no-clutch shifting?

[elkroeger]

Poking around on Wikipedia, I came across this statement about shifting the sequential transmission without using the clutch: "Engagement using dogs only requires a very brief interruption of engine torque to complete a shift into any adjacent gear. This allows shifting between gears without the use of the clutch. The clutch would normally be used only for standing starts."

 

Linky

 

I taught myself to ride, so I might be in the dark on some finer points. I've never heard of this. Although I've probably done it once or twice on accident, I use the clutch every shift, just like my dad taught me in the VW. Am I the only one? Can I really shift to my heart's content and ignore the clutch most of the time? Isn't it hard on the gearbox?

 

 

[Witch_Doctor]

Lots of debate on that. I pre-load which takes very little clutch, and on some occassions, usually in 2nd to 3rd, if I pre-load a bit more than normal it will shift without the clutch. I don't make it a practice, though I don't know that it is really an issue. Takes really good timing to do it right. Will be interesting to hear others thoughts.

[BubbaLa]

oh boy- let the flames begin...

i up shift to,4th,5th and 6th all the time.

preload the shifter and blip the throttle.

down shifts are a whole different deal.

it can be done, but much more timing and engine revving to match speed is needed.

by the way i first learned this on my '64 vw bug.

[Firefight911]

It's completely fine to do.....just go look a the K1300S and/or the S1000RR. They have the shift feature there that does the whole thing for you just be upshifting.

 

I've been doing it as long as I can remember.

[Boffin]

Disclaimer - the handbook for my 1150RT states that the gearbox is not suited to clutch-less changes:

 

I routinely change up the box without the clutch. Just a brief 'dip' in the throttle as it push up on the lever. This will give the smoothest gear changes you have ever got on your Beemer.

 

Down changes take more (crunchy) practice. I can now easily change down without the clutch - opposite to the up-change. push down on the lever and rev-up the engine at the same time. More likely to cause damage this way.

 

I taught myself these tricks in an old Vauxhall (GM) car that ate clutch cables for breakfast.

 

Andy

[eddd]

...I've been doing it as long as I can remember.

 

Me too, but my memory is only good for a couple of days...

 

If I remember correctly.

 

 

On a more serious note, the information provided isn't totally correct. On our big tanker truck I only use the clutch to start and when I stop. It has what the article refers to as a H pattern transmission, but with a high and low range where you start the pattern over after switching into a different range. For drivers of big trucks the clutchless method is the norm for H pattern transmissions.

[ltljohn]

What would be the advantage of clutch-less shifting to the average rider?

[Joe Frickin' Friday]

What would be the advantage of clutch-less shifting to the average rider?

 

All I can think of is less wear and tear on the clutch cable/hydraulics, and less wear on the clutch friction material. However, I imagine the benefit here for the average rider to be rather small. Any other benefits?

 

I'd be more concerned about additional wear and tear from impact loading on the gear box - especially on a big twin bike with a big flywheel from which one hopes to extract 100,000+ miles of reliable operation. It's less of an issue on (for example) a short-lived F1 race car with a V-10 engine that has a tiny, tiny flywheel resulting in miniminal engine inertia.

 

As Andy hints, it definitely is a useful thing to know about when your clutch cable/hydraulics crap out miles from home, and I've had this happen to me as well. I tried to make shifts at very low RPM, where the change in RPM from one gear to the next was minimal, resulting in the least stress on the gear box. When you're just about to come to a stop you can shift into neutral. To get rolling again, you either:

 

A) kill the engine, put it in first and then crank the starter. You'll have to pull the clutch lever for the starter to run. It'll lurch and buck at first, but it should get moving to the point where you're idling down the road in first gear.

 

OR

 

B) leave it in neutral, dismount; push the bike up to a reasonable forward speed, then jump aboard and shift into first gear. This is probably easier on the drivetrain than option A, but it's also a lot riskier, since it involves awkwardly jumping aboard a bike that's already rolling forward.

[upflying]

I snapped a clutch cable on a HD some years ago. Rode 15 miles to a dealer without using the clutch. Stopping for signals was a PITA.

