Lowering the RPM's (Rear sprocket) - Suzuki GW250 Forum
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post #1 of 50 Old 05-19-2014, 05:32 PM Thread Starter
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Lowering the RPM's (Rear sprocket)

Hi..

I drive my GW a lot on highways and tend to take it on a journey to southern Europe this summer, and I do think it runs on pretty high RPM's when doing highway.

When I cruise at 135km/h (84MPH) it's steady at 10.000RPM.

I know that the bike has it's max power output at 8500RPM, so why not lower the RPM 10%?

Has any of you tried with a smaller rear sprocket or a larger front sprocket to reduce the RPM and increase the MPG? If yes, was it successfull?


I've posted a video of my driving in the video section, so you can see what I mean..
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post #2 of 50 Old 05-20-2014, 03:20 PM
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I haven't heard of anyone doing this on our forum. You make it sound like it isn't the hardest thing to do, but I'm not sure that you would get the intended results in isolation. Have you ever seen this done on a bike a different bike? Is it really that simple?
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post #3 of 50 Old 05-20-2014, 03:59 PM
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But will you be ok with the decimated low end? Your mids will still be plentry powerful but anything in the low end is going to feel a bit soggy. If you are in cities at all that might be favourable...
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post #4 of 50 Old 05-21-2014, 12:04 PM
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the only problem that i can see is the speedo is driven from the transmission so will read wrong if you change the gearing.
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post #5 of 50 Old 05-21-2014, 04:42 PM
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Reading wrong will be a problem, if there is a way around that then maybe it will be really worth doing,
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post #6 of 50 Old 05-21-2014, 04:49 PM
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thats not really a problem, once you change your teeth get an accurate GPS reading to figure out what the difference is. Then you can use something like SpeedoDRD to recalibrate your instruments.


SpeedoDRD Speedometer Calibration Device Review

and you can use this app to figure out what the error is on the speedo.

https://play.google.com/store/apps/d...Hv4_Calculator

same goes for if you're fiddling with rear tire sizes..

hope this helps!
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post #7 of 50 Old 05-22-2014, 12:41 PM
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Good to know, thanks for posting that!
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post #8 of 50 Old 05-22-2014, 04:06 PM
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cool stuff

i've always just dealt with it



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post #9 of 50 Old 05-22-2014, 05:13 PM
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Originally Posted by brians View Post
cool stuff

i've always just dealt with it
yea its not a serious issue, once you figure out what the delta is between the two mentally you can just deal with it like you said... Its a little much to deal with perhaps, but if you're the type of person who likes to fiddle with sprockets its probabaly easier to recal the speedo than to constantly try and remember what your differences are...
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post #10 of 50 Old 05-23-2014, 08:49 AM
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somebody check my logic here.
if its a normal Suzuki speedo it'll read about 10%fast. change the gearing to increase you speed for any given revs by 10% & the speedo should read your speed with zero error?
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