Example & Explanation of STURMEY 5 Speed Gear Hub with/without Mountain Drive Option Chart

Go back to TABLE OF CONTENTS

CLICK HERE

Go to ACTUAL DATA ENTRY CHART

CLICK HERE


BROMPTON STURMEY 5 Speed Calculations with & without MOUNTAIN DRIVE OPTION

   

Standard

16.375

teeth

Notes Sprocket ratios other than the Brompton Standard ratio

Brompton Standard Wheel Size

The "Actual" physical wheel diameter size

Data
Entry
Area

Rear Sprocket

13

teeth

50

teeth

The number of teeth in the Rear sprocket (You will be allowed to vary this)

Front Chain Ring

The number of teeth in the Front Chain Ring (You will be allowed to vary this)

Resulting Sprocket Ratio

3.846 to 1

The resulting sprocket ratio

Resulting Direct Drive Wheel Size

63.0

inches

Resulting WHEEL SIZE in Direct Drive

REAR HUB GEAR SELECTION

Resulting Wheel Size

With Mountain Drive Engaged …

1st gear

16.7

inches

19.9

inches

25.2

inches

31.7

inches

37.6

inches

41.6

inches

49.8

inches

63.0

inches

79.2

inches

94.1

inches

RESULTING WHEEL
SIZES with Mountain
Drive Engaged

With Rear Hub 1st gear engaged

2nd gear

With Rear Hub 2nd gear engaged

3rd gear

With Rear Hub 3rd gear engaged (direct drive)

4th gear

With Rear Hub 4th gear engaged

5th gear

With Rear Hub 5th gear engaged

Without Mountain Drive Engaged ….

1st gear

RESULTING WHEEL
SIZES Mountain
Drive Disengaged

NOTE: If you do not own the Mountain Drive Option, these are the ONLY Resulting wheel sizes.
2nd gear

3rd gear

4th gear

5th gear