Questions for Keith Code - Round Two

[Yody]

Don't lower the frontend, raise the rear. That right there will get you some ground clearance back. But honestly I'm not sure why you are leaning so much, on any sportbike if you lean that much you're going to run into problems. As well I noticed your lines are inconsistent from picture to picture, you're in a different spot each time. Of course this could also be due to the photographer but sometimes it seems like you're way off line and have super major lean angle.

I think you're scraping hard parts and leaning so much because the way you ride. I used to ride my F4I similarly and thought it was good that I could lean it so much confidently, but learned that it was not a good idea so much and didn't get as fast as you. Now you're going quickly and you've reached the limit of that riding style and are dragging hard parts and everything. Are you doing a very late apex and going line to line? If you are using the entire track on the entrance of hte turns and taking a late apex this could be part of the reason you are having to lean the bike so hard. I know F4I's can be setup to like that and ride like that (up in back/low in front) but you'll end up right where you are which is having to go too deep into turns and leanign the crap out of the bike to reach the apex

While I don't really have any answers for you (thats Keiths job) I just thought I'd point out those observations. Maybe they're not valid but maybe it could be used as food for thought. I definitely think a track school would do you well.

T-Hill is a great place to work on fundamentals, but its IMO that only going to that track and tryign to get faster and faster is going to make you skip past a huge part of the learning curve.

 

[Keith Code]

Ok I'm probably gonna need an editor again but here goes. My suspension was serviced and I had race tech fork springs changed for my weight by Phil at Aftershocks. He also put a 10 mil spacer in the shock mount and gave me a set up he thought I would like. I was running 208GPA's at the time. I then made a bone head move and got some Dunlop 125/195 takeoff slicks for free from Lance wow was my suspension out of whack from those babys. I worked with Dave Moss for 2 days and still couldn't get it right I removed the spacer and adjusted the forks to try and get rid of the horrible speed wobble. I ended up trashing the Dunlops and became a Michelin man and went back to the 120/180 sizes. I then worked with Jim Lindemann and we got it dialed in however I have done some geometry changes since then and my bike felt much better I raised the forks through the triples 3 mm and what a difference on how the bike handles. In hindsght I'm glad I went through all of that because it allowed me to understand what was a bad setup and a right setup and exactly how I like the bike to react. I was thinking my next move was gonna be taking a little rebound out of the rearend but not sure if that's gonna be sufficient. Is an Ohlins shock the way to get a handle on this or maybe just a fresh spring and revalve on the stock shock with 35,000 miles on her. Thanks for your help and sorry for the long read.

I asked you about your suspension but I'm not the guy to go to for advice on it, not my job and you are already hooked up with some good names.

Having said that, I've heard enough stories about guys sending their bikes to expert suspension people and getting back something that didn't suit them. Personally, I've seen quite a few botched jobs where the set up just wasn't right for the rider.

For my end of the deal you can't make any final decisions on someone's riding until you get them out and watch and coach them. Your problem, if there is one, could be simple or complex but giving an armchair evaluation would just be guessing.

Yody had a good observation, if your lines are inconsistent you are probably having to play with the bike in the turns and may be adding lean that you wouldn't need on a better one.

Keith

 

[jmonte35]

I asked you about your suspension but I'm not the guy to go to for advice on it, not my job and you are already hooked up with some good names.

Having said that, I've heard enough stories about guys sending their bikes to expert suspension people and getting back something that didn't suit them. Personally, I've seen quite a few botched jobs where the set up just wasn't right for the rider.

For my end of the deal you can't make any final decisions on someone's riding until you get them out and watch and coach them. Your problem, if there is one, could be simple or complex but giving an armchair evaluation would just be guessing.

Yody had a good observation, if your lines are inconsistent you are probably having to play with the bike in the turns and may be adding lean that you wouldn't need on a better one.

Keith

I believe they are very valid observations that specific day I was trying to find some better lines through 10, 11, 12 and 13 which the majority of pictures were taken. I've had a lot of instructors tell me I lost a lot of time there where as through 6, 7, 8 many have said they couldn't keep up so I've been really struggling with those corners at T-hill. hmmm...time for a class I believe where I can get some really good one on one. I read in an earlier post than turning the bike in quicker actually reduces lean angle. Is this true? Its something I haven't quite thought about as I try not to just slam the bike on to my knee.

