[Bloodshot]

I'm with Cujo, I still don't see how it's possible for you to "flat shift" faster than a clutchless upshift, or as some call it "power shifting". With a clutchless shift you're only blipping the throttle enough to let the shift lever push up into the next gear, it's happening for less than 1/4 of a second. The only way to shift faster would be a an electronic power shifter, and I'm even skeptical that it would be much faster than someone who is quick at clutchless shifting, barring human error that occurs at times.

 

[capww8]

i support both. However, flat shifting with a slight assist of the clutch lever (hand operated) is the faster of the two. I think the technique is somewhat misunderstood, so I'm going to throw in my own explanation.

when approaching peak of power band preload the shift lever (foot), then, whenever you're ready, brush the shift lever with one or two fingers. It takes very very very very little force, you really do just have to brush it. Don't let off the throttle at all. You'll just feel it drop into gear, the revs will drop a little, and you keep getting faster.

 

[Bloodshot]

You still have to brush the lever though. When clutchlessly upshifting you blip the throttle only long enough to slip the pre-loaded shift lever into gear. I can blip the throttle faster than my fingers could respond to any type of brushing of clutch lever. I still stand by what I said before, I don't see how it's physically possible for flat shifting to be faster.

 

[niuginisbk]

1 Ehh.. No, you don't. (That is what I've been trying to explain...)

2. Dream on...

3 Clutchless shifting is for street or racing. Therefore a lot more versatile.

/

1. You are backing flat changing with your explanation of clutchless shifting.
you said you throttle off when you want to change gear (1 action) then you re accellerate (2nd action)..........so i gotta give you back the "Dream on", not in this lifetime! (notice i haven't even put the knocking the lever in, that's simultaneous with the "throttle off")

2. I'd put money on it! Would you?

3. I use a combination of both on the street, so who's more versatile?

Seems like not many have tried this (or game enough to), try it & i'm sure you'll enjoy it.

 

[SteveG]

You still have to brush the lever though. When clutchlessly upshifting you blip the throttle only long enough to slip the pre-loaded shift lever into gear. I can blip the throttle faster than my fingers could respond to any type of brushing of clutch lever. I still stand by what I said before, I don't see how it's physically possible for flat shifting to be faster.

I shift without the clutch regularly, but have not tried this 'flat shifting.' I'm going to give it a go though, here's how it seems it could actually in fact ultimately be faster:

You never get off the throttle. That means that any energy that's diverted from the tranny/wheel when you brush the clutch to shift is in essence stored in the flywheel, and fed to the road at the end of the process. You've been adding power the whole time.

On the other hand, to shift clutchlessly, you need to reduce power. No matter what, because of this, for a given period of time, (even if the clutchless shift is faster), you've produced less power than you would have if you'd just kept it wfo. It's just physics...

This is not true if you're already at redline, and peg the rev limiter as a result of brushing the clutch, but in every other case, it seems to me that the flat shifting might actually be faster.

Having said that, clutchless shifting (if done properly) is almost certainly smoother, since the flat shifting will result in a slight surge in power as the clutch re-engages (even as minimal as the disengagement is). My guess is that the motogp folks use the ignition cutoff switch because a) they 80% fry their clutches just on the start and can't afford to further abuse them, b) it's smoother than brushing the clutch, c) if already at redline, they overrev the engine if they do the clutch-brush.

All guesses, but it sounds right to me...

 

[niuginisbk]

Steve,
Sounds like a fair analysis to me.

It's quite exciting, especially in the lower gears, if the road surface is powdery it can give you a big wheel slide into the next gear, or on a good surface in the right conditions, into 2nd & 3rd can result in one of those 2" of the ground wheelies which are really cool ;D

I love it ;D

BTW, Been doing it for 2 years & no signs of deterioration in the clutch operation.

 

[niuginisbk]

look at it this way.

Lets assign 1/10th of a second to each mechanical operation required to change gears.

Clutchless Upshifting
0.1sec Throttle off
0.1sec change gear
0.1sec throttle on

Total 3 tenths of a second

Flat Shifting
0.1sec brush clutch lever
0.1sec change gear

Total 2 tenths of a second,
cause i don't have to throttle on, i'm already FLAT STICK!!

Guess i win :

 

[Bloodshot]

nuigimonster you're missing the point, with clutchless shifting

 

[isc]

Hi- I'm a new '02 S4 owner and former racer (TZ250, CBR600F3, R6, GSXR1000), new to this board. Cool board- lots of good info and you guys all seem intelligent (not a normal attribute of motorcycle forums...)

Here's my 2cents on the clutchless upshift question, and keep in mind that I only scanned the comments so sorry if I'm repeating. My R6 racebike had a quickshifter on it, the rest didn't.

