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Compliant Suspension Range


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In the twist 2 video it mentioned that anything 600CC's and over 4000-6000RPM in 4th gear seems to be the most compliant range as far as being in the turn for suspension compression. Now 600's are higher revving bikes then a 1000 and generally from what I understand with a 600 you want to keep it in the higher RPM range so on the drive out of the corner you are in the power band. On my 600RR the power doesn't even come on until about 7500RPM I would say.

 

1. Do you really want to be that low in the RPM's in a turn with a 600? In a 1000 I could see because too much throttle would be a lot easier to lose traction.

 

2. How do you know when the suspension is in it's most compliant range when you are in mid turn?

 

3. One other question, I noticed in other videos I have watched they say "you should be in this gear at this turn" what justifies this? My only knowledge is you should be in whatever gear is best for your turn entry speed. What good is being in say 3rd gear if my turn in speed is putting me at 3000RPM into the corner?

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In the twist 2 video it mentioned that anything 600CC's and over 4000-6000RPM in 4th gear seems to be the most compliant range as far as being in the turn for suspension compression. Now 600's are higher revving bikes then a 1000 and generally from what I understand with a 600 you want to keep it in the higher RPM range so on the drive out of the corner you are in the power band. On my 600RR the power doesn't even come on until about 7500RPM I would say.

 

1. Do you really want to be that low in the RPM's in a turn with a 600? In a 1000 I could see because too much throttle would be a lot easier to lose traction.

 

2. How do you know when the suspension is in it's most compliant range when you are in mid turn?

 

3. One other question, I noticed in other videos I have watched they say "you should be in this gear at this turn" what justifies this? My only knowledge is you should be in whatever gear is best for your turn entry speed. What good is being in say 3rd gear if my turn in speed is putting me at 3000RPM into the corner?

 

I'll have to go back and listen to exactly what he says in the video but I suspect there is a misunderstanding here - in the book (Twist II) on Page 7 in a section called "Light Touch" there is a description of how MUCH acceleration you need through a turn to get the optimum weight transfer (10-20% of the weight rearwards) to optimize traction. It is 0.1 to 0.2G, but that measurement might not be meaningful to everyone, so he specifically equates it to "the force generated by a smooth fifth-gear roll-on in the 4000 to 6000 rpm range on pretty much anything over 600cc". A fifth gear roll-on at 4000 rpm is not going to give you a very strong drive.

 

This is NOT a recommendation to ride all your turns in 5th gear at 4000-6000rpm! It is just a way to illustrate how much acceleration is required to get the optimum weight transfer, the idea being that once you have an idea of how much acceleration you need for standard throttle control, you can control the rate of your roll-on as needed, in whatever gear you are in, to achieve that. So, if you are in second gear at 11,000 rpm, your roll-on would have to be much more gentle and careful than if you were in 4th gear at 5,000 rpm; it would be easy to overdo it or lurch the bike in the lower gear at high RPM. However, on the exit there would be a real advantage to being up in the power band, to maximize your drive.

 

Assuming you are going for max overall speed, what factors can YOU think of that would help you decide what gear to use? At what point in the turn do you MOST need to be in the bike's powerband? How woud you know if you entered a turn at too HIGH an RPM? What would you feel on your exit drive if your RPM was too low?

 

Regarding your second question: The Twist II book gives you a lot of things that will tell you when you are NOT in the most compliant suspension range - what indicators can you think of, that would let you know you are OUT of the most compliant suspension range?

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Assuming you are going for max overall speed, what factors can YOU think of that would help you decide what gear to use? At what point in the turn do you MOST need to be in the bike's powerband? How woud you know if you entered a turn at too HIGH an RPM? What would you feel on your exit drive if your RPM was too low?

 

Regarding your second question: The Twist II book gives you a lot of things that will tell you when you are NOT in the most compliant suspension range - what indicators can you think of, that would let you know you are OUT of the most compliant suspension range?

