Jim’s Tech Talk
By Jim Langley
Two episodes back, we covered chain drop fixes on bicycles with a single chainring. These bike drivetrains are commonly called “one-by,” written 1X. They’re the popular choice today on “gravel bikes” – essentially road bikes designed as much for dirt as for tarmac. And, a few 1X bikes have made their way into the pro-road racing peloton, surprisingly.
In the article we mentioned that one of the appeals – and one of the reasons for the boom in gravel bikes is that the 1X drivetrain is a no-brainer to operate. This appeals to anyone who is afraid of shifting a bicycle with a double-chainring drivetrain (2X, “two-by”).
Imagine You’re Just Getting Into Riding
If you’ve been a roadie for ages, like me, you probably learned how to shift a double-chainring road bike so long ago that hitting gears is as easy as walking up stairs. But put yourself in the shoes of a complete rookie.
I think you can probably imagine how the sight of complicated levers, two chainrings, up to 12 cassette cogs and that contraption with the pulleys, could induce a paralyzing case of gear fear. Beside not being sure how to operate the shifters, you definitely wouldn’t want to risk messing up your new pride and joy with a botched gear change.
Fear of Shifting is a Real Thing
A major bike industry-only Facebook group recently focused on gear fear, in fact, as one of the reasons standard double-ring road bike sales may be dropping while 1X gravel and road/mtb rigs are picking up.
But what sparked today’s topic wasn’t that online discussion. It was requested by my son-in-law, Frankie Machado. He teaches at Menlo School in Atherton, California – smack dab in one of the USA’s most bike-crazy counties. That’s Frankie with me in the photo (he’s in the white jersey).
Since he recently bought a new Felt and wanted to ride with a group, Frankie got the idea to start a weekly ride with fellow teachers. A few of them – new roadies all – went straight out and bought double-chainring models. And, on the first ride they had no idea how to shift their double drivetrains.
Frankie rides a Felt with a single chainring, so their shifting questions prompted him to ask me (his bike-nut father-in-law) to explain in simple, easy-to-understand terminology how to shift a double-chainring (2X) road bike for his team Menlo riders.
I’m going to do that here. Please help me out by adding your best tips for beginners in the comments.
Please note: I’m assuming here that you beginners know how to use your shift levers. Due to the power of patents, every brand operates a little differently. The good news is that you only need to know how to shift the ones you have. If you’re not sure and you just bought the bike, you might try heading back to the shop and asking them to show you. Most shops do this anyway so hopefully you learned from them when you picked up the bike.
Also, here’s a GCN video showing how to operate three of the most common shifters, Campagnolo, Shimano and SRAM
Important Rules for All Shifting
Before we get into how to handle 2X drivetrains, there are three basic shifting principles to know.
1. In order to shift, you must be pedaling
2. It’s best to only shift when you aren’t pushing hard on the pedals – because hard pedaling stiffens the chain making it much harder for the derailleurs to be able to move the chain to complete the shift.
3. On most modern road bikes, you shift by moving levers or buttons built into the left and right brake levers on the handlebars. While you squeeze these levers to brake, you push inward (toward the stem) to shift most road bikes. Some have buttons that you press. It is possible to brake and shift at the same time.
Tips for Shifting with Light Pedal Pressure
Rule number 2 might sound impossible. Because it’s logical that you will want to shift into easier gears going up hills when you HAVE to push hard on the pedals to keep from falling over. But there’s an easy trick for this.
What you do is push even harder for a couple of pedal strokes to get the bike going slightly faster. Then because you created a little momentum, you will have time to ease the pedal pressure enough to make a smooth shift. This technique takes a little practice but is not difficult to master.
And, everywhere but on tough climbs, it’s easy to back off pedal pressure during shifts. You just have to develop the habit.