Yody
I have ventured elsewhere however T-hill was my first track and still one of my favorites and a place I know well enough to know exactly where I need work so I use this as reference. I agree to try not to lower the front end however I don't have a ton of choices with the stock shock. I'm thinking about putting the spacer in again but I just never quite got the geometry right with it. Its a huge trade off and I'm not willing to do that just for added ride height all that will do is give me short term solution and the bike just wont turn the way I want it to. I think your advice will get me headed the right direction though. Even though I'm consistent in terms of time I do believe I need to be more consistent in my lines and then adjust accordingly. I do find myself referencing the apex rather than other markers around the track and I'm sure that picking up more reference points will help me greatly I think that's where I'm at now getting better braking and figuring out ways to get on the gas sooner but aren't we all!!!!! and as for a lap timer I don't run one on a normal basis I don't want to rely on just times because I will in turn probably just try and race my previous time and thats not learning. But I'm being very liberal in my estimate and not even a hot lap where I'm really getting on the brakes I usually don't get on the brakes very hard at trackdays. I get worse tire wear and I don't feel like I'm improving when I push hard I really like staying at 90%. Running the times I'm running I can still get 4 solid days out of Michelin take offs I get from Gregg Spears and I've seen guys on similar bikes running similar times eat a new set in two days. I'm sure a lot of it has to do with my weight though.

 

[Keith Code]

I believe they are very valid observations that specific day I was trying to find some better lines through 10, 11, 12 and 13 which the majority of pictures were taken. I've had a lot of instructors tell me I lost a lot of time there where as through 6, 7, 8 many have said they couldn't keep up so I've been really struggling with those corners at T-hill. hmmm...time for a class I believe where I can get some really good one on one. I read in an earlier post than turning the bike in quicker actually reduces lean angle. Is this true? Its something I haven't quite thought about as I try not to just slam the bike on to my knee.

Yody
I have ventured elsewhere however T-hill was my first track and still one of my favorites and a place I know well enough to know exactly where I need work so I use this as reference. I agree to try not to lower the front end however I don't have a ton of choices with the stock shock. I'm thinking about putting the spacer in again but I just never quite got the geometry right with it. Its a huge trade off and I'm not willing to do that just for added ride height all that will do is give me short term solution and the bike just wont turn the way I want it to. I think your advice will get me headed the right direction though. Even though I'm consistent in terms of time I do believe I need to be more consistent in my lines and then adjust accordingly. I do find myself referencing the apex rather than other markers around the track and I'm sure that picking up more reference points will help me greatly I think that's where I'm at now getting better braking and figuring out ways to get on the gas sooner but aren't we all!!!!! and as for a lap timer I don't run one on a normal basis I don't want to rely on just times because I will in turn probably just try and race my previous time and thats not learning. But I'm being very liberal in my estimate and not even a hot lap where I'm really getting on the brakes I usually don't get on the brakes very hard at trackdays. I get worse tire wear and I don't feel like I'm improving when I push hard I really like staying at 90%. Running the times I'm running I can still get 4 solid days out of Michelin take offs I get from Gregg Spears and I've seen guys on similar bikes running similar times eat a new set in two days. I'm sure a lot of it has to do with my weight though.

On the turning of the bike quickly. Have you ever looked through "A Twist of the Wrist, Vol II"? There are 8 sections on steering: what it is, how it is applied to get specific results, what goes right, what goes wrong and how to fix it.

Guys like me write books because of questions like yours. Now we've filmed that book and I'm working on the editing but it'll be a few months before it is out.

One point you should look at is the idea that you can make big time on the brakes. It is false. No matter whether you brake straight up or trailbrake to the moon you can't expect to knock off seconds with the brakes, never happened.

If your braking is just "OK" you still aren't going to make up seconds with more aggressive and harder braking alone. There are a number of other foundation skills that MUST be in place before harder braking becomes important.

And give me a break, if you don't know what those skills are, just read the book.

There isn't any magic in blowing through riding barriers but there is a technology to riding and once you familiarize yourself with its parts you will have a fighting chance of being able to correctly identify errors in the "basics" and figure out ways to fold them into your riding.

It's an art. Everyone starts out with paint and brushes and a canvas to make a painting but the guys who understand the basics, no matter how they got that knowledge, seat of the pants and experience or from training, are the good ones.

