UCI Rule Question
 

I heard that a recent stage winner in La Vuelta had a water bottle from a different team at the finish. So clearly he got help from an opposing team’s car and/or rider.

Is that UCI legal??

What about getting a wheel or other assistance from a different team??

A wheel definitely not. There are recent-ish precedents of penalization for doing that.

It's not uncommon for teams to water other riders.

Clintonesque discussion of what "assistance" means.

P.S. UCI Regs, look at Part II Road Races, pp. 44-46.

Feeding and technical support are covered by different regs. Technical support is explicit that a rider may not receive support from anyone but their own team, neutral support, or the broom wagon. Feeding is different, the wording says who may feed riders, not from whom a rider may receive a feed.

I honestly don't know whether the accepted interpretation of that is a cross-team feed is illegal. I do know that it is typically not enforced. Though the feeding locations are rigorously enforced, e.g. too close to end of race.