2X Shifting Simplified
Now, to get to the actual shifting, here’s all that most beginners need to know to hit the road – and essentially exactly how even the most savvy roadies use 2X drivetrains. While it’s a lot to read, I’ve tried to keep it simple. If you read to the end of this article and follow our last tip, it should all start to come clear for you. If not, ask a friend who rides a double-chainring bike to give you a lesson. They’ll probably be flattered you asked and be happy to show you.
Understanding How the “Sprockets” Work
A double-chainring bicycle has two sprockets in front on the crankset that the pedals are attached to. Front sprockets are called “chainrings” or shortened to just “rings.” There are also multiple sprockets on the rear wheel. These are called “cassette cogs,” or just “cogs.”
When you shift the chain onto a different ring, it’s called a front shift. And, when you shift the chain onto a different rear cog, it’s called a rear shift.
The Way the Sprockets “Work” (the Way They’re Used) is:
1. Because there are two chainrings and the chain is already on one, when you make a front shift, you are only making 1 (one) shift. You only have one choice, either onto the smaller or larger chainring.
2. Because there are multiple rear cogs, when you make rear shifts you have many choices and you can shift many times if needed.
3. Shifts that move the chain onto larger rear sprockets make the bike easier to pedal and shifts onto smaller ones make it harder to pedal.
4. Shifts that move the chain onto the larger front sprocket make the bike harder to pedal and shifts back onto the smaller front sprocket make the bike easier to pedal.
Yes, you read 3) and 4) correctly: to make it harder or easier to pedal works the opposite for rear and front shifts. You get used to this when shifting though, because the chain moves in the same direction for rear and front shifts into easier or harder gears.
When to Make Rear and Front Shifts
The thing that makes double-chainring drivetrains confusing is those two rings up front. So here’s a way to think about them while shifting that simplifies things:
First, in case you’re new to rear shifting, I’ll explain that:
1. We’ve established that you can make multiple rear shifts because there are so many cogs. Having so many means that there are more gears to choose from and each shift onto a different cog makes it a LITTLE easier or harder to pedal. To make it a lot harder or easier means shifting down or up multiple cogs – making multiple rear shifts, which is perfectly fine. Climbing a steeper and steeper hill, for example, you will keep shifting until you’re on your largest cog, your easiest gear.
2. Now about the front shifts: We’ve established that you only have one shift, either up onto the larger ring or down onto the smaller. If you look at the rings you’ll see that they vary significantly in size. And this size difference means that shifts onto the other chainring, makes it a LOT easier or harder to pedal.
Two Sets of Gears
One way to think of this to keep it uncomplicated is to think of yourself as having a bike with two different sets of gears. When you leave the chain on the small chainring and only make rear shifts, think of yourself as using your lower/easier set of gears.
And when you shift onto and leave the chain on the large chainring, and only make rear shifts, think that you are now using your higher/harder gears. Which chainring you’re on determines whether you’re in your low or high set of gears.
In actuality the gearing on double-chainring bicycles usually overlaps which means if you wanted to hit each progressively harder or easier gear, it would require shifting between rings, not just leaving it on one. But, using the rings one at a time as I described is the way a lot of roadies do it most of the time.
Front Shifts Make it A Lot Harder or Easier to Pedal
Keep in mind that anytime you need to make the bike a lot harder/easier to pedal, the front shift is always available. And the advantage of making this shift is that the major change in pedaling effort happens right away because it’s just one shift.
A common example is when climbing over a peak and descending the other side. You used your largest rear cog to get to the top and then made a couple of rear shifts to make the pedaling feel better since the bike’s speed picked up so quickly going down the hill.
But the bike is still accelerating. So, a good choice is to make a front shift onto the large chainring. With that one shift, you’ll make the bike’s gear high enough that if you want to pedal, you will be able to.
If you don’t make that front shift, and you try to pedal, you will find that the rear wheel is spinning so fast that there’s no resistance from the pedals because the gearing is too low for the speed of the bike.
Simultaneous Front and Rear Shifts?