Keith

 

[afm199]

Keith is right about the brakes. I used to be a ferocious late hard braker. I don't do it anymore and get the same lap times braking earlier and lighter. And at the end of the day I am not worn out from all the effort and strain.

 

[jmonte35]

I do agree I always seem to be just as fast when just being smooth rather than braking later and harder and trailing it doesn't seem like much is to be made up. I watched twist of the wrist it was good but I did not get your second book I believe I have a friend who has it I'll pick it up from him. I'm thirsty for knowledge and opinion and I'm always willing to try something new. Not everything I've been told or taught works for me but like you said it's an art and everyone does do it their own way but very true about fundamentals. I will pick up the book and see what happens and I will update. Thanks Keith I love BARF for its good for the old kick in the ass when you need it. I do believe there are some fundamentals to my riding that need work and I'll do my best to apply it.

 

[DubbleRNR]

Hanging Off and Traction

Here's one for you, Keith. (I don't think it's been discussed in this thread)

Is there a relationship between hanging-off to minimize lean angle and traction?

 

[Keith Code]

Here's one for you, Keith. (I don't think it's been discussed in this thread)

Is there a relationship between hanging-off to minimize lean angle and traction?

This must be a trick question. Are lean angle and traction connected? Yes. Does less lean angle allow a rider to accelerate more aggressively? Yes. As lateral load on the tire decreases the rubber is more capable of handling acceleration.

Keith

 

[Alexey]

This must be a trick question. Are lean angle and traction connected? Yes. Does less lean angle allow a rider to accelerate more aggressively? Yes. As lateral load on the tire decreases the rubber is more capable of handling acceleration.

Keith

Ah, but wait a minute. If I'm going the same speed and in one case I hang off more and in another less, the only difference in terms of lateral loads is the size of the contact patch. Sometimes it is decreased with more lean, sometimes it is actually increased. The latter can happen if the tires have a pointy profile (many Dunlop DOT race tires and slicks do for example) and the bike is nowhere near maximum lean, increasing lean will put the bike on the flatter section of the tire and actually increase the contact patch area.

 

[DubbleRNR]

This must be a trick question. Are lean angle and traction connected? Yes. Does less lean angle allow a rider to accelerate more aggressively? Yes. As lateral load on the tire decreases the rubber is more capable of handling acceleration.

Keith

It's not a trick question, Keith.

I know that traction is finite and that braking, accelerating and cornering are all consumers.

I came across this and am a bit confused.

I think you'll find it interesting.

http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=1857&SearchTerms=hanging+off

 

[Yody]

OMG who has time to read all that!

 

[DubbleRNR]

The first few posts give you the gist of it.

 

[Burning1]

From what I understand, hanging off typically increases traction, but not to the degree people might expect. For example, a rider might increase his traction reserve by hanging off far enough to decrease the motorcycle's lean angle by 15%. However, if another rider was using 15% less lean angle by virtue of a slower speed, he would have more available traction than the first rider, assuming all other factors are equal.

We've discussed earlier that using less lean angle allows the suspension to be used more effectively. Hanging off also puts the contact patch closer to the center line of the bike. If the rider is cornering on the edge of the tire, it may also provide more of a contact patch.

I apologize if I'm cutting in on Keith's thread. This is only my understanding. I hope I'm not off base.

 

[Keith Code]

It's not a trick question, Keith.

I know that traction is finite and that braking, accelerating and cornering are all consumers.

I came across this and am a bit confused.

I think you'll find it interesting.

http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=1857&SearchTerms=hanging+off

Alexey and DubbleRNR

I liked that thread (I couldn't read it all either) and it does bring up the difference between the perceived value and feel you get when hanging off and what the physics of the equation are.

Like a lot of things, feel isn't always the whole picture and I'm guilty of falling for it myself.

The agreement about hanging off is that lean angle is decreased for a given speed and radius of turn and it feels that way when you do it so those two things seem to add up.

One other factor is how the suspension works at greater lean angles. The more lean you have the less complaint the suspension is because it has to move more than it can to handle a given surface change.

A .5 inch bump requires .7 inches of travel at 45 degrees of lean. In addition, the bump tends to roll the bike around its longitudinal axis.

Does the suspension actually travel the extra .2 inches needed to handle the .5 inch bump? I'm not sure of that I hope to find out.