As I slowed to a stop, I snicked neutral. After coming to a stop, shut the engine off and hit first. When the light turns green, I used the starter motor to get me going.

[outpost22]

All of my race bikes were mostly shifted clutchless, except on starts where you didn't want to suffer any kind of "bog" while shifting. On the starts, the clutch was "bumped" just enough to keep the engine revs up. A "bog" would result in losing at least 5-6 places to the first turn.

 

My KTM's were the worst though as they refused to upshift under power clutchless with any uphill situation. They have probably gotten better over the years. The nice part was that these old race bike trannys could be taken out of the bike and torn down in very little time. My old Bultaco Pursang could be "unframed" and down to the shift drums in 30 minutes. Unfortunately, this was a common occurrence. The most time was spent draining the gearbox oil.

 

I don't shift clutchless anymore except sometimes off road due to hidden obstacles. Preloding the shifter and barely bumping the clutch on the boxer makes for a very smooth shift with very little effort. The Rotax single takes almost no effort to shift regardless of method.

 

As far as clutch slippage, if you are matching revs/shifting, I don't think much clutch slippage even occurs, and figuring that a gearbox is probably one of the most expensive parts of these bikes to fix, I'll error on the safer side.

[Tank]

I snapped a clutch cable on a HD some years ago. Rode 15 miles to a dealer without using the clutch. Stopping for signals was a PITA.

As I slowed to a stop, I snicked neutral. After coming to a stop, shut the engine off and hit first. When the light turns green, I used the starter motor to get me going.

 

 

Bingo.... weather you use the technique or not , one should learn the technique for just this reason . I lost a slave cyl. a couple hundred miles from home and it was no big deal getting home, though I did ruin the clutch with fluid.

[Polo]

I snapped a clutch cable on a HD some years ago. Rode 15 miles to a dealer without using the clutch. Stopping for signals was a PITA.

As I slowed to a stop, I snicked neutral. After coming to a stop, shut the engine off and hit first. When the light turns green, I used the starter motor to get me going.

 

I've driven cars like that also out of necessity. I know it can be done, but I just don't see a significant advantage in comparison to the even remote possibility of damage to the transmission.

[Mister Tee]

I did not shift my 1200RT without the clutch. The ratios are too wide to shift smoothly. I have no issues shifting either my GSXR or Concours C14 clutchlessly, up or down.

 

Done properly there is absolutely no difference between clutch and clutchless shifts in a constant mesh transmission (this is NOT true of a sliding gear transmission in a car or truck.) Done improperly you can do some damage. Upshifting is relatively easy to do properly. Downshifting is not. You have to do a "reverse blip", i.e. add a little throttle to unload the transmission, shift, then back off the throttle.

[Jim Moore]

I tried to make shifts at very low RPM, where the change in RPM from one gear to the next was minimal, resulting in the least stress on the gear box.

 

As a quick note, you'll find it is easier to shift without the clutch at high rpm, while accelerating. Clutchless shifting at low rpm and/or steady-state speed is more difficult.

 

You naysayers should give it a try. It's fun and cool!

[GunshipDriver]

They taught this at the Keith Code Total Control Clinic I attended a few years back... They talked about how it could be advantageous during acceleration.. but they did not reccomend it for downshifting.

[Polo]

I tried to make shifts at very low RPM, where the change in RPM from one gear to the next was minimal, resulting in the least stress on the gear box.

 

As a quick note, you'll find it is easier to shift without the clutch at high rpm, while accelerating. Clutchless shifting at low rpm and/or steady-state speed is more difficult.

 

You naysayers should give it a try. It's fun and cool!

 

I limit my risk-taking at going to breakfast with MARK GOODRICH. He forgets his wallet 3 out of every 4 times. Come to think of it, I have spent enough for a new transmission already...

[ShovelStrokeEd]

They taught this at the Keith Code Total Control Clinic I attended a few years back... They talked about how it could be advantageous during acceleration.. but they did not reccomend it for downshifting.

 

The drag racing guys have an interesting setup whereby there are springs within the shift drum such that whenever a higher gear would transmit more torque than the lower gear, the transmission if prompted by an external force on the shift lever (air cylinder) upshifts without the need of ignition kill or blipping the throttle. A 5 speed automatic is worth better than 0.1 seconds in 1/4 mile acceleration. Not practical at all for street use as backing off the gas will cause the transmission to try to go into 2 gears at once with the corresponding carnage.

