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You have decided to embrace road cycling in all its Lycra glory. You are convinced that the only thing standing between you and the maillot jaune is a better bike.
Once you reach this level, the bikes that will take you on that journey will likely be equipped with either a Shimano Tiagra or 105 groupset.
For those unfamiliar with groupsets, it is basically a catch-all term for the mechanical components on a bike that are designed to work seamlessly together.
In simple terms it is the components that transfer leg power to bike power as well as the brakes.
Shimano, a name familiar to most cyclists, dominates the groupset market. They have a groupset for everyone one; from entry-level to performance:
- Dura Ace
In this article we look at the Shimano 105 versus Tiagra groupset to help decide which one is best for you and your budget.
What Is A Groupset?
Groupsets bring together the mechanical components on the bike, from the gears to the brakes and everything in between. A groupset means that all the components are designed to work harmoniously together for improved performance.
With groupsets split across various budgets, there are obvious differences that ultimately affect the overall performance.
The main difference between the Shimano groupsets is the number of sprockets on the rear cassette. As the price increases so too does the number of sprockets.
Whilst the gear ratios across the range are broadly similar, the extra sprockets improve pedalling efficiency as riders can select the most optimal cadence for their effort. The extra sprockets mean smoother shifting and less clunky torque changes.
As price increases there are also differences in the weight of the components and the overall quality. On paper the weight differences may seem tiny but out on the road these marginal gains can make all the difference on epic climbs.
At the high end, there are also electronic options that do away with mechanical cables completely. This option is available on the Ultegra and Dura Ace groupsets. You would struggle to find a rider in the pro peloton not using electronic shifting these days.
Read More: 105 vs Ultegra
The trickle-down effect means that it is perhaps only a matter of time until electronic shifting is a common choice for us mere mortals.
As you get towards the Shimano Tiagra and 105 groupsets there is a more obvious emphasis on quality and performance. These groupsets dominate mid-market road bikes and offer an excellent balance between value and performance.
105 vs Tiagra: The Key Differences
- Number of sprockets. The 105 comes with an 11-speed sprocket compared to a 10-speed sprocket on the Tiagra.
- Weight. The build quality of the 105 crankset leads to an almost 300g weight saving compared to the Tiagra groupset.
- Brakes. Both the Tiagra and 105 groupsets offer excellent hydraulic disc brakes. If you stick with rim brakes, the 105 offers superior performance through the SLR-EV Dual Pivot design.
Shimano Tiagra 11-32 Cassette
The most obvious difference between the 105 and Tiagra groupsets is the number of sprockets in the rear cassette. The Tiagra uses a 10-speed cassette compared to an 11-speed cassette on the 105 groupset.
The 105 is available in 11-25, 11-32 and 12-25 options.
The Tiagra is available in 11-25, 12-28, 11-32 and 11-34 options for the cassette.
This looks complicated but these numbers simply represent the number of teeth on the cassette. The first number, the smaller of the two, represents the smallest sprocket size and the second, larger number, and is the number of teeth on the large sprocket.
Video: Bike Gear Ratios | Everything You Need To Know
The extra sprocket on the 105 allows the rider to find the most efficient and optimum cadence for their efforts.
Although both the 105 and Tiagra cassettes use the same nickel plated steel sprockets, the 105 cassette is considerably lighter despite having an extra sprocket.
The chain also needs to be matched to the number of sprockets. The 105 chain is designed for 11-speed rather than 10-speed and is narrower and therefore a little lighter than the Tiagra chain.
Shimano 105 Rear Derailleur
Whilst there used to be barely any discernible difference between the 105 and Tiagra rear derailleurs, recent iterations of the 105 groupset use something known as a Shadow rear derailleur.
This technology is designed to reduce damage to your rear derailleur should you crash since of the biggest culprits of poor shifting performance is a bent rear derailleur.
The 105 rear derailleur is also more compact looking than the Tiagra whilst still being able to support a 30t cog on the cassette.
