Surly Narrow Wide X-Sync Ring 28t 58mm BCD Stainless Steel MFPN=TB72910000 ISIS is a splined interface

ISIS is a splined interface bottom bracket/crank design used by Truvativ FSA Raceface and other brands

Stiff and strong

Diameter 20in Brand Sun Ringle Model Envy RR ISO 406 ID Width 21

}Park Tool MW-13 Metric Wrench 13mm Blue/Chrome

Friction front shifter is compatible with all major brands of front derailleurs

Surly Narrow Wide X-Sync Ring 28t 58mm BCD Stainless Steel MFPN=TB72910000 ISIS is a splined interfaceSurly Narrow Wide X Sync Ring 28t 58mm BCD Stainless Steel. Surly X Sync ChainringsSRAM licensed X Sync technology Narrow wide tooth profile positively engages chain for better performance with single chainring drivetrains 304 Stainless Steel TECH SPECS Tooth Count 28 Ring Position Type Inner Drivetrain Speeds 10 Drivetrain Speeds 11 Drivetrain Speeds Single Speed 3 32" Chainring BCD 58 Color Silver Defined Color Silver Material Steel