SRAM Eagle X-Sync II chainring is a classic example of a product packing a huge amount of technology that passes most riders by.

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Originally designed to prioritse chain retention, the latest X-Sync chainrings are not only significantlt better in this regard than others on the market, but also improved in terms of longevity and wear, which also translates to extra chain and drivetrain lifespan. The alternate thick/thin design now also has an ‘open’ groove at the base of the teeth designed to purge mud and cack for better clearing.

I’ve visited SRAM in Germany, met its chainring engineers and seen first hand how much work and testing went into the design. Basically, every detail’s been sweated, from the reinforced webbing that boosts lateral stiffness through FEA analysis (to improve power transfer and smoothness) to a much more sophisticated tooth profile than rivals.

This complicated cog shaping spreads chain load over more teeth concurrently (three) than other chainrings, and also uses ramps and shaping to ease peak chain loads and reduce friction. The weird-looking wavy profile on the forward-facing edge encourages the chain roller to ‘disengage’ more when downstroke torque loads are highest and keeps the stroke more fluid, which further reduces chain wear. The Eagle chainring works best with SRAM’s rounded-inside chain plates, but I’ve found it also reduces drag on off-brand chains too.

X-Sync II is light years ahead of the competition in terms of smoothness, quietness and wear life. I’ve used it over thousands of kms without a single dropped chain, and it actually makes your bike noticeable easier to pedal compared to rival systems. Considering a chainring is essentially just a forged and machined piece of aluminium, the price is quite hard to stomach (no matter how much development took place), but I reckon lasting so long and offering superior performance is worth it.