Re: Calculations for the Engine RPM with the Vehicle speed Known

BAJAJ PULSAR 200 NS
Tyre Size: 130/70-17
Tyre Diameter: 24.1653"
Tyre Circumference: 1.929m
Tyre at 1KMPH (A): 8.64 RPM
Primary Reduction (B): 3.272
Final Reduction (C): 2.6
Top Gear Ratio (D): 0.9166
TS Ratio (ABCD): 67.37
At 9K RPM, True Speed: 133.6KMPH

Re: Calculations for the Engine RPM with the Vehicle speed Known

Thanks. What speed it attend while on 10000 rpm in 6 gear.

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Re: Calculations for the Engine RPM with the Vehicle speed Known

Bro, its self explanatory calculations. For any bike at top gear, just divide the RPM by TS ratio, you get the speed.
Ex: 10000/67.37= 148.4 kmph.
I think its hard for NS to reach 10000RPM in 6th gear though.

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Re: Calculations for the Engine RPM with the Vehicle speed Known

Thanks

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Re: Calculations for the Engine RPM with the Vehicle speed Known

However, in 5th gear, at 10K RPM bike will be at:
10000/76.84= 130 KMPH

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Re: Calculations for the Engine RPM with the Vehicle speed Known

I have a doubt that how can a karizma has more top speed than ns while you calculate

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Re: Calculations for the Engine RPM with the Vehicle speed Known

It's highly impossible to touch 10k at 6th gear ,tried to do it but it needs a good amount of length
However if you shift aggressively, then 130kmph comes very quick ,in 12-16 sec. After that bike becomes slow and further speeds are attained like if you're riding a 150bike .but it does 140 easily and 150 kmph in some conditions.
* above speeds are speedo indicated.
And as of now I asked on karizma forum, karizma tops out at 130 kmph despite having faring and all.
Though old zmr touched 137 when I rode it back in 2010.

Re: Calculations for the Engine RPM with the Vehicle speed Known

Nice one,
See that karizma has max power of 20BHP @ 8000 RPM. While NS produces 23.5BHP @ 9500 RPM.

So at 8000 RPM, ZMR will be at 124 KMPH. But NS at 9500 will be at 141 KMPH.
The calculations have no connections with the engine. Its only dependent on the power distribution in the bike.
If karizma had an ability to reach 9500 RPM, it will cross 147 KMPH, which is practically not possible.

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Re: Calculations for the Engine RPM with the Vehicle speed Known

FOR HARLEY DAVIDSON,

HD STREET 750
Tyre Size: 150/70-15
Tyre Diameter: 23.2677 "
Tyre Circumference: 1.857m
Tyre at 1KMPH (A): 8.975 RPM
Primary Reduction (B):
Final Reduction (C):
Top Gear Ratio (D):
Overall Ratio (BCD),( Directly mentioned in Website)
5th Gear: 5.04
6th Gear: 4.53
TS Ratio (ABCD),
5th Gear: 45.234
6th Gear: 40.656
At 4K RPM,
5th Gear True Speed: 88.42 KMPH
6th Gear True Speed: 98.38 KMPH
At 8K RPM, True Speed at 6th Gear: 196.7 KMPH.
( If any mistakes, please notify by PM)

Re: Calculations for the Engine RPM with the Vehicle speed Known

Thanks but can you please tell me That which one has real top speed between pulsar 220 and 200ns.

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Re: Calculations for the Engine RPM with the Vehicle speed Known

Sorry brother, this is not possible to say by calculations. To my experience NS has better power and Top speed than 220. You please discuss this in respective threads. You will get a reliable answer.

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Re: Calculations for the Engine RPM with the Vehicle speed Known

TSR - Tacho-Speed Ratio is good name btw.

However, I'm not sure why you call True-Speed. Doesn't Theoretical-Speed make more sense?

Also, instead of giving out speed at a random(8k, 8.5k, 9k) RPM, speeds at MaxTorqueRPM and MaxPowerRPM would help a lot.

e.g. GS150R that I ride has TSR : 70.62 ; btw newer versions have final-reduction-ratio of 3.0 (42/14) -> new sprockets.

Theoretical Speed [MENTION=6892]max[/MENTION]TorqueRPM = 6000/70.62 = 84.96 ≈ 85 km/h
Theoretical Speed [MENTION=6892]max[/MENTION]PowerRPM = 8500/70.62 = 120.36 ≈ 120 km/h

Actual(real-time) speeds seen may be less like 80 km/h & 110 km/h. It gives us an insight about bike's cruising speeds on highways.

cheers

Re: Calculations for the Engine RPM with the Vehicle speed Known

Initially I thought the same. Since there are speedo errors, I named it true speed so that people can actually know at what speed they are riding in. My friend with ZMR and me with Pulsar 180 while riding side by side, I always observe those errors. His reads 28KMPH and mine 29 KMPH. If I name it Theoretical, then people won't even compare it with their bikes. Only some understand the importance. Ofcourse its completely theoretical

Tacho- Speed Ratio was suggested by John. A nice name.

I shall soon update the speeds at the max Torque and RPM. However almost I already calculated are at max Power. Only some are random .
I had these calculations done for GS around two years ago. Thanks for the updated values.
And reguarding Suzuki, the TS Ratio holds good only above 100+ kmph. Within 30-40 range, the TSR has 10-20% error. I personally tested it in my close friend's Gixxer 155.
Thanks bro for the suggestions. Any new bikes/ scooters like chethak, RX, RD, with details, then please let me know.



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Guessing RPM

Since my Hero Glamour does not have a tachometer, I really never know at what RPM I am riding. I have so far covered 1200 kms of distance so the break-in period is over I guess. Till now I was maintaining 40kmph speed always, however, I am currently going over 50 to 60 kmph often. What I noticed is, the engine does not make any sound at all while at 40kmph. But when I go over 50kmph, I can hear the engine's roaring sound even when my helmet on. Is the RPM range going way over reasonable limit? In general, what could be the possible rpm when riding at 60kmph speed on 4th that is the highest gear?

Re: Calculations for the Engine RPM with the Vehicle speed Known

how we calculate rpm and sped with GR