 

 

In deciding what gear to use you would want a gear that keeps you towards the bottom of your RPM range so you are not risking the bike coming from under you and you can have a better drive coming out of the corner instead of hitting your exit point and then shifting shortly after because you ran out of RPM right after the turn?

 

As far as what point in the turn you most need to be in the powerband I would have to say the apex.

 

As for knowing if you came into the turn at too high of an RPM would be if you found yourself chopping the throttle to avoid shifting mid turn or shifting mid turn because you ran out of RPM mid turn.

 

Without doing any reading this what I think the answers are.

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bump?

 

Hi mate,

 

 

 

I don't want to jump into this as Hotfoot has already started a direction with you. She's pretty nusy at the mo, and I know she is struggling for time, so you might need to just bare with her a little mate.

 

 

 

Bullet

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I'll jump in with a piece of advice from one of the books (forget which one now) where you ideally want to be towards the top end of the rev range coming out of the turn, so if the bike does spin up and you get a slide, it only has a few hundred RPM to develop into, rather than several thousand.

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bump?

 

Hi mate,

 

 

 

I don't want to jump into this as Hotfoot has already started a direction with you. She's pretty nusy at the mo, and I know she is struggling for time, so you might need to just bare with her a little mate.

 

 

 

Bullet

 

 

Oh I understand, I am open to anyones input which is the reason I bumped it that's all.

 

 

 

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I'll jump in with a piece of advice from one of the books (forget which one now) where you ideally want to be towards the top end of the rev range coming out of the turn, so if the bike does spin up and you get a slide, it only has a few hundred RPM to develop into, rather than several thousand.

 

 

 

Is this why I see people in MotoGP or WSBK their rear tire get a little squiggly after coming out of a turn and hitting a straight?

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In deciding what gear to use you would want a gear that keeps you towards the bottom of your RPM range so you are not risking the bike coming from under you and you can have a better drive coming out of the corner instead of hitting your exit point and then shifting shortly after because you ran out of RPM right after the turn?

 

As far as what point in the turn you most need to be in the powerband I would have to say the apex.

 

As for knowing if you came into the turn at too high of an RPM would be if you found yourself chopping the throttle to avoid shifting mid turn or shifting mid turn because you ran out of RPM mid turn.

 

Without doing any reading this what I think the answers are.

 

 

Sorry for the lag - thanks for bumping the thread to get it back on top. (And hey, Bullet, you can jump in any time!! No worries on that!)

 

OK, good job thinking this through. These answers are somewhat bike dependent - for example if your bike is a fire breathing dragon and hard to control in its powerband, you might intentionally enter a turn in a low RPM range, to keep you from being in the max power range while at full lean, to prevent you from spinning up the rear, or to help you be smooth on throttle application. On the other hand, if you ride a low HP bike, you migh have to be at a high RPM in your peak powerband just to get enough acceleration to stabilize the bike through the turn!

 

Exactly right on your second point, if you are hitting the rev limiter mid-turn and it is making you hesitate on the gas or have to shift mid-turn, you would likely want to try entering the turn in a higher gear/lower RPM the next time to avoid that situation.

 

If you are in too HIGH a gear, you can sometimes feel that the bike is not accelerating much... or you might just notice that other bikes are pulling away from you. :)

 

Usually the ideal for racing would be to be have to MOST power available to you during your exit drive - at the point where you are standing the bike up and can do anything you want with the throttle.

 

NOW - what about suspension compliance? What might the bike do, or what might you feel, that would let you know that you might NOT be in the ideal suspension range? (Hint - you may want to review Chapter 5 in Twist II for some help on this one.)

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In deciding what gear to use you would want a gear that keeps you towards the bottom of your RPM range so you are not risking the bike coming from under you and you can have a better drive coming out of the corner instead of hitting your exit point and then shifting shortly after because you ran out of RPM right after the turn?

 

As far as what point in the turn you most need to be in the powerband I would have to say the apex.

