Description
Shimano Dura-Ace RD-7800-GS Long Cage Rear Derailleur Triple 10 Speed Silver
Has been inspected, Ultrasonic cleaned, and lubed. Ready to be used.
Inventory number: 08302 TM-SL25
Industry Information:
The Shimano Dura-Ace RD-7800 Long Cage rear derailleur is a component of the highly regarded 10-speed Dura-Ace 7800 mechanical groupset, which was a top-tier road cycling group from the mid-2000s. The long cage version, often designated with “GS” for “Grand Sport,” was designed specifically to accommodate a triple chainring setup.
Key Features and Compatibility:
- 10-Speed Specific: The RD-7800 is engineered for Shimano’s 10-speed road system. It has a different cable pull ratio than later 10-speed groups like Tiagra 4700, and is not compatible with 9-speed, 11-speed, or 12-speed systems. It must be paired with Dura-Ace 7800 series shifters for proper function.
- Long Cage Design: Unlike the more common short cage “SS” version, the long cage derailleur is built to handle the larger chain wrap capacity required for a triple crankset.
- Cog Compatibility: Shimano’s official specification for the RD-7800 GS is a maximum large cog size of 27 teeth. However, in practice, many users have reported successfully running a 28-tooth cassette with a properly adjusted B-tension screw and chain length.
- Total Capacity: The derailleur has a total capacity of 37 teeth, which is a key metric for compatibility. This number is calculated as: (Largest Front Chainring – Smallest Front Chainring) + (Largest Rear Cog – Smallest Rear Cog). The derailleur must be able to take up this amount of chain slack. This capacity is suitable for a triple setup with typical gear ranges.
- Construction: As a Dura-Ace component, it’s made from high-quality, lightweight aluminum with a distinctive polished silver finish. It’s often praised for its smooth, precise, and durable performance, and remains a popular choice for restoring or building high-end classic road bikes from that era.
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A little about the seller:
I’ve been in the cycling industry for more than 30 years (I know, that makes me old!). I’ve been a professional bicycle mechanic for most of those years, including working locally at Lee’s Cyclery before they became Trek Stores. Now I work from home as a Customer Success Manager for a software team. But I still love fixing up and working on bikes and riding them too!
Purchase from me with peace of mind. Not only can you trust my years of experience, but I will also fit you for the bike and provide any mechanical insight at the time of purchase.
Shipping information:
I ship USPS Ground. I try to keep it simple. It will be packed very well, but if you see any damage to the box or Part, keep the box and packing material plus, take pictures. I do insure all parts that are shipped. In addition, if shipped out of Colorado, there is no Sales Tax. You can also combine shipping with multiple items.
