Because of the components used... not the ingredients neither the materials!!! just the route map of building a engine. Lets not go OT here...

Btw is there a review regarding shifting specifically for Indian Bikes?? i would love to see that!!!

Also what is the conclusion here?

@ abhimanyu : Thanks for the article man! Was a fantastic read! Though am not sure whether I understood everything or not very clearly.

I feel that if you are in a drag race, where what you want is maximum acceleration from the start line, its best to change the gear at a point where the rpm on the next gear will be where you get max torque.

For example Dazzler has max torque at 6500rpms and max power at 8500rpms. So shifting around 8500rpms should be good for for first gear since shifting into second will bring my tacho needle to 6500rpms which is the max torque spot.

However i will need to lower the shift point while shifting from second to third because of the gearing difference between these two gears.

So that was for acceleration.

For top speed you would want to keep the engine always at the max rpm spot, so basically you redline all the way upto 9500rpms (in my dazzler) and then progressively keep shifting the points such that when you shift into 5th gear, the bike is still as near to 8500rpms as possible.

Now this was my understanding BEFORE I read the article. After reading the article all that has changed in my understanding is that instead of taking max torque rpm as your reference point, you should take "max driving force" as your reference point where "max driving force" is the product of the different variables as given in the formula in the article.

(Also after reading the article, I feel that the my top speed theory is stupid and pointless since there is only one optimal shift point and it is there for acceleration, because if you want top speed, change into 5th gear at 30kmph , go WOT and then wait for 5 min till the bike pulls all the way to 8500 rpms and you will eventually reach topspeed! Point being top speed will be same no matter where you shift, it is the time that will vary. So basically the concept of shift points makes sense only in the context of acceleration)

For now am happy with this understanding! Will be following this thread to learn more! Please correct me if I am wrong!

The method of calculating the optimal shift points described on the site requires the use of a dyno and any bike. Even a tvs xl will do.

The dyno is run off the bike's wheel, from which it measures power\torque being produced.

So regardless of technology or any disparities in tech, the power at the wheel of any bike is what is taken into account.

You can dyno your chosen bike and get the appropriate bhp and torque values, among other values needed to enter into the excel spreadsheet(given on the site), which automatically calculates the optimal shift points for that specific bike.

Its all just physics as abhimanyu31 said. Nothing to do with differences in technology. Take a look at the spreadsheet to be sure yourself.

No buddy you're wrong here. There is no such theory regarding peak torque rpm and peak power rpm to deliver best pick up and top speed respectively.
Moreover, technically speaking, "pick up" should not be used here, acceleration would sound better.

Only launch at peak torque rpm? and can you tell when to shift gears during drags?

Each engine has a different rpm range in which it will produce the most power. The trick is to keep the engine in this sweet spot from the moment you cross the starting line all the way to the finish line, without any of this peak power being wasted. Launching a bike hard from a dead stop is accomplished by slipping the clutch and spinning the tires, both within reason. Power is lost here, but most engines have narrow power and torque bands, so the fastest launch will include wheelspin and slipping the clutch. The only way to find out how much slipping would be just right is to experiment at the track, holding the throttle at various rpm levels at launch to see how much juice is needed for the quickest start.

about gear-shift i guess it would be in between 5000-6000 rpm.

@threadstarter
I shift at anywhere between 6500 - 7000 rpm on my '08 zma-r on pretty much all gears.

I rarely cross 80k - 90k on streets with the zma, so top speed does not really matter for me - only acceleration does, i've had good responses with a few mods on.

The build quality on this particular bike is simply spectacular, having thrashed the previous ZMA it in many ways, you have nothing to worry about red-lining regularly.

The TS rides a Karizma.
If anyone tries this out:
1. Keep shifting up at max torque rpm and record the time to reach any speed for reference.
2. Keep shifting at an rpm from where each time after upshift the rpm needle crosses the max power rpm again and again (yes, I wrote max power here) and record the time to reach the same speed.
He will notice that he does not require to even record the time in each case, the second case will be faster obviously.
So, your 5000-6000 rpm shifts are ruled out, in a drag, iff the target is to win, because max power rpm in a Karizma is above the range you mentioned plus again a margin(1200-1500rpm) taken care to manage for the upshift!

This couldn't be further from the truth. There is no way on earth they can possibly do that.

