BMX Race Racing Chainrings Sprockets & Bolts

A true and straight chainring helps with chain tension and drag, if you have tight spots in your chain, one of the first places to look could be your chainring. Look for worn out or bent teeth, or try loosening your chainring bolts, giving the crank arm a few spins to center the ring and re-tighten. If it's time for a new chain ring, be sure to determine if you have a 4 bolt or 5 bolt spider on your crank arms. Beyond tight spots and delivering power from the crank arms to the rear wheel, proper chainring selection is vital to snap and speed on the track. Higher rollout/Higher gearing usually means higher top speeds, but less “snap” out of gates and turns. Lower rollout/gearing gives better acceleration, but lower top speeds. Standard rollouts range from 50-55ish for most riders with younger riders with little legs going even lower than that and larger stronger riders on the higher ends. Riders will adjust rollout for track conditions, track length, and their competition. If you're unsure of whether you have the right rollout, make sure you start in that range, but ultimately its really about the physical attributes of the racer and your track. If your legs are “spinning out” add gearing by going up in tooth count on the chainring or down a tooth on the rear cog. If you're getting blasted out of the gate and can’t get your pedals spinning, then we recommend lowering the gearing. Making changes on the front Chainring are less drastic than making changes on the rear cogs.
Not all Chain Rings are the same. look for a high quality aluminum 7075 chain ring. The cutout portions of a chainring are done to reduce weight, but maintain proper strength and structure. Rennen chainrings offer two version, a standard and a threaded. A threaded chainring, in our experience, is the easiest to install and guarantee a perfect true. Simply use the front side of a chainring bolt and install right into the chainring. Rennen also makes "Decimal Chainrings" allowing for more refined adjustments to find the perfect rollout. Using a Rennen Decimal Chainring does not require a special chain or rear Cog. For all BMX Gearing questions, please refer to our Tech Help, BMX Ultra, or reach out to one of our technicians.