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noamkrief

Downshifting While Braking

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Although I can shift clutchless up and down, I find that it takes all my attention to do smooth downshifts sans clutch. I have nothing left for braking or anything. It's one of the hardest things for me to do on a motorcycle. Operating the clutch and blipping the throttle while downshifting doesn't require any particular attention from me, which is why I stick with it.

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I guess with some practice it would get easier...? I will concur it takes more time to get the clutchless downshift right than the clutchless upshift...

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For me, it's not worth it. I've ridden perhaps 200 miles without using the clutch, but it doesn't get easier. I tense up, concentrate like crazy and still only get it perfect 2 out of 3 times. Just not coordinated enough. And if Pedrosa can win races using the clutch, I surely can stroll around on the local backroads using the clutch :D

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For me, it's not worth it. I've ridden perhaps 200 miles without using the clutch, but it doesn't get easier. I tense up, concentrate like crazy and still only get it perfect 2 out of 3 times. Just not coordinated enough. And if Pedrosa can win races using the clutch, I surely can stroll around on the local backroads using the clutch :D

 

My good friend says its a very good technique to have if your clutch cable goes kaput... :mellow:

 

At least you can still ride it back to the repair shop :rolleyes:

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Yes, the majority of my training stems from a non-functional clutch release :D It's quite easy to ride sans clutch if you use low rpm and concentrate a bit, but it's not an action I can combine with other stuff like braking hard or changing direction.

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It is no necessity but good to know as pointed out.This is how i do it.Ready your foot by keeping on the gear lever,roll off gas.Blip.In the highest part of the blip ie the max throttle, press down.It will be smooth and you will keep going like nothing happened.The timing has to be proper or the bike will jerk forward/not shift.

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It is no necessity but good to know as pointed out.This is how i do it.Ready your foot by keeping on the gear lever,roll off gas.Blip.In the highest part of the blip ie the max throttle, press down.It will be smooth and you will keep going like nothing happened.The timing has to be proper or the bike will jerk forward/not shift.

 

In that sequence you can actually complete the clutchless downshift as part of the initial roll off, its not really a track technique but for street riding I do 95% of my shifting clutchless and about 2/3's of my downshifts are with a roll off instead of a blip

 

Tyler

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I guess when you are cruising about it won't matter if the revs rise when you downshift with a roll off but when you are racing it could cause problems...

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The slipper clutch modification that was mentioned above is just to remove one of the springs so there are only 2 instead of 3. This allows the slipper to "slip" easier and do it's job. That's what most of the R6 racers do.

 

I have thought about doing that to my R6 but I would personally rather build the skill then rely on mechanical parts to help me with my lack of skill in a specific area. I am in the same boat as you, except my main issue is the timing and losing RPM/speed because I am too late getting the clutch back out after the blip. It's almost like my brain says "what were we trying to do again"? lol

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I don't cruise about, only own a race bike and BIR is a fast course....not the track you want to learn clutchless downshifting on when you are coming out of turn 2 in 6th gear and braking/ downshifting for turn 3.

 

I think my bigger issue is I am coming up to my corner and I have my braking point established, I apply the front brake but I don't downshift until roughly halfway to 3/4 of the way through my braking so now I am almost to my turn point and rushing to grab gears which further increases my timing mess up and coordination because now I am trying to accomplish too many things at once.

 

In my notes for the next trackday I am going to work on downshifting before the braking or right when the braking starts. This way I don't have to blip the ###### out of the throttle to match the RPM's to wheel speed because I waited too long after braking.

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Are you saying your bike is not street legal? Because you have a slipper, get the downshifting done and focus on your entry speed instead.Remember you can downshift with a roll off also...

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I don't cruise about, only own a race bike and BIR is a fast course....not the track you want to learn clutchless downshifting on when you are coming out of turn 2 in 6th gear and braking/ downshifting for turn 3.

 

I think my bigger issue is I am coming up to my corner and I have my braking point established, I apply the front brake but I don't downshift until roughly halfway to 3/4 of the way through my braking so now I am almost to my turn point and rushing to grab gears which further increases my timing mess up and coordination because now I am trying to accomplish too many things at once.

 

Didn't you self-diagnose right there?

