Bike gears primer
October 4, 2020 7:56 AM   Subscribe

Please explain how to use bike gears to me as though I am a 10 year old who just got their first geared bike. Let's say I'm riding along in a flat road and my gears are set so that this is comfortable. Now I see a hill! What do I change my gears to, and when do I do it? Then what? What if it's a giant hill? What do I do after the hill? What do I do when I'm going down a hill?
posted by xo to Sports, Hobbies, & Recreation (25 answers total) 18 users marked this as a favorite
Have you ever driven a manual (stick-shift) car?
posted by EndsOfInvention at 8:14 AM on October 4, 2020 [1 favorite]

The answer (and complexity of the answer) will depend on whether (1) you have multiple gears only on your back wheel or (2) you have multiple gears on your back wheel and you have multiple gears on the part connected to your pedals.
Here is an example of (1).
Here is an example of (2).
Note that in both examples, the pedals have been taken off.
Can you tell us if your bike is (1) or (2)?
posted by hhc5 at 8:19 AM on October 4, 2020

For the gears by the crank and the pedal, you do all the work. For the gears on the rear wheel, the wheel is doing the work for you.

So when you're going up the steepest of steep hills, you want the gear up front by your pedal to be as small as possible, and the gear in back on your wheel to be as big as possible. (That gear combination would mean you were cross-chained, so don't do it too much because it will stretch out the chain, and then you have to replace the chain, and if you don't replace the chain you end up having to replace the gears, too.)

If you have an internal gear hub, you can change those gears when you're stopped. Otherwise, you always change gears while moving. So downshift before you stop at a stop sign or stop light so you have an easier time getting started again.
posted by aniola at 8:31 AM on October 4, 2020 [1 favorite]

It’s kind of complicated because there are two sets of gears, and they work in opposite. In general, in the front chainrings, smaller is easier. Most bikes these days seem to be sold with two rings, so there’s just big and little, but I used to love my triple because I could just park it on the middle ring and do anything.

In the back, bigger is easier, but you’ve got a wider variety of choices. The only real rule is that you don’t want to cross - never go big/big or small/small.

The “right” answer for what gear to shift into is whatever gear will allow you to keep pedaling at the same cadence. If you’re a novice cyclist, you probably won’t just know that, though. It’s something that comes through trial and error. Every hill is different, every rider is different. So just experiment. Go ride by yourself and shift your gears to see what it feels like.

The good news is that there is a right time to shift, and it’s whenever you feel a difference in your pedaling cadence. If you start pedaling slower, shift down in the back. If you’re spinning, shift up. Then keep doing so.

I’ve spent most of my time riding in Ohio, so there aren’t many hills that this method can’t account for. :)
posted by kevinbelt at 8:31 AM on October 4, 2020 [2 favorites]

I ride one-speed bikes (cruisers) with coaster brakes because I'm a grown person who is very confused by gears, so thank you for asking this question!

From my husband, a long-time bicycle lover:

Let's start with basic 3-speed gears like you might find on an old cruiser with coaster brakes.

There's only one shifter, which goes between easy, medium, and hard -- the bike goes faster in the hardest gear for the same number of pedal strokes.

When you start going uphill and it takes too much strength to pedal comfortably, shift to an easier gear. Repeat until you're comfortable or you run out of easier gears.

When it levels out and feels too easy -- the pedals are spinning on their own -- move back through harder gears.

On a 10/12/21-speed bike with two shifters, it's a little more complicated because the gear ratio is a combination of the left and right shifters. The right shifter makes small adjustments, so it's the least disruptive to your pedaling. But since the adjustments are small it can't reach the whole range of gear ratios alone. When approaching a hill, I might downshift on the left to an easier gear range, and simultaneously shift up on the right to try to maintain my combined gear ratio. Then as the hill steepens I can use the right shifter to gradually make it easier. When I run out of gears on the right, it's time to left-shift to the easiest chain ring and adjust the right shifter for max pedaling comfort.

