Big ring for me. I shift to 53x20 (or 52x20 depending on bike) at stoplights. Shift up a couple for cruising speed.

Assuming not too much wind, of course.

You're right, it is more like 26.5 according to the details you provided (53/15, 95 rpm). Here is the calculation: (53 teeth X 26.5 in X 3.14 X 95 rpm X 60 min/hr) / (15 teeth X 12 in/ft X 5280 ft/mile) = 26.5 miles/hr. At the lower end of the cadence range you mentioned, 90, it would be 25.1.

If I'm on a shorter ride, a couple hours then I'll keep it in the big ring pretty much the whole time. On longer rides that have more elevation changes and I'm on crushed limestone most of the time, I'll usually be in my small ring to save my legs and knees. I'm running a compact crankset and 11-25 cassette.

You might like the 52/36 mid-compact front with an 11-25 then.

You loose a tiny bit of top end and get about 7% lower gears on the low end.

I don't see the point of even calculating an average speed on my rides. On a one hour ride, I'll have to stop at least 15 to 20 times, many of them at stoplights, the rest at rec trail stops for cross traffic.

I never doubted your speed claims. Heck if a shlub like me could routinely cover 20 solo miles in an hour and occasionally 50 miles in 2.5 hours in the Houston heat and humidity BITD, then there are no limits on what anyone could do. The only difference is that back then just like today I rode almost exclusively on the small ring. Of course back then it was a 42, not today's 39. I would have to be going a lot faster than that to have needed the 52. These days when averages are more like 16 mph solo, the 39 is fine and dandy all the time.

Hmm, that does sound appealing, well, the 7% lower part anyway! I'll pull up a calculator and take a look at the numbers, and consider my rides. I'm thinking of grabbing a Salsa La Cruz for dirt road rides, so that may be the ideal setup for that bike. The roads around here are hardback most of the time, so pretty fast and often rideable on 23c, but having a fatter tire and less concern for recently graded, loose surfaces and the potholes will recommend slightly lower gearing than a standard. Thanks!

Most cycle computers will pause when the bike is stopped. Yes, your average goes down when stopping or slowing for lights and then accelerating back up to speed.

Some of us do 18mph+ even after all that.

Moving speed only as most modern calculators provide. It isn't the be all and end all, and there is no sense reopening that argument here. It is just a tool, that's all. If one rider's moving average speed was 17 mph and another's was 23 over a course, well you could understand them being on different rings most of the time. A quick and dirty.

Tons of rollers where I live. Lots of undulation. I'm always flipping back and forth looking for the right gear.

I have a sigma BC 16. Does that calculate moving speed only?

Some of these speed claims do sound high. I rode with a university cycling team on numerous occasions, and I was one of the faster riders, and I tend to doubt that we ever averaged over 20 mph on rides.

Group riding dynamics are very different, however. Some of the riders were quite slow, some were very fast, we tried to stay together as a group not to drop riders, focused on paceline technique, other times we talked a lot together during the ride, etc.

Also, we rode very hilly terrain, which also dropped average speeds quite a bit.

I do think we tend to ride quite a bit faster on solo rides, however, which are the norm anyway.

I'm in flatland. Zilch climbing. I have to admit, when I see how hard I work to make a 16 mph average these days (67 yrs old, 1 heart attack), I almost doubt my own memory about what I used to do. But no, my moving speeds (and there were hardly any stops) did often average 20 when I was riding solo back then.

Sam, it's pretty easy to tell. You just ride two or three blocks, look at the avg. speed and then sit there a minute or two. If it stays constant, the answer is yes. If it steadily drops, then no.

50/11 all day, all terrain.

I kid. On my old bike, I used the small ring a lot, but it was a Shimano 2300 group with no extra trim levels up front. Now with the 105 5800 group, I'm almost always in the big ring unless I'm climbing pretty hard and in need of the biggest cogs in the back. I'd say about 90% of the time (or more), I'm in the big ring. 100% of the time on flats. I feel like the big ring is much more efficient in power transfer.

I ride on flat terrain only. 42/16 or 15 for casual solo riding, 52/16 or 15 for paceline or tailwinds.

You must be awesome to average that when I see spots with more than 7000% grade on that profile. (Yeah, Strava bug, but funny...)

From what I've gathered through brief experience and some amount of reading and tinkering on HTML5 Gear Calculator, joy or misery with a compact double is hugely dependant on the cassette you use. The wrong cassette will have you cross-chaining all the time, but with the right one, you can use that 50T for the bulk of your riding, only shifting to the 34T for steep and/or prolonged climbs. For example, I would be pretty miserable with a compact and 11-21T cassette, because my preferred flatland gear of 72" is near the extreme in both rings, and there are 2-3 gears on the top that would never get used by me. By comparison, a 12-25T or 13-26T would be much nicer.

That said, my road bikes have 130BCD doubles on them, and after installing a 42T inner ring on one of them (replacing a 39T), I can see the appeal. A 42T works really nicely for starting out, riding on flatlands, and getting some decent speed before shifting to the big ring. I can do my whole commute to work, which is very gradually uphill with a few dips and faster sections, without needing to shift the front, which is nice.

Finally, I'm a big fan of identifying the biggest gear I need for my riding, and then "tuning" my cassette and big ring combination to eliminate any gears I don't want. By switching to a 48T or 50T big ring on my bikes, I've gained that advantage of the compact where I can use the big ring a lot more.

You might also consider replacing the 34T with a 36T if you don't use the lowest gears on your bike. That would fix a little of the cross-chaining you get with that ring and improve shifting a little. Hope at least some of this helps.

I think I'd run out of gear if I used the small ring... definitely the big ring. Spend most of my time in 50x16, 50x15, or 50x14 @ 90-95 cadence

You spend most of your time going 25mph?

50x16 is like 22mph at 90rpm. Usually going 22-26 on flat terrain

I remember that!

I had a 54/45 front with a 12/17 straight block rear when I moved from FLA to L.A. and almost died the first time I rode up to Mulholland...

I miss riding in places without stop signs.

Okey, dokey.

Very nicely said. My one bike with a compact is coupled to a 12-23T 9 speed, and there is zero overlap ring to ring, barring the two crosschain combos. As long as one is comfortable multishifting, it is very easy to not worry about what ring you are riding.