 

If you feel rushed, back a bit off like on the CSS drills; build the right technique in at a lower speed and only then increase the speed.

 

What about trying to start down-shifting about 1/2 half through the braking? would this make you feel less rushed?

 

Downshifting before braking (without a slipper) would send the engine into a lot of RPMs, and possibly over-rev it (or lock up the rear wheel).

Does this sound right to you?

I think that this article by Keith is exactly what you need: Brake/down.

 

Kai

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No, I am saying that maybe you should do all hard braking first (full braking force to reduce a gross amount of speed quickly) and start with downshifting only during the last phase of braking (softer braking force just to adjust the entry speed), which should never be 100%.

 

From Chapter 24 - Efficient Braking of A Twist of the Wrist 2:

"Trapping yourself into heavy braking at your turn-point is working against the desired result. The basic product (end result) of braking is to get the speed set accurately for the turn."

 

If I can use softer braking force during the last phase of braking, it only means one thing. It means that I could have braked later and used 100% braking force (until the trailing zone begins).

 

There is the same problem with cars which is better documented since there are alot more books about driving fast than riding.

 

In a car, the technique is called heal and toe. While braking, you use the right side of your foot to blip the throttle for the downshift.

The books and multiple authors are aware and note that the driver's ability to maintain constant brake pressure while blipping the throttle is reduced. For experienced racers it's less of an issue, but it ALWAYS IS. So if I'm in a car without ABS braking at 100% and I blip the gas, I would personally err on the safe side and release 5% pressure off the brakes while blipping. Because if I screw up and accidentally apply an extra 1% of brakes, my wheels will lock. So going from 5th gear to 2nd, I blip 3 times in a car and each blip I go to 95% of max brake which costs about 1/10's of a second for that particular zone.

 

So the authors recommend skipping gears in a car which allows the driver's right foot to focus 100% on the braking force and the sensitivity it requires in order to achieve 100% brakes...

 

 

I rode my BMW Hp4 the other day and slowly started testing out its slipper clutch. I can do 80mph, pull in the clutch, RPMS at idle, pop to 2nd gear and JUMP off the clutch, it I barely feel anything. It sounds just as if I SLOOOWLY released the clutch. So you're right - my r6 slipper clutch stinks.

 

I'm all about blipping while braking and 95% of the time I do it pretty good. 4% I mess up and 1% I totally screw up and fail to blip at all - for that, it would be nice to have a good slipper to save my butt.

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There is something that could be causing confusion with the terminology "100% braking". As the bike slows down, the amount of brake lever pressure required to maintain the same rate of deceleration decreases. So, a rider that is paying attention to that will be tapering off pressure on the brake lever as the bike slows. So, while I think noamkrief intends "100% braking" to mean maximum possible braking force allowed by the traction conditions, someone else might think he means squeezing the brake lever as hard as possible.

 

Presumably, and rider that is INCREASING brake lever pressure all the way to the turn point is doing it because SRs are kicking in hard!

 

At CodeRACE there is a brake/downshift drill that actually MEASURES your braking so you can look at graph to see how consistent you stayed while downshifting and blipping - and compare it to the chart of the ideal, which is Will doing it. :)

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Also, in response to the above poster about slipper clutches and blipping - thats what I have unfortunately gotten accustomed to doing with my slipper. .. However, I have been admonished that I should still be blipping on the way down (even with the slipper) to match revs to the gear. Basically the slipper while able to not throw you off or lose you traction, its purpose is not to match revs while downshifting and you're always better off to match revs while downshifting or downshifting/braking.

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...late to the party here but my experience is you can still get rear wheel hop with a slipper clutch. Once I learned this soon after installing one I rode like I didn't have a slipper clutch and blipped like I did beforehand. The slipper is now used as my "margin of safety" and it has been an effective approach for me; YRMV. Rain

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There is something that could be causing confusion with the terminology "100% braking". As the bike slows down, the amount of brake lever pressure required to maintain the same rate of deceleration decreases. So, a rider that is paying attention to that will be tapering off pressure on the brake lever as the bike slows. So, while I think noamkrief intends "100% braking" to mean maximum possible braking force allowed by the traction conditions, someone else might think he means squeezing the brake lever as hard as possible.

