DCT Transmission Clunky

[AsureDawn]

I dunno, when I drove my brother's standard trans suzuki sedan I was shifting smooth as butter, despite only having driven manual dirt bikes and automatic cars before.

Edit: interesting youtub vid, dunno how accurate it is, but it looks about right to me.

 

[davidc83]

How this thread went from a normal clunky dct shifting to what is or is not a automatic transmission?????
As I tell people, the DCT is not an automatic, it has not one but 2 clutches but the operator doesn't have to use the clutches, the bike uses them itself...

 

[670cc]

I present evidence straight from the manufacturer. Honda calls the DCT in their 670cc motorcycles an automatic transmission. Refer to the description of the transmission from the CTX700 page from the Honda Powersports a Web site. 2016 CTX700 DCT Overview - Honda Powersports. There are many other examples from Honda, but that was the first page that popped up in the search.

I will quote the page just in case it's not clear. "The CTX700 offers an automatic transmission and ABS version . . ." And if there is any point made that this is a CTX and not an NC700, rest assured it's the same transmission.

 

[Nofear2trek]

Again, to the lay person any transmission that shifts automatically is an automatic transmission. That is incorrect.

Actually...it is correct. The definition of an automatic transmission is:

An automatic transmission is a type of motor vehicle transmission that can automatically change gear ratios as the vehicle moves, freeing the driver from having to shift gears manually. (Notice, smoothness of the function is not a disqualification.)

Perhaps this article from Automotive News can shed some light on the subject...

Actually not because it was concerned about 'smoothness' of one design of automatic transmissions over another design and not the basic defined functionality.

'would change gears just as smoothly and behave exactly the same as a regular hydraulic automatic transmission.'

The issue is that the lay people <think> they have a smooth shifting, torque converter equipped, fluid drive transmission (the definition of an automatic tranny) but they don't.

As shown above, this definition is incorrect.

All torque converter equipped, fluid drive transmissions are automatic transmissions, but not all automatic transmissions are torque converter equipped, fluid drive transmissions.

We have the clunking one.

Ray

 

[Deleted member 5383]

[video=youtube;nAmqP6hStds]https://www.youtube.com/watch?v=nAmqP6hStds[/video]

 

[Nofear2trek]

[video=youtube;nAmqP6hStds]https://www.youtube.com/watch?v=nAmqP6hStds[/video]

Just another confirmation, never bet on red.

Ray

 

[ld_rider]

We have the clunking one.

If it were an automatic transmission and not a manual that shifted automatically, those clunks would disappear ;-)

 

[lootzyan]

How this thread went from a normal clunky dct shifting to what is or is not a automatic transmission?????
As I tell people, the DCT is not an automatic, it has not one but 2 clutches but the operator doesn't have to use the clutches, the bike uses them itself...

Basically, you're telling people, the DCT is "an automatic non-automatic"... (or maybe opposite?).

 

[lootzyan]

If it were an automatic transmission and not a manual that shifted automatically, those clunks would disappear ;-)

And why is that?
Clunks or noises are coming from the inside of transmission and are by design. Engineers easily could design quieter transmission but two factors are against it: cost and compactness of such transmission. This is just for NC (CTX) platform and not for Mars rover or Lamborghini.

 

[Nofear2trek]

I present evidence straight from the manufacturer. Honda calls the DCT in their 670cc motorcycles an automatic transmission.

Err....never mind. (I'm just a bit grumpy from age and bored because it just won't stop raining out here on the Oregon coast and I have too much time on my hands.) I stated my case, others mileage may very. No more beating this dead horse from me.

Ray

 

[ste7ios]

It's futile to compare motorcycles with cars. Motorcycles will always be behind by far in technology. No space, more challenging physics, a niche market (less profitable) and more is the reason...

The lights, the charging system, various electronic systems (ABS is an exemption), the transmission are only some examples of primitive technology...

It's a miracle that Honda put a DCT in a such small package, even clunky... Also BMW's Adaptive Headlights is a state of the art HID headlight, and it was possible because there is some space in K1200s.

 

[ld_rider]

And why is that?

Automatic transmissions have no mechanical connection to the engine and instead use a fluid coupling (torque converter). Manual transmissions use a clutch (or two!) and create an actual mechanical connection between engine and drive wheels. Imagine riding your motorcycle while sitting on an oak plank compared to say an Airhawk filled with gel. You will probably experience less harshness on the Airhawk.

The fluid coupling found in automatic transmissions will have a similar effect on driveline smoothness and shifting.



The torque converter (by its design) also allows "slippage" between the engine and drive wheels. That slippage is controlled by the torque converter's "stall speed" and determines how and when the power from the engine will be delivered to the drive wheels. All automatics must have some slippage otherwise the engine couldn't run when the car is in Drive and stopped. Once an automatic transmission vehicle get moving a certain speed, there is a mechanical "lock up" that creates a direct connection to the engine and drive wheels just as the manual transmission has. The difference is the lock up isn't in play when the transmission is shifting, only when cruising. The result is smooth, quiet shifts.

Because of that slippage, the fluid coupling between engine and drive wheels, and a few other mechanical differences, automatic transmissions are smoother in their power delivery than manual transmissions. That is the number one complaint with all these DCTs...People expect automatic transmission smoothness and are disappointed with how these manual transmission actually perform.

The reason is because the clutch isn't as forgiving as the fluid coupling and the result is a lot of noise, jerking, roughness, etc when shifting.

Ford has been sued multiple times over the harsh behavior of their DCT because lay people thought they were purchasing an automatic transmission with typical automatic transmission NVH characteristics. Instead, they were rudely awakened to the inherent harshness of the manual transmission that is in their shiny new Focus or Fiesta PowerShift "automatic".

