Not just done for weight reasons.. also for custom (eg. longer spindle) and cost saving. I was looking at the Zeros, but want a 56mm spindle (which is what I after-market installed on my old X pedals). The Excel price for the 56mm spindle Zero stainless was I think $285 (not listed on their site any longer though). The CroMo version is $144, and the ebay Ti spindles as you say about $35.. quite a price difference. For the Zeros, is the pedal body identical between CroMo, Stainless and Ti versions?