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1. ## calling all xperts!!!

hey guys...i've been noticing this strange thing while riding my bike...here it goes

when i change first three gears at 5-6K rpms...it takes me to 90km...when i change the first three gears at 7.5K rpms (which i think is ideal)...it again takes me to 90km ...

now when i compared both runs on TIME basis...i concluded that changing gear at 5-6k rpms was faster than the 7.5k gear changing...

so why do most of the riders prefer changing gears at higher rpms if they can achieve quicker accelration with quick gear changes??? or is it the case only with me ??

2. In economics, this is called diminishing marginal returns

3. LLOLZ this is too pro for me to answer

4. @spectra well said!!! can not be a better explination then this.

One more thing can you send me the attachment for the case study which you had on the the Volvo or Renault SUV which you posted few month back at PW. my email kamran.aslam@yahoo.com

5. @kamran
its volvo and i can send it tomorrow after getting a scan of what i have. It was not a case study but just one example. You can build on it easily.

6. Spectra bhai thanks.....i doing BBA-H from IoBM (CBM karachi) will be waiting, looking forward to learn more business studies from you....appriciate you reply

7. The amount of any one input is increased, holding all other inputs constant, the amount that output increases for each additional unit of the expanding input will generally decrease!!

8. Anne Robert Jacques Turgot and Thomas Malthus will be turning in their graves if they saw their law applied in such manner and so incorrectly.

@Foosa
The reasoning behind this is long but I will try to explian in simple terms. Your bike's power curve is located low to mid range from what I can make out by what you said. Different engines have their power curves on different rpms. And you r bikes power output is maximised at around 6k rpm and not at 7.5krpm hence the faster times. That is what I can make out from the info given. But it does not mean that there might not be other reason or factors for such engine characteristical behavior.

Maybe your bike is starving on the top end, or etc. I am just speculating!

9. @Racerf1

@foosa

Ashfaq bhai already described it very well but i wana share one practical thing derived from same theory if u know the exact RPM @which ur engine deliver max tourqe then try to shift gears up slightly above than that RPM & your vehicle will accelerate at its peak widout touching danger zone RPM.

10. Try to guess at what gear ratio your bike stops accelerating, this will be the point to change to next gear... if you don't than increasing gear ratio will only increase noise and damage to engine not speed....this method is simple and makes sense

11. @foosa

What comes to my mind is that the maximum power of your bike is achieved as you get to 5-6k rpms. There is a maximum power point on all bikes, it would be between 5 and 6k rpms for you. Thats what I think it is..

12. @all..

thanx for the stats...physics and whatever it was lessons ..

and imran bhai, 7th and hasan

i think im getting ur points...but what i didnt understand was why did they put the red line at 8.5 RPMs then ?...i was changing the gears at 7.5 thinking the red line was at 8.5...but like you guys said that perhaps the the max power achieved is between 5-6 rpms...then why did they put the red line at 8.5 ?

13. Its for the higher gears I would say. Power and speed are different things. Smaller gears are more powerful and the higher gears give you more speed, the rpm counts would increase as more throttle is opened..more rpms more storkes per minute means more combustion in the engine and hence more speed. Makes sense?

14. Also, the red line shows the last safe rpm count where you may ride the bike and it is not a count for the maximum power. Imranbhatti might be able to clear you more on this point..

15. BTW laws of diminishing returns/utility were never specific to anything. those are and can be proved to be general. In simple words incremental gain in power after 6K rpm to 7.5K rpm is less then what it is up to 6k rpm.

Thats what the law is and that is what the situation is. The power curve (from a dyno), as referred can also be proved to be the same as that of law of diminishing returns.

But then i am an accountant and we are trained to tailor the answer of 2+2 as per situation

16. I cant explain it further i think there is nothing left as different experts have described it very simply & wid diffrent aspect.

17. @spectra
what a brilliant reply. KOOZAY MEIN DARYAA BAND KAR DIYA.

18. @all

got it ...thanx all...now im gonna do another technical xperiment and bug you all laters (Y)...thanx alot for clearing this one out

19. understand ur bike and u will have no trouble riding it in any way
i ride my bike in diffrent mods according to my mode i guess as i have learned how to play with it
keep practicing learning never stops for a biker

20. @foosa

I though someone like you would already understand the theory behind the power band and fuel curve. and if i already didnt know which buke you had i would sugested that you cheked the exup valve or any other alternates your bike might have had. anyways you bike seems to be starving at higher end if not chocking on exaust back pressure

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