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changing front sprocket to 15T from 16T


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after hearing good results with ppl going to a 15T front sprocket, I pulled the trigger, hit the local bike store for a sprocket, cost me $25 
 
so far the biggest improvement I noticed was the flat power spot in the lower RPMs was gone, now its just as lively as it can be...
 
the odd surging ppl get at 35mph is practically gone, I noticed it a tiny bit but didnt bother me when using the 16T sprocket even with a tuned ECU
 
the front end dive is reduced when I quickly let off the gas
 
when I do a drag strip launch the front end carries/stays up much better than the 16T sprocket which felt like the TC just chops the power rather than slowly reduce power when using the 15T sprocket...
 
I do also notice way less vibrations coming from the bike in general...could be due to 15T having no rubber damping disc or it could be due to the 1.5inches of chain slack Im currently running...gonna bring it in to just over an inch of slack...
2012 wr250f - C-class 30+ age group
2015 fz-07- Hordpower Edition-80whp
2015 fj-09- Graves Exhaust w/Woolich tune by 2WDW @120whp
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after hearing good results with ppl going to a 15T front sprocket, I pulled the trigger, hit the local bike store for a sprocket, cost me $25  
so far the biggest improvement I noticed was the flat power spot in the lower RPMs was gone, now its just as lively as it can be...
 
the odd surging ppl get at 35mph is practically gone, I noticed it a tiny bit but didnt bother me when using the 16T sprocket even with a tuned ECU
 
the front end dive is reduced when I quickly let off the gas
 
when I do a drag strip launch the front end carries/stays up much better than the 16T sprocket which felt like the TC just chops the power rather than slowly reduce power when using the 15T sprocket...
What should one do to reduce the frequency of searching for seventh gear when at highway speed, as when touring?   Bike runs at 4000rpm at an indicated 100kph (60mph) and I'd like to lower that somewhat.   I realise it may chop a little off the more-than-adequate acceleration, but no problem there for me.   Would like some insights into this.

Riding a fully-farkled 2019 MT-09 Tracer 900 GT from my bayside home in South East Queensland, Australia.   

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after hearing good results with ppl going to a 15T front sprocket, I pulled the trigger, hit the local bike store for a sprocket, cost me $25  
so far the biggest improvement I noticed was the flat power spot in the lower RPMs was gone, now its just as lively as it can be...
 
the odd surging ppl get at 35mph is practically gone, I noticed it a tiny bit but didnt bother me when using the 16T sprocket even with a tuned ECU
 
the front end dive is reduced when I quickly let off the gas
 
when I do a drag strip launch the front end carries/stays up much better than the 16T sprocket which felt like the TC just chops the power rather than slowly reduce power when using the 15T sprocket...
What should one do to reduce the frequency of searching for seventh gear when at highway speed, as when touring?   Bike runs at 4000rpm at an indicated 100kph (60mph) and I'd like to lower that somewhat.   I realise it may chop a little off the more-than-adequate acceleration, but no problem there for me.   Would like some insights into this.
im doing the opposite of what your trying to accomplish... im still in 4th gear at 60mph majority of the time... 
your options are to run a bigger front sprocket or smaller rear sprocket to get less rpm in 6th gear at 60mph... my shift point is at 9k rpms 
 
general rule of thumb:
 
1T change on front sprocket is roughly equal to 4T on rear sprocket
 
- Bigger front sprocket = more speed
-smaller front sprocket = more accel
 or
- bigger rear sprocket= more accel
-smaller rear sprocket= more speed
 
 
http://www.gearingcommander.com
nifty little website
 
 
 
2012 wr250f - C-class 30+ age group
2015 fz-07- Hordpower Edition-80whp
2015 fj-09- Graves Exhaust w/Woolich tune by 2WDW @120whp
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Erm, you have now 16 front/45 rear. So closer to a 1:3 ratio.
If you try to increase by one tooth in the front, you'll see about 17/16ths increase in speed/rpm. About 6.25%. Problem is that there's a chain guide above the sprocket that won't let you put a bigger sprocket in there without the chain hitting it. You can leave the guide out at your risk. It supposedly protects from the chain breaking/bunching up in there and going through the engine wall.
You can go to a 43 rear, (same as the FZ?) easily. 4.65% increase in speed/rpm. Bolts right on, no changes in chain required. I've been using it for a few thousand miles and also no problem with the chain rail on top of the swing arm.
In both cases, no problems with the speedo readings, as they're taken from the rear ABS encoder.
Now, if you want a little more, you can step up from a 55 to a 60 profile tire. That will get you a few percent more, but it will throw your speedo off a little. Maybe mess with your ABS/TC function as well as the front and back won't match per factory specs anymore. Maybe there's a fix in the ecu setup, dunno.
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Erm, you have now 16 front/45 rear. So closer to a 1:3 ratio. If you try to increase by one tooth in the front, you'll see about 17/16ths increase in speed/rpm. About 6.25%. Problem is that there's a chain guide above the sprocket that won't let you put a bigger sprocket in there without the chain hitting it. You can leave the guide out at your risk. It supposedly protects from the chain breaking/bunching up in there and going through the engine wall.
You can go to a 43 rear, (same as the FZ?) easily. 4.65% increase in speed/rpm. Bolts right on, no changes in chain required. I've been using it for a few thousand miles and also no problem with the chain rail on top of the swing arm.
In both cases, no problems with the speedo readings, as they're taken from the rear ABS encoder.
Now, if you want a little more, you can step up from a 55 to a 60 profile tire. That will get you a few percent more, but it will throw your speedo off a little. Maybe mess with your ABS/TC function as well as the front and back won't match per factory specs anymore. Maybe there's a fix in the ecu setup, dunno.
stock is 16/45... I went to 15/45... 
2012 wr250f - C-class 30+ age group
2015 fz-07- Hordpower Edition-80whp
2015 fj-09- Graves Exhaust w/Woolich tune by 2WDW @120whp
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- Bigger front sprocket = more speed -smaller front sprocket = more accel
 or
- bigger rear sprocket= more accel
-smaller rear sprocket= more speed
 
 
http://www.gearingcommander.com
nifty little website
 
 

This is what you need to know. And I highly recommend Vortex steel sprockets. Key word is steel.

'15 FJ09

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  • 9 months later...
 
 
 
20170904_054304.jpg
 if you look closely you can see that one end of the link pushes further into the rubber than the other end... 
2012 wr250f - C-class 30+ age group
2015 fz-07- Hordpower Edition-80whp
2015 fj-09- Graves Exhaust w/Woolich tune by 2WDW @120whp
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