on my 12 mile stop and go, nyc commute, i got a readout of roughly 13, 14/15 mph on a good day, with hitting alot of greens, and blowing reds, on my fixed/ss/track bike, however, on my road bike ive been seeing 17/18 miles per hour easily. Anyways, gears help when trying to keep pace with others, no matter how you slice it, i found it very hard to keep pace with packs on my century ride on my ss bike, however my road bike made it a breeze to keep up, and even setting pace every now and then for some groups. I feel ss/fixed is awesome for setting ones own pace, but otherwise they tend to fall behind, for its harder to be consistently paced , and consistently fast on ss/fixed.