Question DCT downhill engine braking

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670cc

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These hills are just what you’re looking for. ;-)

I’m certain that if the DCT was ever going to shift on its own while coming down a mountain it would have done so rather than screaming along at almost 4500rpm in second gear. I don’t know about “incline sensors”, I really haven’t read up on all the wizardry that goes into these transmissions, but I‘m thinking the closed throttle position mentioned previously must be a key factor.

I’ve really enjoyed adapting to the technology and learning how to use it to its full potential in any riding condition I encounter - every time I start mulling over something new and different in the garage - and deciding what must go, I decide all over again this NC STAYS!

But that doesn’t mean I know jack about what makes it work.
I bolded your statement that doesn’t quite make sense to me. I would want the DCT to allow revving to 4500 and beyond towards redline in second gear if that is what is required for engine braking in a steep downhill situation. So you are saying you are certain it would upshift on it’s own at that point rather than continue to engine brake?
 

Red Rider

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I bolded your statement that doesn’t quite make sense to me. I would want the DCT to allow revving to 4500 and beyond towards redline in second gear if that is what is required for engine braking in a steep downhill situation. So you are saying you are certain it would upshift on it’s own at that point rather than continue to engine brake?
That is why I always apply the brakes in this situation to give the engine braking some assistance. I wouldn’t normally allow the bike to just continue to the bottom of the hill un-assisted by me on the brakes - knowing that the hill is too steep for the bike to completely and adequately hold down the speed on its own - the rpms just keep creeping up although it still keeps the speed down - relatively speaking. Still needs some help with light brake application. I don’t feel it’s all that good on the bike at that point and an assist with the brakes is what I feel more comfortable doing. (but that’s just the opinion of a guy who is overly concerned about abusing his bike ;-)

I’m saying given my unscientific tests - down the mountain in D mode and second gear with a closed throttle, it shows no indication that it is ever going to upshift. Would it? If allowed to go even higher in the rpms? Don’t know the answer to that. Maybe there really is a point it would reach and initiate a shift - but I doubt it. I’d have to go looking for a much longer hill to go down to test it further.

Don’t get me wrong, it does hold down the speed - but not to, say, 15mph...

May not be able to get back out for a few days due to weather, but next chance I’ll give it another go and keep track of the RPM AND the associated speeds. (often times there’s a copper at the bottom around the bend just licking his chops at the prospect of some nut coming down and around at “ludicrous speed”... it’s a 20 mph zone... if i gets me a ticket I’m gonna come begging
 
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DirtFlier

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I would assume that the DCT will not downshift until it reaches a fairly low speed because the bike doesn't know it's going downhill. As far as the bike is concerned, it's still on flat ground while picking up speed in 6th gear. :)
 

670cc

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To be clear, the question is fairly simple. On a downhill slope, closed throttle, with RPM and ground speed slowly increasing due to the slope, will the latest version DCT in auto mode hold the gear selected, or will it upshift, or will it downshift on it’s own? My experience with a generation 2 (2012-2015?) DCT was that it shifted to a higher numbered gear once the speed increased to a certain point, when the more logical choice would have been to downshift to attempt to bring the speed increase under control.

I wanted to leave brake application and any other workarounds for slowing out of the discussion, unless activating the brake lever switch might be what triggers a downshift.

I thought maybe this could be answered easily by people familiar with the latest model DCT, but it now seems clear there are too many situation variables and communication obstacles to consider when comparing my experience to the experience of someone else.

Thanks for everyone’s time.
 

lootzyan

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To be clear, the question is fairly simple. On a downhill slope, closed throttle, with RPM and ground speed slowly increasing due to the slope, will the latest version DCT in auto mode hold the gear selected, or will it upshift, or will it downshift on it’s own? My experience with a generation 2 (2012-2015?) DCT was that it shifted to a higher numbered gear once the speed increased to a certain point, when the more logical choice would have been to downshift to attempt to bring the speed increase under control.

I wanted to leave brake application and any other workarounds for slowing out of the discussion, unless activating the brake lever switch might be what triggers a downshift.

I thought maybe this could be answered easily by people familiar with the latest model DCT, but it now seems clear there are too many situation variables and communication obstacles to consider when comparing my experience to the experience of someone else.

Thanks for everyone’s time.
Depending on who would conduct the experiment, you might get conflicting answers. As you mentioned yourself, too many variables can affect the behavior of DCT (initial speed, acceleration, gear, mode D or S, inertia and time of downhill ride), even if the PCM program could take into account the downhill gradient, which I rather doubt.
 

TacomaJD

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2018 DCT here - I don't know if my experience is universal, but there goes ...

I most always ride in S1 (Sport 1, the lowest of three sport modes but not as "dull/boring" as the default "D" or Drive setting) When I'm in S1 on a long descent, I can use the paddle shifter to drop a gear (or two) and the bike will generally stay in that lower gear as long as the engine is really providing a substantial amount of engine braking. After I've slowed enough, either because the initial engine braking really overcomes the hill steepness and I'm actually slowing down or perhaps because the hill is actually flattening out over the course of the downhill run, the DCT will upshift. If the descent isn't steep enough to really justify engine braking from the start, it upshifts sooner.

