DCT and similar transmissions

[IndigoJo]

I've been a truck driver for years and the automatic manual transmission (AMT) is a standard now on pretty much anything above 7.5 tonnes (ie. anything recognisably a truck rather than a van). What distinguishes them from the auto gearboxes on cars is that just putting them in drive won't make it move forward; you have to use the gas pedal to get clutch bite (the clutch itself is automatic). They were dreadful when first introduced in the late 2000s (e.g, the mode switch just not working, gear changes that were just wrong and slowed you down suddenly for no good reason) but have got a lot better and very few new trucks are manual now.

 

Lately AMTs and DCTs (Volvo trucks have had these for years) - or at least the terminology - have been showing up on motorbikes. Do these work the same way? Are they the same things just adapted for bikes or a different machine altogether? Anyone here who's used both?

[husoi]

Automatic gearbox is becoming quite common.

Goldwing have it.

I know other brands started fitting them.

Not something I'm interested in, so I don't really play much attention to it.

Then you have the obvious one, electric bikes all have automatic gears

[Bender]

Honda been using them for a good while

 

https://www.honda.co.uk/motorcycles/experience-honda/dual-clutch-transmission.html

 

[Mawsley]

Not sure how my hand is going to take to a clutch again. I kinda like DCT.

[bonio]

MV Agusta TV SCS has had a recluse clutch since Methuselah had his Mark 1 delivered. It wasn't for me though... I couldnt work out how to feather the clutch.

[Nick the wanderer]

The early automatics on lorries were awful, the worst thing was the delay when you wanted to set off from a standing start. You'd put your foot on the gas and nothing would happen for a couple of seconds. Horrible when trying to get out of anywhere. The last lorry I had was a Volvo, that was great, apart from the auto braking etc safety features.

Never had auto on a bike, I like dropping the clutch!

 

[RideWithStyles]

In the car world:

Simply SMT / dct have a manual gear box housing and gears, only an actuator / solenoid to move the selector to the gear required and the clutch.

These could be sequential or rowed.

Cheaper than autos but more to make than manuals but they had their own set of rules for emissions so for the manufacturer that cost was passed on but still some what attractive. 

the problem for early systems (and still modern ones like vw) were premature wear, control problems, crude operating, lack of service and cheap parts. They were a stop gap and later on away of getting around emissions, as these where ment to have they’re own test.

 

depending on clutch type and design they couldn’t handle as much power and particularly torque aswell as either a true torque converter or manual.

 

true automatics are costly, heavy, less fuel efficient bar the motorway cruise and have actual gears but very durable especially if its maintained properly.

 

cvt are cheaper work fairly similar on a very basic term but different compared to a manual and auto.

Cvt is more practical on a bike due to its light weight and compact design, quite cheap and simple to maintain, can handle a decent amount of power/torque/revs for a bike with less weight of the vehicle to push about but some people can’t get their head around the dynamic sound and feeling of the design that the speed and sound it does compared to the engine as it operates due to it not actually having gears as such but always sounds like it’s working hard.

 

on cars I didnt mind either auto or a manual, but the smt/amt (even a good one) is a compromise that doesn’t really solve anything to the user other than come with its own set of problems.

 

Off memory most of not pretty much all electric cars (and pretty much most proper electric bikes to i think) don’t come with a conventional gearbox as such with loads of cogs as the electric motor has so much torque from rest to an absurd spinning speed to reach a terminal velocity that a single gear and torque is managed by the ecu so their is no need for extra weight and complexity.
Even cheap small medium cars go over 90mph in only forward gear they have and reach it in a very convincing manner, not many cars manage near that feat, only super bikes do that with fraction of the weight and near power.

Edited October 28, 2024 by RideWithStyles
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[Bender]

You missed out the first widely available auto box, the 2 speed powerglide, make a car with enough power and you only need 2 gears