 

As for knowing if you came into the turn at too high of an RPM would be if you found yourself chopping the throttle to avoid shifting mid turn or shifting mid turn because you ran out of RPM mid turn.

 

Without doing any reading this what I think the answers are.

 

 

Sorry for the lag - thanks for bumping the thread to get it back on top. (And hey, Bullet, you can jump in any time!! No worries on that!)

 

OK, good job thinking this through. These answers are somewhat bike dependent - for example if your bike is a fire breathing dragon and hard to control in its powerband, you might intentionally enter a turn in a low RPM range, to keep you from being in the max power range while at full lean, to prevent you from spinning up the rear, or to help you be smooth on throttle application. On the other hand, if you ride a low HP bike, you migh have to be at a high RPM in your peak powerband just to get enough acceleration to stabilize the bike through the turn!

 

Exactly right on your second point, if you are hitting the rev limiter mid-turn and it is making you hesitate on the gas or have to shift mid-turn, you would likely want to try entering the turn in a higher gear/lower RPM the next time to avoid that situation.

 

If you are in too HIGH a gear, you can sometimes feel that the bike is not accelerating much... or you might just notice that other bikes are pulling away from you. :)

 

Usually the ideal for racing would be to be have to MOST power available to you during your exit drive - at the point where you are standing the bike up and can do anything you want with the throttle.

 

NOW - what about suspension compliance? What might the bike do, or what might you feel, that would let you know that you might NOT be in the ideal suspension range? (Hint - you may want to review Chapter 5 in Twist II for some help on this one.)

 

 

 

 

Will do thanks for your input!

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As a supplement to Steve, it has often been said that you want to exit corners on trailing torque, that is past peak torque, since you're much less likely to be spat off in a highside then. As Steve said, you're also closer to run out of revs, further aiding you in controlling the bike should the tyre spin up for you.

 

Of course, with modern electronics in the form of traction control, this is much less important.

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As a supplement to Steve, it has often been said that you want to exit corners on trailing torque, that is past peak torque, since you're much less likely to be spat off in a highside then. As Steve said, you're also closer to run out of revs, further aiding you in controlling the bike should the tyre spin up for you.

 

Of course, with modern electronics in the form of traction control, this is much less important.

 

 

 

I haven't been on a bike with traction control but not sure if I want it......seems like it takes the skill building out of the rider and relying more on the technology to make up for your mistakes which I don't think is right.

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In deciding what gear to use you would want a gear that keeps you towards the bottom of your RPM range so you are not risking the bike coming from under you and you can have a better drive coming out of the corner instead of hitting your exit point and then shifting shortly after because you ran out of RPM right after the turn?

 

As far as what point in the turn you most need to be in the powerband I would have to say the apex.

 

As for knowing if you came into the turn at too high of an RPM would be if you found yourself chopping the throttle to avoid shifting mid turn or shifting mid turn because you ran out of RPM mid turn.

 

Without doing any reading this what I think the answers are.

 

 

Sorry for the lag - thanks for bumping the thread to get it back on top. (And hey, Bullet, you can jump in any time!! No worries on that!)

 

OK, good job thinking this through. These answers are somewhat bike dependent - for example if your bike is a fire breathing dragon and hard to control in its powerband, you might intentionally enter a turn in a low RPM range, to keep you from being in the max power range while at full lean, to prevent you from spinning up the rear, or to help you be smooth on throttle application. On the other hand, if you ride a low HP bike, you migh have to be at a high RPM in your peak powerband just to get enough acceleration to stabilize the bike through the turn!

 

Exactly right on your second point, if you are hitting the rev limiter mid-turn and it is making you hesitate on the gas or have to shift mid-turn, you would likely want to try entering the turn in a higher gear/lower RPM the next time to avoid that situation.

 

If you are in too HIGH a gear, you can sometimes feel that the bike is not accelerating much... or you might just notice that other bikes are pulling away from you. :)

 

Usually the ideal for racing would be to be have to MOST power available to you during your exit drive - at the point where you are standing the bike up and can do anything you want with the throttle.

