Function and effect

 

1. Function

 
 
 
 
 
 
 
 
 
 
 
 
 
 
With mountain-drive get enough low gears to climb up even the steepest hills without strain.

mountain-drive doubles the existing gears (blue bars). You get lower gears (red bars), normally without any overlap.

Please note, that the gear range of a bike equipped with mountain-drive is much wider than the range of a 24- or even 27-speed bike with derailleur, where several gears (about 10 from 24) are provided in two- or threefold (see diagram at the bottom of this page). However, the total gear range is much smaller than with mountain-drive.

 

2. How to shift?

It's so easy: push with the heel of your shoe either on the right or on the left side of the axle on the push button to change from high to low gear or vice versa! That's all! 
< Shift mountain-drive by a touch of your mouse!
     

The new easy-shift levers make shifting a real pleasure - even with clic-in-pedals or small shoes.
< Shift mountain-drive by a touch of your mouse!
     

 

3. The effect

7.5/94
5.5/69
4.0/50
3.0/38
2.2/28
1.6/20

Gear range: 466%

   3-speed hub + mountain-drive

The blue bars show the development (in meters) resp. the inch gears of a 3-speed bike.

The red bars show the additional 3 speeds, if mountain-drive is engaged. A gear range of 466%!

(Example: 46 tooth chainring, 18 tooth cog, 700C rear wheel)
     
8.4/105
7.1/89
5.6/70
4.4/55
3.7/46
3.4/43
2.8/35
2.3/29
1.8/23
1.5/19

Gear range: 560%

   5-speed hub + mountain-drive

The blue bars show the development (in meters) resp. the inch gears of a 5-speed bike.

The red bars show the additional 5 speeds, if mountain-drive is engaged. A gear range of 560%!

(Example: 46 tooth chainring, 18 tooth cog, 700C rear wheel)
     
10.1/127
8.6/108
7.2/90
5.8/73
4.7/59
3.9/49
3.3/41
4.0/50
3.4/43
2.9/36
2.3/29
1.9/24
1.6/20
1.3/16

Gear range: 761%

   7-speed hub (SRAM Spectro 7) + mountain-drive

The blue bars show the development (in meters) resp. the inch gears of a 7-speed bike.

The red bars show the additional 7speeds, if mountain-drive is engaged. A gear range of 761%!

(Example: 42 tooth chainring, 16 tooth cog, 700C rear wheel)
     
8.3/104
7.1/89
6.1/76
5.3/66
4.6/58
4.0/50
3.4/43
3.3/41
2.8/35
2.4/30
2.1/26
1.8/23
1.6/20
1.4/18

Gear range: 611%

   7-speed hub (Shimano Nexus) + mountain-drive

The blue bars show the development (in meters) resp. the inch gears of a 7-speed bike.

The red bars show the additional 7speeds, if mountain-drive is engaged. A gear range of 611%!

(Example: 44 tooth chainring, 18 tooth cog, 700C rear wheel)
     
7.8/98
7.1/89
6.1/76
5.4/68
4.8/60
4.1/51
3.6/45
3.1/39
5.9/74
5.4/68
4.7/59
4.1/51
3.6/45
3.1/39
2.7/34
2.3/29
4.1/51
3.7/46
3.2/40
2.8/35
2.5/31
2.1/26
1.9/24
1.6/20

Gear range: 486%

   Comparison: 24 speed derailleur system.

(Example: triple chainrings 42/32/22, cassette 28/24/21/18/16/14/12/11, rear wheel 26")

Several gears (see black columns) are provided in two- or threefold, however, the total gear range is much smaller than with mountain-drive.
     

 

3. How do I calculate "development" and "inch gears"?

For the calculation, you need the following details:
- Tooth number of the chainring
- Tooth number of the rear cog
- Circumference of the rear wheel (= diameter * 3.14)

You get the "development" by the following formula:

Tooth number of the chainring / tooth number of the cog x circumference of the rear wheel (in meters)

You get the "inch gears" by the following formula:

Tooth number of the chainring / tooth number of the cog x circumference of the rear wheel (in inches)/ 3.14

For a derailleur system, calculate all gears according to the formula above.

For a rear hub, multiply all results with the following factors:

3-speed-hub:
1.speed: 0.75
2. speed: 1
3. speed: 1.33

5-speed-hub SRAM Spectro 5:
1.speed: 0.67
2. speed: 0.78
3. speed: 1
4. speed: 1.28
5. speed: 1.5

7-speed-hub SRAM Spectro 7:
1.speed: 0.57
2. speed: 0.68
3. speed: 0.81
4. speed: 1
5. speed: 1.24
6. speed: 1.48
7. speed: 1.74

7-speed-hub Shimano Nexus 7:
1. speed: 0.632
2. speed: 0.741
3. speed: 0.8431
4. speed: 0.989
5. speed: 1.145
6. speed: 1.335
7. speed: 1.545

 

For calculating the mountain-drive effect, divide all results by 2.5.

For calculating the speed-drive effect, multiply all results with 1.65.

 

Are you looking for even more detailled infos? Just download our manual (pdf-file): mountain-drive manual english