Detailed Introduction to SHIMANO and SRAM Road Bike Gear Systems
Let's first get acquainted with road bike gear systems
Like mountain bikes, road bike gear systems also include a cassette, bottom bracket, crankset, chain, brake levers, shift levers (known as "brifters" on mountain bikes), rear derailleur, front derailleur, and cables. However, unlike mountain bike gears, road bike gear systems lean more towards speed, aerodynamics, and lightweight design, while mountain bike gears focus more on off-road performance, rigidity, and durability.
Currently, most road bike gear sets are double chainring systems, and single chainring setups have not become widespread yet. One of the most well-known single chainring road bikes today is the 3T Strada.
The road bike gear market is mainly dominated by three brands: Shimano, SRAM, and Campagnolo, while FSA and Rotor represent more niche options.
This article will primarily explain Shimano and SRAM.
SHIMANO
Shimano is perhaps on par with SRAM in the mountain bike arena, with each having their own strengths and followings.
However, in the road bike realm, it must be acknowledged that Shimano holds a more dominant position.
According to Shimano's official road bike gear classification list, road bike gear systems can roughly be divided into 3 levels.
Top Tier:
Dura-Ace Di2
Dura-Ace R9100
Ultegra Di2
Mid-High Tier:
Ultegra R8000
105 R7000
Entry-Level:
Tiagra R4700
Sora R3000
Claris R2000
Claris Series:
Claris R2000, being Shimano's lowest-tier model, is designed for daily commuting and is available in both STI dual control (for drop handlebars) and STI shift lever (for flat handlebars) versions. Despite its entry-level status, Shimano has given Claris internal cable routing to eliminate the "mantis effect" and has used a four-arm chainring design. It supports 8/16-speed options.
Sora Series:
Sora R3000, an upgrade from the 3500 series, was released in 2016 and is aimed at entry-level recreational riders for daily fitness and city riding. R3000 utilizes a four-arm chainring design and, due to the technology trickle-down, features 9-speed internal cable STI dual control. Riders can choose between a 50-34T double chainring or a 50-39-30T triple chainring, with a maximum cassette size of 11-34T.
Tiagra Series:
Tiagra 4700, released in 2015, is optimized for daily riding and light off-road use, targeting entry-level enthusiasts. It borrows key technologies from higher-end gear series, offering chainring options of 52-36T and 50-34T. However, in terms of speeds, the R7000 is 11-speed, while the 4700 is 10-speed. In terms of total weight, the R7000 is 2540g, while the 4700 is around 2866g.
105 Series:
The new 105 R7000, released in early 2018, is aimed at entry-level enthusiasts and introduces disc brake versions. 105 has always been synonymous with high value, appearing on many road bikes priced from 800 to 2000 euros. R7000, as Shimano's most affordable 11-speed groupset, shares many features with Ultegra and Dura-Ace. R7000 has shorter lever throw for quicker, more precise shifts. As for front and rear derailleurs, R7000 offers chainring options of 50-34T, 52-36T, and 53-39T.
Ultegra Series:
Ultegra R8000, released in 2017, is targeted at enthusiast riders looking to take their cycling to the next level. Ultegra has long been known for its great price-to-performance ratio, often found on road bikes priced from 800 to 2000 euros. R8000 features many of the same technologies as Ultegra and Dura-Ace. It offers excellent shifting performance with shorter lever throw, and it provides chainring options of 50-34T, 52-36T, and 53-39T.
Ultegra Di2:
Ultegra Di2 is the electronic shifting version of Ultegra and is one of Shimano's two electronic shifting groupsets. Ultegra Di2 can be configured with either synchronized or semi-synchronized shifting, allowing the rider to choose between using the front (full) or rear (semi) derailleur for automatic gear changes, optimizing the chain's position for each gear to avoid chain rub. Additionally, Ultegra Di2 introduces new customizable top cover Di2 buttons to enhance shifting customization.
Dura-Ace Series:
Dura-Ace R9100, released in 2016, is targeted at elite racers and professionals for racing and high-level training. R9100, as Shimano's top-tier gearset, comes with numerous upgrades and optimizations over R9000. The shift levers have been redesigned for improved ergonomics with anti-slip patterns on the hoods. The front and rear derailleurs have been optimized for cable routing, and the front derailleur features an integrated cable tension adjustment mechanism. The rear derailleur still boasts Shimano's renowned Shadow technology. R9100 chainrings have increased crank arm width and feature hollow construction for improved stiffness and transmission efficiency.
