Basics about Chain Rings
Ranges are measured in the number of teeth. For road bikes, the larger sizes are around 52T/53T, going as small as 39T for hilly rides or a 42T in flatter terrains.If you’re riding a mountain bike, you’ll want a slightly different range, of 24T-28T teeth for hill climbing and a larger ring of 46T-50T teeth for use on faster courses. Mountain bikes nearly always have a triple set of chain rings up front; road riders can consider this, too, if their rides tend to be hilly.
Mini Velos or Folding bikes by virtue of the smaller tires compensate gearing range by the use of bigger chainrings so it is no surprise that you will find 53T or 55T chainrings configured on folding bikes. The bigger chainring actually helps small wheeled bikes attain the same speed without the need to peddle like a “hamster” or “lab mice”. On the contrary, smaller wheels have the advantage of faster pick up.
Some of the stronger riders have actually configured a 57T or 60T chainring but this is where bigger does not mean better as we are relying on muscle and stamina to drive the transmission, NOT a foot pedal that feeds fuel to a engine in a car. You really got have the legs to power such a large chainring.
For those who can settle for a 53T 130 BCD, we have Ovalised Chainrings. Oval-shaped chainrings may not be a new invention, but these days they’re proving more effective than they ever did in the past. Advocates include the 2008 Tour de France winner Carlos Sastre, and the UK’s Bradley Wiggins who ﬁnished fourth in 2009. They’re designed to eliminate something known as the dead spot when you pedal.
BMC UK Racing Team’s training bikes are already being equipped with Rotor’s Q Rings to enable team riders to gain the benefit of the rings when training.
Long rides and hills – smaller chainring
Acceleration on flats – bigger chainring
Transmission efficiency is also affected by the wheel hubs and BB.
Before you go rush out and buy that 55T or 60T chainring. Make sure you check the BCD – bolt-circle diameter It si the Diameter of the bolts that hold the chainring to our crank. It is typically 130 mm or 110 mm