A common shifting questions is if it’s okay to make front and rear shifts at the same time? As long as you use light pedal pressure, it’s okay to do it. Some electric drivetrains do it automatically even. But, from a purely mechanical perspective, it’s asking a lot of the chain and derailleurs to move the chain so drastically. I recommend not making these shifts manually very often.
Finding the “Right” Gear
To share the wisdom passed down when I started road riding, the way to determine what gear is right is to think of yourself as the motor that’s driving the bike down the road.
Like a car’s motor, you only have so much power at your disposal. And, you might be riding up a long climb or fighting a fierce headwind. You don’t want to risk exhausting yourself far from home. The best way to be able to make it to the end of any ride is to find a pace that your legs, lungs and heart can keep up for the duration of your ride.
Monitor Your Pedal Cadence
That’s where the gears and shifting come in. You should shift so that you’re never working too hard for too long. As a general rule, most riders can pedal steadily at approximately 70 to 90 pedal revolutions per minute (called “cadence”). And, with a little experience (or you can use a computer that displays your cadence), you learn to feel at what RPM you’re lugging your engine and working too hard to turn over the pedals.
Before that point, you should shift into an easier gear. And by constantly shifting to ensure you keep pedaling at an efficient cadence for your fitness level, you will have no trouble finishing rides in all types of terrain and weather.
To sum up, you know you’re in the “right” gear when you’re able to spin your legs at a cadence that feels right to you for the type of terrain you’re currently riding. And if it’s rolling terrain, you will shift a lot to keep fine-tuning the gears so that you can maintain your same pace.
Best Way to Practice
I saved this for last because it’s my favorite way to teach shifting – and I find that not enough new riders learn this way. I’m hoping to change that.
Suspend the Bike
If you’ve got a new bike and a bad case of gear fear, I want you to suspend the bike to practice and master shifting while standing next to the bike, NOT while riding it. A bike repair stand works for this if you have one. Alternatively, a car bike rack with arms that hold the bike by the frame can do the trick. You can do it with the bike on an indoor trainer and the resistance device turned off, too.
If you don’t have any of those, you might have a garage with a roll-up door. If so, you can open the door halfway and stop it there. Then rest the tip of the seat on the bottom crossbar on the door. Be careful. Make sure the door is strong enough to hold the bike and that the saddle can’t slip off the door. I have a common aluminum garage door and it works fine (photo).
If you don’t have a garage, maybe you have a door jamb in the house with trim at the top that can support the bike’s weight. Or a tree with a low branch that you can suspend the bike the same way it hangs off the garage door.
Shift by Hand Repeatedly
Once you’ve got the bike suspended, you can take as much time as you want to learn how to shift. Simply turn the pedals with one hand, operate the shift levers and be sure to watch how the chain moves over the front and rear chainrings and cassette cogs.
If that’s too much to keep track of at first, have someone else turn the pedals while you move the levers and watch what happens. But, be sure to take a turn shifting while pedaling by hand so that you can feel how the effort to turn the pedals changes as you run through the gears. Hold your rear brake on slightly while pedaling to really feel this.
When you get good shifting by hand like this, you’ll be ready to try it for real. You can do it. And don’t worry about harming anything. As long as you follow the basic rules here, it’s highly unlikely you can do any damage shifting your new machine. Just be careful out there. Don’t look down at the drivetrain while shifting out on the road unless you’re absolutely sure it’s safe to do so. And, don’t forget that even parked cars can hurt you and your bike.
Ride total: 9,403
Jim Langley is RBR’s Technical Editor. He has been a pro mechanic and cycling writer for more than 40 years. He’s the author of Your Home Bicycle Workshop in the RBR eBookstore. Check out his “cycling aficionado” website at http://www.jimlangley.net, his Q&A blog and updates at Twitter. Jim’s streak of consecutive cycling days has reached more than 8,000. Click to read Jim’s full bio.