Clutchless upshifts are great if done at high rpms with a strong smooth motion, will not hurt the tranny, and need you to back off the throttle for a fraction of a second. Most racers do this.

Clutchless downshifts are a great way to trash your transmission. Almost no racers do this. Troy Corser does this and goes through a lot more transmissions because of it (WSB commentators said a few years ago). My engine builder told me not to do this.

There is no way in hell that you can upshift as fast without the use of a good quick shifter like KLS, but you had better be really good if you're going to spend $$$ on that because it'll only get you about 1/2sec per lap at a track like Willow Springs.

So, the points are, clutchless upshifts are good at high rpms, clutchless downshifts are bad, and no one is faster than a quickshifter set up properly. Or else the MotoGP bikes wouldn't have them, huh....

 

[niuginisbk]

Bloodshot,

 

[Cujo]

look at it this way.

Lets assign 1/10th of a second to each mechanical operation required to change gears.

Clutchless Upshifting
0.1sec Throttle off
0.1sec change gear
0.1sec throttle on

Total 3 tenths of a second

Flat Shifting
0.1sec brush clutch lever
0.1sec change gear

Total 2 tenths of a second,
cause i don't have to throttle on, i'm already FLAT STICK!!

Guess i win :

Correction. To use you own example...

Flat:
0.1sec Reaching for the clutchlever. (Moving your fingers from the handle bar, to the clutchlever)
0.1sec pull clutch lever
0.1sec change gear
-----------------------------------
total 0.3sec

Clutchless:
0.1sec throttle off, and upshift. (Don't have reach for anything.)
0.1sec throttle on.
---------------------------
total: 0.2 sec

This is my last post in this subject.
I'm not wasting any more time on a person that claims he can "outshift" GP roadracing professionals...

/

 

[niuginisbk]

Now where getting Coc ky eh.

Fingers already on the clutch lever "Super Shifter"

Calculate that!

 

[niuginisbk]

Furthermore........

You don't read real well Cujo, huh?

I said Flat Changing only applies to Straight line flat out (drag Racing) type riding,

You said ""outshift"

 

[Vasil]

Just came back form practicing clutchless up-shifting. Man its so addictive! I love it. I gotta have the feel for it, but its definately a very quick way to upshift. Its easier in the higher gears.

 

[niuginisbk]

Vasil,

 

[Bing]

There's a lot of argument here over techiques that will save you tenths of seconds. If you're an A-grade racer this could be valid but for the street I think it's pretty much up to the individual. At the track I'll often use clutchless upshifts but I always use the clutch changing down so I can match revs to speed as I enter the turn - it's also a poor mans slipper clutch technique.

Mind you my laptimes wouldn't bother a D grade racer so what would I know?

One more thing to think about. 5 time world GP champ **** Doohan didn't use a ignition cut-out for his gear changes. He used his clutch and rear brake (using the same hand remember - thumb rear brake) to control rear wheel spin and lock-up.

 

[test-reg]

I don't _really_ want to fan any flamewars, but I've got a question for you Chris, and a few comments to make too...

Chris, if you're holding the throttle pinned to the stop, then feathering the clutch, how much over-rev do you get, and how close to the optimal shift point can you get without risking reving past redline while the shift happens?

And a comment about the "load lever, quickly roll off and back on the throttle" technique - one of the reasons this isnt actually as quick as a "proper" quickshifter is that by even momentarily closing the throttle, you're slowing the air in the inlet manifolds down, which then needs to speed back up again when the throttle is re-opened. A quickshifter cuts either the sparks or the fuel (obviously youi can only do fuel quickly enough on injected bikes) while leaving the throttle wide open and the air flowing at maximum speed.

Chris? You _really_ should try to get a ride on a bike with a properly set up quickshifter, they're quite astounding when they're working well - a friend of mine reckons the quickshifter on his Formula Extreme R1 is worth about 2 bikelengths per gearchange down the main straight over good bikeracers with great technique but no technology to help them.

Of course, I've been known to use the "poor mans quick shifter", my poor little Honda Spada used to get the thottle pinned coming out of the last corner onto the straight, then I'd just apply upwards pressure on the gear lever and wait for the rev limiter to cut in, at which point the next gear would slot home - I'd then release pressure and re apply and wait again ;-)
(that actually wasn't the quickest way down the straight though, optimal gear change point was about 500rpm below the rev limiter on that bike...)

big

 

[niuginisbk]

Big,

 

[tex-mex]

I don't use the clutch upshifting or downshifting. If done correctly it's the smoothest possible way to shift. You have to be accelerating on the upshift. You can downshift as long as you aint accelerating. I wouldn't worry to much about 1/4 or 1/2 throttle twist, just flick your wrist. Practice.