RENNEN 4-Bolt Threaded Decimal Chainring
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Description
The Rennen 4-bolt threaded decimal chainring solves a well-known issue for BMX Race riders: changing by one full tooth shifts the gear development by a whole step, which is often too much for fine-tuning your rollout. Rennen Design Group therefore developed intermediate tooth counts — here 42.2 / 42.7 / 43.2 / 43.7 teeth — allowing you to fine-tune your gearing in half-steps.
In practice, a rider who finds a 42-tooth ring too short and a 43-tooth too tall gets two extra gear options in between. Out of the starting gate, where everything is decided in the first few pedal strokes, that fine adjustment really counts.
The construction features Rennen's signature expertise: 7075-T6 aluminium CNC-machined in the USA (rated 83% stronger than 6061), 3/16" thickness (approx. 4.8 mm), and a dedicated single speed tooth profile. The integrated threads eliminate the need for chainring nuts and chainring spanners: the bolt screws directly into the machined threads for a precise, wobble-free fit. 104 mm BCD, compatible with 8 and 9-speed chains.
Ref: 16086922232188
Key features
Decimal Tooth Counts: 42.2 / 42.7 / 43.2 / 43.7 teeth to fine-tune your gear development in half-steps.
Fine Rollout Adjustment: Two intermediate positions between 42 and 43, where a full tooth jump is too drastic.
Integrated Threading: Machined threads in the chainring — no chainring nuts or chainring nut wrench required.
7075-T6 Aluminium Machined in the USA: Alloy claimed to be 83% stronger than 6061.
Single-Speed Tooth Profile: Specific design engineered to extend chainring lifespan.
104 mm BCD: Standard 4-arm, compatible with 8 and 9-speed chains.
