Our topic this week comes from a great question by RoadBikeRider reader David Stihler who wrote, “I have heard many times that you can’t/shouldn’t cross-chain. I was just on another ride where a modern bike with Shimano Ultegra components kept getting hung up (not able to shift) because the rider cross-chained. I ride a triple Campagnolo drivetrain and cross-chain all the time and believe that most modern bikes can handle the stress if accidentally cross-chained and that it’s not the no-no that it was a few years ago. Can you put this myth to rest (or not)?”
Basic gearing terminology
Thanks for the question, David. It’s a good one and raises a concept that’s helpful for beginning to expert riders to understand. Let’s start with a little terminology. Road bicycles have front and rear sprockets, at the crankset/pedals and at the rear wheel, respectively. In talking about gearing, we call the front sprockets “chainrings” or “rings,” and the rear sprockets “cogs.” When talking about the whole front or rear range of sprockets, riders will say the “crankset” or “cranks” and the “cassette” or “freewheel,” for the front and rear, respectively.
If you haven’t done it, it’s educational to have someone else shift your bike by hand so that you can watch how shifting changes your drivetrain’s geometry. And it will help you appreciate the phenomenon of cross-chaining.
Suspend your bike and stand behind it so that you can sight down the length of the chain. Now, have a friend shift up onto the largest cog and back down to the smallest cog. You should be able to see that the chain angle changes pretty drastically on the outmost 2 cogs. Next, shift onto each chainring (front sprockets) and repeat shifting up and down the cogs. This time watch from behind and from the side and see how the rear derailleur (the mechanism that accomplishes the rear shifts) is much more stretched out when the chain is on the large chainring(s), than when on the small.
Instead of “cross-chaining,” you might also hear someone call it riding in your “crossover gears.” But, both mean the same thing: that you have shifted your chain onto (and are riding in) one of two extreme positions. Every derailleur bicycle drivetrain has cross-chain positions, and there are always two. One is when you’re on the largest chainring and the largest cog and the other is the opposite extreme, the smallest chainring and the smallest cog.
Is it a problem riding in cross-gears?
To cut to the chase and answer David’s question, he’s right that on modern drivetrains that are set up correctly, it should not cause problems if you end up riding in the crossover gears every now and then. Our modern chains flex enough to handle it.
That’s a good thing because you can cross-chain even when you try to avoid doing it. This happens when you forget that you’re on the large chainring and, instead of shifting off it when the going gets tough and you need easier pedaling, you just keep shifting up the rear cogs and end up on the largest one.
Alternatively, you can forget you’re on the smallest chainring and keep shifting onto smaller and smaller cogs to hit your higher gears and end up on the smallest ring and cog cross-chain position. The way most riders tend to shift, it’s more common to end up in the big/big cross-chain position than in the small/small.
Known issues from cross-chaining or cross-chaining too frequently
While it shouldn’t cause any issues to cross-chain once in awhile on a properly set up bicycle, on imperfect bikes it has been known to cause problems. And that’s why some roadies will tell you you’re cross-chaining when they see you doing it on a ride.
For example, beginning cyclists have been known to sometimes leave new bikes in the small/small cross-chain position. This happens because they’ve been told or reason out that if they have 20 gears, being on that 10th cog should be a nice “medium” gear to ride around in until they get used to shifting. But, experienced cyclists know that it’s not actually a medium gear and that it would be better to shift to a true medium gear, and to practice and get good at shifting, too.
That “hung up” modern Shimano drivetrain and dropping the chain
And, as David references in his “hung up” Shimano Ultegra drivetrain example, if the drivetrain isn’t set up correctly, it’s in the cross-chain positions where you may experience problems. In his example, cross-chaining on the big/big is the most common cause of a chain getting hung up and not being able to be shifted down off the big cog or chainring. The cause is usually a chain that’s been sized too short. In most cases, simply adding links will resolve the problem and the bicycle will not get hung up anymore. So, you might tell your friend with that bike to check his chain length, David.
The other issue you might run into when using the big/big cross-chain position is having the chain fall off the chainring when you shift from the large chainring to the small chainring. This can happen if the front derailleur isn’t perfectly adjusted. It’s more likely to kick the chain off shifting from the big/big because the chain is as far to the inside already since it’s on the largest cog. The chain is also tensioned as tightly as possible when it’s on the big-big.
The combination of the spring tension and chain position makes it much more likely for an out-of-adjustment front derailleur to throw the chain off. The fix is dialing in the front derailleur adjustment. If you can’t do that on the ride, change your shift sequence and shift down onto a smaller rear cog before shifting from the big to small chainring – and you won’t have the chain fall off.
In closing, if you’re riding a modern road bike and experience issues in the cross-chain positions, they can probably be resolved so that occasionally using those gears won’t cause any problems for you on rides.