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120 BCD cranksets were introduced with SRAM 2x10 drivetrains and are excellent candidates for a 1x conversion with our patented Drop-Stop® chainrings. These rings will allow you to convert your 120 BCD crankset, like the SRAM XX and others, to a 1x drivetrain.

 

  • Fits 120 BCD cranksets or 4-bolt spiders

  • Drop-Stop technology. On Wolf Tooth’s patented wide/narrow chainring, the wide side of the tooth has maximum contact on the drive side which spreads the load and improves chainring life. The narrow side allows clearance for mud and debris which reduces friction.

  • Alternating wide/narrow tooth pattern prevents chain derailment

Compatibility

  • These rings fit any 120 BCD crankset or 4-bolt spider.
  • You must use M10x.75 bolts with a shoulder on them. These are not standard bolts and Wolf Tooth's bolts will not work with this chainring. Note that only about 3 threads will engage (same with the stock SRAM rings)
  • SRAM is the only supplier of the  M10 x .75 bolts 
  • 36t is the smallest number of teeth that fits on a 120 BCD
  • If using a 9-speed drivetrain use a 10-speed chain (shifts and works well on a 9-speed drivetrain and fits the ring tighter for better chain retention).
  • Chainline - 51mm for 36t and 52mm for 38t (38t is wider for more chainstay clearance)
  • NOT compatible with FSA 4 bolt cranksets


Recommendations

 

Before you buy a 120 BCD ring, check to see if your cranksets has a removable spider and compatible with our direct mount rings. To determine if your spider is removable, see the top two boxes in the decision tree (the 4th picture in the product pictures).  

 

If you plan to ride in very muddy conditions, we recommend a chainguide or chainkeeper along with a clutch style rear derailleur for the best chain security. Without these precautions, you may experience chain drops and/or chainsuck.

Tech Specs

Weight: 36T • 54g  |  38T • 59g
Material: 7075-T6 aluminum
Made in the USA

 

Patent and trademark information

Wolf Tooth is committed to provide the most precision components possible and has three different tooth profiles for optimal performance based on your chain type.


Tooth Profile

Tooth Profile

Drop-Stop® B

Drop-Stop® A

Drop-Stop® ST

Chain Compatibility

Chain Compatibility

All 9s, 10s, and 11s Chains

12s Chains:

  • Connex
  • Wipperman
  • Campagnolo
  • SRAM Eagle
  • SRAM Road and Transmission (T-type) Flattop chains

Not compatible with 12s Shimano HG+, KMC, or 13s Campagnolo chains

All 9s, 10s, and 11s Chains

12s Chains:

  • SRAM® Eagle
  • Connex
  • Wippermann

You can use Drop-Stop B when Drop-Stop A is not available*

Not compatible with 12s SRAM Transmission (T-Type) and Road Flattop, 12s Shimano HG+, 12s KMC, 12s Campagnolo, or 13s Campagnolo chains

12s Chains:

  • Shimano HG+
  • 12s KMC

Not compatible with all other chains

Details

Details

Tooth shape is nearly identical to Drop-Stop A, but has narrower teeth. Valley between teeth is deeper to accommodate larger rollers on Flattop chain. Outside faces of narrow and wide teeth touch chain to guide alignment.

Drop Stop B Chainrings navigate_next

The original Drop-Stop tooth profile. The wide teeth are wider than Drop-Stop B. Outside faces of narrow and wide teeth guide chain alignment.

Drop Stop A Chainrings navigate_next

Narrower teeth than Drop-Stop A. Wide teeth use Symmetric Trapezoidal (ST) profile to match extended inner edge on chain to create alignment (outside faces of wide teeth do not touch). Interaction of narrow teeth and chain are similar to Drop-Stop A and B.

Drop Stop ST Chainrings navigate_next

*We are in the process of migrating most Drop-Stop A to Drop-Stop B to make them compatible with  SRAM Road and Transmission (T-type) Flattop chains.

WARNING Handling this product will expose you to chemicals, including lead, known to the State of California to cause cancer and birth defects or other reproductive harm. Wash hands after handling. For further information go to www.P65Warnings.ca.gov.