DarkSpeedWorks wrote:
I think the pulleys themselves are not super expensive to make.
And several companies make great drop sealed bearing pulleys for reasonable prices.
But to make the larger pulleys plus manufacture a fully-tested much larger pulley cage (to hold the larger pulleys--the large pulleys won't fit in a standard pulley cage) that is also perfectly compatible with all the major brands of high end derailleurs? That, I imagine, is far more expensive.
RAL tech makes some very nice aero 15/15 cages with ceramic bearings. Unfortunately, last time I check they were not taking new orders.