Shimano Dura Ace 7900 Rear Derailleur

Shimano Dura Ace RD-7900 Rear Derailleur

The choice of champions - and anyone else looking for perfect performance - the RD-7900 Rear Derailleur is a perfect marriage of new-world carbon and Shimano's traditional cold forged aluminium technological supremacy.

• Lightweight carbon cage.
• Cold-forged aluminium body construction for lightweight strength and durability.
• Wider links. This means that the shift plates that connect the pivot and knuckle are further apart, so they resist flexing and twisting when you shift under load.
• The tough DuPont Zytel pulley wheels spin on cartridge sealed ceramic bearings for near friction-free performance.
• The pulley wheel plates are carbon fibre to enhance rigidity and reduce weight.
• Wide link design gives quick accurate shifts.
• Self-lubricating micro-machined fluorine-coated link pivot bushings guarantee low-friction shifting.
• Total 33t capacity means the RD-7900 can readily cope with a wide gear range set up such as a 34/50 chainset with an 11-28 cassette.
• Approximate weight: 166g - that's 16g lighter than the RD-7800 Dura-Ace rear derailleur. That's the benefit of carbon.

Review
'By using carbon fibre composite cage plates and jockey pulleys that spin on ceramic bearings, Shimano are clearly looking for more stiffness and less weight.

More weight is saved by the titanium main pivot bolt and cable clamp bolts - bringing the overall weight down to 165g - and the four pivot pins in the mech main body are fluorine-coated to reduce friction and increase durability.

And although that front plate pivot body (the bit that the mech cage fits into) looks like alloy, it isn't – it's a resin-reinforced thermoplastic.

The Shimano mech was slightly slower than its Campagnolo Record rival when it came to shifting but out on the road it felt quicker due to the smooth and near silent manner of those shifts.

It has a whopping 33-tooth capacity, which means it handles all of the available gear combinations in the Dura-Ace range with ease.'
bikeradar.com

Shimano