Do pro riders use compact cranksets for hilly races? I'm trying to determine if switching to a compact double will mean I don't have the top end speed to be competitive in higher levels of racing (I'm not a pro racer) and unfortunatly I haven't been able to find information on the setup of top racers.
While pro riders often change gearing or whole bikes depending on the nature of the race or the stage, you do sometimes see compact cranksets, particularly among domestiques in mountain stages or races.
A big-name example is Tyler Hamilton in the 2003 Tour De France. After crashing and breaking his collarbone before the huge mountain stages he was unable to climb out of the saddle. FSA who makes compact cranksets and was a team sponsor set up his bike with a 52/36 crank; allowing him to climb seated. FSA did a couple of releases and maybe ads about it - and I started to see a lot more compact doubles in local rides.
Just note - a lot of times you can accomplish the same goal (bigger and smaller gearing) by switching the typical 12-23 racing cassette for one that is 11-25 or 11-27 at a lower cost.
You can play around with Mike Sherman's Bicycle Gear Calculator to help you make a decision.
As already mentioned, pros will use compact cranks on serious climbing courses. It is important to remember that the pros are not like us. Their power to weight ratios are extremely high--much higher than even you see at even the elite amateur level. So, they don't need gearing as easy as mere mortals most of the time. And, the top sprinters and their leadout trains are ungodly fast, and they actually can use a 53x11 to good effect.
I use a 50x34 with an 11-27 in the back. I spin out the 50x11 only on reasonably fast downhills and flat sprints that have a very strong tailwind. I use the 34x27 more often than I would like to admit if I am on a sustained climb that is steeper than 7%, and I don't want to hammer it. So for me, compact makes sense. But my threshold power to weight ratio is only 4.15. Pros are more like 6 or 7. If I had that kind of power, I would be rolling the 39x23 up long climbs at the same relative effort that I now do in the 34x27.
In the 2010 Giro, on the Plan de Corones, Vinokourov rode an 11-32 cassette to 8th place (with compact (34) up front). Gadret rode the same setup to place 3rd on the stage.
Contador used a compact and a large, I think 30-something rear cog, on l'Angliru in the 2009 Vuelta a Espana. Compacts are definitely used by PROs, but only on really steep stages.
The opposite end of the spectrum, PROs will often ride 53-42s (or some variation, sometimes 44, sometimes 40) for the classics.
Agreed. Most non-elite amateurs cannot sustain rpms to use a 53x11 or even the 12 cog in a competitive ride/race. A 50x34 (or 36) w/terrain-suitable cog range makes better sense for more road riders than what is typically used. Many pro group training rides cruise 4-5 hour rides on their 53x17's at > 90 rpm. They don't live on those super-human gears the mags and "experts" tout. Great advice in this forum with excellent real life examples. We used to have a restricted-gear early Spring race series (February to end of March) w/little ring and 12 or 13 cog to encourage using a tolerable gear and developing cardiovascular fitness prior to the April-October road season.