I don't think the UCI has ever fully explained their reasoning. On page 10 of this PDF [1], they explain that they are responsible for regulating technical inn

I don't think the UCI has ever fully explained their reasoning. On page 10 of this PDF [1], they explain that they are responsible for regulating technical innovation, and they talk about some of the advantages of having live GPS data. On-rider cameras are also banned, and the issue of who has rights to the footage is mentioned. Interesting, they say that other live data — speed and heart rate and power etc. — isn't banned, but this only seems to be because it hasn't been submitted to the UCI for approval, which means it's banned anyway. The first lot of comments on this post from The Inner Ring [2] discuss the issue, and it seems most likely that the UCI doesn't want third parties transmitting anything from races, although this doesn't explain why they're not allowed to transmit data back to the team car. (Perhaps it's got something to do with the ban on race radios?) 1. http://www.uci.ch/Modules/BUILTIN/getObject.asp?MenuId=&ObjTypeCode=FILE&type=FILE&id=ODEyOTU&LangId=1 http://www.uci.ch/Modules/BUILTIN/getObject.asp?MenuId=&... 2. http://inrng.com/2012/09/vuelta-power-analysis/ http://inrng.com/2012/09/vuelta-power-analysis/