Road riders are very particular about the function and feel of their drivetrain, braking, and shifting mechanisms, a collection of components known as a group, groupset, or “gruppo,” if your love of Italian cycling affectations was never sullied by Breaking Away.
Shimano has built a reputation for building superb groups with technology that trickles down from one elite generation of Dura Ace components, down through Ultegra, 105 [one oh five], Tiagra, Sora, and the humble Claris line.
Is it worth the upgrade to 105 or does Tiagra fit the bill? Let’s take a closer look.
Tiagra’s main attraction is the group’s verstility. You can build a Tiagra 10-speed group onto a bike with road drop bars or flat handlebars with the appropriate brake levers and shifters.
Tiagra has a far wider range of gears, including four cassette ranges and three chainring arrangements (two doubles and a triple-ring option).
A Tiagra drivetrain can be honed for a Euro-style butterfly-handlebar, cantilever brake, loaded touring rig, to a budget racing whip, a disc-brake gravel crusher, or a spiffy city commuter.
105 components are more oriented to speed and performance over versatility and thrift.
The main attraction to this tier is the 11-speed drivetrain. Experienced riders will remember the limits of 6-speed cassettes from “back in the day,” fighting hard to cope with the drastic change in effort and RPMs needed between jumps.
Every subsequent additional cog in a drivetrain adds an option to spin more efficiently, and riders who can tell when they are pedaling optimum cadence for the given context will appreciate that they have more subtle, but essential, gear in their arsenal to push them ahead (or at least keep up) with the pack.
Similarities and Differences
Shimano’s current third- and fourth-tier road groups are very similar in features and appearance, but appearances can be deceiving. Both use Shimano’s 4-bolt, 110 mm bolt circle diameter spider and chainrings, trickle-down technology from their premium Dura Ace and Ultegra level components.
The 4-arm spider across all road and mountain groupsets was a move to make a wider range of chainring sizes fit on all cranksets, including “standard” race-oriented 53/39 combo, conventional “compact” 50/34 combo. This gives riders more choices and presumably makes the manufacturing process easier for Shimano.
Both groups can be built with conventional mechanical brakesets, or Shimano’s new road-specific hydraulic disc brakes.
Purists will opt for the clean simplicity of road caliper brakes, but there’s no denying the versatility and all-weather stopping power of Shimano’s renowned hydraulic braking technology that have dominated the mountain bike market for many years.
Both groups also feature svelt under-the-bar-tape brake and shift cable routing now that Tiagra has dropped the cluttered look of routing the shifter cables out the interior sides of the hoods. Some argue that the resulting extra bends result in additional friction, dragging Shimano’s otherwise buttery shift action, but the included Shimano housing seems to mitigate those concerns.
The 11 Speed Advantage
Given the choice between the two groups as an upgrade to your current bike, which one should you choose? The price difference between the two is not staggering, so if both groups check all the boxes for your needs in terms of drivetrain range, I would go with 105 for the smoothest shifting and the benefits of 11-speed gears.
This is also, in effect, future-proofing your drivetrain. Now that the 11-speed genie has been let out of the lamp, she’s not going back in, so there’s no point in willfully choosing an “old” 10 speed arrangement.
However, you must check the compatibility of your current rear wheel, as 11-speed Shimano cassettes will not fit on most hubs with 8-, 9-, and 10-speed in mind.
Check with your hub manufacturer or your local bike mechanic to see if your hub is 11-speed compatible. If not, and new wheels are not in the budget, you may be relegated to 10-speed, which is not the worst scenario, considering how nice the current Tiagra group is.
If you need the gear range afforded by a triple ring crankset or are building a bike with flat-type handlebars, Tiagra is going to be a superior choice.
It will also be a more budget-friendly choice for any style of bike, as every penny can count when you’re building a whole bike from scratch or upgrading an existing bike with dated parts.