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This may be a noob question, maybe I'm over thinking it. But on the bike I just ordered, when I I move from the smaller to the larger rear sprocket, the dial on my shifter counts down. But on my front gears, when I shift from the smaller to the larger gear, the counter goes up. Is my rear sprocket setup backwards???

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3 Answers 3

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This is normal. This number is not here to indicate the size of the sprocket. This number is here to indicate how easy the gear will be.

The lower the number, the easier the gear is.

Indeed, the impact of the size of the sprocket is opposite between the front and the rear. The smaller sprocket on the front is the easier gear, meanwhile on the rear it is the harder gear.

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The gear numbers for both front and rear shifter are indicative of distance per pedal turn, which in mechanical terms is measured in ratios. Similar to a car gear box, in which case the higher the gear number the more distance you would travel, which in cars is shown as Kilometers per Hour.

So from a mechanical point of view, your bicycle gear number for the front shifter is indicative of a ratio, a ratio of one turn of your front-ring/(or one turn of your pedal) to chain distance. The larger the chain ring the longer the chain will travel per turn. The smaller the chain ring the shorter the chain will travel per turn, therefore the gear number for your front derailleur is higher the bigger your chain ring because it has a longer circumference, therefore your chain travels a bigger distance.

Similarly the rear derailleur shifter indicates a ratio, in this case it's wheel distance per chain length yielded by your pedal chain ring. The smaller your rear sprocket the more rear wheel turns you would get (therefore more distance) for the same chain distance as that applied to a larger sprocket.

The combination of your front chain rings, rear sprocket and bicycle tyre size will yield a certain distance per pedal turn. An online bike calculator like this one, BikeCalc, would breakdown these distances for you if you put in the size of your bicycle chain rings, sprockets and tyre size.

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I don't think about the number of a gear when riding. Instead - know that pushing the lever one way makes it easier (for starting or going up hills) and the other way makes it harder (therefore faster)

The other shifter is reversed too - because the front cogs/chainrings have the larger-tooth count most outboard, whereas at the rear of the bike the smallest tooth count is outboard.

The only time I use a Visual Gear Indicator is when I'm wondering if there's another gear, and that's either when I'm on a steep climb, or when there's a howling tail wind and the legs are spinning out. In both times I'll just push the lever to change and if it goes nowhere, I was out of gears.

In short: ride more and develop muscle memory for changes, based on your leg cadence. Don't worry about numbers.

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    No! We need a dual-input, cable-tension-actuated multiplication machine that dynamically calculates your gear-inches and shows it in a big dial on the handlebars. (I jest.) Apr 4 at 20:38
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    @Michaelcomelately check out some of the "automatic" gear systems for bikes. Some of them use spin-weights like a governor and change gear based on crank speed. Some are terrifyingly mechanical.
    – Criggie
    Apr 5 at 3:36
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    @Michaelcomelately You might jest, but I'd totally buy that Apr 5 at 10:29

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