Sprocket Ratios

[Piezak]

I am contemplating an NT1100. Took one for a test ride and liked it. Has anyone changed the sprocket ratios or considered doing so? Factory (as I’ve read) is 16T front and 40T rear.
I’ve thought about …
17T front & 40T rear
or
16T front & 38 or 39 rear.
I don’t ride fast and any loss of power wouldn’t be an issue for me. The additional range would be what I would hope to achieve.
Thanks for your thoughts.

 

[Woodaddict]

Been riding for 10 months, I see no need to change ratio. At 75 mph, RPM about 4,200. Remember this bike here in USA is only DCT. I don't want to mess with computer shifting points or possible change in front and rear wheel difference rpm. They have speed sensors on wheels for anti lock brakes.

Now you do have option for manual shifts all the time, or go into sport mode, 1 of 3 choices

With current ratio, even 75 mph highway speeds going to work, this bike can get 40-45 mpg, and the tank can get 210 miles before reserve

 

[dduelin]

If you do this you have to know it can cause the DCT to go into a limp mode and remain in first gear and not shift. There is a "gang of 5" sensors that operate collaboratively to choose shift points based on rpm, throttle opening, road speed, relative wheel speeds, rate of acceleration/deceleration and God knows what else. Changing gear ratio with sprocket changes or changes from OEM tire sizes can cause the transmission committee to pause deliberations and go into limp mode. That said there is some leeway to make changes, how much change is too much is an experiment. I've been in an NC700/750 forum for 14 years and some NC DCT owners have changed tire sizing and gotten away with it but I can't remember a sprocket change that worked.

 

[junglejim]

Same change - different motorcycle. I changed my front drive from a 16 to a 17 on my Triumph Tiger 800. No issues with sensors or computer. It reduced my highway speed RPMs by about 150-200, but also made 1st gear bit taller. I got slightly better fuel mileage but didn’t like the taller 1st gear. The Triumph triple engine is so smooth that I couldn’t feel the difference at highway speeds. So I already have new factory spec chain/sprockets on my bench ready to install when the time comes in about another 10k or 20K miles. OEM chain/sprockets went a little over 30K miles with very little stretch/sprocket wear until almost 30K miles but then the chain stretched quickly. The “gearing commander” website may give you some more information.

 

[dduelin]

Same change - different motorcycle. I changed my front drive from a 16 to a 17 on my Triumph Tiger 800. No issues with sensors or computer. It reduced my highway speed RPMs by about 150-200, but also made 1st gear bit taller. I got slightly better fuel mileage but didn’t like the taller 1st gear. The Triumph triple engine is so smooth that I couldn’t feel the difference at highway speeds. So I already have new factory spec chain/sprockets on my bench ready to install when the time comes in about another 10k or 20K miles. OEM chain/sprockets went a little over 30K miles with very little stretch/sprocket wear until almost 30K miles but then the chain stretched quickly. The “gearing commander” website may give you some more information.

My response was predicated on the fact the US spec NT1100 has a DCT transmission, not a standard manual transmission like your Tiger 800.

 

[junglejim]

My response was predicated on the fact the US spec NT1100 has a DCT transmission, not a standard manual transmission like your Tiger 800.

Right. Auto shifting transmission monitor lots of inputs. In your case the computer is mainly concerned with the wheel speed and engine rpm and throttle position (not counting the ride mode selection). It seems your small gearing change would be OK. BUT those systems are complex and you should be concerned.
I should have clarified that the point of my post was that I don’t think it was worth while to gear up in my case.