Unless you’re a die-hard single speeder or have converted your bike to a 1 x and have forgotten what it’s like to have more than one chainring, smooth and effective shifting between chainrings is a basic, but crucial, skill.
And with some pretty cool technology on the market, there’s never been a better time to make sure you’ve got your shifting under control.
Question: Why do (some) bikes have gears?
Answer: To be able to ride comfortably over a variety of terrain.
It’s easy to focus on mastering how to use the gears at the back while leaving things pretty much alone at the front. For many people, the front gears are the go-to only when things point up or start to point down! By learning to change between the front chainrings you can add or take off a whole lot of gears in one quick move.
As you work down (or up) to the last few gears in the cassette, have you ever heard that grinding/rubbing noise? That’s the chain rubbing on the front mech as the angle of the ‘chainline’ gets more diagonal – also known as cross-chaining.
Want to be able to use the full range of your gears without that pesky rubbing noise? With the trim function on your front shifter, you can make the bad noises go away.
You may have heard the word Trim before used in connection with shifting, or you may have even done it accidentally while shifting but never knew the name for it. Either way, “trimming” is an important skill to have if and as you access the gears in the extremes of your bike’s range.
The trim function is essentially a ‘microshift’ with moves the front mech ever so slightly without moving the chain off the chainring. The silence is most useful when planning surprise uphill attacks on your riding mates.
NB – Even though the trim function can help take care of the noises, when the chain is at the inner and outer most extremes it isn’t kind on the hardware.
Chain and driveline parts wear faster and shift less reliably if constantly cross-geared. Also, not all bikes have a trim function. You will need to look up the model you have to find out.
All still seems like hard work? It’s ok, technology is here to save us! Now you know about trimming get ready to have your mind (and wallet) blown. Automatic Trimming in electronic groupsets.
These are top of the range bits of kit, such as EPS, Etap and Di2 from the big manufacturers. These electronic grouppos ‘sense’ when the chainline is getting too extreme and trim for you. I know, right?
The most advanced electronic groupset, Shimano’s Di2 for MTB, goes one step further and will actually automatically shift the chain between rings front and rear as it senses cross-gearing. Think Auto gearboxes for bikes! (You can, of course, turn this function off if you develop iRobot related concerns about whether or not your bike is subject to the Three Laws)
So, technology is aiding to eradicate cross-gearing, but even if you have a mechanical set up, there’s high chance that with a few gentle clicks you can experience quieter, better riding and stealth your way past your mates on that hill!