Dura-Ace Di2:
As the electronic shifting version of Dura-Ace, Dura-Ace Di2 is currently the most expensive model in Shimano's road bike gear lineup. Unlike SRAM Etap, Dura-Ace Di2 is not truly wireless in the traditional sense, though it does offer some wireless functionality. Dura-Ace Di2, like Ultegra Di2, uses Shimano's synchronized shifting technology. Additionally, both front and rear derailleurs have built-in crash protection. Compared to the previous generation Dura-Ace electronic shifting, Dura-Ace Di2 has seen improvements in shifting efficiency, weight, and functionality.
SRAM
According to SRAM's official road bike gear classification list, road bike gear systems can be divided into 3 levels.
Top Tier:
Red eTAP
Red
Mid-High Tier:
Force
Rival
Entry-Level:
Apex
In the SRAM road bike gear product list shown above, the items within the red boxes represent the current mainstream road bike gear models (rim brake versions), while those marked with the number "1" represent the single-chainring disc brake versions of those models. Force CX1 is designed for off-road road cycling.
Apex Series:
- Double Chainring Version
- Single Chainring Version
Apex is SRAM's entry-level gear system, targeting amateur riders, but with lighter weight compared to similar products in its class. Apex is available in both rim brake and disc brake versions, as is common across SRAM's entire lineup. It offers 11/20-speed options. Apex features a compact crankset, and its rear derailleur boasts SRAM's WiFli technology, providing a wider range of gear ratios on the cassette (11-36t), offering more gear combinations than a standard triple crankset and reducing extra weight. Additionally, Apex inherits some features from SRAM's top-tier models, such as Zero Loss shifting, brake lever reach adjustment, and Exact Actuation shifting.
Rival Series:
Rival is aimed at enthusiast riders, on par with Shimano 105. Rival, thanks to improved materials over Apex, offers better weight and durability, delivering a superior riding experience. Rival, as SRAM's most affordable 11/22-speed road bike gearset, comes in both double (2x11) and single (1x11) chainring configurations. Rival features a five-arm chainring design and, thanks to its WiFli rear derailleur (available in medium and short cage options), provides a wider gear range on the cassette, with a maximum cog size of 28T.
Force Series:
Force is aimed at advanced enthusiasts and offers 11/22-speed options, competing with Shimano R8000. It is commonly found on mid to high-end road bikes. Force shares many top-tier features with Red but adds 300g in weight. Force utilizes lightweight high-end aluminum and carbon fiber materials and supports GXP, BB30, and PF30 bottom bracket standards for enhanced weight savings, stiffness, and adaptability, making it one of SRAM's most cost-effective gearsets. In addition to the standard Force groupset, there is the Force 1 groupset, which is SRAM's highest-end road bike single chainring system, and it has been used effectively on 3T Strada road bikes. Besides Force 1, there is also Force CX1, designed for off-road road cycling.
Red Series:
Red was released in 2014 and is designed for elite racing and professional training. It competes directly with Dura-Ace and Super Record. Red components are constructed using ultralight materials, including high-end aluminum, extensive carbon fiber, titanium, and ceramic bearings. SRAM Red also offers the WiFli technology, allowing for an extra-wide range of gear ratios. Notably, Red is currently the lightest among mainstream gearsets, weighing in at only 1758g (BB30 version). In 2015, SRAM made significant upgrades to the Red hydraulic disc brake kit, expanding aerodynamic options, adding new gear ratio choices, and introducing two new WiFLi cassettes along with a 52/36t semi-compact chainring option.
Red eTAP:
Red eTAP, released in 2015, represents SRAM's top-tier road bike gear system and is the only wireless electronic shifting groupset among the three major gear brands. Red eTAP features individual front and rear derailleur batteries for sending and receiving shifting signals based on SRAM's proprietary wireless protocol. Red eTAP is easy to install, with a very low chance of misconfigurations. Shifting is precise and clean, and Red eTAP chainrings are available in four specifications: 46-36T, 50-34T, 52-36T, and 53-39T, with six crank arm lengths ranging from 165mm to 177.5mm. eTap offers both short and medium cage rear derailleurs. The short cage rear derailleur supports a maximum cassette size of 28T, while the medium cage rear derailleur can accommodate a 32T cassette. In terms of weight, eTAP has a total weight of 1955g (rim brake), making it an impressive option among electronic shifting groupsets.
