Oval Direct Mount Chainrings for SRAM Mountain Cranks
OVAL-SDM28-BST-B
Pairs well with
Oval Direct Mount Chainrings for SRAM Mountain Cranks
Free WT-1 With Chainring Purchase
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Promotion Expires 12-31-2024
More power, better traction, less shifting. Wolf Tooth oval chainrings use our proprietary PowerTrac design that has all the benefits of oval, but without the funky, uneven pedal stroke. Ride one once and you’ll wonder why you waited so long to try oval.
Think of an oval chainring as two chainrings in one. A major benefit of oval is how the shape of the chainring alters your gearing in two important phases of your pedal stroke by harnessing your body’s natural biomechanics. Here’s how it works. The area of the chainring with the larger diameter engages with the chain at the optimal point on the downstroke, which is what’s known as the Power Zone. If you were to look at a clock, the Power Zone would be between 1-5 and 7-11. Conversely, the Recovery Zone – back to the clock face, between 11-1 and 5-7 – is the weakest part of the pedal stroke, when the oval maximizes your efficiency. A 34T oval chainring behaves like a 36T chainring when you want power, while behaving like a 32T chainring when you’re climbing.
We’ve also engineered our oval chainrings to provide smoother, more efficient pedal rotation. This equates to better traction because of steadier torque on the rear wheel. With a Wolf Tooth oval chainring, you can harness more of your strength in the Power Zone, while having easier pedaling in the Recovery Zone.
The direct mount chainrings for SRAM cranksets replace your existing spider and chainring with one clean looking, lightweight, and stiff piece of machined billet. They are available in 3 different offsets: 6mm offset for 49mm chainline, 3mm offset for 52mm chainline, and 0mm offset for 55mm chainline and SRAM Transmission optimization. They are available in various tooth profiles to suit your drivetrain, including Drop-Stop B, which is optimized for SRAM T-Type Transmission and compatible with many other chains. Crankset and chainring compatibility questions? Check out our helpful guide here.
Compatibility
- These direct mount chainrings will replace your existing chainring and spider, which is attached via 3 bolts on the back side of the spider near the spindle. You will use these same 3 bolts to attach the Wolf Tooth SDM® chainring. Note that these chainrings are NOT compatible with SRAM 8-bolt direct mount cranksets.
- Also compatible with Cane Creek eeWing cranksets.
- There are 3 offsets:
- Boost: 0mm offset for 55mm chainline required for SRAM Transmission
- Boost: 3mm offset for 52mm chainline or Transmission compatibility with Super Boost bikes
- BB30: 0mm offset for BB30 short spindle cranks for 49mm chainline
- Standard MTB: 6mm offset for non-Boost mountain bikes, GXP and long spindle BB30 cranks for 49mm chainline
- Fat Bikes: If you are planning to use this on an X9 or XX1 fat bike crankset with a 190/197 rear hub spacing use the 0 offset ring. If your fat bike has a 170/177 rear hub spacing, use the Standard 6mm offset
- Praxis Works Road/CX cranks use the 6mm offset. Praxis Works mountain cranks use the 3mm offset for their DM-A and 0mm offset for their DM-B chainrings.
- If you have a BB30 crankset (30mm diameter aluminum spindle) the measurement pictured below will help you determine whether it is a long or short spindle.
- You will need chainring to chainstay clearance for a chainring two teeth bigger than the elliptical chainring (max diameter is that of a chainring two teeth bigger).
- 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).
Recommendations
- Recommend the use of a clutch style rear derailleur for the best chain security.
- A T25 Torx wrench is required to remove the bolts that secure the chainring or spider to the crankarm.
- An L-wrench works best since the crank spindle may contact a socket adapter and prevent it from engaging properly.
- Use the same 3 bolts to attach the Wolf Tooth ring or if you need, we carry replacement bolts
Related Products
- We recommend using a T25 L-Wrench or similar for removal and installation of the bolts.
- Replacement Bolts
Tech Specs
Weight: 28t • 60g | 30t • 68g | 32t • 74g | 34t • 83g | 36t • g
Material: 7075-T6 aluminum
Made in the USA
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:
Not compatible with 12s Shimano HG+, 12s KMC, or 13s Campagnolo chains |
All 9s, 10s, and 11s Chains 12s Chains:
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:
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 |
 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 |
 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 |
*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.