Back when I wrote about proper gearing and shifting, I said it’s not a good idea to “cross chain.”

In other words, you don’t want to use the big ring and big cog combo or the little ring and little ring combo, because you’re putting the chain at an awkward angle. (See a cross chaining example here.)

But sometimes it’s actually smart to cross chain for short periods of time!

Yes, there are a few times when cross chaining will actually help you out! It’s usually only necessary when racing though, so you should still focus on keeping a straight chain line most of the time.

Without further ado, here are the times when you should cross chain:

short steep hill

1. When you encounter temporary changes in terrain.

Let’s say you’re on a fairly flat road and cruising pretty fast in a big gear, say 53×17.

Next thing you know, you’re facing a short, steep hill dead ahead!

If it was a long hill, you’d definitely want to shift to your little ring and use a small gear to get up the hill. But you need to get over this little hill and then get your speed back up as fast as possible or you’ll get dropped.

It would be beneficial to remain in the big ring, even if it means shifting to the big cog. So you stay in the big ring, but use a gear such as a 53×23 and power over the hill.

Once you’re over the top, you can quickly shift back down to a smaller cog.

Not having to shift the front derailleur during that little ordeal saved some time and energy which could come in handy later in the day!

Alternatively, you could use the small ring and small cog for temporary flat sections of a long, steep hill.

chain slap

2. On rough, rocky terrain, especially going downhill.

Say you’re out mountain biking and when you look ahead, the trail starts to drop off into a rough and rocky downhill.

If you’re in a smaller chainring, there are two big problems you should be worried about:

One, chain slap, which is when there is enough slack in the chain that it slaps the chainstay, ruining your frame’s paint job.

Two, the chain might fall off. If there isn’t enough tension on the chain, it could be flapping around enough that it ends up falling off the chainring and onto the bottom bracket shell. This will hurt your paint job and require effort to get it back onto the ring.

So the first order of business is to shift onto the big ring. That will take up a lot of slack by itself.

But you should stay on a medium to large cog, possibly a 44×30 gear.

Not only will this keep your chain steady, but if you hit a short flat or uphill stretch, the big/big combo is an easy enough gear that you can pedal a few strokes.

There you have it – the two times when you actually want to cross chain!

Photo credits: Hill climb by johnthescone | Chain by Paul Jerry

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  1. One other point to mention would be how some full suspension designs react to pedalling in different chainrings. My single pivot is more supple in bigger rings, so in rougher terrain it’s easier to climb faster in the middle ring than slower in the granny. On smoother but looser or muddier terrain it works out better in the granny ring as the wheel is forced down with each pedal stroke, improving traction.

  2. @Shaggy

    True, some full suspension bikes react to pedaling input. (But that’s not a reason to cross chain.)

  3. I ride daily and most always use large front and large rear sproket coming up the steep incline….just seems most comfortable for me….like the gear ratio and the speed. Note: been doing this for 25 years….the same age as the bike.

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