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, 1/8 alloy track cogs. Like every Easton wheel, the EC90 TKO is entirely hand built and acoustically tuned in Eastons own factory.