Know and use the proper terms for the chainrings (or rings) and the cogset (cassette or cogs). Chainrings, or rings, are up front and attached to your cranks. The cogset — a.k.a. cassette or cogs — is in the rear and attached to the hub of the rear wheel. The larger the cog, the easier the gear and the slower the speed (climbing.) The smaller the cog, the harder the gear is to pedal and the faster the speed. In other words, shift up the cogset to larger cogs to climb and down the cogset to smaller cogs to go fast. While understanding the gears on the cogset is easy and intuitive, the same cannot be said for what is happening with the front chainrings.
For less experienced riders, understanding the front chainrings seems to be the biggest challenge. Currently, there are three options for front chainrings: triple-, double-, and single-ring systems. Here’s a quick-and-dirty description of these systems.
Triple Chainring — The old mainstay triple chainring may be on its last leg but it’s still common. Less experienced riders will ride primarily in the middle ring up front and all up and down the rear cogset. Steep climbing requires shifting into the small chainring, also called the granny gear. I suggest only using about four gears down the cogset in the small ring. If you get too low on the cogset while in the small ring, your chain will be very loose and also begin to be cross-chained (at an awkward angle as opposed to being straight), so once you’re three or four cogs down and needing even more speed, shift up into your middle ring.
Likewise, many people suggest you don’t use the biggest chainring and your two or three biggest cogs. This also crosses your chain and leads to more wear. However, I always disregarded this advice and would use that gear to pop up over a hill or in other brief situations when I knew I’d want to be back in the big ring again a few seconds later. I would always cut my chains to just allow them to fit big ring to big cog.
Double Chainring — I feel like this really simplifies shifting by expanding the range of two rings and eliminates a substantial number of front derailleur shifts. I have been using SRAM 2x10 for a few years now and can’t even imagine riding a triple chainring. In my opinion, the only reason to stick with a triple would be if you cannot get a low enough gear for climbing in a double or a single ring system. I’m dying to try the new SRAM 1x11. Single ring systems eliminate the need for a front shifter, the front derailleur, the cable and housing, etc., but the biggest thing it eliminates is the sketchiest shift in mountain biking.
Front derailleur shifting has been the cause of countless jammed chains, broken chains, bent chains, dropped chains, marred rings causing chain suck, etc. — I could go on. Shift gently, with finesse and with good leg speed, spinning, always trying to stay on top of the gear. If you get behind your gear (meaning you’re mashing a lower cadence) it makes the shift tougher because you cannot really back off any more to release some pressure and allow the chain to move. This is especially true for shifting with the front derailleur. Also, don’t try to force a shift that you know you have blown and risk breaking something. Get off, shift the bike by lifting it and pedaling it with your hand and get back on the bike where you will have the best chance of staying on. This situation is likely to happen if you are suddenly faced with a climb that you were unprepared for and you didn’t shift and lost all of your momentum.
Anticipate your shifting and allow the system just a moment of ease so that the chain can quickly, easily and safely move to the next ring, cog or both. You simply cannot get away with too many shifts under full power. It won’t work and soon enough, you’re going to break your chain or tear something else up and your ride will be over or you’ll have something to fix, at the very least. Loud popping and pinging while shifting? Not good. You’re probably trying to shift while still putting pressure on the pedals. I have put lots of miles on mountain bikes and I have never had a chain break for no reason. I either didn’t put it together right or I blew a shift and bent a link. If you are breaking lots of chains, you might want to either get a new mechanic or take a good hard look at how you shift our bike.
Lighten up. Shifting should not be aggressive. It should be smooth and reek of finesse. This combined with anticipation and a good spin will allow both you and your bike to reach the end of the ride.