They might be fractionally better in a given gear due to very slightly higher power in standard mode, but not enouigh to get excited about. Where the S models win in climbing is that the high power mode has a higher multiple, i.e. typically 2 times standard power rather than 1.5 times on low speed models.
The models I know of are as follows, the prices shown are old UK ones though. Some of these models may no longer be current:
C Series; 26” wheel size
Low step size: XS(41cm) S(45) M(50) L(55)
Cross Bar size: S(45cm) M(50) L(55) XL(60)
3 x Power settings Eco (50%) Standard (100%) High 150%)
250 Watt. 10Ah Li-i / Mn. 26V 2.6kg
Red, Silver, Black or Blue
C5; Shimano 8 gear Nexus Standard, Shimano Roller brake, Seat-Cushy SR Suntour XY, Busch and Muller Lumatec Fly lighting, 24kg £2,034
C6; 8 gear derailleur, Shimano roller brake, Seat- SR Suntour NCX,
Busch and Muller Lumatec IQ-Fly lighting, 23kg £2,195
C8; Shimano 8 gear Nexus Premium, Walk pace setting 6km/h, shimano roller brake Busch and Muller Lumatec IQ-Fly lighting, 24kg £2,276
C9: 8 gear Alfine sport. Walk pace setting 6km/h, Magura HS33 hydraulic brake Busch& Muller Lumatec IQ-Fly Lighting 24kg £2,679
T Series; 28” wheel size
T5 “ £2,034
T6 “ £2,195
T8 “ £2,276
T9 “ £2,679
K Series; 21 kg, Carbon Fibre frame, 28”wheel size
Low step, S(45cm) M(50) L(55)
3 x power settings, 250 Watt 10Ah Li-I / Mn 26V, Busch & Muller Lumatec IQ Lighting.
K-Street; SRAM dual drive 3x8 gear derailleur, Magura Louise Brakes, 25-45km/h £4,131
K-Urban Option of Walk Pace 6km/h, Shimano 8 gear Alfine sport, Shimano Alfine Brakes, 25km/h
£4,131
K-Rohloff, 14 gear speedhub £4,695
THS Series; 24kg,As T series + Sport Motor, 25-45km/h
T8HS; SRAM dual drive 3x8 gear, Magura HS33 hydraulic brakes £2,760
T9HS; Shimano 8 gear Alfine Sport, Shimano Alfine brakes £2,921
T14HS;14 gear Rohloff hub, Magura HS33 hydraulic brakes £3,889
S Series Low Cross bar, S(43cm) M(50) L(55) XL(60), 3 x power settings, Sport-Motor, 250 Watt, 25-45 km/h, 23kg
S-Urban 26” wheel, Shimano 8 gear Alfine sport, Shimano Alfine brakes, Starrgabelshock’s £3,204
S-Street 26” wheel, Sram 3x8 duel drive gears, Magura Louise brakes, Starrgabel shock’s £3,204
S-Cross-Country Shimano 9 gear derailleur , Magura Louise brakes Rock shocks Tora £3,204
S-Urban 28”wheel ShimanoAlfineBrakes, Shimano 8 gear Alfine sport, Starrgabel shock’s £3,204
S-Street 28” wheel Sram 3x8 dual drive gears, Magura Louise brakes, Starrgabel shock’s £3,204
S Series Rohloff hub £3,890
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