Serious resistance for serious riders. We mean it. Approximately 90 more resistance compared to the 4.5's, the Alloy 2.25's will waste no time putting you in the Red Zone. Designed for the US Cycling Team for easier portability and higher resistance. The Challenger is like the Alloy 2.25's, but with Poly end caps for a more economical option. Drums measure 2.25 x 15. Purchase a Kreitler Universal Frame for co
)
