Ultimate Guide: How to choose correct chainring size (Oval and Round) | Cycling Boutique

Ultimate Guide: How to choose correct chainring size (Oval and Round)

by Biju K on January 13, 2024

How to choose correct oval chainring size (and round too)

Those who doesn't appreciate maths often get overwhelmed with the often confusing terms of gear ratio, teeth size etc. This lead to everyone using generic cranks added to the fact that unlike top-skilled bikeshops like Cycling Boutique Experience Center doensn't often do have the capacity to do those kind of skilled tasks or practical knowledge from riding large segment of bikes over decades of time to understand whats needed for each rider!

  • 26T Oval chainring has the ovality of 24/28T and is best for someone who uses currently 26T round ring. (Fatbikes!)
  • 28T Oval chainring has an ovality of 26/30T and is best for someone who uses currently 27 or 28T round ring.
  • 30T Oval chainring has an ovality of 28/32T and is best for someone who uses currently 29 or 30T round ring.
  • 32T oval ring will suit best someone who uses 31 or 32T chainring currently. While pedalling, you will feel similar effort to the one riding round 31T ring, but you will gain the speed similar to riding 34T chainring.
  • 34T Oval chainring has an ovality of 32/36T and is best for someone who uses currently 33 or 34T round ring.
  • 36T Oval chainring has an ovality of 34/38T and is best for someone who uses currently 35 or 36T round ring.

  • 46/30T is best for great gravel adventures where lots of climbing is involved and bike is packed with gear. Or simply for you to actually enjoy road climbs like Sa Calobra in Majorca or Alpe d'Huez in France.
  • 48/32T is ideal for general road climbing and day to day riding. Planning L'Étape du Tour? This size is right for you (30T would be too slow).

Ramps on big rings are specially configured for combinations: 50/34, 52/36, 52/38, 53/39T.

  • 34T inner chainring should be used with 50T outer ring. It has 6.5% ovality. Use a 34T to help with spinning higher cadence and hilly terrain.
  • 36T inner chainring can be used with 50 or 52T outer ring. It has 11.4% ovality. Use a 36T if you’re a strong rider or for rolling terrain.
  • 38T inner chainring should be used with 52T outer ring. It has 11.4% ovality. Use a 38T if you’re a very strong rider or for flat terrain.
  • 39T inner chainring should be used with 53T outer ring. It has 11% ovality. Use a 39T if you’re a very strong rider or for flat terrain.
  • 50T outer chainring – Choose this size if you ride for pleasure or sportive events. This is the most versatile and comfortable size.
  • 52T outer chainring - if you race and feel strong, it's the classic outer chainring size and a great option for experienced riders.
  • 53T outer chainring - if you race and feel very strong, it's the classic outer chainring size and a great option for powerful riders.

Remember when selecting your chainring sizes - it's not about what others use, but about ensuring YOUR ability to maintain a comfortable and effective cadence across the terrain you ride most often. If you ride chainrings that are too large (round or oval), your cadence will be lower. This can affect your performance by prematurely tiring your legs and possibly lead to stress injury in your knee joints.


  • 44T Oval chainring is best suited for someone who uses wide gravel tires, plenty of bike mounted camping gear or simply ride in mountain terrain.
  • 46T Oval chainring is best suited for fast hill riding with majority of gravel roads and some tarmac roads.
  • 48T Oval chainring is best suited for someone who rides majority of tarmac roads and occasional off-road flat terrain.
  • 50T Oval chainring is best suited for road oriented riders with occasional flat fire.

Most CX riders choose 38T as most versatile option. If you feel strong try bigger size.

  • 36T Oval chainring has the ovality of 34/38T and is best for someone who uses currently 36T round ring (also good for MTB).
  • 38T Oval ring will suit best someone who uses 37 or 38T chainring currently. While pedalling, you will feel similar effort to the one riding round 37T ring, but you will gain the speed similar to riding 40T chainring.
  • 40T Oval chainring has an ovality of 38/42T and is best for someone who uses currently 39 or 40T round ring.
  • 42T Oval chainring has an ovality of 40/44T and is best for someone who uses currently 41 or 42T round ring.

*Article Courtesy: Abolsute Black Inc. - Our channel partners in delivering the state of the art cycling speciality products, including oval chainrings.


You can find great collection of chainrings of all configurations at Cycling Boutique in India - Our technical support team is highest skilled and experienced to support you anything for cycling!.

 

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