 

[ld_rider]

Err....never mind. (I'm just a bit grumpy from age and bored because it just won't stop raining out here on the Oregon coast and I have too much time on my hands.) I stated my case, others mileage may very. No more beating this dead horse from me.

Ray

Ray, I think your idea might have legs, don't give up on it ;-)

IT’S a cliche so worn, it’s almost comical — women are bad drivers.

That old stereotype is at the centre of a potential billion-dollar class action case against Ford over 70,000 allegedly dodgy cars.
Thousands of disgruntled Ford customers will begin legal proceedings today against the company, accusing it of misleading and
deceptive conduct in selling 22 different models of Fiesta, Focus and EcoSport vehicles between 2011 and this year.

The affected models are equipped with the Ford PowerShift transmission, which promises to deliver “acceleration much smoother
than a conventional automatic”. “The dual clutch transmission has some of the features of a manual gearbox
but it drives like an automatic,” AutoExpert’s John Cadogan said.

“It’s meant to function exactly like an automatic.” But cars with Ford PowerShift transmission have been nicknamed “shutterboxes”
by unhappy customers because they shudder and jerk unexpectedly.



The above was posted in June 2016 and goes on to say that Ford blamed the women for "not having the skills" necessary to operate
the transmission properly. No, I'm not going to touch that one ;-)

 

[Mi_ka]

True automatic motorcycle



that novelty false automatic NC proves that
They Don't Make Em Like They Used To

 

[lootzyan]

Automatic transmissions have no mechanical connection to the engine and instead use a fluid coupling (torque converter). Manual transmissions use a clutch (or two!) and create an actual mechanical connection between engine and drive wheels. Imagine riding your motorcycle while sitting on an oak plank compared to say an Airhawk filled with gel. You will probably experience less harshness on the Airhawk.

The fluid coupling found in automatic transmissions will have a similar effect on driveline smoothness and shifting.



The torque converter (by its design) also allows "slippage" between the engine and drive wheels. That slippage is controlled by the torque converter's "stall speed" and determines how and when the power from the engine will be delivered to the drive wheels. All automatics must have some slippage otherwise the engine couldn't run when the car is in Drive and stopped. Once an automatic transmission vehicle get moving a certain speed, there is a mechanical "lock up" that creates a direct connection to the engine and drive wheels just as the manual transmission has. The difference is the lock up isn't in play when the transmission is shifting, only when cruising. The result is smooth, quiet shifts.

Because of that slippage, the fluid coupling between engine and drive wheels, and a few other mechanical differences, automatic transmissions are smoother in their power delivery than manual transmissions. That is the number one complaint with all these DCTs...People expect automatic transmission smoothness and are disappointed with how these manual transmission actually perform.

The reason is because the clutch isn't as forgiving as the fluid coupling and the result is a lot of noise, jerking, roughness, etc when shifting.

Ford has been sued multiple times over the harsh behavior of their DCT because lay people thought they were purchasing an automatic transmission with typical automatic transmission NVH characteristics. Instead, they were rudely awakened to the inherent harshness of the manual transmission that is in their shiny new Focus or Fiesta PowerShift "automatic".

What all of this got to do with why people choose to describe something as being "automatic" or, as taken from origin of that word: "acting of one's own will"?

From user point of view, who cares what is inside of transmission box: many metal toothed wheels or ... bunch of pedaling hobbits.
It's automatic. Period.

 

[ld_rider]

True automatic motorcycle

View attachment 33063

Not according to this highly regarded engineering definition ;-)

"An automatic transmission is a type of motor vehicle transmission that can automatically change gear ratios as the vehicle moves, freeing the driver from having to shift gears manually."

The motorcycle in question must be shifted manually from 1st to 2nd gear using a conventional foot lever. It is incapable of shifting through the gears "automatically".

Logic suggests that either A: the above definition of an automatic transmission is incorrect and the 750A really is an automatic motorcycle or that B: Honda marketing is lying ;-)

I'm going with "A" ;-)

 

[wideguy]

If it were an automatic transmission and not a manual that shifted automatically, those clunks would disappear ;-)

If it was a DCT that didn't clunk, it would be like most all the DCTs ever built...

I test drove a 1973 911 Porsche with their "Tiptronic" DCT back in '73, and it didn't clunk.

No matter, I'm sorry this happened, but I'm glad to be reassured that my clunk doesn't mean the transmission is destroying itself, so thanks for that.

BTW, Porsche called the "Tiptronic" a manual/automatic because you could use it either way! How cool is that?

 

[670cc]

Not according to this highly regarded engineering definition ;-)

"An automatic transmission is a type of motor vehicle transmission that can automatically change gear ratios as the vehicle moves, freeing the driver from having to shift gears manually.

That highly regarded definition describes the NC700X automatic dual clutch transmission exactly. I think we've finally got this settled now. The NC700X DCT is an automatic transmission. The Ford Getrag Powershift is also an automatic transmission and Ford is/was correct in calling it one.

 

[wideguy]

That highly regarded definition describes the NC700X automatic dual clutch transmission exactly. I think we've finally got this settled now. The NC700X DCT is an automatic transmission. The Ford Getrag Powershift is also an automatic transmission and Ford is/was correct in calling it one.

But... Does it clunk?

 

[670cc]

But... Does it clunk?

The Ford transmission has been reportedly known to shudder or grind, but nope, no clunk.

By the way, I bought my Fiesta specifically so I could get the Powershift transmission. I like the way it works. It's also the only readily available 2500 pound car that I liked with an automatic transmission that I can tow indefinitely with all four wheels down behind my motor home.