Transmit torque from the gearbox output to the differential.
A DID 520VX3 X-ring chain. The X-rings internally seal grease, which decreases roller wear. Design Philosophies and Processes: Non-sealed chains are not recommended on bikes over 450 cc or on engines outputting more than 70 hp. Increased chain life, combined with precise control of centre-to-centre distances through differential carrier manufacturing, eliminated the need for a chain tensioning system entirely.
Centre-to-centre distance was calculated in a spreadsheet called 'Sprocket Calcs' under CR22/Powertrain/Design/Drivetrain/2 ~ Analysis/Final Drive. The selected centre-to-centre distance differs from the nominal chain count by -0.2266 in. That distance works and achieves acceptable chain tension, but the reason the calculation differs from the actual is recorded as unknown, and the difference has to be carried forward when centre-to-centre distances change.
CR22 ran a DID 520VX3 X-ring chain, 110 links as purchased, cut down to 48 links before install. Use an old chain to measure how many links are needed and where to cut, then remove the pin with an angle grinder. Do not use a rivet style master link: master links become single use and the drivetrain becomes extremely difficult to clean and service. Clip style master links have given no trouble when the correct parts are used. Never mix clips, seals or plates from different master links, or a chain failure becomes likely. If part of a master link is lost, order a new one, and always keep a complete spare master link on hand. If the sprocket or chain is new the chain may be slightly snug, needing some force to squeeze the master link in. That is acceptable as long as excessive force is not required. If a new chain does not fit, run an old chain for the first few drives to wear the rear sprocket in.
DID 520VX3 X-ring chain.
Fault Vault, 2026-07-12, CR26I, Operational Errors, Performance Failure. The chain did not fit on the 34 tooth sprocket during testing, which ended a day and wasted time. The cause was either stock left on during milling or a misunderstanding of the centre-to-centre analysis. Corrective action: check the machined sprocket on the centre-to-centre checker before it goes on the car, and confirm it fits on the car in the shop before going out to testing.
Check the machined sprocket on the centre-to-centre checker before it goes on the car, and confirm chain fit on the car in the shop before going out to testing.
Over 500 miles on a single chain with no loss of tension or failure. This saves time at competition swapping chains between events and lowers the risk of not finishing an event; a chain failure can also cause major damage to surrounding systems. From the cost report drawings and CAD: Measured mass, as built: CR25 0.3 g (0.001 lb). Source: CR26e Weight Tracker.xlsx, Final IRL Weights (weighed, not CAD)
Nothing in CrimsonStorage covers these yet.