Even more important: downshift to a good starting gear anytime you anticipate stopping or slowing way down.

Have fun!
posted by RobinofFrocksley at 8:32 AM on October 4, 2020 [4 favorites]

Basic principles: shift down to go up hills (or when you’re slowing to a stop at lights or a junction), shift up when riding on flats.

When you hit an incline, you’ll feel it in your legs; the moment you do is the signal to shift down. If that’s still tough on your legs, shift down again if you can. It won’t take long to get a feel for it.

How you do this practically depends like hhc5 said on the gear system of your bike. I ride an 18-speed hybrid, but that’s really a theoretical maximum number of gears. That 18 is a product of six (the gear cogs on my rear wheel) and three (the cogs where my pedals are). The chain never leaves the middle cog of the latter, ie that shifter (on my bike it’s the left one) is always on 2. I only shift up or down the six gears on the right shifter, and in general it’s best to keep this in the middle, at 3, for ease of starting off from a dead stop, and easing stress on the chain and whatnot.
posted by macdara at 8:33 AM on October 4, 2020

oh oh oh and if you're lucky enough to have a steep U-shaped down-then-up hill! use the hardest gear that makes sense and FLY down that hill, get momentum, and then be prepared to rapidly switch through easier and easier gears to get up the hill on the other side until you've lost all momentum.
posted by aniola at 8:35 AM on October 4, 2020 [1 favorite]

So, your bike has a bunch of gears.

Some bikes have multiple gears both near the pedals (these are called chainrings) and near the back wheel (these are called cogs).

If you have two chainrings, you'll mostly want to use the smaller one when you're going slow and the larger one when you're going fast. If you have three, you'll want to use the smallest one for steep uphill and/or off-road riding, the middle one for most normal riding, and the largest one when you're going downhill and/or fast. Most of your shifting won't be at the front derailleur (that's the thing that moves the chain between chainrings), but at the rear derailleur (that's the thing that moves the chain between cogs). Shift the front derailleur only when you're already using one of the smallest or largest cogs.

If you're riding along a flat road, and you come to a hill, you'll want to shift to a lower gear (usually a larger cog, but, for a really steep hill, maybe a smaller chainring) so that you can keep pedaling at roughly the same speed (this is called cadence). You'll be going slower, but pedaling at the same cadence with roughly the same effort. That's kind of the goal of geared bikes, by the way--your body is most efficient within a certain range of pedaling speed and force on the pedals, and multiple gears help keep you in that range.

If the hill is long, or it gets steeper, you'll shift to a larger cog again. Once the ground evens out, you'll shift back to a smaller cog. If you're going down a hill, you can shift to a smaller cog again.

A couple things to watch out for--generally, when you're shifting gears, you'll want to reduce the amount of force you put on the pedals. Keep pedaling, but do it gently--this reduces stress on the drivetrain. And, on a bike with three chainrings, you'll want to avoid using either the largest chainring with the largest cogs or the smallest chainring with the smallest cogs--this puts stress on the chain, and similar gear ratios are available with the middle chainring.
posted by box at 8:36 AM on October 4, 2020 [1 favorite]

PS about chain stretch - you can at any time walk into a bike shop and they will measure your chain for free and tell you if it's stretched out or not. Takes like 2 seconds.
posted by aniola at 8:44 AM on October 4, 2020

If you're finding pedalling hard (you're pedalling slowly and having to really strain to push the pedals around), you're in too high a gear. Change down gears one at a time until you're pedalling at a comfortable rate.
If you're finding pedalling too easy (your legs are spinning around with hardly any resistance), you're in too low a gear. Change up gears one at a time until you're at a comfortable rate.
If you see a hill approaching, no need to change gear until you feel one of the above situations taking effect.
posted by EndsOfInvention at 8:46 AM on October 4, 2020 [6 favorites]

