Sorry it’s been so long. We’ve had some technical difficulties with the site. But I’m back again for some more chat on shifting. I’ll start with the easy stuff first and then if you’re still with me, we will get into some of the “why”. I’m a curious sort, so it helps me to know a little of the “why”. Hopefully it will help you too.
In Part 1 we learned that we want to shift in order to stay at roughly the same cadence. On a ride with a lot of changes in terrain or a lot of stops, that will mean a lot of shifting. Your bike gears are designed to be changed while the pedals are moving. However, your components will work better and last longer if the pressure on your pedals is lighter during the shift. So if it’s possible, ease up just a tad when you shift until you hear/feel the click. Then pick back up where you left off. Also, try not to shift when you are starting to stand up in the saddle. That hard pressure might make your chain come off.
In Part 1 we also talked about anticipating the shift when you are coming to a stop or gearing up to take off in a “go zone”. Being in the right gear at the right time is key. But have you ever shifted from a gear to the one that you think is “right next to it” and get a shock when your feet all of a sudden spun way too fast? Or have you shifted the chain ring on the front and all of a sudden you can barely make the pedals go around? If it’s all about steady cadence, you don’t want to drastically change the level of difficulty at which you are pedaling in one shift of the gears.
So who thought (thinks) that on a 20 speed bike that gears 1-10 are on the small chain ring and 11-20 are on the big chain ring? Yeah, if only it were that easy. Stupid math and physics. Essentially the ordering of the gears is a ratio called “gear inches” that takes into account the number of teeth on the front chain ring divided by the number of teeth in the rear sprocket that your chain is sitting on. DON’T DOZE OFF! It’s not important to be able to do the math. But it is important to roughly understand where your gears are on your particular bike so that you can shift smoothly.
To illustrate, I calculated (well a website calculated) how my bike’s gears lay out. I have a 50/34 “crankset” on the front (big chain ring has 50 teeth, small chain ring has 34) and a 10-gear “cassette” on the back that ranges from 11-28 teeth. There are a bunch of websites that can spit out these calculations. Here are a couple I found.
Mike Sherman's Gear Calculator
Anyway, back to my bike, which I think is pretty standard “off the rack” for a road bike, but if you get curious – or bored – you should check out yours. And if you have three chain rings up front, you should really check yours out because it will be even more different.
| Gear | CRxFW | GI | GIDiff |
| 1 | 34x28 | 33.51 | 16.67% |
| 2 | 34x24 | 39.10 | 14.29% |
| 3 | 34x21 | 44.69 | 10.29% |
| 4 | 50x28 | 49.29 | 0.21% |
| 5 | 34x19 | 49.39 | 11.76% |
| 6 | 34x17 | 55.20 | 4.17% |
| 7 | 50x24 | 57.50 | 8.80% |
| 8 | 34x15 | 62.56 | 5.04% |
| 9 | 50x21 | 65.71 | 2.00% |
| 10 | 34x14 | 67.03 | 7.69% |
| 11 | 34x13 | 72.18 | 0.62% |
| 12 | 50x19 | 72.63 | 7.67% |
| 13 | 34x12 | 78.20 | 3.81% |
| 14 | 50x17 | 81.18 | 5.09% |
| 15 | 34x11 | 85.31 | 7.84% |
| 16 | 50x15 | 92.00 | 7.14% |
| 17 | 50x14 | 98.57 | 7.69% |
| 18 | 50x13 | 106.15 | 8.33% |
| 19 | 50x12 | 115.00 | 9.09% |
| 20 | 50x11 | 125.45 | 0.00% |
CRxFW = Chain Ring (front) and FreeWheel (back)
GI = Gear Inches
GIDiff = % Difference between that gear and the next higher gear
Let’s take a ride! So it’s a nice Thursday night and I’m pedaling down Teel in the group. I’m in the pack so I’m getting good draft and I haven’t really been paying attention, but now I am on the small chain ring and the outer gear on the back (34x11). We are just turning the corner for the Stonebrook “go zone” and I feel good tonight. I know I am maxed out on torque for the small chain ring and I realize I need to shift up because I want more power. But now I’m out of gears on the small chain ring. (It happens to be gear #15, but I just learned that looking at this chart.)
Actually that’s a gear you aren’t supposed to stay in for long periods of time because it’s hard on the drive train. If you look down at your chain, it is at the sharpest angle it can be. It’s called “cross-chaining”. Perhaps I should worry, but I don’t worry too much if I’m only going to be in the gear for a couple minutes. But if I know I want to keep going for a long time at that “gear feel” or I want to even shift up for more power, I know I need to shift up to the big chain ring because that’s where the rest of the gears are. If you have three chain rings up front, you have to be even a little more aware of the angles of some of the gears because the angle can be sharper because the crankset up front is wider. Just take some time to look at your chain while you are riding and learn where the “no-no” gears are.
Now we are leaving the parking lot after the Compass climb and I probably shifted all the way or nearly all the way down. But now it’s time for a nice downhill on Legacy. Guess when I’m going do to? Yep. As we head towards the start of the “go zone”, I’m going to get in the middle of the cassette and pop into the big chain ring. Because I want all the big gears going down the Legacy hill!