In essence, if ya really need engine braking, i.e. it's really keeping you from accelerating 'cause of gravity, you can have it when ya ask for it. If ya don't really need engine braking, the DCT will kick it up a gear (saves some revs , I guess) It actually works pretty well - color me impressed.

Of course, this is auto mode. In manual mode, it's your choice - just pick a gear!

That help??
This is my experience, as well. In both my 2013 and 2016 DCT NC's. The 2016 has the different sport mode options. I ride in S1 on the 2016 and only S mode on the 2013. The 2016 DCT seems to allow me to gear down earlier (at a slightly higher rpm) than the 2013. But regardless, I ride in sport mode and then override the auto system with a push of the button to downshift. You can be in S or D and still push the shift buttons to manually change gears when desired, without having to click the manual mode button. I always downshift for engine braking when going downhill or slowing to a stop. Every now and then you might encounter an unwanted upshift if trying to coast down a long hill, but it hasn't been my experience that it's un-manageable or really even the slightest bit annoying. I definitely like the DCT in the 2016 better than my 2013.
 

670cc

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This is my experience, as well. In both my 2013 and 2016 DCT NC's. The 2016 has the different sport mode options. I ride in S1 on the 2016 and only S mode on the 2013. The 2016 DCT seems to allow me to gear down earlier (at a slightly higher rpm) than the 2013. But regardless, I ride in sport mode and then override the auto system with a push of the button to downshift. You can be in S or D and still push the shift buttons to manually change gears when desired, without having to click the manual mode button. I always downshift for engine braking when going downhill or slowing to a stop. Every now and then you might encounter an unwanted upshift if trying to coast down a long hill, but it hasn't been my experience that it's un-manageable or really even the slightest bit annoying. I definitely like the DCT in the 2016 better than my 2013.
The part that I bolded in quoting your post is the answer I was looking for (except in my case I found it very annoying). Apparently the 2016 NC DCT version does not incorporate any new logic to detect downhill situations. What I thought I had read about an advancement in that area may have applied to the Africa Twin. Thanks.
 

TacomaJD

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A simple click of the manual mode button for a long downhill encounter would be the solution. I couldn't imagine the bulk of your riding consisting of needing to do this extremely frequently and would think the times that it is needed, once accustomed to it, clicking to manual mode on the fly for some downhill engine braking would be a simple solution. Although different than working a shifter with your foot and clutch with your hand to gear down for a downhill descent, you just click a button with your right hand and then select which gear you want to be in with your left hand, and once you've completed your descent, swap back to auto mode with one more click of a button. Still less work than riding a manual bike, just requires a bit more in the thought process until you are used to it, then it's just as simple as riding the manual bikes you are used to.
 

670cc

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A simple click of the manual mode button for a long downhill encounter would be the solution.
Yes, I realize there are workarounds. My question is whether the latest DCT design has undergone improvements where the bike can sense it is on a downhill and behave appropriately In automatic mode.
 

dduelin

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To be clear, the question is fairly simple. On a downhill slope, closed throttle, with RPM and ground speed slowly increasing due to the slope, will the latest version DCT in auto mode hold the gear selected, or will it upshift, or will it downshift on it’s own? My experience with a generation 2 (2012-2015?) DCT was that it shifted to a higher numbered gear once the speed increased to a certain point, when the more logical choice would have been to downshift to attempt to bring the speed increase under control.

I wanted to leave brake application and any other workarounds for slowing out of the discussion, unless activating the brake lever switch might be what triggers a downshift.

I thought maybe this could be answered easily by people familiar with the latest model DCT, but it now seems clear there are too many situation variables and communication obstacles to consider when comparing my experience to the experience of someone else.

Thanks for everyone’s time.
I thought you replied earlier in #8 that you weren't sure if you had closed throttle or not so your example of unwanted upshifts may or may not have happened the way you remembered it.

I would agree there are communication problems.
 

the Ferret

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Yes, I realize there are workarounds. My question is whether the latest DCT design has undergone improvements where the bike can sense it is on a downhill and behave appropriately In automatic mode.
I think that's pretty clear. and why I said it was a good question earlier.

I will be able to answer it in a month or so.
 

670cc

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I thought you replied earlier in #8 that you weren't sure if you had closed throttle or not so your example of unwanted upshifts may or may not have happened the way you remembered it.

I would agree there are communication problems.
You are correct. I allowed for the chance that I may have moved the throttle. Regardless, I was riding a gen 2 DCT. My question in the first post was how the later model transmission (what I would call gen 3) behaves in the situation I tried my best to describe. Vehicle manufacturers seem to dedicate a lot of effort lately to adding situational awareness abilities to the vehicle. I wondered where the NC DCT stood in the area of hill sensing. I did not expect it to be this difficult to find a consistent answer, so apparently I will need to answer it myself next time I obtain a test bike.

It's probably a good time to close the thread. If anyone has or obtains a definite answer, I would appreciate a follow up in a private message. Thank you all for your answers in the thread.
 
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