I've ridden bikes my whole life, but I'm still confused by what it means to "shift up" or "shift down," or which is "high gear" and which is "low gear." I think those are not intuitive terms that people just memorize by association with stick-shift cars (which I don't drive). So I'm not going to use those terms. I'm also going to assume you have gears in both the front and the back. For this explanation, by "gear" I mean the toothed disc of varying size over which your chain runs. By "back" I mean the stack of gears connected to the middle of your back wheel." By "front" I mean the 2 or 3 gears connected to the part where you pedal. This is not the proper terminology, but it's the terminology you used, so I hope you understand it.
The "easiest" gear is the combination of the smallest gear in front and the biggest gear in back. This lets you pedal with the least resistance and is the easiest combination to pedal up a hill. The tradeoff is that for each revolution of your pedals, you go the least distance and go the slowest.
The "hardest" gear is the combination of the biggest gear in front and the smallest gear in back. This combination creates the most resistance when you pedal, but helps you maintain or increase your speed going down long or steep hills.
The various combinations between these two extremes represent various trade-offs between less pedaling resistance (and ease of pedaling uphill) versus more pedaling resistance and greater speed. If you keep your bike on too-hard a gear combination going uphill, the resistance on the pedals may be too great and you not have the muscles to keep pushing down on the pedals, and will stop moving forward and tip over. If you keep your bike on too-easy a gear combination going downhill, you may find the wheels are turning too fast from gravity alone for pedaling to add any additional power/speed. If you find that happening after you crest a hill and start going downhill, shift to a "harder gear."
On a mostly flat road with only short ups and downs, you can probably shift only your back gears to maintain a comfortable ride without undue exertion. Using just the back gears, shift to a bigger wheel for uphill, shift to a smaller wheel for downhill/faster.
Your bicycle is not made to operate on the smallest gear in front and the smallest gear in back, nor on the biggest gear in front and the biggest gear in back. Avoid those two combinations.
Change gears at the bottom of the hill, before you notice the resistance causes you to slow down your pedaling very much. You'll be more comfortable that way. And very expensive bicycles have high-quality parts that let you shift gears when the pedaling resistance has already increased halfway up a hill and you haven't yet changed your gears. But if you try that with a bicycle under, say $800, the pedaling resistance could keep the gears from shifting.
posted by hhc5 at 8:48 AM on October 4, 2020 [1 favorite]

I have a 7yo and have been explaining bike gears and shifting to them. Here is what I'm saying to them. I know you asked for 10yo but this is 7yo level. Many of the other posts cover the other details.

1. Don't shift the front. Just leave it on the small one and get use to how the shifting works in the back.

2. Higher numbers are for faster, lower numbers are for hills. (She has indexed shifting with a little number window. The higher number gears for the rear on her bike are the larger ones.)

3. The shifter will only work when you are peddling. So don't shift when stopped.

4. Right now in this part of learning, you don't need to shift. You can go on a bike ride and just use the same gear the whole time. But try shifting now and then to find out what it is like.
posted by bdc34 at 8:55 AM on October 4, 2020 [4 favorites]

If you're finding pedalling hard (you're pedalling slowly and having to really strain to push the pedals around), you're in too high a gear. Change down gears one at a time until you're pedalling at a comfortable rate.
If you're finding pedalling too easy (your legs are spinning around with hardly any resistance), you're in too low a gear. Change up gears one at a time until you're at a comfortable rate.
If you see a hill approaching, no need to change gear until you feel one of the above situations taking effect.

