I’m currently training for Ironman Cairns (fairly flat) in 28 weeks. My race wheel options are Zipp 900 disc with 23mm, or the matching Zipp 808 Firecrest with a 25mm (either option would be with Vittoria Corsa tyres).
As the Zipp 900 is quite narrow, I don’t think the 25mm will work/fit that well, so got me thinking - will the drop in rolling resistance of the 25mm tire on a 808 outweight the aero benefits of a disc??
For reference, I will be running the Zipp 808 with 25mm at the front.
Edit - wheels are tubulars.
Any thoughts or advice appreciated.