CRUPI 4-Bolt Chainring

7000 Series T-6 CNC Machined aluminum plate transformed into a ring of beauty!  Like Crupi's original 5-bolt gears, these are machined (not stamped) right here in the USA!  The 7000 series aluminum is more expensive but it makes a stronger and stiffer gear.  

CRUPI 5-Bolt Chainring

With a fresh new design, Crupi chainrings are better than ever!  CNC machined from 6061-T6 aluminum plate right here in the USA.  Machining rather than stamping our rings ensures that each gear is perfectly round and flat.  Crupi rings have been the best on the market for nearly 15 years now!  

To buy or see more details, click on the picture

CRUPI Solid "Snowflake" Sprocket

Crupi sprockets are not just another CNC machined sprocket, they  are precise, strong and great looking.  What makes ours better than all the others is we make them fit certain crank spindles instead of trying to fit them all.  

SINZ 4-Bolt Chainring

SINZ 4 bolt chain rings are affordable, lightweight and machined for a perfect fit. Manufactured to fit the 4 bolt 104mm bolt pattern found on many BMX and MTB cranks.  Laser etched logos and size markings make the SINZ chain rings stand out.  Fits 3/32 or 1/8" chains.  

SINZ 5-Bolt Chainring

SINZ Expert Chainrings are affordable, lightweight and machined for a perfect fit. 36t through 46t sizes in black to fit your 110mm bolt pattern.  Fits 3/32 or 1/8" Chains.

SINZ Chainring Bolts

Available in Aluminum or Steel, Set of 5

Chainring Nut Wrench

The CNW-2 makes chainring bolt set installation and removal easy. It securely holds the slotted nut to prevent spinning when tightening or loosening the bolt. Double-ended to fit most slotted-type nuts, including the Crupi and Rhythm chainring nuts. 

Gear Charts

Find gear ratios for all tire sizes at the bottom of each chain ring page.  Download and print them too!

Don't forget tools!