 

Presumably, and rider that is INCREASING brake lever pressure all the way to the turn point is doing it because SRs are kicking in hard!

 

At CodeRACE there is a brake/downshift drill that actually MEASURES your braking so you can look at graph to see how consistent you stayed while downshifting and blipping - and compare it to the chart of the ideal, which is Will doing it. :)

 

Thanks for clarifying :) I indeed meant 100% according to traction. I believe if any of us pressed as hard as we can on the brake lever, the bike would either lock the front (if applied too abruptly) or the rear will come up over the front of the bike and the rider fly over the handlebars. So obviously - yes - 100% of the capability of the bike.

 

If I understand correctly, unlike in a car which you can easily exceed the traction of the tires under braking where either the ABS kicks in or if no-ABS, the tires skid, on a motorcycle with decent track slicks the limit of the tire is actually never reached. Assuming you properly load the front. the rear of the bike will start coming up. This will almost always under dry conditions with good tires be the first thing that will happen. At this point, if you brake harder, the rear will come up higher and higher until it can just go over the front. Ideally, max brakes is when the rear tire is just barely off the ground - maybe 1/8th of an inch. In racing like motogp they seem to not brake at 100% but more like 98% leaving if I had to guess about 5lbs of weight on the rear tire because if the rear is off the ground, risk in increased and the bike become more unpredictable than it already is.

 

The longer the wheelbase of the bike, and the lower C.G., more forward G's have to take place before the rear starts lifting off the ground (100% braking).

That's why in a documentry about motoGP I saw called "fastest" one of Rossi's techs states "max braking of a bike is 2.5G's". He's not speaking of what the tires are capable of, but he knows the wheelbase and C.G. of the Yamaha and can tell you at 2.5 forward G's of deceleration, the rear end comes off the ground at which point, you can't brake any harder (unless of course the rider can scootch his butt farther back on the seat which is very limited because the arms still much reach the handlebars).

 

I am going to install my data acquisition system from my racecar onto my bike and will be able to see on the laptop how consistent my braking force is while blipping the throttle. I'm certain I'm not reaching 100% because my rear end doesn't feel weightless under braking.

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A motorcycle cannot stop better than 1G at lower speeds. Well, I've seen some ABS equipped bikes marginally get beyond 1G thanks to superb ABS, sticky tyres and long wheelbases along with high tration asphalt. Race reps cannot reach one G because they will flop over before that limit.

 

However, at highers speeds, wind resistance helps immensely. I don't know the figures, but at 350 kph I wouldn't be surprised to learn that it was in the region of 1.5G from drag alone. Formula 1 can brake with about 5G from higher speeds, which is pretty spectactular. They can also corner with 5G. No wonder you cannot build a motorcycle to get close to an F1 car around a track ;)

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With all the ABS generations I've seen student on, we could always get the rider to stop the bike in a shorter distance by not engaging the ABS. Well, assuming that the rider was well trainable, that is :)

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That BMW, I think it was a K1300R, is the only bike I know of where the MOTORRAD test rider couldn't beat the ABS no matter how many attempts. But generally, manual control by a splendid rider can out-do the ABS - on a track under conrolled conditions and after a couple of attempts.

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Eirik,

 

These were ordinary riders, coming to a traffic safety course like the ones that NMCU does. Not just "splendid" riders. Sure, this was during braking drills in a closed area. We encouraged all riders with bikes equiped with ABS to brake so hard that the ABS engaged, so they got comfortable with how the bike/ABS system reacted. Once they could do that, we encouraged them to back off just enough for the ABS to not engage. I had many students volunteer to me that they were surprised that they got a shorter stopping distance without the ABS engaging. One student told me that his Triumph Owner's Manual claimed that this was "impossible" and the manual encourage the rider to alway rely on the ABS.

 

:rolleyes:

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That doesn't sound right about the manual, unless it was written by the tea boy. I don't think anyone ever claims that ABS will reduce your stopping distance, it simply gives you more control and the ability to continue to add steering input without locked-up tyres.

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Kai, how quickly did they stop and from what speed? IIRC, the K1300 stopped in 35.8 metres from 100 kph with the ABS.

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