The bicycle is a paradox – it’s remained relatively similar since the late 19th century but is also markedly different. Evolution not revolution we think they call it, and this evolution’s clear at this year’s Spin Cycling Festival with cutting-edge technology melded to bikes with very traditional geometry.
Electronic or mechanical?
One area that’s moved on in recent times is the groupset. If you’re new to cycling, this refers to the parts that are involved in braking, changing gear or running the drivetrain, which translates as the shifters, brake levers, front and rear brake calipers, front and rear derailleurs, crankset, bottom bracket, chain and cassette.
Each component has invariably become lighter with the main choice historically boiling down to whether you choose a crankset that features two chainrings or three. The advent of the compact crankset, usually featuring a 50/34t combination (50 teeth on the big outer ring; 34 teeth on the smaller, inner ring), has made the third chainring almost obsolete.
Instead, arrow in on the mechanism for switching gears and you enter a brave new world of shifting. Where once mechanical groupsets ruled, now electronic groupsets are threatening their dominance. Electronic groupsets are now omnipresent in professional cycling but an increasing number of recreational riders are following suit.
What are the major differences? The primary one is where traditional mechanical groupsets utilise a slight movement of a cable to shift between gears, electronic sends a current down a wired cable to a motorised device which moves the derailleurs. The advantages then for Shimano’s Di2 and Campagnolo’s EPS include more precise, quicker gear changes, reduced chainwear, and the capacity to place the shifting buttons where you so wish.
That swiftness of shifting and positioning is particularly important during the spring classics, where races like Flanders and Roubaix are often decided by breaks on steep, sharp climbs (the former) or stretches of large cobbles (the latter). The ability to shift up or down gears at speed is game-changing. There’s also Sram’s wireless eTap, which has moved electronics on again, dispensing with any cables, and FSA’snew K-Force WE wireless system which is due to hit the market any time soon.
So all good… nearly… but of course there are a few cons. Firstly, you must remember to charge the system’s battery. This has improved over the years but the best still need recharging after 1,000km. For many that’s quite a few months. For the committed roadie, that could be less than four weeks. There’s also maintenance logistics. It’s rare that something will go wrong with electronic but when it does, invariably you’ll have to seek out an expert. And then there’s cost with Shimano’s Dura Ace Di2 and Sram’s eTap well over £1,500 for the full groupsets.
Hub-based gear systems
So mechanical or electronic, the choice is yours… unless, of course, you choose a belt-drive and internal-hub system. You’ll see a few of these at Spin. Unlike traditional bikes where the gears are on the outside of the back wheel, hub-based gear systems, like the famous Sturmey-Archery system seen on Brompton folding bikes, see the gears safely tucked away within the hub.
What advantages does this offer? Well, unlike traditional systems, you can shift gears when the bike is stationary. You’ll find this really useful if you have to stop at the lights halfway up a hill, ensuring you won’t have to set off in too high a gear. Enclosing the gear mechanism within the hub also makes transmission more weather resistant, while the lack of derailleurs removes one of the more vulnerable areas of the bike.
You’ll often find hub-based gear systems paired with a belt rather than chain, further adding to the low-maintenance possibilities. Take the Gates Carbon Belt Drive system, which is basically a mix of carbon fibres and rubber. Tests have shown these last up to four times longer than chains because they don’t stretch and wear in the same way. They also don’t need lubrication and don’t attract grime like chains, so are particularly useful for commutes where you want to keep your jeans nice and clean.
On the downside, some belts are susceptible to making a lot of noise on sandy, dry roads, while purchasing a spare belt at any old bike shop is pretty darn impossible. Belts can also not be used with drivetrains.
As you can see, when it comes to transferring your muscular power into forward propulsion, it’s not as simple as it first seems. But the good news is that there’s clearly a drivetrain for you.