheel slip is that it's not really a longitudinal speed differential calculation since the front wheel doesn't really slow down, but rather detecting a departure from the intended longitudinal direction (a sudden, slight lateral movement of the front wheel with respect to the bike's expected path). I don't know how you could calculate that. but then again i'm a little hung over.
I agree with you there. For my data analysis abilities it would be very tough if not impossible to see. It might even be a challenge for someone who has a lot of experience. Observing multiple channels and how they relate to one another might give you the picture though. My bikes are not equipped with DDC but the DDC equipped bikes could also give lots of hints as well such as sudden changes to the dampening settings that don't normally happen in that corner with a data overlay from a "non sliding' lap. Reading the data is a bit of an art. With all of the sensors my guess is at least one or two of them might detect "something" that could tell you something useful.
My mechanic who's a former race champion took my bike for a test ride and had a bit of fun. I was able to see his fun and later had fun chastising him for it (he knew I was joking). Here's a screen shot from one of the several of the wheelies he performed on the bike with the slip rate going ballistic. It's the aqua colored line. His requested throttle is orange and bike provided throttle is blue (wheelie control coming in). The data is just raw but if you look at the data together you can put together what happened. The two red lines are the front and rear wheel sensors and the green line if I remember correctly is RPM. You can see the bike's wheelie control working and ruining his fun.
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Traction is a concern of mine as well. The Datalogger on my BMW is quite helpful for being able to "see" the limits of traction that I have. I have been on a bike that was sliding and not equipped with TC. The training that I got at the Superbike School made surviving the back stepping out second nature and a complete non issue.
Datalogging may reveal that the back tire is losing traction (front/rear speed bias), but there's really no way to electronically detect the front sliding. And THAT'S the crux of this post. With modern traction control strategies you can get the back end a bit sideways without much drama, and having tracked a low tech V twin liter bike for the last several years I've become accustomed to some sideways attitude on corner exit, but I'm WAY more interested in cornering: how much braking can you carry into the corner, and then how hard (fast) can you corner before you run out of traction. That last bit is the intriguing part. As a "planted and solid" type rider I THINK that i'm approaching the point at which my tires can no longer support the cornering load. It's a gut estimate. But if I take that corner faster and faster as my confidence increases, at some point things are going to change... hopefully the feedback from the bike is subtle but obvious and I get a sensation of sliding that I can recover from. Or, if I'm really comfortable, I can ride in that "slide zone" which is where I presume the top 1% ride. If the slider bike can teach that, i'll be tickled pink!
I'm not really sure that's accurate about the Datalogging. The 2d system that is on my BMW's provides front and rear wheel speeds independently in two seperate data channels. The Slip Rate metric is a percentage calculated by the difference in speed from the two wheel sensors. I'm pretty sure if the front starts sliding it will change speed and get lumped into the slip rate metric. In addition to that you could observe the data trend in speed between the wheel speed channels independently to see them "letting loose". If you wanted to get super anal there's an add on for the front and rear shock that could show you their travel. Suspension that's topped out or bottomed out could reveal a loss of traction as well as lots of sudden changes in the suspension's position where it does not correlate to the track's surface (an overlay with a lap where you did not loose traction). You could literally observe the bike becoming "unsettled" in the suspension from the data. All of these data points observed together could give you a pretty good idea of what's going on.
Possibly the most important thing in analyzing data is knowing what you are looking at and knowing exactly what it means. I'm certainly not to that point yet but I know where I would start looking if I thought the front end was pushing. I also know some people to ask if I really wanted an explanation to a sudden loss of traction in the front.
I do however agree with your point. Knowing how to react when the bike is sliding is the most important skill. The data can tell you what happened but only after it's happened when you have pulled the data off the bike and are looking at it on a Laptop. That's not really useful in real time when you are on the bike in the middle of a slide. It's very useful for understanding the limits and pushing them safely though. Being able to correlate that "feeling" with actual data is incredibly useful. These systems exist because the professionals found them useful. Luckily for us they are starting to become available in the consumer market. They are surprisingly advanced considering their low cost relative to what they originally cost in the racing world.
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Amazing videos. One has to wonder how active suspension technology eventually may change the speeds at the TT. Modern Superbike technology has taken it a long way already in a very short time span.
What I find most interesting with many of the TT onboard videos is how the riders often have to commit to the turns before they even can see some of the corners.
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Cardio and strengthening your lower body would be a good start. Some work on flexibility is good too so that you can use some of the more aggressive body position without as much effort. Lower body strength is always a plus for a solid grip on the bike.
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Traction is a concern of mine as well. The Datalogger on my BMW is quite helpful for being able to "see" the limits of traction that I have. I have been on a bike that was sliding and not equipped with TC. The training that I got at the Superbike School made surviving the back stepping out second nature and a complete non issue. Simple basics such as throttle control and remaining loose on the bike seem pretty simple but pay dividends when things aren't going according to plan.
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It's really awesome to watch Will, the school mechanic, ride the school's slide bike. He can get in a circle and just run that back tire through its paces - from no visible slide all the way up to smoking and spinning, and everything in between, all without losing control of the bike. Watching him do that is a good reminder that sliding the tire does not have to be like falling off a cliff - it can be done a little, or a lot, and anything in between; the trick is learning good technique so that you can be in control of the bike.
Can I sign up for a level 4 and just do the slide bike all day
Make that two people wanting to do that.
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I still get a kick out of the people who think that driving a car or riding a bike is "easy" because you are seated most of the time. It's a quite physical affair regardless of the location of your posterior.
One lap of the average track is like doing 10+ squats (depending on the turn number and arrangement) getting your body into position on the bike for turns.
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P.S. I have two bikes with Michelins on them. Great tires as well. My MV Agusta F4 is on Michelin Pilot Power Supersports and I have an R6 on Pilot Power 4's. I would not recommend the Supersports for the rain.
