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Applying 40/60 Rule.


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While I'm going through the basics of track riding with my wife, we're working at really low speeds. 40/60 is hard to gauge. I'm really starting to pay attention to it at higher speeds, and am learning that it takes more throttle than I initially thought. My thinking is that it takes even more throttle to combat the deceleratory forces of the lean. Is this correct? I'm finding that to get more pressure on the rear, I don't have to crack the throttle, but I do have to give it much more of a twist than I initially thought. Am I getting this right, or am I setting myself up for something nasty when I get back on the track?

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While I'm going through the basics of track riding with my wife, we're working at really low speeds. 40/60 is hard to gauge. I'm really starting to pay attention to it at higher speeds, and am learning that it takes more throttle than I initially thought. My thinking is that it takes even more throttle to combat the deceleratory forces of the lean. Is this correct? I'm finding that to get more pressure on the rear, I don't have to crack the throttle, but I do have to give it much more of a twist than I initially thought. Am I getting this right, or am I setting myself up for something nasty when I get back on the track?

 

Hub,

 

When you are on the throttle and holding it steady, not increasing, or decreasing and you are going in a straight line, will the speed be constant? Lets say it will, 60mph. Then, you lean the bike in (with no change in throttle). What happens to the speed, will it slow down? If so, do you have to roll the throttle a little just to keep the speed the same? Another way to look at it in this scenario, what will it take to get to 50/50?

 

CF

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While I'm going through the basics of track riding with my wife, we're working at really low speeds. 40/60 is hard to gauge. I'm really starting to pay attention to it at higher speeds, and am learning that it takes more throttle than I initially thought. My thinking is that it takes even more throttle to combat the deceleratory forces of the lean. Is this correct? I'm finding that to get more pressure on the rear, I don't have to crack the throttle, but I do have to give it much more of a twist than I initially thought. Am I getting this right, or am I setting myself up for something nasty when I get back on the track?

 

Hub,

 

When you are on the throttle and holding it steady, not increasing, or decreasing and you are going in a straight line, will the speed be constant? Lets say it will, 60mph. Then, you lean the bike in (with no change in throttle). What happens to the speed, will it slow down? If so, do you have to roll the throttle a little just to keep the speed the same? Another way to look at it in this scenario, what will it take to get to 50/50?

 

CF

 

I'm thinking that if you apply a constant speed then dip it into a corner without any adjustment, more weight is going to the front. I felt it for the first time about a week ago (or I just started paying attention), and thought that more throttle is necessary to get to 40/60.

I think I'm normally weighted toward the front on the track now that I think about it, but I know that in May during my last trackday, I was throwing lots more weight to the front, especially in one particular corner. I was letting the lean scrub some speed, and when I saw my front tire, session after session I knew I wasn't correcting it. I was fighting the basic principle of "take the slow corners slow." I don't know how I didn't lose the front end that day. My front tire was chewed.

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It seems to me that the basic idea it to give it enough throttle to generate slight acceleration to get the "40/60." My observation is that at lower speeds and lower rpms, it takes very little throttle do to this, but at higher speeds and/or higher rpms, it takes more throttle to do this. So at slower speeds/rpms the smooth throttle roll-on begins with it just barely cracked open. At higher speeds/rpms the gradual throttle roll-on might begin from 1/4 or half throttle. If near top speed obviously you have to have it almost all the way open just to maintain that speed, so this kinda makes sense. I also think this may be more noticeable on less powerful bikes because what made me think about it this recently is I went from riding a gsxr600 to an sv650.

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"My thinking is that it takes even more throttle to combat the deceleratory forces of the lean."

 

I figured it had a lot more to do with wind resistance. At top speed the bike is using most of its power to push through the air.

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"My thinking is that it takes even more throttle to combat the deceleratory forces of the lean."

 

I figured it had a lot more to do with wind resistance. At top speed the bike is using most of its power to push through the air.

 

 

True, going fast, wind resistance is the big factor.

