'14 675R Optimal Up-Shifting RPM? - Triumph675.Net Forums
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post #1 of 9 Old 09-11-17, 05:01 Thread Starter
Chicken Strips
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'14 675R Optimal Up-Shifting RPM?

Hi,

I've put about 25 trackdays on my Daytona and I've gotten used to upshifting at 14,000 RPM's through feel. I just wanted to make sure that I'm not losing any ground by waiting until I hit 14,000. Is this where I should be upshifting or should I be doing it sooner?

Thanks,
Elan
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post #2 of 9 Old 09-11-17, 13:44
MGFChapin
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Power trails off after 13k so that's where I generally shift. No need to go up to 14 unless you're avoiding a shift in a long corner or something.
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post #3 of 9 Old 09-11-17, 16:13
hzhong456
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I have my shift light set to 13,200 and it's where I feel is the best range to shift.
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post #4 of 9 Old 08-20-18, 16:49
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Take a look at a dyno chart. Shift to keep yourself right at the power peak as much as possible. Assuming peak power at 13k, and (making this up, depends on gearing) a 1200 rpm drop between shifts, you should be shifting at ~13.6k RPM. That will provide the most 'area under the curve'/most acceleration.
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post #5 of 9 Old 08-20-18, 21:26
Nastybutler
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Quote:
Originally Posted by hawker View Post
Take a look at a dyno chart. Shift to keep yourself right at the power peak as much as possible. Assuming peak power at 13k, and (making this up, depends on gearing) a 1200 rpm drop between shifts, you should be shifting at ~13.6k RPM. That will provide the most 'area under the curve'/most acceleration.
I could be wrong, but I thought it was best to shift where your RPMs drop down to peak torque. So your downshift above peak power (which is 12.5k) should put you close to the peak torque at 11,900.

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post #6 of 9 Old 08-22-18, 20:17
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Quote:
Originally Posted by hawker View Post
Take a look at a dyno chart. Shift to keep yourself right at the power peak as much as possible. Assuming peak power at 13k, and (making this up, depends on gearing) a 1200 rpm drop between shifts, you should be shifting at ~13.6k RPM. That will provide the most 'area under the curve'/most acceleration.

What an excellent reply. It is indeed this. May I ask what you have studied/are studying?
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post #7 of 9 Old 08-22-18, 20:33
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Quote:
Originally Posted by Nastybutler View Post
I could be wrong, but I thought it was best to shift where your RPMs drop down to peak torque. So your downshift above peak power (which is 12.5k) should put you close to the peak torque at 11,900.

This could be a good rule of thumb but from a mathematical/engineering standpoint it only works coincidentally, when it works. If you had an engine that peaked its torque very early, then as hawker mentioned above, you'd still want to keep your RPMs around and as close as possible to your peak power value. Take a look at this hypothetical graph I made: The grey box shows where you'd want to be RPM-wise and it's obvious that its lowest RPM value is far-far away from where the peak torque is.
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Last edited by Plasmablaster; 08-22-18 at 20:39.
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post #8 of 9 Old 08-23-18, 10:07
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If you are racing or really going for it, just before redline. Torque drops off after 13k but hp stays about the same from 13k to 14k. Shifting at 13k will net a slower bike.





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post #9 of 9 Old 08-11-19, 15:38
ThatsAgood1Jay
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Quote:
Originally Posted by tottenham12712 View Post
If you are racing or really going for it, just before redline. Torque drops off after 13k but hp stays about the same from 13k to 14k. Shifting at 13k will net a slower bike.








Is that a stock bike? I thought power trailed off >13k.....I need to go adjust my shift lights.
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