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How about Dunlop Q3's? They heat up fast. Have a good amount of grip and as a student you get a discount off of the price if you buy them through the school. The discount is pretty decent from what I understand.
My 2014 BMW S1000RR has just over 2400 miles on it and 9 track days. The dealer swapped the tires for me to Q3's before I took delivery. The Q3's perform well in the rain both on the road and track. Q3's have a slightly more "pointy" shape to them for faster turn in. After 9 track days and some street riding they still have a LOT of life left in them.
I think the Q3 is a great tire myself. One word of advice if you go with the Q3. Ignore the pressure recommended by the bike manufacturer. I usually run track pressures on the street with 1-2PSI added if I am noticing too much center wear. Setting the Q3's to the BMW pressure on the bike makes it a bit twitchy for my taste.
Because I'm trying to explore a bit more I'm going to be moving to the Pirelli Supercorsa SP next season. This is the factory provided tire for the BMW HP4 and if I understand correctly a lot of the traction control programming was done using this tire.
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I have never seen a school bike on slicks. The coaches bikes use the higher end Dunlops.
As for the "taste of riding on slicks". I have had the chance to borrow a race prepped S1000RR at the track on slicks. At my pace I did not really notice much of a difference with the tires. The bike itself was mind blowing! Unless you are really pushing the limits of DOT tires slicks feel just like any other tire. I loaned my stock S1000RR on Q3's to a professional racer and watched the footage from my onboard camera. It was pretty obvious he was used to the better grip of his slicks as the TC light came on all the time to the point he eventually turned TC off. My bike did things I did not think was possible.
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I have done both. They both have their advantages depending on what you are looking for.
Two day camps offer a lot more riding. This is an advantage and a disadvantage. The advantage is a lot more track time. The disadvantage is not having much time for other things such as recovering or thinking. It's a very fast paced day.
The single days don't offer as much riding but there is more time to think and recover. Its a much more relaxed day. Personally I prefer the single days as I have time to rest and time to think about what I just accomplished and what I need to accomplish the next time out.
Either choice you make it's top notch learning. On both the single and two day camps I have always met the goals I had for the day including ones that the coaches came up with during the day. My expectations have always been exceeded.
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I love eating squid so that sausage sounds interesting.
Someone fill in a Atlanta native about squid ridge!
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Certainly more questions than answers. That we can probably both agree on.
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That's pretty unscientific. Lets punch some holes for some fun.
On your commute were you doing 150mph+ down the expressway then hard on the brakes into a sharp corner?
The cold blast of air down the straight was pretty brutal. Towards the end of the sessions I was short shifting just to stay warm. I suspect a LOT of the cooling happened on the straight at least that's where most of the cooling was happening to me.I'm actually pretty curious now so I'll haul out the thermometer next time.
Here's something interesting as well. A wind chill chart. It does not go up to 150mph though.
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Benny. Will do for sure! Might be a while but I'm quite curious myself. If I had to guess based on the track I was riding with mostly right hand turns the center would be the warmest followed by the right hand side and the coldest side would be the left.
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upgrading the ABS on my bike (apparently I can get the upgrade to the 2015)
getting in shape (physically)
suspension tackling
body positioning (upper body just will not listen and relax and lay on that tank making me and the tank one)
bend those elbows and drop them to the tank more efficiently
staying smooth and working as one with the bike
Those sound like some great goals. Looking forward to riding with you again in 2015 and doing CSS @ Barber again!
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Oh yes. I'll admit it's not accurate at all. Just the comparison between the temps that I saw previously with the warmers when they were first plugged in vs this time was shocking for me.
That's actually a pretty good idea though. I even have a laser thermometer in my tool box. Next time I'll have to do an experiment. Leave the thermometer on the pit wall and take a reading "right off" the track. But that will have to wait until next year unless I luck out on a private day before spring.
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I recently had an experience with tire warmers that I wanted to share. I went to a track day in December and the outside temps barely got into the 60's all day and most of the time it was in the mid 50's. I have had some great experiences in the past with warmers but I suddenly realized the shortcomings after the cold time I spent at the track.
My bike is a BMW S1000RR on Dunlop Q3's. I typically run a hot pressure of 31 front 26 rear. My warmers are set to 160F. For the cold I set the pressure to 34 and 28 hot because the cooling effect from going from 160 down would reduce the pressure lower than I wanted. I asked a few experienced people about the pressure because of the cold temps. Their advice was odd but made sense. I'm glad I went with it even if I don't fully understand.
What was most shocking to me is how quickly the tires cooled off. When I returned from most of the sessions I was seeing temps in between 65F and 73F. This was an unscientific test of course since I was using the temps off of the warmers themselves but it was a surprise that the tires were unable to hold a good temperature.
Overall I'm an average rider and not one of the "fast guys". I use warmers not out of need but for an extra margin of safety. In a normal temperature environment warmers might be a slight pain but they provide some great peace of mind knowing the tires are "as hot as they can be" right away. They don't stay that way though if it's cold out.
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I can scratch one of my goals for next year off the list. Wheelies no longer bother me.
I borrowed a friends highly tuned S1K's for a few laps. Being the responsible type I stuck it in rain mode right away and was really respectful of the extra power it has. When I was coming down the straight and slowly and carefully rolling on the throttle (I smash mine open but on this one it's not a good idea) the engine suddenly was in the sweet spot of power and the wheel just came right off the ground and stayed there. I was horrified at first but then was laughing like a crazy person after the wheel landed. I completely understand the obsession many people have with them now.
Refresher Please - Front Tire Sliding In Turn..
in Cornering and Techniques
Posted
Nothing to add here. But this is a great topic with lots of great info.