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The_Missile

Fun Factor Per Gear

3 posts in this topic

Inspired by Yamakaze and a slow day..... Yamakaze, assuming you went from a 14 x 50 sprocket combo to a 14 x 53 combo you will be increasing the "fun factor per gear" about 6% (but will still be 1.6% behind my own FFPG rating !!!). If you go for the 13 tooth from the 14 with the same 53 sprocket you will get about 14.5% more FFPG vs your 14 x 50 combo !

Bottom line.... careful in first & second !!

Also... top speed in each gear will drop by approx the same amount as you can't make your engine run any faster !

There's obviously more to this than straight math (techies welcome to comment on friction coefficents and efficiencies etc...) but the table below may be useful to ID what additional (if any) changes to gearing you may want to do...

Yamakaze's chart follows, always in relation to a 14 x 50 combo as the start reference.

Table Shows : Increase in FFPG with a 14 x 50 as the reference/starting combo.

The column header (12, 13 14 etc) is offset due to formatting... sorry...

12 13 14 15 16 17

48 12.0% 3.4% -4.0% -10.4% -16.0% -20.9%

49 14.3% 5.5% -2.0% -8.5% -14.3% -19.3%

50 16.7% 7.7% 0.0% -6.7% -12.5% -17.6%

51 19.0% 9.8% 2.0% -4.8% -10.8% -16.0%

52 21.3% 12.0% 4.0% -2.9% -9.0% -14.4%

53 23.7% 14.2% 6.0% -1.1% -7.3% -12.7%

If you dont have a 14 x 50 combo you need to calculate your own chart:

Use the below table as a start. Choose your combo (eg 14 x 50) as your ref/start number.

Create a second table of % as follows : divide each number by the number of your ref/start number and subtract 1 from the result. This will then give you a -ve or +ve value AS COMPARED TO your ref/start number. Multiply this number by 100 gives the %. +ve % = more FFPG, -ve % = less FFPG

Table : Sprocket Ratio Chart

The column header (12, 13 14 etc) is offset due to formatting.... sorry...

12 13 14 15 16 17

48 4.00 3.69 3.43 3.20 3.00 2.82

49 4.08 3.77 3.50 3.27 3.06 2.88

50 4.17 3.85 3.57 3.33 3.13 2.94

51 4.25 3.92 3.64 3.40 3.19 3.00

52 4.33 4.00 3.71 3.47 3.25 3.06

53 4.42 4.08 3.79 3.53 3.31 3.12

Explanation : eg The 12 x 48 combo figure is 4, ie a ratio of 4:1, or for 4 revolutions of the drive sprocket the rear sprocket revolves once and so on....

Enjoy....

------------------

The Missile

'99 WR400F

Airbox Lid - gone

Throttle Stop - shorty!

Plastics/Tank/Seat - One Industries

Street Legal

[This message has been edited by The Missile (edited October 01, 2001).]

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15T x 48T

wheelies in first and second under power, flat out in top within 400 yards. can't see. 2001 a race odyssey.

FF10

Taffy

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