Considering the fact that these people do not get Pulsars and Karizmas as their daily bikes (assuming the Developed world i.e.). If someone has a bike like, say, an R1, which maxes out at 180kmph (or 112 MPH) in 1st gear, where will he have the speed limit on public roads where he can max out even in 1st gear? Most speed limits, even in developed countries with access controlled motorways is 85-90 MPH. Speed limits in town are even lower. Where do you think these people go for their 'casual rides' where they redline everytime they upshift?

please clarify this line in simple words.

In simple words, he is saying that since Karizma makes max power at 7000 rpm, a short shift of 5-6 krpm will NOT win you the drag.

In a drag, its better to shift a way that you pass through the power spot while upshifting. Which means that if it makes max power at 8000 rpm, you can upshift at 8500 -9000 rpm each gear.
And no, red lining is not for top speed only. It can be for great acceleration too.

I've no idea how redlining can be a danger to the vehicle. I've red-lined many many times during my 5 years ownership of my Pulsar 180. No problems as yet (except for silencer troubles that have nothing to do with redlining).
But its better to keep in under the red mark if you're touring for a long duration.


Regarding launch, there can't be one theory. If possible, it should be launched at full acceleration as the rpm lowers on leaving the clutch so it will reach peak power rpm. But, its not practical as it might cause an accident. A lot depends on the grip levels, clutch-accelerator technique, power output, etc.


@ antz: Everything correct. But do the litre class bikes touch 180 kmph in first gear? Its more around 140-150 kmph at redline, that too on speedo I think.

I think the point here is that for best acceleration, the thing to keep in mind is the rpm where the engine produces peak torque and peak rpm. Since this is different for different motorcycles, the shift points are different for different motorcycles.

Like I said earlier, the Dazzler has a peak torque rpm of 6500, the Unicorn (same engine, different state of tune) has peak torque at 5500pms (a full 1000rpms below Dazz) and the Bajaj Platina 100 has a peak torque rpm of 4500rpms. IMHO Shifting gear for each bike at redline is just stupid behaviour. You are never going to get the same results for different bike with this redline shifting!

And that is the whole point of the article abhimanyu cited, that reagardless of the rpm where your bike redlines, you will be fastest when you shift gears such that max torque reaches the rear wheels!

@antz and @samarth whether its 140kmph or 180kmph, it is still above city speed limits of US which range between 30-40 mph inside city! point being no responsible rider of US redlines every gear in any kind of casual riding, period.

Thanks for explaining on my behalf.

I've seen R1 doing 159 kph in first gear, yeah on the speedo and guess it could have done a bit more, say 165 kph. And the rev-limiter hits when it is doing 167 kph on the speedo. http://www.youtube.com/watch?v=5hXP-...eature=related

@Samarth There is a reason why I chose the R1 specifically for my example. (And the reason is 2010 Crossplane Crankshaft R1)

But my point was not to test SBK knowledge of fellow xBHPians. The point was if just the 1st gear is up and over all legal speed limits, when will this rider shift to 3rd, or 4th for that matter? Especially on a 'casual ride' on a public street.

Anyways, as far as winning Drag Races is concerned, all you need to do is work the torque. The ideal upshift point is the RPM where your engine produces peak power. This particular RPM is usually 1000-2000 RPM above the RPM where the engine produces peak torque. When you upshift at this point, the RPM should ideally drop extremely close to where your engine produces peak torque. This particular band is the meatiest part of the powerband and if you stick to this band, you should get the best acceleration timings. All these RPMs are a bit below where the redlines start so there is no need to redline the bike to get the fastest timing.

eg. ZMA-R
Peak Torque - 6000 RPM
Peak Power - 7000 RPM
Redline - 8200 RPM

Pulsar 220 carb:
Peak Torque - 7000 RPM
Peak Power - 8500 RPM
Red-line - 10000 RPM

CBR250R
Peak Torque - 7000 RPM
Peak Power - 8500 RPM
Red-line - 10500 RPM

So for example in CBR and P220 if the power starts dropping after 8500 RPM, why would you want to rev all the way upto 10.5k/10k ?

I study at Amrita and since there are alot of foriegners around the place they usually settle for our indian bikes. The bike in question was a Yamaha 125cc bike, some call it the gladiator and other call it the SS125. These people on their return just sell them off.

And the rider who was riding the bike zoomed past while redlining in every gear, which could be understood from the engine grunt. So later when got an oportunity to talk to him. Thats how I came to know about this.

@ Everyone.
I wasnt talking about extracting max power from the bike. I was just curious whether redlining in every gear is doable or not. Which was clearly explained by Abhimanyu in a pm.

Can you post that info here,so that everyone benefits?