The EC90 TKO was designed from the ground up for elite level track racing. We didnt simply take our stock road wheels and add a fixed cog. The resulting wheelset is the stiffest, strongest, fastest pista option available. We custom designed and fabricated 56 millimeter deep composite rims, added proprietary hubs and created a clever system for mounting the rear cog it attaches with a splined lockring, like a cassette and requires no chain whip. Each EC90 TKO wheelset comes compete with three custom machined, 18 alloy track cogs. Like every Easton wheel, the EC90 TKO is entirely hand built and acoustically tuned in Eastons own factory.