This, this, this. All the theory is good, but it comes down to pedaling at a constant cadence with sustainable effort. Shifting is all about how your lungs and legs feel, not about what the terrain is doing.
posted by bfranklin at 9:03 AM on October 4, 2020 [9 favorites]

I personally hate the feeling of pedaling the same speed and going slower, so when I approach small to medium hills I shift into a harder gear to get some momentum, then drop back one and see how much I can crank out before I make it easier again. This doesn’t work on the Alps or up Twin Peaks, but I just want you to know if you hate the official way, that’s ok too.
posted by dame at 9:47 AM on October 4, 2020

While you’re pedaling on a flat surface, shift gears—there are different mechanisms for this, but turn/click the thing once, or turn it to the next number up or down. I’d recommend focusing on the shifting dealie that has more numbers on it for now. You will hear a click near your feet after shifting, it may take a couple of turns for it to click into place. Pedaling will feel different; either easier (moving slower while pedaling at the same speed) or harder (moving faster while pedaling at the same speed.) Try going the other way, and see how the resistance changes.

The lower numbers will feel “easier” and the higher numbers will feel “harder.” They feel easier because you are moving your feet more to push yourself the same distance. With a bit of muscle memory this will be easy.

Once you get the hang of the gearshift with more numbers, do the same process with the gearshift on the other side. Most cyclists only use that one under somewhat unusual circumstances (i.e., a lot of hills.)
posted by tchemgrrl at 9:59 AM on October 4, 2020 [1 favorite]

Response by poster: Thanks so far. These are the gear specs for the bike:
21 speeds of smooth, seamless shifting come from the all-SHIMANO drivetrain. The SHIMANO Revoshift twist shifter and SHIMANO TY-30 indexed rear derailleur combine for smooth performance. (link)
posted by xo at 10:38 AM on October 4, 2020

Shimano twist shifters are what I have; you might find the left one (for the front derailleur) is a bit stiffer than the right but like most have said, you probably won’t be using that one often unless you’re climbing very steep hills for sustained periods.

Also, just to be extra clear about what shifting ‘up’ or ‘down’ means - up is from the lower number to the higher, so on your right shifter, 1 is your lowest gear and 7 is your highest. For standard flat rides the left shifter should be at 2 and the right at 3, maybe 4 depending on how it feels to push off.
posted by macdara at 11:56 AM on October 4, 2020

A couple people have mentioned cadence, and that is the central theme to focus on here. You shift gears up and down to keep the pedals (and your feet) spinning at about the same rate, regardless of the back wheel. If you are pushing really hard and the pedals are going really slow, you're doing it wrong -- you're in the wrong gear.

As far as the specs you added above for a 21-speed gear set, that means 3 gears on the front and 7 gears in the back. They multiply together to produce 21 possible different combinations and is probably the most common combination. But, wait, just stop right there. Most people, average recreational cyclists, don't shift the front at all, rather just shift the back. You stick the front on a middle gear and just leave it there forever (literally, for life). Then you just use the rear shifter and the 7 gears available to tackle hills. Just forget about the front shifter and use the rear.

Again, it's all about cadence. If your pedals are going slow and you're pushing really hard, shift down to get your cadence up. The pedals (and your feet) should be spinning pretty quickly.

Now I see a hill! What do I change my gears to, and when do I do it?

You down-shift, so as your bike slows down, you keep pedaling at the same rate.

Then what? What if it's a giant hill?

You down-shift, so as your bike slows down, you keep pedaling at the same rate.

What do I do after the hill? What do I do when I'm going down a hill?

You up-shift, so as your bike speeds up, you keep pedaling at the same rate.

Pay attention less to the hills and more to your pedal cadence, and shift accordingly in reaction to what's happening to your pedal cadence.
posted by intermod at 1:45 PM on October 4, 2020 [2 favorites]

Lower gears for power, higher gears for speed.
posted by vitout at 4:29 PM on October 4, 2020

If you are standing up to bike up a hill, you're in the wrong gear.
posted by aniola at 4:49 PM on October 4, 2020

Aniola, not necessarily. Standing while climbing is a normal thing. In fact, sometimes a hill is so steep that you have to stand or you risk the front wheel popping off the ground.
posted by computech_apolloniajames at 4:52 PM on October 4, 2020

I would put it this way:

Think about how fast your feet are spinning on the pedals, and how hard you are pushing the pedals.

