How to choose your transmission group?

Weight, operation, type of braking, number of speeds, compatibilities and durability define the range level of a transmission group on a bicycle. route or triathlon. Let's see what elements to take into account in addition to the price of the complete bike or that of the groupset as a second-hand product for define the group you need.

By Guillaume Peephole – Photos: ProCycleShot/Wouter Roosenboom/3bikes.fr/DR

=> SEE AS ​​WELL : 2019/2020 Group Prices and Weights route

Summary:

• How many speeds?
• By cable or electronic?
• What type of braking?
• Differences in ergonomics
• What level of range?
• Options
• Compatibilities

A bike's ride quality and handling are first defined by the frame, then the wheels, and finally the components that make up the drivetrain and brakes, which we call the groupset. A groupset has little effect on the bike's overall dynamics unless you factor in weight of its elements and of the bearing quality. The rest is comfort, precision, pleasure and possibly safety.

How many speeds?

Public chat the groups route or triathlon, we find transmissions from 10 to 13 speeds for the cassette at the rear, and with one to two chainrings. The 13 is exceptional and only available with a single chainring at Rotor. The 10 is largely outdated, even if we can still find spare parts, because The 11-speed has been around for at least ten years. Which is enough to answer all the questions concerning the reliability of the system, and in particular the durability of the chains and cassettes. This last type of transmission still holds the rope since it is the number of speeds still used today by Shimano, the main player in the market, whether on standard bikes or for replacement groups. But Campagnolo and Sram have released their 12-speed drivetrains (with two chainrings), which should prompt Shimano to react soon.

=> SEE AS ​​WELL : 12 or 13 speeds, the latest on the new transmissions

DThe choice of the tooth combination depends on the comfort of use and the versatility of the bike.. It is in this sense that The 12 speeds are interesting because the extra cog can be useful to fill a gap in the gear combination or to increase the gear range..

By using a cassette with a wide range of developments, you can tackle very different terrains, from the plain to very steep climbs. On the other hand, a cassette with less gap between each sprocket allows for smoother pedaling and less jolts when changing gears. The most assiduous cyclists with 11 speeds often have one or more spare cassettes, which they adapt according to the terrain, in order to optimize their pedaling. This is no longer necessarily useful with 12 speeds. The 13 is currently only offered with a single chainring, and there are still fewer different ratios available than in 11 or 12 with two chainrings.

Mechanical or electronic transmission?

There are two ways to move the front and rear derailleurs : with a cable from the combined brake/shift levers located on the pilot stationtage, or by electronic impulse with (Shimano, Campagnolo) or wireless (Sram). This solution provides more precision and comfort, while offering in some cases several interesting options: automatic alignment of the front derailleur with the position of the chain on the cassette to avoid friction, the possibility of customizing the action of the levers via dedicated software or adding additional controls on the handlebars, or even semi-automatic operation of the entire transmission with a single lever. Little difference in weight with mechanical groups, but a clear difference in price, especially to be taken into account at the level of spare parts. Clearly, Electronic transmission brings above all comfort and pleasure of use.

What type of braking?

Hydraulic disc braking is beginning to take hold on the route, since Shimano, Sram and Campagnolo offer this option, which can be coupled with electronic gear shift levers. We know the advantagestagis this type of braking : better power whatever the weather conditions, better modularity and no wear on the rim surface. In short, more safety, an essential argument for some users.

But also the inconvenients : a group with disc brakes weighs 250 to 400 g more than its equivalent with rims, not counting the additional weight imposed on the frame and fork (the constraints are different), the wheels, and sometimes even the tires (which must generally be wider to support the braking power). And of course no compatibility with the previous elements. Add to that more delicate maintenance and precise adjustments that make the maintenance and transport of the bike more complex. There remains a sometimes perfect integration of the brake hoses in the rider's positiontagand the front of the bike, which makes modern equipped bikes look extremely good. 

=> SEE AS ​​WELL : Disc braking, the point in 2019

What are the differences in ergonomics?

The main signature of Shimano groupsets concerns the brake levers with integrated gear changes. : moved laterally, the large lever is used to brake, but also to raise the chain on the large sprockets or the large chainring. The small lever located behind is used to lower the chain from one sprocket to another. DI2 groups use two pucks with the same functions as mechanical groups. The handling of the pucks is customizable, and you can take advantage of the Synchro-Shift option which consists of a pilotage of the two derailleurs with a single lever. Note the presence of a button hidden under the brake hoods, to change gear or operate the meter without taking your hands off the handlebars.