 

NOW - what about suspension compliance? What might the bike do, or what might you feel, that would let you know that you might NOT be in the ideal suspension range? (Hint - you may want to review Chapter 5 in Twist II for some help on this one.)

 

 

 

 

I just read chapter 5, the things I saw in there that would let you know your suspension is out of range is reduced rear tire traction and the bike not holding a line. The other stuff I saw was more directly of throttle control......unless you are saying that with proper throttle control your suspension will always be in a compliant range?

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I just read chapter 5, the things I saw in there that would let you know your suspension is out of range is reduced rear tire traction and the bike not holding a line. The other stuff I saw was more directly of throttle control......unless you are saying that with proper throttle control your suspension will always be in a compliant range?

 

 

Good on ya for reading up on it! :)

 

YES, one of the primary benefits of good throttle control is that it keeps your bike's suspension in the best range. Excellent observation.

 

First sentence in Ch 5: "...good throttle control is responsible for good cornering control (i.e., suspension in best range, tires delivering optimum tracion, line predictable, etc.)..."

 

Yes, you named some things that could tell you that your suspension is out of its best range: reduced rear tire traction, bike not holding a line - those are great ones!

 

But there are more...

 

If you look at the list of "Off-Gas Results", I see some other items that address bike handling, if you overweight the front end (front suspension out of ideal range, compressed too much):

 

Bike overreacts to pavement irregularities

Steering can get twitchy (steering angle steepens due to fork compression)

Ground clearance is reduced

 

These are things you can feel, that can give you info about your suspension - the bike feels twitchy or can feel like the front end gets chattery over bumps, or chopping the gas can compress both front and rear suspension and make you suddenly scrape a peg on the ground in a corner.

 

What about under braking - if you overload the front so much that you bottom out the forks, what would you feel?

 

Other folks out there, jump in! What specific things have you noticed that told you that you might be over- or under-loading your suspension, or possibly that your suspension is not set up correctly?

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Yea the "off the gas results" were what lead me to think with proper throttle control your suspension will pretty much be in it's compliant range. I will have to do some more reading on what would happen or what you would feel if you overloaded the front forks.

 

I know tires can show how well your suspension is setup, for example if you are getting too much rebound your trailing edges or leading edges on your tread will be different heights which means you rebound settings need to be adjusted. That's about all I know.

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As a supplement to Steve, it has often been said that you want to exit corners on trailing torque, that is past peak torque, since you're much less likely to be spat off in a highside then. As Steve said, you're also closer to run out of revs, further aiding you in controlling the bike should the tyre spin up for you.

 

Of course, with modern electronics in the form of traction control, this is much less important.

 

 

 

I haven't been on a bike with traction control but not sure if I want it......seems like it takes the skill building out of the rider and relying more on the technology to make up for your mistakes which I don't think is right.

 

 

Traction control isn't a saviour of ham fistedness. You're much better to learn to ride with feel and skill than rely on traction control. electronics are reknowned for failing, and if you only rely on it, you could be saving up a big accident. even the top level riders still get highsided with it from time to time. I have traction control on my Ducati racer, (only factory fitted), and I don't use it, and have it turned off. It interferes too much in the feeling of what the bikes doing. I do think TC is a very good thing for road riding, certainly in poor conditions, but if you really want to learn to ride, I don't think you need TC unless your riding a 240-250BHP monster.

 

 

Bullet

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Yea that is the point I was getting at, when they advertise it as "it makes slower riders faster" then it isn't really benefiting the rider by learning how to control and feel bike without it first!

 

The other thing TC does do well, is it protects tyres well too. Stopping a litre bike sliding too much (you want some slide if you can get it, ala nice darkies), but you don't want the bike destorying the tyre too quickly. Especially with tyres as expensive as they are.

 

Bullet

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Yea that is the point I was getting at, when they advertise it as "it makes slower riders faster" then it isn't really benefiting the rider by learning how to control and feel bike without it first!

