The Riser Crown Race offers 5mm or 10mm of added height compared to a traditional crown race. It can be used to gain downtube clearance for fork crowns. The 5mm version typically reduces head angle by approximately 0.25º, while the 10mm version offers a 0.5º change though the exact effect will vary based on your bike's geometry. \n The Riser Crown Race is compatible with any 1.5" headset using 45º bearings, giving you the flexibility to finetune your setup with ease. \n Compatible with 45º bearings, 1.5" ID aluminum construction