I don't know about you, but after a long ride on a hot day, there's another cold, fizzy beverage that tastes really great to me but I digress. Carbonated water isn't the best choice for post-workout hydration, but not because the bubbles interfere with your ability to absorb the water into your system. The biggest trouble with carbonated beverages is that people typically stop drinking them sooner, and hence consume less fluid than they would have if the water contained no bubbles.
When I was working with PowerBar on their line of Endurance and Recovery sports drinks, we looked into the issue of carbonating one of them, or both. We rejected the idea because when people tried it in the past, athletes found that carbonation essentially got in the way and prevented them from drinking enough. Granted, that was with sports drinks designed to be consumed during exercise, when an athlete wants to be able to gulp down much more than a sip at a time. However, the same phenomenon happens with carbonated water.
In the two hours after a long run on a hot day, you need to consume 1.5 times the amount of water weight you lost during the run (weigh yourself before and after the run, without clothes to find this number of ounces). That means that if you lose two pounds (32 ounces) during the run, you need to drink 48 ounces of fluid, which can be difficult with carbonated water if the bubbles make you feel full faster or tickle/irritate your throat, which makes you have to take smaller sips.
However, there's no reason to completely eliminate carbonated water from your post-workout fluid intake. I'd encourage you to consume a full bottle of water or recovery drink (non-carbonated) as soon as you come in off your run and then grab a glass of carbonated water, or vice versa. The most important thing is to make sure the carbonated drink doesn't keep you from consuming enough total fluids in the first two hours after exercise. And don't forget that you also need calories and electrolytes after those long runs in order to recover and run again in the coming days.