Clutchless shifting
Road Warrior
Joined: Jul 2007
Posts: 1,898
Likes: 67
From: Saint Amant, Acadiana
I happen to know very well how gearbox - any gearbox - works. The very idea of gearbox is to adapt the working range of engine to the actual speed of vehicle. Regardless how many steps a gearbox has they still are steps. Which means RPM of the engine is gradually changed while switching thru gears which it is not the case with variator transmission for instance. Thus, when changing the gear ratio instantly the RPM of engine has to change in same instant - which contradicts all what mankind knows about physics.
Furthermore, whoever said racers do it all the time ... I'd really ask what kind of racing we are talking about?
In closed circuit racing where one accelerates out of turn while still leaning a clutchless gear change will result in a highsider with certainty. MotoGP, Superbike, etc. all use clutch, although sometimes it is automatic when switching up.
Stellar HDF Member
Joined: Oct 2010
Posts: 2,601
Likes: 189
From: east texas
Can we discuss it, please? Without getting excited?
I happen to know very well how gearbox - any gearbox - works. The very idea of gearbox is to adapt the working range of engine to the actual speed of vehicle. Regardless how many steps a gearbox has they still are steps. Which means RPM of the engine is gradually changed while switching thru gears which it is not the case with variator transmission for instance. Thus, when changing the gear ratio instantly the RPM of engine has to change in same instant - which contradicts all what mankind knows about physics.
Furthermore, whoever said racers do it all the time ... I'd really ask what kind of racing we are talking about?
In closed circuit racing where one accelerates out of turn while still leaning a clutchless gear change will result in a highsider with certainty. MotoGP, Superbike, etc. all use clutch, although sometimes it is automatic when switching up.
I happen to know very well how gearbox - any gearbox - works. The very idea of gearbox is to adapt the working range of engine to the actual speed of vehicle. Regardless how many steps a gearbox has they still are steps. Which means RPM of the engine is gradually changed while switching thru gears which it is not the case with variator transmission for instance. Thus, when changing the gear ratio instantly the RPM of engine has to change in same instant - which contradicts all what mankind knows about physics.
Furthermore, whoever said racers do it all the time ... I'd really ask what kind of racing we are talking about?
In closed circuit racing where one accelerates out of turn while still leaning a clutchless gear change will result in a highsider with certainty. MotoGP, Superbike, etc. all use clutch, although sometimes it is automatic when switching up.
well said , kinda like all engineer's.."It works in my mind , and on paper"
"any gearbox" ??? there are more than a few ..dogshift, syncromesh,open ,keywaydrive, some move actual gears, some dont
"A helicopter cannot fly" ," neither can a hummingbird".(engineering 101)
however , if you have the slightest mechanical feel, and understand the physics of a constant mesh trannny, any can be shifted clutchless without harm .
It does take the understanding of the machine ..
yes you can clutchless shift while leaning without highside .
But it requires a ability to understand the machine ..just not the theory...books are fine , theory is fine ..
"what part of "blipping the throttle" confuses you ?.
last I checked ,that changes, maybe matches the rpm for seamless shifting....go figgure
I am out of this discussion ,,,no winners...every one have a good one.
Last edited by heybaylor; Apr 16, 2011 at 07:37 PM.
Road Warrior
Joined: Jul 2007
Posts: 1,898
Likes: 67
From: Saint Amant, Acadiana
however , if you have the slightest astronomical feel, and understand the physics of a solar system, all of the planets, including the Earth are flat .
It does take the understanding of the planet system ..
yes you can sail to the edge of Earth without falling over the edge .
But it requires a ability to understand the planet ..just not the theory...books are fine , theory is fine ..
It does take the understanding of the planet system ..
yes you can sail to the edge of Earth without falling over the edge .
But it requires a ability to understand the planet ..just not the theory...books are fine , theory is fine ..
Cruiser
Joined: Feb 2010
Posts: 187
Likes: 1
From: north cak
I do it when cruising with only my hand on the throttle and feeling lazy .. so long as you feel it out and get used to it , there is no difference in the feeling between clutch and clutchless shifting .. my .02
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
Well we've wandered off topic here, which was to be expected. I have been using clutchless changes on the road for about 40 years. The technique works best on the road with close ratio transmissions, as the change in engine speed required is relatively less. On a loose surface, riding a dirt bike, the dirt will give the rider a helping hand, but the bike probably has a close-ratio set as well.
In my experience the technique is less suitable for Harleys, largely because they have a fairly wide-ratio transmission. The change from first to second is not something I would normally try, indeed I normally only skip the clutch changing into top gear (my Harleys are all five-speed).
Despite all the debate there is absolutely no reason for not riding with clutchless changes, they simply require a little skill. But then that can be said of using the clutch!
In my experience the technique is less suitable for Harleys, largely because they have a fairly wide-ratio transmission. The change from first to second is not something I would normally try, indeed I normally only skip the clutch changing into top gear (my Harleys are all five-speed).
Despite all the debate there is absolutely no reason for not riding with clutchless changes, they simply require a little skill. But then that can be said of using the clutch!
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