Ride along a flat road or trail at a constant speed, say 10mph.

Take the good advice above for now--put the front shifter (3 gears) into the middle gear. This is probably labelled 2 and is also the middle of the 3 "chainrings" that are attached to your pedals.

In doing the exercises below, just shift the rear gear shifter, which will have 7 gears.

When you click the gear shifter in one direction--remember to keep your speed constant at 10mph!--you'll find your feet spin faster and faster in order to keep up. Each click makes the pedals easier to push, but also makes your feet spin faster and faster to keep up.

Now click the gear shifter in the other direction. Again maintain your constant speed--10mph. You'll notice with each click, the pedals spin slower, and it seems to take more force from your feet pushing into the pedals to make them turn over.

If you just keep going along your flat path at 10mph, clicking the gears one direction you'll soon find the pedals must spin around so fast to keep up with your speed that it is hard to spin them fast enough. Or maybe it's so fast you can't even do it!

Clicking the other direction, you'll soon find the pedals turning around slowly, so slowly. But it is so hard to push them around each time! It might become so hard to push you can't even do it.

So you get the point--clicking the gears one way makes your feet spin fast and easy. But go too far and they are spinning too fast--you can't keep up.

Clicking the gears the opposite way slows down the rate your feet must spin, but it becomes harder and harder. You'll reach a point where the pedals are so hard to push you barely move them.

It is pretty obvious now that the point of shifting your bike's gears: Your trying to find that happy medium between ultra-fast pedaling that is so fast you can't keep up, and ultra-slow pedaling that takes so much force you can't push that hard.

So as you are riding along your flat path at 10mph, keep clicking your gear shifter back and forth until you find that happy medium--your feet are moving along kind of fast, but not too fast, and they are pushing a little with each turn of the pedals, but not pushing so hard you'll soon wear yourself out.

You'll probably find you can pedal along just fine in at least 3 gears--one's a bit too fast but still OK, one's a bit too slow and hard-to-push but still OK, and the one in between those two is just right.

Pedal along in that "just right" gear for a while, and remember how fast your feet are moving.

Because that is the key to the next phase: hills.

Whether you go uphill or downhill, the goal is the same: Click the gear shifter until your feet are moving at your "just right" speed.

So you come to a hill, your feet slow w-a-y down. Suddenly they are pushing so hard just to make the pedals turn so slowly.

What do you do? Well, you need to speed your feet up. Click the gear shifter once or twice in the direction of "move feet faster". If they're still too slow, keep clicking more times in that direction until your feet are moving at their "just right" speed again.

You come to a different hill. You find your feet moving around the pedals a bit faster than normal, and pretty soon they are going so fast you can barely keep up. What to do?

Oh, yeah. We are shooting for "just right" speed for our feet. So we click the gears in the direction of "go slower". Keep clicking in the "go slower" direction until your feet have slowed down to your "just right" speed.

And there you are: Feet going around too fast, click the gears until they're going at the "just right" speed. Feet going around too slow--and hard to push--click the gears until they're going at the "just right" speed again.

So that is the rear gears. What about those front gears?

Go back to your flat path and constant speed. Try shifting gears again, but this time use the front shifter instead of the rear.

What you'll notice:

- The front shifter does the same basic thing as the rear shifter--clicking one direction speeds up your feet, the other direction slows them down

- But, the change in foot speed for one click of the shifter is much larger than it was with the rear shifter.

- Also it can be a little harder and take a little more time to get the front shifter to complete a shift.

Putting all that together, the front shifter does the same basic job as the rear shifter, but people use it just a little different:

- You can just put it in the middle gear and forget it, especially at first

- You can use the front shifter as a sort of "reserve extra emergency shifting power". You wait until you run out of gears on the back shifter. Say you're climbing a long, steep hill. Your feet slow down, so "click the rear gears" to speed them up. Slow down more, "click" again. Repeat this seven times. Darn, I'm out of gears and STILL too slow and too hard to turn those pedals over.

