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True speed per 1000 revs calculation helper


Oilyspanner

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Something I did to quickly work out true speed in each gear  _ this is for gsxr1100 k-n and b1200

Quick calculation helper numbers.

1st gear  0.25381

2nd gear 0.37099

3rd gear 0.4841

4th gear 0.58182

5th gear 0.66275

Then measure rear wheel circumference in inches - you multiply with this number.

 work out final gear ratio, you divide the number by this. This give mph per 1000 rpm.

Often used final gears and ratios

14 : 48 = 3.43

15 : 48 = 3.2

15 : 47 = 3.1333

15 : 46 = 3.0667

15 : 45 = 3

Here's 4th gear speed for my bike for example.

0.58182 ÷ 3.0667 × 79.5 inches = 15.08 mph per 1000 revs

For 5th

0.66275 ÷ 3.0667 × 79.5 = 17.18 mph per 1000 rpm

 

All I did was work out most of the calculation minus final drive and tyre circumference , I just like working things out .... hopefully someone will find it useful too.

 

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32 minutes ago, Oilyspanner said:

Something I did to quickly work out true speed in each gear  _ this is for gsxr1100 k-n and b1200

Quick calculation helper numbers.

1st gear  0.25381

2nd gear 0.37099

3rd gear 0.4841

4th gear 0.58182

5th gear 0.66275

Then measure rear wheel circumference in inches - you multiply with this number.

 work out final gear ratio, you divide the number by this. This give mph per 1000 rpm.

Often used final gears and ratios

14 : 48 = 3.43

15 : 48 = 3.2

15 : 47 = 3.1333

15 : 46 = 3.0667

15 : 45 = 3

Here's 4th gear speed for my bike for example.

0.58182 ÷ 3.0667 × 79.5 inches = 15.08 mph per 1000 revs

For 5th

0.66275 ÷ 3.0667 × 79.5 = 17.18 mph per 1000 rpm

 

All I did was work out most of the calculation minus final drive and tyre circumference , I just like working things out .... hopefully someone will find it useful too.

 

Or just let gearing comander work it out for you

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1 hour ago, Dezza said:

I still do not understand how you get from gear ratios, final drive reductions and the circumferance of the tyre in inches to mph per 1000 revs without including figures for the primary drive reduction and a conversion of inches into miles O.o.

Are you a maths teacher Dezza? :v

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