Gear up! And clench some teeth ...cuz this goes deep

• If you’re riding anything over a 6-speed bicycle this write-up might be for you.
• If you have heard about cross-chaining but aren’t sure what it means then it is essential you read this.
• If you happily believe that your bike gives you 27 gears because the label tells you so, or because you did the math up to multiplying, say, 3 (chain rings) times 9 (rear cogs) equals 27, then this will be a humbling but enlightening few words of gyaan (Coming soon in the next post)
  

Not to be disappointed with that last one – 3 times 9 will always equal 27, but the idea of this post is to tell you that more can, and should, be had with less. More (range of gear ratios) can be had with less (number of shifts) AND again, that more (performance life of components) can be had with less (wear, damage and breakage). On that uplifting note, let’s get into this Zen like business of getting more from less!

Let me start by elaborating on the 3 points right there on top.

What’s with over 6-speed that makes this article useful?

Most bikes up to 6-speed will have all cogs at the rear freewheel / cassette and one chain ring up front. The entire gear range can be used by shifting the sole rear derailleur. Cross-chaining has an almost negligible presence in this scenario.

Anything over a 6-speed bike, and we have a new set of variables – the front crankset of 2 to 3 chain-rings plus the front derailleur. This is where cross-chaining can rear its rattling head and put your bike’s health in the red.

What is cross-chaining and why you shouldn’t cross paths with it.

Two terms needs to be mentioned before cross chaining:

Chain-line: the angle of a bicycle chain relative to the centre-line of the bike's frame.http://en.wikipedia.org/wiki/Chainline

Centre-line (of the frame): an imaginary vertical plane that runs down the centre of the bicycle frame. It is essentially the plane of symmetry of the frame.

The happiest situation is with a chain that’s perfectly parallel to the centre-line of the frame, equidistant at the bottom bracket and rear hub. This will be found on all well-built single-speed bikes. That’s probably one of the reasons why purists love their single-speeds so much ;)

On a geared bike, selecting gears involves moving the chain closer to or further away from the centre-line at either end. This causes the chain to not remain parallel to the centre-line to varying degrees. Push this to the extremes and you have cross-chaining. For example, selecting 3^rd gear (outermost) on the crankset and 1^st (innermost) at the freewheel OR 1^st (innermost) on the crankset and 9^th (outermost) on the freewheel.

In general, cross-chaining is a consequence of selecting gear combinations that bend the chain considerably out of ‘chain line’. Chains for geared bicycles are engineered to flex a certain amount for smooth shifting and will tolerate operation out of chain-line without much complaint. So how will you know when you are cross chaining? You will know the symptoms when the chain starts telling you about it, literally.

Video about cross chaining

The usual symptom is a rattling sound from the chain, caused by the chain rubbing against the derailleur body. In addition, a rattle could also come from the chain rubbing against the side of the next larger cog. You hear any of these rattles, you know you’ve gone over to the dark side. Don’t stay there too long! Those light rattles will slowly but surely eat away at your chain, derailleurs and cogs. Prolonged riding under cross chaining will weaken your chain, deform your derailleurs, and grind away the cog’s teeth, even knocking them off after some time. No dentist around to fix those broken teeth.

The drive-train of a geared bicycle is a complex and expensive system, and one which has a lot of demands placed on its performance. Cross-chaining is one of its worst enemies – don’t bring it with you when you ride!

Next post - Good shifting pattern (coming shortly since I'm crunching some numbers and figuring out some MS Excel tricks)