As the bike is brought up or leaned less the roll force would be decreased and you'd have some degree of better traction. I don't know how much better.

For sure, radial tires have a huge leaned over contact surface area and the newer race tires running pressures as low as 12 psi gives another perspective on that.

Keith

 

[bikerdr]

For sure, radial tires have a huge leaned over contact surface area and the newer race tires running pressures as low as 12 psi gives another perspective on that.

Keith,

Great seeing you at Laguna, thanks so much for providing a great school.

I have heard of the N-Tech tires that run on low pressure. Can you explain how these tires work? 12 psi baffles me.

Thanks!

 

[Yody]

harder carcass with lower pressure makes a larger footprint simply put

 

[DubbleRNR]

Alexey and DubbleRNR

I liked that thread (I couldn't read it all either) and it does bring up the difference between the perceived value and feel you get when hanging off and what the physics of the equation are.

Like a lot of things, feel isn't always the whole picture and I'm guilty of falling for it myself.

The agreement about hanging off is that lean angle is decreased for a given speed and radius of turn and it feels that way when you do it so those two things seem to add up.

Keith

So, am I correct in stating that lean angle has no effect on side/lateral force?

For example, if I go 60 mph through a certain corner and my lean angle is 40 degrees the side force is the same as if I go through that same corner at the same speed with 45 degrees of lean angle.

 

[Keith Code]

So, am I correct in stating that lean angle has no effect on side/lateral force?

For example, if I go 60 mph through a certain corner and my lean angle is 40 degrees the side force is the same as if I go through that same corner at the same speed with 45 degrees of lean angle.

Absolutely correct. No matter how you rearrange the forces the numbers have to balance or you wouldn't continue to go around the corner at the same riding radius.

That's what I meant, it's easy to become swayed by personal experience and feel and ignore the simple forces at work.

As I understand it, leaned over to 45 degrees = 1g of load on the lateral, 60 degrees = 2g load on the lateral component.

I don't think the tire sidewalls are "stiffer" in the normal sense of the word. They are able to maintain a massive squish area and not feel squirmy with the lower pressures. It is a function of how they weave the carcass of the tire. I think you'd actually find that in most ways they are "softer" until there is a load applied to them.

Keith

 

[Keith Code]

Keith,

Great seeing you at Laguna, thanks so much for providing a great school.

I have heard of the N-Tech tires that run on low pressure. Can you explain how these tires work? 12 psi baffles me.

Thanks!

The Dunlop N-Tech tires run around 18psi, I was referring to the MotoGP tire technology where the B'Stones and Michies are running in that pressure range.

The N-Tech tires are phenomenal. They can run at extremely high temperatures. Even at my sedate pace I got the rear up to 207f at VIR earlier this year on a warm day.

Keith

 

[Alexey]

Alexey and DubbleRNR

I liked that thread (I couldn't read it all either) and it does bring up the difference between the perceived value and feel you get when hanging off and what the physics of the equation are.

Like a lot of things, feel isn't always the whole picture and I'm guilty of falling for it myself.

The agreement about hanging off is that lean angle is decreased for a given speed and radius of turn and it feels that way when you do it so those two things seem to add up.

One other factor is how the suspension works at greater lean angles. The more lean you have the less complaint the suspension is because it has to move more than it can to handle a given surface change.

A .5 inch bump requires .7 inches of travel at 45 degrees of lean. In addition, the bump tends to roll the bike around its longitudinal axis.

Does the suspension actually travel the extra .2 inches needed to handle the .5 inch bump? I'm not sure of that I hope to find out.

As the bike is brought up or leaned less the roll force would be decreased and you'd have some degree of better traction. I don't know how much better.

For sure, radial tires have a huge leaned over contact surface area and the newer race tires running pressures as low as 12 psi gives another perspective on that.

Keith

If the rider hangs off, preserving the same speed, thereby bringing the suspension closer to vertical, the effect is not only the wheels being able to roll over the same bump at a straighter trajectory, but the suspension is less compressed to begin with because its angle gives the springs more leverage against the centripetal force pushing the bike "down" through its suspension travel. If anyone's interested in a picture, I can make one up. The only adverse effect is increased stiction due to the same issue of the suspension being more out of plane from the forces involved, but I suspect that's negligible with today's materials.