[James Clark]

They taught this at the Keith Code Total Control Clinic I attended a few years back... They talked about how it could be advantageous during acceleration.. but they did not reccomend it for downshifting.

 

The drag racing guys have an interesting setup whereby there are springs within the shift drum such that whenever a higher gear would transmit more torque than the lower gear, the transmission if prompted by an external force on the shift lever (air cylinder) upshifts without the need of ignition kill or blipping the throttle. A 5 speed automatic is worth better than 0.1 seconds in 1/4 mile acceleration. Not practical at all for street use as backing off the gas will cause the transmission to try to go into 2 gears at once with the corresponding carnage.

 

They bevel the backsides of the dogs on the gears and clearance the drum to allow the previous gear to slide out of engagement of their own accord. The damage is done when your shift drum is trying to hold a gear while the dogs are trying to force the gear out of engagement.

[terryofperry]

Wow! 5 speed in a quarter mile. We ran a 2 speed Powerglide. 5 speeds must have been fun.

 

Terry

[ShovelStrokeEd]

They taught this at the Keith Code Total Control Clinic I attended a few years back... They talked about how it could be advantageous during acceleration.. but they did not reccomend it for downshifting.

 

The drag racing guys have an interesting setup whereby there are springs within the shift drum such that whenever a higher gear would transmit more torque than the lower gear, the transmission if prompted by an external force on the shift lever (air cylinder) upshifts without the need of ignition kill or blipping the throttle. A 5 speed automatic is worth better than 0.1 seconds in 1/4 mile acceleration. Not practical at all for street use as backing off the gas will cause the transmission to try to go into 2 gears at once with the corresponding carnage.

 

They bevel the backsides of the dogs on the gears and clearance the drum to allow the previous gear to slide out of engagement of their own accord. The damage is done when your shift drum is trying to hold a gear while the dogs are trying to force the gear out of engagement.

 

Exactly. If you are lucky and only back off for a tiny period, you'll only bend the shaft on which the shift drum rides (I carried a couple of spares). Do it for a little longer and the transmission will lock up and either shell gears, blow cases or skid the rear tire, not likely with a hot 10" wide rear slick. It ain't pretty nor is it much fun to ride the bike considering there is very little time in a run when you are under 100 mph (A little longer than 2 seconds on my bike)

[ShovelStrokeEd]

Terry,

Easy as pie. Dump clutch, hit button 4 times. In my case, I didn't even have to dump the clutch as I had a slider clutch that worked more or less like a go cart clutch. I just let go of one button, moved my thumb to the other button and hit it. Once I got the chassis right, a circus monkey could have ridden the bike. While I was learning, things got a bit more interesting.......

[Jack Herbst]

 

sheeeeeze Ed 11525 posts? You need to get a life of your own and get out from behind that computer! It'll ruin your health.

 

Jack

[ShovelStrokeEd]

sheeeeeze Ed 11525 posts? You need to get a life of your own and get out from behind that computer! It'll ruin your health.

 

Jack

 

Tee Hee! When you average it out over 8 years it ain't so bad.

Trust me, I'm looking for a less eventful life by this point. Been averaging the rest of my life out for 69 years. Some years a bit more interesting than others.

[Fubar]

On a more serious note, the information provided isn't totally correct. On our big tanker truck I only use the clutch to start and when I stop. It has what the article refers to as a H pattern transmission, but with a high and low range where you start the pattern over after switching into a different range. For drivers of big trucks the clutchless method is the norm for H pattern transmissions.

Yup, the clutch is only used when stopped in tractor-trailers, otherwise, up shifting, grab a gear, ease the throttle a split second and go, same with range changes. Downshifting requires rev-matching but is otherwise the same. They even have air-shifters to do the work for you.

On my old bike I occasionally shifted up w/o clutch, usually by accident. Always felt odd and like others I could see no real benefit to doing so.

These are not the same as the new cage sequential trannies like Porsche's PDK, et al.