SRAM 39T 120mm BB30 Alloy - 11.6215.188.270
39T 120mm BB30 Alloy - 11.6215.188.270
SRAM

SRAM 39T 120mm BB30 Alloy - 11.6215.188.270

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SRAM 39T aluminum outer chainring for BB30 2x10 cranksets. 4‑bolt BCD120 design delivers lightweight durability and precise 10-speed shifting for road setups.

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Product Details

Overview & Technology

SRAM 39T 120mm BB30 Alloy is a CNC-machined aluminum outer chainring engineered for 10-speed SRAM 2x10 BB30 crank systems. The ring uses a 4-bolt, 120mm BCD pattern and is finished in hard black anodizing to resist corrosion and maintain a clean appearance on road bikes. This ring is built for predictable, fast shifts with SRAM's 2x10 S-pin chainring interface and ramped tooth profiles tuned for 10-speed chains. At roughly 0.3 lb (shipping weight), it balances stiffness and low mass for responsive power transfer without adding unnecessary weight to your drivetrain.

Key Features & Construction

Material and machining: precision CNC-machined aluminum alloy with a durable black anodized finish for long life and consistent shifting behavior. The tooth profile includes ramps and shift aids optimized for 10-speed chains to make front shifts crisp and reliable under load. Design details: 39 teeth, 120mm BCD, 4-bolt mounting and specific S-pin compatibility ensure correct fit on SRAM BB30 2x10 crank systems. The outer ring construction prioritizes lateral stiffness to maintain chainline and reduce flex during hard efforts.

Fit, Compatibility & Installation

This chainring fits 120mm BCD, 4-bolt crank spiders and is intended for SRAM S-pin BB30 2x10 configurations. It is an outer ring sized for an All 26/39 2x setup, meaning it pairs with a smaller inner ring (commonly 26T) in SRAM 2x10 compact setups. It is optimized for 10-speed chains; compatibility with 11-speed chains is not guaranteed. Installation notes: use correct length chainring bolts and follow crank manufacturer torque specs — typically around 10-12 Nm for chainring bolts. Inspect chainline and shifting performance after installation and replace chainring bolts if they show wear. If you have a different crank interface or an 11-speed drivetrain, confirm fit before purchasing.

Who This Chainring Is For

This chainring is aimed at road riders running SRAM 2x10 BB30 cranksets who want a lightweight, durable replacement or a tuned upgrade for crisp front shifting. It suits racers, club riders, and commuters who maintain 10-speed drivetrains and need correct BCD fitment. If you're converting drivetrains, changing tooth counts for cadence preference, or replacing a worn outer ring while keeping your original SRAM BB30 crankset, this ring gives a direct bolt-on option without fuss.

Key Features

  • ✓ CNC-machined aluminum alloy for stiffness and low weight
  • ✓ 39 teeth outer ring tuned for SRAM 2x10 S-pin BB30 systems
  • ✓ 4-bolt 120mm BCD fits common compact and road crank spiders
  • ✓ Black anodized finish resists corrosion and road wear
  • ✓ Ramped tooth profile and shift aids optimized for 10-speed chains
  • ✓ Light shipping weight — approximately 0.3 lb for easy handling
  • ✓ Direct replacement for All 26/39 2x10 configurations

Specifications

BCD 120
Chainring Bolts 4
Chainring Comp. S-pin BB30 2x10
Teeth 39
Material Aluminum
Position Outer
Primary Color Black
Speed 10

Product Identifiers

Vendor Item # 11.6215.188.270
UPC 710845660627

Frequently Asked Questions

Will this chainring fit my crankset?

This ring fits crank spiders with a 120mm BCD 4-bolt pattern and is specifically designed for SRAM S-pin BB30 2x10 setups. Confirm your crank uses the 120mm BCD and S-pin interface before buying. If your crank is a different interface or an 11-speed-specific model, this ring may not be compatible.

Is the ring compatible with 11-speed chains?

The SRAM 39T here is optimized for 10-speed chains and tooth profiles tuned accordingly. While some 11-speed chains may physically fit, shifting performance and wear characteristics are not guaranteed, so we recommend matching ring tooth profiles to your chain speed.

What torque should I use when installing this chainring?

Follow your crank manufacturer torque specifications for chainring bolts — commonly around 10-12 Nm for many road setups. Use quality chainring bolts and a calibrated torque wrench to avoid over-tightening or loosening under load.

Can I replace only the outer ring or do I need to change both rings?

You can replace just the outer ring if the bolt pattern and BCD match and the inner ring is in good condition. However, if the inner ring is worn or the chain has significant wear, replacing both rings and the chain is recommended to restore optimal shifting and reduce premature wear.

How long will this aluminum chainring last?

Lifespan depends on riding conditions, maintenance, and chain wear. With regular cleaning, a well-maintained chain, and replacing the chain when stretched, a quality aluminum chainring like this can last thousands of kilometers. Gravel, muddy, or salty conditions will accelerate wear.

Do I need special bolts or hardware to fit this ring?

Use chainring bolts that match your crank's bolt length and thread type. For BB30 S-pin systems, standard 4-bolt chainring hardware is typically used. If your crank uses rivets or a proprietary mounting system, you may need specific hardware.

Buying Guide

When choosing a replacement outer chainring, match the BCD, bolt pattern, and chain-speed rating to your existing crankset. For SRAM 2x10 BB30 systems choose a chainring like this 39T 120mm option to maintain correct chainline and front shifting dynamics. Check whether you run an All 26/39 setup or another tooth combination to ensure the ring pairs correctly with your inner ring. Consider materials and riding style: aluminum chainrings offer an excellent balance of weight, stiffness, and cost for road use. If you ride in extremely abrasive conditions or want the longest service life, consider heavier-duty or steel options, but for most road cyclists a CNC-machined aluminum ring provides precise shifts and reliable performance.

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