We all know that a bigger pulley has lower drag as it spins slower. However, the top pulley has structural limits. Derailleur design varies – the largest top pulley that each derailleur can accommodate are different, and it’s not worth trade-off shifting performance for that marginal gain. Pulley size is just one of the factors – bearing technology, pulley tooth profile, and surface treatment all matter. All Shuriken models are designed not only for efficiency but also for best shifting performance and easy adjustment.