With several brigades and riders using single- chainring setups during this time’s Spring Classics, 1x drivetrains for road bikes are back in the discussion again.
While 1x setups do have their advantages in certain scripts, and new mecca gear tech is a implicit game- changer, a 1x revolution on road bikes still feels a long way out.
In my opinion, frontal derailleurs are just too good these days and, for the utmost part, what you gain from jilting them on a road bike does n’t overweigh the downsides.
When does 1x on a road bike make sense?
As spelled out in our 1x drivetrains explained composition, there are a number of advantages( and disadvantages) to single- chainring setups for road bikes.
In scripts where a wide range of gears is n’t demanded, similar as during fairly flat lifts or races, also a 1x drivetrain can give all the gears you need in a simpler package.
1x drivetrains can also be more aerodynamic. According to UK- grounded experts AeroCoach, switching to its bow 1x aero chainrings can save between “ between 1 to 4 watts at 30mph/ 48kph ”, depending on the size of the frontal derailleur you are removing.
That’s a borderline gain, but one decreasingly exploited on time trial and criterium bikes.
Using a chain guard( which helps help the chain from dropping off the chainring) naturally compromises any aerodynamic earnings kindly.
Still, similar setups can give lesser chain security compared to a 2x setup, which can be critical in races similar as Paris- Roubaix.
Wout van Aert, for illustration, used a 1x SRAM Red eTap AXS drivetrain at both Milan- San Remo and Paris- Roubaix this time, likely for this specific reason.
Depending on setup, a 1x drivetrain can also be lighter. devoted hill rise bikes nearly always use 1x drivetrains, for illustration.
The disadvantages of 1x drivetrains on road bikes
It’s clear, also, that there are some advantages to 1x drivetrains on the road in certain scripts. There are, still, some disadvantages too.
Utmost obviously, jilting your front derailleur and one of your chainrings means significantly reducing the number and range of gears on your bike.
It’s possible to compensate for this by using a wider- range mail out back and precisely matching your chainring size to each lift. still, getting close to the range of a 2x setup comes with negotiations.
Originally, wide- range cassettes( which are needed if you want to maintain a analogous gearing range to a 2x system) can be heavier than tighter bones.
further problematically, however, they generally come with much larger jumps between gears and use lower cogs at the nethermost end to help you gain redundant range with a lower frontal chainring.
This can be annoying because grade changes on the road are generally more gradational than out- road, and large gaps between the gear rates can leave you searching for an optimum gear and meter in certain scripts.
The lower cogs, similar as the 10- tooth or 9- tooth performances seen on SRAM AXS or Campagnolo Ekar cassettes, and chainrings are also hardly less effective than larger bones ( because the chain needs to articulate at tighter angles than with larger bones).
Though SRAM and Shimano would argue it is n’t cross chaining in the truest sense of the word, 1x drivetrains also force the chain into further extreme angles at the ends of the mail compared to 2x drivetrains.
Both of these factors can lead to increased frictional losses within the drivetrain, which in turn means slightly lower of your trouble reaches the pedals with a 1x drivetrain compared to a 2x drivetrain( all differently being equal).
In terms of how much less, testing by CeramicSpeed on behalf of VeloNews has shown a 2x 11- speed Shimano drivetrain was around 3 watts more effective on average than a SRAM Force 1x drivetrain.
The differences widen when using the lowest cogs on each mail, however. A 53 × 11 gear was shown to be around 6 watts more effective than a 48 × 10, for illustration.
Of course, if you ’re not keeping your chain impeccably clean at all times, also effectiveness losses from optimising sprocket and chainring sizes are arguably a questionable point.
Still, It’s easy to see how frictional losses can snappily cancel out any implicit aero gain, if you size down your chainrings and mail cogs when switching to 1x.
Front derailleurs are just too good
Anyhow of the specific advantages and disadvantages mentioned over, the major reason I wo n’t be switching to 1x on my road bikes any time soon is this frontal derailleurs are just really good currently.
Ultramodern road bike groupsets at nearly every position offer similar excellent front shifting performance that choosing to antedate a frontal derailleur feels like cutting off your nose to malignancy your face.
The gold standard for frontal stirring is, without mistrustfulness, presently set up on electronic groupsets. numerous( myself included) consider Shimano to be the request leader in this area, but SRAM and Campagnolo do n’t pause far behind at all.
Still, indeed mechanical groupsets manage frontal shifting fantastically well, these days.
I ’m presently testing the new Trek Émonda ALR 5, which uses a Shimano 105 R7000 drivetrain, and the frontal stirring is virtually indefectible.
Of course, a inadequately timed shift or bad setup can still beget issues, but frontal shifting generally does n’t feel like a problem that needs working presently.
My Giant TCR Advanced Pro Disc, for illustration, is presently set up with a Shimano Dura- Ace Di2 R9200 groupset, with a 12- speed 11- 34t mail out back and anon-standard, 53/ 36t chainring combination up front.
Despite falling outside of Shimano’s recommendations( I ’m indeed using 11- speed chainrings on a Stages LR Ultegra R8000 power cadence crankset), it shifts brilliantly. I get a lovely big chainring for fast riding, an easiest gear rate small enough to spin my way up nearly any Muur, and gear rates that are enough tight too.
I ’ve indeed tried 53/ 34t before( with both electronic and mechanical Shimano groupsets) and set up it works OK too. It’s not relatively as good as when set up as Shimano intends( 53/ 39t, 52/ 36t or 50/ 34t), but it’s impeccably usable when you need lower climbing gears for a short period and do n’t want to reset your derailleur height and string pressure.
Is the Classified Powershift mecca a game changer?
Classified’s Powershift mecca gear system is a wirelessly controlled, 2- speed planetary gear system integrated into a hinder mecca. It’s frequently touted as a ‘ frontal derailleur killer ’, but I just do n’t see that passing.
While our full review of the system is still in the workshop, it’s fair to say our original prints have been veritably positive. It does appear to offer results to numerous of the disadvantages of 1x mentioned above – perhaps we can have our cutlet and eat it after all.
The issue for me, however, is that it’s just far too precious. Classified’s R50 and G30 Powershift wheelsets, for illustration, cost£ 2,300 – only£ 25 lower than the entire Trek Émonda ALR 5 mentioned preliminarily.
And what do you actually gain for all that cash compared to sticking with a 2x drivetrain? A borderline enhancement to aerodynamic effectiveness and that’s about it?
Of course, the cost of Classified’s mecca tech will probably come down over time if it proves popular, but considering a 105 R7000 crankset and frontal derailleur have RRPs of£159.99 and£44.99 independently( and can generally be set up online for far lower), I do n’t suppose price equality is on the horizon any time soon.
Thanks 1x, but no thanks
I will not deny that I ’ve toyed with the idea of running 1x drivetrains on some of my bikes.
My Planet X Exocet 2 time trial bike and 2009 Giant TCR Advanced SL – which could be granted a new parcel of life as a hill rise bike since I got my Giant TCR Advanced Pro Disc( look out for that in Hill Climb journals at some point) – are potentially ideal campaigners for 1x transformations.
On my lower specialised road bikes, however, 2x is where it’s at.
With the kind of performance and versatility offered by ultramodern frontal derailleurs, the small implicit advancements offered by 1x drivetrains just do n’t feel worth it – indeed for someone like me who waxes chains, wears aero baselayers and generally obsesses over the smallest earnings.
Rather, 1x for road bikes still feels like a result in hunt of a problem.