 

Hub--think you are on to it. Gotta have enough acceleration to overcome the other forces (wind or tire resistance), and get a little more on the rear

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Cobie, please correct me if I'm making the wrong assumptions:

 

TOTW - I don't have the book with me but Keith mentions that the force to get to the 40/60 is similar to 4th gear 6000rpm on the throttle (something like that).

 

Recently, I'm cracking the throttle on immediately after the quick turn instead of letting the bike settle first. Keith also mentioned that this (throttle on) settles the bike quicker.

 

The result for me is I find the bike is faster and leaning more to keep the same line (I'm off the seat to lower the CG and keep bike as upright as possible), yet more stable thru the turn.

 

Thanks

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Cobie, please correct me if I'm making the wrong assumptions:

 

TOTW - I don't have the book with me but Keith mentions that the force to get to the 40/60 is similar to 4th gear 6000rpm on the throttle (something like that).

 

Recently, I'm cracking the throttle on immediately after the quick turn instead of letting the bike settle first. Keith also mentioned that this (throttle on) settles the bike quicker.

 

The result for me is I find the bike is faster and leaning more to keep the same line (I'm off the seat to lower the CG and keep bike as upright as possible), yet more stable thru the turn.

 

Thanks

 

YNOT--above you say "...the bike is faster and leaning more to keep the same line..." If you are having to lean the bike more, while on the throtlte, then sounds like you might be coming into the throttle either TOO SOON, or giving it throttle while you add lean angle. Neither is desirable, and can be quite dangerous. You don't want to add throttle and lean angle at the same time, that's the deadly combo. Can't sense what the tires are doing , and you are asking them to do 2 things at the same time, corner and accelerate. Slides caused by those 2 together are often unrecoverable and super fast.

 

Make sense?

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Cobie - what you say makes sense - adding throttle & lean at the same time. I'm not sure exactly what is going on thru the turn. I will describe briefly the difference between the "old" and "new" turn:

 

before: My turn entry speed slower, quick turn, lean angle less severe, I wait for bike to settle, speed scrubbing off, I get on the throttle slightly before the apex to maintain speed thru the turn.

 

after: Faster turn entry speed, quick turn, lean, throttle on to maintain speed thru turn. I find that my lean angle may be increasing more in the turn - yup you're right.

 

I guess that I'm increasing my lean angle thru the turn before the apex, therefore getting my knee to the ground at some point in the turn, instead of at the begining and all the way thru the turn? (Yes I get it - BAD)

 

Does Corner entry speed dictate lean angle from turn in point? If true does that mean my knee should be dragging from quick turn point thru past the apex. (Using knee as indicator only)

 

- getting on the throttle to MAINTAIN speed thru the corner?

 

Thanks

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Cobie - what you say makes sense - adding throttle & lean at the same time. I'm not sure exactly what is going on thru the turn. I will describe briefly the difference between the "old" and "new" turn:

 

before: My turn entry speed slower, quick turn, lean angle less severe, I wait for bike to settle, speed scrubbing off, I get on the throttle slightly before the apex to maintain speed thru the turn.

 

after: Faster turn entry speed, quick turn, lean, throttle on to maintain speed thru turn. I find that my lean angle may be increasing more in the turn - yup you're right.

 

I guess that I'm increasing my lean angle thru the turn before the apex, therefore getting my knee to the ground at some point in the turn, instead of at the begining and all the way thru the turn? (Yes I get it - BAD)

 

Does Corner entry speed dictate lean angle from turn in point? If true does that mean my knee should be dragging from quick turn point thru past the apex. (Using knee as indicator only)

 

- getting on the throttle to MAINTAIN speed thru the corner?

 

Thanks

 

Hi YNOT,

 

I know you directed your question to Cobie, but I am curious about something, after reading your post above, hope you don't mind if I interject a question. When you initiate your turn-in, do you have a specific apex point you are aiming to? Or are you starting your turn, then finding you have to tighten your line a little bit more to make it to the apex you want?

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