No carbon cranksets from the Japanese, but generally very smooth gear changes and very powerful braking. Also note that Dura-Ace, Ultegra and 105 cranksets accept chainrings from 34 to 55 on the same crank spider. On the disc brake side, the new Dura-Ace and Ultegra hydraulic Di2 levers have exactly the same dimensions as their rim brake equivalents.

At Sram, the two new flagship groups named Red or Force eTap AXS are equipped with 12 speeds, with wireless electronic transmission, are available with disc or pads, but above all have a first pinion of 10 teeth associated with smaller chainring combinations than the competition. The idea is to offer a wider range of developments, with tighter gaps between each sprocket. In terms of operation, theThe puck located under the right lever is used to lower a sprocket on the cassette

The puck on the left is used to mount a sprocket. Simultaneous action on both pucks changes the chainring. But it is also possible to customize the action of the levers using a smartphone application, or to set a semi-automatic gear change. At Sram, theThe disc brake retains more prominent handles to house the hydraulic system. Sram also offers 1x drivetrains, with a single chainring (and therefore the absence of a front derailleur) and cassettes with a wider gear range, in order to simplify gear changes. 

At Campagnolo, the ergonomics of the handles are typical with a lever to raise the sprockets or the large chainring, and a small lever located at thumb height to lower them. The Italian brand has, as often, been the first to pull out an extra sprocket with a 12-speed cassette, but retaining traditional chainring pairs and an 11-tooth start. Compared to the usual 11-speed references, the Campagnolo transmission actually offers an additional gear, which is often enough to keep the same cassette all year round and on all terrains. By making extensive use of carbon on the shifters, cranksets and derailleurs, the three highest groups in the range (Super Record, Record and Chorus) are light.

The gear changes are frank and virile in the mechanical version (and very smooth in the electric version), the braking is efficient and the bearings of the pedals are generally very fluid. On the disc brake side, the handles are larger than their rim equivalents, whether for cable derailleurs or for the EPS electronic transmission, which does not have the possibility of adjusting a semi-automatic gear change. 

Rotor and FSA offer high-end alternative groupsets, but which are currently struggling to gain market share. In any case, we were not able to try either of these groups. The first one uses a hydraulic system for handling the derailleurs, and kinetics close to Sram. It is available in 12 or 13 speeds, with a single chainring. The FSA KForce Wee groupset has ergonomics close to Shimano, with wireless transmission from the levers to the battery.

What level of range?

Investing in a high-end and therefore expensive group is justified in terms of performance, but also longevity : less play, better quality bearings, teeth less sensitive to abrasion, more rigid chainrings, less fragile axles, pivots and mechanisms. On the condition of course that maintenance intervals are respected and minimum care is taken of the equipment. For the rest, It is often a choice of opportunities that is required, depending on the budget, aesthetic or ergonomic preferences and the offers of the brands of bicycles sold complete. 

The second level of the range often offers a very interesting compromise : these groups offer services very close to the leading groups, with a weight only slightly higher. At the entry level, the operation benefits from the advances made in previous years on the high end, but with heavier and sometimes less well finished materials. At the strict level of weight, there is a difference of around 900 g between the lightest group on the market and the heaviest group.

Options

A group is always available with different configurations.

• Rim or disc brakes
• Cable or electronic transmission
• Multiple choices of cassette teeth
• Multiple choices of tray combinations
• Multiple choices of crank lengths

This last point is very important because it influences the performance and comfort of pedaling. This is one of the limitations of buying a complete bike., because the crank length is most of the time imposed (especially at the entry and mid-range), and this position is particularly expensive to replace if the length is not suitable.

Compatibilities

Each element of a group is designed to work in perfect harmony with the other accessories of the same group, or at least of the same brand., provided that the electronic elements or those related to the type of braking (rim or disc) are retained. You should therefore be wary of associations between derailleurs, chain and cassette of different brands. Some montagThey can help, but without offering perfect operation. Many bikes are offered for sale with cranksets of other brands than those of the transmission groups. A way to save a little weight most of the time while remaining in the same prices. This is also the method used by fans of mytagare lightweight, or that of manufacturers who offer cranksets that match the frame. Few bad surprises to expect in terms of compatibility with transmission groups. However, operation remains a little less fluid than with a crankset of the same brand as the transmission. Before fitting a replacement group, you should also check the compatibility of the frame with the bottom bracket, and whether or not you need an adapter. For the wheels, you need to check the compatibility of the cassette body (10, 11, 12 speeds, Shimano/Sram or Campagnolo imprint). 

With all this information, we hope that you will be able to see things more clearly when choosing your group., with in particular the prices and weights indicated in the second part of our file.

=> TO FOLLOW : Prices and weights of all market groups