USER INSTRUCTIONS: The BLUE entry points   Blue  below are where you may enter combinations of different values for the number of teeth on the CHAIN RING and REAR sprockets and the chart will compute the resulting Wheel Sizes for the different Gear Settings. If your browser is MS Internet Explorer then to compute the result after entering new data you may press Enter or click on any other part of the form. With other browsers use only the second method. On changing the option in the combo box the result is computed automatically.

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Mouse or Keyboard TAB key: You may reach the DATA ENTRY points by pressing the TAB KEY on your Keyboard which cycle you through the various data entry points or by MOUSE CLICKING the entry point allowing you to enter different spocket teeth values for comparison combinations.
HELP Messages & Notes: On the right side of the chart, you will see the words HELP and NOTE. MOUSE CLICK on these words for the Help or Note message associated with that area.

SRAM 6 Speed Rear Derailleur with Front Derailleur Option

   

standard

inches

Brompton Standard Wheel Size

Data
Entry
Area

SMALL Chain Ringt

teeth

teeth

teeth

teeth

LARGE Chain Ring

LARGE Rear Sprocket

SMALL Rear Sprocket

1st Resulting Sprocket Ratio

inches

inches

inches

inches

2nd Resulting Sprocket Ratio

3rd Resulting Sprocket Ratio

Note

4th Resulting Sprocket Ratio

Resulting 1st Direct Drive Wheel Size

Resulting 1st Direct Drive Wheel Size

Resulting 1st Direct Drive Wheel Size

Note

Resulting 1st Direct Drive Wheel Size

REAR HUB GEAR SELECTION

Resulting Wheel Size

Resulting % of Direct drive

Small Chain Ring and
Large Rear Sprocket

1st gear

inches

inches

inches

inches

inches

inches

73%
2nd gear

100%

Note
3rd gear

136%

Small Chain Ring and
Small Rear Sprocket

1st gear

73%
2nd gear

100%

Note
3rd gear

136%

Large Chain Ring and
Large Rear Sprocket

1st gear

inches

inches

inches

inches

inches

inches

73%
2nd gear

100%

Note
3rd gear

136%

Large Chain Ring and
Small Rear Sprocket

1st gear

73%
2nd gear

100%

Note
3rd gear

136%