Rad Gnar Products, LLC DBA RadGnaRack does not support Shimano Ultegra FC-6800, Dura-Ace FC-9000, Ultegra FC-R8000, Dura-Ace FC-R9100 and FC-R9100P 11-Speed Bonded Hollowtech Road Cranksets manufactured prior to July 2019 sold individually and on bicycles sold by other manufacturers such as Trek and Specialized. A crankset is the component of the bicycle that the chain and pedals attach to for pedaling. The recalled models have printed ‘Ultegra’ or Dura Ace’ logos on the arm. The affected models are pre-July 2019 production and have the following two-letter production code on backside of the crank arm where the pedals are attached: KF, KG, KH, KI, KJ, KK, KL, LA, LB, LC, LD, LE, LF, LG, LH, LI, LJ, LK, LL, MA, MB, MC, MD, ME, MF, MG, MH, MI, MJ, MK, ML, NA, NB, NC, ND, NE, NF, NG, NH, NI, NJ, NK, NL, OA, OB, OC, OD, OE, OF, OG, OH, OI, OJ, OK, OL, PA, PB, PC, PD, PE, PF, PG, PH, PI, PJ, PK, PL, QA, QB, QC, QD, QE, QF, QG, QH, QI, QJ, QK, QL, RA, RB, RC, RD, RE, and RF.