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Appendix

A Redmount Roller recumbent trike finished in RAL 9005, Jet Black.

Typical Gear Ratios

Notes for 2008 Rollers

Next season's Rollers will be fitted with triple chain rings, a Campagnolo  Centaur front  mechanism and a twist grip changer on the left hand bar as standard. This arrangement provides a practical, light-weight and cost-effective means of extending the already wide gear range when using the DualDrive or Rohloff hub gears.  If weight or cost is a consideration then the Roller can be provided with either a single chain ring or a double chain ring with manual change-over as fitted previously.

A triple chain ring and 9-speed sprocket derailleur system can be also provided, but the range of gears will not be as wide as the options shown below.  

As all Rollers are hand-built to order, we are happy to consider alternative gearing arrangements to meet a customer's specific requirements - please call and discuss.

 

 

If you are new to cycle gearing then you may wish to know what the various numbers shown in the tables below mean. 

The figures on the green background are usually shown on the gear shifter on the handlebar.

"Sprocket" refers to the number of driven gear teeth on the rear wheel.

"Chain ring or C/R" refers to the number of driving teeth on the pedal crank.

"Fast, Normal and Hill" refer to the three positions of the thumb lever on the DualDrive gear shifter.  The numbers 1.362, 1.000 and 0.734 are the internal gear ratios of the hub.  The 14 internal ratios of the Speedhub 14 are also shown, e.g. gear 11 is direct drive ratio of 1.00:1.

"Wheel" (in this case 20) refers to the nominal diameter, in inches, of the driven wheel of the Roller.

"Inches"  (the figures on a white background) refer to the diameter of a virtual driven wheel obtained by the gearing.  One revolution of the pedals rotates the virtual wheel one revolution.

The calculation is: inches = (chain ring teeth/sprocket teeth) x wheel size.  When a hub gear is used the resultant is further multiplied by the internal gear ratio. The "gear inches" method of describing a cycle gear ratio is mainly used in previously non-metric countries, and stems from the days of the early machines when the pedals were attached directly to the front driving wheel.  The maximum gear ratio then was limited by the length of the rider's legs.

"Range" is the ratio of the highest gear divided by the lowest gear.

 

 

SRAM DualDrive 3 x 9

Triple Chainrings

SRAM DualDrive 3 x 9   9 8 7 6 5 4 3 2 1   Diff.
Wheel/CR/Sprocket 20 52 11 13 15 17 20 23 26 30 34 Cass 23
Fast 1.36   122 104 90 79 67 59 52 45 40 CR 22
Normal 1.00   90 76 66 58 49 43 38 33 29 Total 45
Hill 0.73   66 56 48 43 36 32 28 24 21
    42                      
Fast 1.36   99 84 72 64 54 47 42 36 32    
Normal 1.00   73 61 53 47 40 35 31 27 23    
Hill 0.73   53 45 39 34 29 25 23 20 17
    30                      
Fast 1.36   71 60 52 46 39 34 30 26 23    
Normal 1.00   52 44 38 34 29 25 22 19 17    
Hill 0.73   38 32 28 25 21 18 16 14 12 Range 994%

Rohloff Speedhub 14

Rohloff 14   0.136                            
Wheel 20 Gear 14 13 12 11 10 9 8 7 6 5 4 3 2 1
Sprocket 13 Ratio 1.47 1.29 1.14 1.00 0.88 0.77 0.68 0.60 0.53 0.47 0.41 0.36 0.32 0.28
Chain ring

52

  117 98 86 76 67 59 52 46 40 35 31 27 24 21
Chain ring

 42

  90 79 70 61 54 48 42 37 32 29 25 22 19 17
Chain ring 30   64 57 50 44 39 34 30 26 23 20 18 16 14 12
Development   m 5.13 4.52 3.98 3.50 3.08 2.71 2.39 2.10 1.85 1.63 1.43 1.26 1.11 0.978

 

 

Colours

The Roller is normally available in nine standard RAL colours as follows:

Jet Black - RAL 9005

Signal White - RAL 9003

Ruby Red - RAL 3003

Purple Red - RAL 3004

Gentian Blue - RAL 5010

Deep Orange - RAL 2011

Traffic Yellow - RAL 1023

Opal Green - RAL 6026

Traffic Purple - RAL 4006

Other colours are available to special order but will probably incur extra costs and time.

 

Overseas Shipping Information

If you can't collect your Roller trike we can arrange to ship the machine to you.  The trike is completely assembled, adjusted and test-ridden.  The wheels are then removed, the boom disconnected and the chassis is split into two parts - these assemblies are packed into two large boxes.  A few hours of straight-forward re-assembly is required - full instructions are provided.  Please contact us to discuss this option and the costs involved.

 

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Last updated: 24 June 2007

 

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