In 2011, Huestis, Mazzoni and Rabin wrote an interesting review about cannabis as doping in the scientific journal Sports Medicine (volume 41, number 11, page 949-966). An important remark they make is that the amount of THC or other cannabinoids when they're used for doping purposes are usually much lower than the intake for recreational uses. Even at lower concentrations, most cannabinoids will alter/modulate central nervous system activity.
In rodents is has been found that anxiety-related behavior diminishes after administration of low dosages of THC. Studies with human subject tend to show that cannabis lowers anxiety and risk-aversion, while it does not affect decision making. It also tends to suppress anxiety-related memories, such as traumatic events during sports. Not surprisingly, a survey under college athletes in France showed that cannabis is regularly used in 'sliding sports' such as skiing or snowboarding; users claim that it helps them overcome anxiety, which helps them during their descents. Another often claimed positive effect is the easing of (the sensation of) pain, enhanced creativity, and less disrupting thoughts.
There are also some indications that cannabinoids will reduce muscle tension and tremors and, although disputed, might enhance the oxygenation of tissue*. There were no studies indication increase in grip strength or other strength enhancing effects. Recreational quantities do, however, disrupt coordination and fine muscle movements, not something you want with riders riding in the peleton.
If you take these findings together, I think you can say that the use of cannabinoids might benefit athletes and not only those relying on fine muscle movements. Dosing at lower than recreational quantities might benefit riders who are scared of descending (hey Frandy!) or have problems with disruptive thoughts (which I think a lot of riders have during training or races). Thus, it might benefit you.
*) This is actually from a study done with cyclists. While the overall performance of cyclists was reduced 10 minutes after cannabis use (administered by smoking a cannabis cigarette), there were some signs that the oxygenation of tissue was enhanced, such as dilation of the air ways (bronchodilation) and dilation of the blood vessels (vasodilation). The question at hand is if taking cannabinoids via other ways than smoking will also have those effects and if using lower quantities of cannabinoids will have the same effect. If the latter holds than using cannabinoids might help oxygenation while not having the negative effects on performance.