Suddenly, you remember "Oh, yeah! I can click the front gears, too! They do the same thing!" So then you click the front gear in the "easy/fast" direction and wow! Now you can keep going up that hill!

(Same thing goes for going downhill, just in reverse. Even though you've clicked through all of the 7 gears in the rear, still your feet must spin sooo fast to keep up. Click the front gear shifter a time or two and now your feet can keep up.)

- After a while most people realize that when an uphill is coming they need the "small" gear (the smallest chainring/the one that makes your feet spin fastest) in front so as they approach the uphill they shift into the small chainring at first opportunity.

Going down a big hill is the reverse. Coming over the crest of the hill you shift into the largest chainring at first opportunity, and then you're ready for whatever the downhill throws at you.

That is a lot of words. But remember:

* If your feet are spinning too fast, click the gear shifter until they slow down to a normal speed

* If your feet are turning way too slow--and taking way to much force to move the pedals around--click the shifters the opposite way to make them move faster and easier again.

* You're always shooting for your feet to moving around at the "just right" speed--not too slow, and not too fast.
posted by flug at 10:20 PM on October 4, 2020 [2 favorites]

Here is a quick video that explains the basic concepts--and adds a few details not mentioned above, like remember to shift down (towards easier/faster pedaling gears) before you stop. If you don't it can be too hard to push those pedals around when you start again.
posted by flug at 10:24 PM on October 4, 2020

Agree with most of what's been said.

It's helpful to think of the three chainrings (on your cranks) as setting your high/medium/low ranges, and the sprockets on your rear wheel as your specific position inside the range. Also, it's important to note that these ranges overlap a fair amount. So that if you're in the middle ring and a small sprocket in back, that might be the same effective ratio as being on the big ring and a big sprocket in back (the small ring is mostly just for very steep hills).

Also, for whatever it's worth, it's never helpful to talk about gears as "first gear" or anything like that, because the sequence is not linear. If you really want to get into it, each ring and sprocket has its tooth count stamped on it somewhere, so you can say "I'm in my 32x17" or whatever.
posted by adamrice at 2:31 PM on October 5, 2020 [1 favorite]

If I am actually explaining this to a 10 year old:

If you have 21 gears, you probably have 3 in the front (left-hand shifter) and 7 in the back (right-hand shifter). You can click between these from easiest to hardest.

On the left shifter, which controls the front gears, you have 3 settings. "Normal", on the middle ring -- and then one for going very fast or downhill, and one for going very slow or uphill. Keep this one on "normal" AKA the middle most of the time, especially when you are first learning. We'll talk later about when to use the other two.

Mostly when riding, you will shift with your right hand. Shift this right-hand (back gears) a LOT! As you are riding, just keep toggling it a little bit, one click at a time, to keep the difficulty of riding (resistance of the pedals) where you like. Gets too hard? One click easier, try it, a second click if needed, etc. Gets too easy? One click harder, try it out, a second click if needed, etc. After you click the shifter, you have to pedal a stroke or two to complete the shift. Only shift one click (ring) as a time, don't do the next till you complete a stroke or two and feel the shift happen. (You would see the chain change between rings if you looked down, and you will feel the resistance change.)

Now, if you are going really fast, or up a really steep hill, the range of the right-hand (rear) gears paired with just the front middle ring won't be enough. You are going to need to use one of the outer rings in the front. Do this when you get to the "end" of the right-hand shifter - you are all the way on the easiest or hardest setting up but you need more. That's when you shift the left-hand/front gear.

A special warning: You don't want to "cross" your chain too far. When you are on the inner front ring, you don't want to put the chain on the outermost back ring, and vice versa. This can stress and snap your chain, and wear your gears from rubbing. This means that on the inner and outer front rings, you don't have full use of all the back gears, only 4 or so of them. If you need to keep shifting, it's time to shift back to the middle front ring.
posted by amaire at 2:40 PM on October 8, 2020

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