Shimano 105 Crankset
The cranksets may look the same but there are significant hidden weight savings with the 105 crankset compared to the Tiagra.
The design on both cranksets, with uneven spacing between the four spider arms, improves strength and stiffness for efficient power transfer.
The 105 and Tiagra cranksets are available in 165mm, 170mm, 172.5mm and 175mm crank lengths. The 105 comes with an extra small 160mm crank length.
Shorter cranks lengths have found a lot of traction with pro riders as there are tangible aerodynamic and physiological benefits.
Ultimately, the right size for you is the one that puts you in the most comfortable position on the bike for your style of riding.
The Tiagra double crankset is available in 52-36 and 50-34 tooth options. The 105 crankset also comes with the racing-ready 53-39 tooth option.
The Tiagra groupset comes with the option of a triple front crankset (50-39-30) compared to compact double offered on the 105.
Triple cranksets are not as popular as they once were due to weight and maintenance but they do offer extra gearing for getting over steep climbs. They are still a popular choice for touring bikes for this reason.
Read more: Compact vs Standard cranksets compared
The differences between the Tiagra and 105 really start to show in the brakes, especially for purists who prefer rim brakes over disc brakes.
The 105 groupset uses the same SLR-EV Dual Pivot rim brake design that can be found on the premium Ultegra and Dura-Ace groupsets. This means more equal braking forces through each arm providing better modulation and stopping power.
The rim brakes on the Tiagra groupset offer perfectly acceptable braking performance but lack the confidence-inspiring feel of the 105 brakes.
Upgrading the one-piece brake blocks on the Tiagra rim brakes to cartridge style pads will bring immediate improvements.
Shimano states that the 105 and Tiagra rim brakes will fit wheels up to 28mm wide although many riders have successfully fit 30mm wide wheels with 105 brakes.
With the trend in road cycling heading towards wider tires, for both comfort and performance, having this option with the Tiagra and 105 is a great way to future proof your bike. It could even open the door to some fun gravel rides.
As you would expect in groupsets aimed at riders who value performance, the 105 and Tiagra groupsets come with hydraulic disc brake options. Across the entire range, Shimano disc brakes offer consistently excellent performance.
Disc brakes offer increased modulation and stopping power compared to rim brakes, especially true in wet conditions.
Read More: Best road bike brake pads
Shifters and Levers
The Shimano shifters, or STI’s (Shimano Total Integration), are excellent across the entire range. Dual control levers are used on the Tiagra and 105 groupsets meaning that the levers control both the gear selection and the brakes.
The main difference in the dual control levels between the groupsets is that the Tiagra is 10-speed and the 105 is 11 speed.
The Tiagra STI shifter is also compatible with a triple crankset whereas the 105 shifter only works with a double crankset.
On both groupsets the cables are routed under the bar tape for a much more decluttered cockpit. This has long been the standard on the 105 groupset but even more budget-friendly groupsets, like the Tiagra, are seeing this aesthetic improvement.
When equipped with hydraulic disc brakes, the 105 dual control shifter is a much more compact and refined package compared to the Tiagra.
The 105 shifters are also available in small sizes which can be a game changer for riders with smaller hands.
With both options the STI levers are ergonomic and precise.
The Tiagra and 105 STI levers both feature a simple reach adjustment screw under the hoods.
|Number of Sprockets
* Rim brake option
Shimano groupsets, right across the range, deserve their excellent reputation amongst cyclists. Riders benefit from decades of trickle down from the pro riders and that translates into great value components.
It is possible to upgrade the 105 groupset with premium Ultegra or Dura Ace components down the line which may be a selling point for a lot of riders.
At the end of the day every rider has to work within their own budget and this will ultimately determine which groupset is best for you. You won’t be let down with either the 105 or Tiagra groupsets.
The latest iterations of the Tiagra groupset have improved greatly on its predecessors, with improved shifting and braking as well as neater cable routing.
It would be great to hear your experiences of using these groupsets and what you would recommend to fellow riders in the comments below.
Read More: Sora Vs. Tiagra groupsets
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