Thank you for purchasing through links and ads on this site.
OWC / MacSales.com...
diglloyd Deal Finder...
Buy other stuff at Amazon.com...
Capacities up to 48TB and speeds up to 1527MB/s
Organic Lab Tested Full Spectrum CBD
20% off with coupon code diglloyd20 at NuLeafNaturals.com

100% organic non-GMO, no additives or preservatives.
Legal in all 50 states

Standard 53X39 or Compact Double 50X34 Chainrings?

Last updated 2011-05-28 - Send Feedback
Related: gear, Road Bikes, Shimano

When buying a bike, one consideration is which chainrings to choose. I absolutely prefer a double front chainring, having ridden a triple front chainring for years, which I deem too fiddly. Plus, it won’t work with DI2 electronic shifters as far as I know.

See pricing at Amazon for Shimano DuraAce.

While there are some other atypical standard double choices, the choice boils down to either:

  • 53 X 39 standard double chainrings or
  • 50 X 34 compact double.

Along with an appropriate cassette to match to it— I recommend the 11-28 for anyone doing much climbing.

Update May 28, 2011: my 2nd Trek Madone 6.9 SSL uses a 50 X 34 compact double, and I can say that the friendlier 50 X 34 gearing is of great value on climbs, so much so that I suspect that eventually I’ll convert my first bike to a 50 X 34 also. I’m running the 11-28 cassette on both bikes.

OWC Mercury Elite Pro Dual 16TB
Up to 24TB

FAST USB 3.1 gen 1 interface +
eSATA + RAID stripe or mirror or independent drives.

Compact double advantages

The compact double has some key advantages:

  • The compact double weighs a bit less, and allows a smaller cassette for similar gearing, thus cutting weight from the cassette also (e.g., a 25-tooth gear instead of 28).
  • The loss of 3 teeth on the big front ring can be compensated for with an 11-tooth sprocket, versus a 12-tooth for a 53 ring. At any rate a 53/12 is a ratio of 4.42 versus 50/12 for a ratio of 4.17 or 50/11 for a ratio of 4.55.
  • Considerably lower and more tightly-spaced gearing is possible with the 34-tooth front ring, making an 11-25 a very attractive option, and allowing a 12-27 for when really low gearing is needed. Even a 12-23 is a bit easier than a 12-28 on a standard double.

Gear ratios

For the graph below, the gear ratio is plotted: higher values are more difficult pedaling. For steep climbs, concentrate on the right side with gears 5/4/3/2/1.

The 11-25 has a tight spacing for cruising in just the right gear on moderate terrain.

Dropping to a 50x34 + 12-27 offers a very comfortable 1.26 ratio, a big help on really steep climbs. The 53x39 + 11-28 offers a more difficult 1.39, which is 10% harder, a crucial difference for some riders on very steep climbs.

In short, use of a compact double offers a big plus for both climbing and for cruising in just the right gear. Even an 11x23 cassette might make sense for some riders where there are modest hills.

Sony FE 400mm f/2.8 GM OSS
Only 6.4 lb / 2.9 kg! 3 Fluorite Elements, 1 ED Element, nano coating, 11 blade diaphragm, weather sealed

About 1.3 gears more for a compact double — 14%

As the graph below shows, a compact double essentially moves the gearing down one gear, giving you one more gear for climbing with a 34 X 28 instead of a 39 X 28 — a 14% difference in gearing that might be enough to save your quadriceps and knees.

The downside is that the 50 ring yields about 6% less top end: 50 X 11 instead of 53 X 11 — a fair trade since ferw riders spend much time in the 11-tooth ring.

Gear ratios with various cassettes using standard or compact double (39 or 34 teeth for small ring)
Lowest 5 gear ratios with various cassettes using standard or compact double (39 or 34 teeth for small ring)

All 10 gears

The graph below shows the entire gear range in the small front chainring (39 or 34 teeth).

Gear ratios with various cassettes using standard or compact double (39 or 34 teeth for small ring)

MacPerformanceGuide.com
B&H Deal ZoneDeals by Brand/Category/Savings
Deals expire in 34 min unless noted. Certain deals may last longer.
$1632 SAVE $700 = 28.0% $165 GIFT CARD LG C8PUA 55" Class HDR UHD Smart OLED TV in Electronics: Televisions
$3097 SAVE $200 = 6.0% $77 FREE ITEMS Nikon D850 DSLR in Cameras: DSLR
$1797 SAVE $200 = 10.0% Pentax K-1 Mark II DSLR in Cameras: DSLR
$998 SAVE $400 = 28.0% Sony a7 II Mirrorless in Cameras: Mirrorless
$1798 SAVE $200 = 10.0% Sony a7R II Mirrorless in Cameras: Mirrorless
$3998 SAVE $500 = 11.0% Sony a9 Mirrorless in Cameras: Mirrorless
$799 SAVE $199 = 19.0% Sony DSC-RX100 V in Cameras: Point and Shoot
$5987 SAVE $1839 = 23.0% ZEISS Loxia 5-Lens Bundle in Lenses: Mirrorless
$11594 SAVE $3157 = 21.0% ZEISS Otus ZF.2 3-Lens Bundle in Lenses: DSLR

diglloyd.com | Terms of Use | PRIVACY POLICY
Contact | About Lloyd Chambers | Consulting | Photo Tours
Mailing Lists | RSS Feeds | Twitter
Copyright © 2019 diglloyd Inc, all rights reserved.
Display info: __RETINA_INFO_STATUS__