 

The other thing TC does do well, is it protects tyres well too. Stopping a litre bike sliding too much (you want some slide if you can get it, ala nice darkies), but you don't want the bike destorying the tyre too quickly. Especially with tyres as expensive as they are.

 

Bullet

 

 

 

Ah that I did not know!

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I remember following Hollywood around Silverstone South in 2009, and he was putting down a nice thin dark line from the chicane (after 'Club') to the 'Ireland' corner on the YZF-R1 2008(?). No tracking control here :)

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Secretly, we used to have little competitions in the crew, see who could leave the longest darkie. I once made it all the way from turn 1 at Rockingham all the way to turn 2 (before you braked), it was a good 250meters, and a gear change. :rolleyes:

 

 

 

Bullet

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Other folks out there, jump in! What specific things have you noticed that told you that you might be over- or under-loading your suspension, or possibly that your suspension is not set up correctly?

I'm riding a new bike this year and I had noticed a few times the bike would give a subtle "wobbly" feeling - the front and rear moving up/down at minutely different rates. I had not noticed, but later realized, the bike actually was running wide in the corners. These were issues I hadn't actually recognized as issues with the suspension - I had assumed it simply was how the new bike worked, or road conditions, or something I did to unsettle the bike.

I recently got with a local suspension tuner and we found most of my suspension settings were well off - I have since learned this is a common situation. Among the list of issues: the front was way too soft, front and rear rebound rates were incorrect and not uniform, and the rear was sitting too low. He spent about 45 minutes taking measurements and making adjustments (I should've taken notes rather than just observe) but I had to head home so we didn't get to fine tune the new baseline.

I learned on the brief ride home what a tremendous difference the new settings made. The bike felt completely different; vastly improved. I struggled to come up with the correct adjectives - precise, connected, harmonious... The bike felt more firm but not harsh and it tracked through the turns with precision - this is when I realized the bike previously had been running wide. It felt as though the suspension was smoothly moving up/down with the road surface without moving the rest of the bike (if that makes sense) - no more wobbly feelings.

I'll have the bike on the track again in a couple weeks and I'm very excited to see how it will handle.

 

 

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I learned on the brief ride home what a tremendous difference the new settings made. The bike felt completely different; vastly improved. I struggled to come up with the correct adjectives - precise, connected, harmonious...

Sounds like what I would describe as the bike being "on rails" around the corners. Absolutely precise and predictable steering.

 

Great that you got the tuner to help you fix it, Brad! It's an experience like this that made me a convert to adjusting and setting up the suspension on my bikes.

 

Kai

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Suspension adjustment is a great area to get into if you are the bookish, nerdy type. Personally, I love it! You can accomplish a lot on your own if you read a little and experiment. I recommend Andrew Trevitt's book on motorcycle suspension tuning as a superb introduction.

 

Generally, it starts with setting sag, measuring travel, and figuring out if you need to respring. Getting the spring rates right is the most profound thing you can do to your suspension, and you can't really compensate for incorrect springs by adjusting preload. After the springs and sag are correct you are on to damping. Once a person has a little bit of basic understanding of how to tune the damping adjustments, it is pretty straighforward to find a good setup.

 

The other thing to realize is that suspension adjustment is not an exact science - it includes a lot of rider preference. For example, some riders like a stiffer spring but lower compression damping, while others will prefer a softer spring, necessitating higher compression damping rates to limit travel over the bumps. It's this rider preference element that, IMHO, gives an advantage to those riders who are comfortable twiddling the knobs themselves and experimenting, rather than relying on someone else to help them find the "right" setup.

 

Last thing - suspension tuning, unfortunately, is a bit of an art. Lots of people who are good at it actually labor under some pretty severe misconceptions about what they are actually doing. For example, some really well known tuners will talk about "stiffening" the suspension by adding preload, which, physically, is 100% incorrect. That doesn't mean they won't be able to help you find a good setup, it just means that they don't actually understand the physics of what they are doing.

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