Longfemur

My steel bike, just ordinary Columbus Brain tubing, weighs in at 23.5 lbs, with the triple on it. Not a big weight penalty to having the triple, as far as I'm concerned. When I ride, I ride for distance and endurance rather than speed. I'm not racing myself, nor anybody else, nor any cyclo-computer (I don't even own one). When I get to a hill, I'm not earning any points for king of the mountains. I just want to get up and then down. I don't want to burn my legs for the rest of the ride. So, I like to have that third small ring there. There's no way that a compact double can approach the versatility of a road triple. With the double, you can get the same overall range of gears, I suppose, but you will have bigger steps, because you just don't have as many usable gears. I got hooked on triples about 18 years ago when I bought a hybrid for some rides in the woods with my kids. I had only used doubles before, but the advantages were so clear that I decided my next road bike would have one. So far, been riding it for 10 years without a problem. I think that all of us are prone to thinking too much and tweaking too much. Sometimes it's better to just stop reading magazines and the internet, leave the bike alone and just ride the damned thing.

One factor among others in your choice might be the bike you have. You usually don't want to have a triple on a bike that has the rear wheel jammed up against the seat tube. If you're racing others or yourself all the time, then a triple might not be your choice.

Sluggo

One reason that compact doubles have become a useful option is that standard cassettes come with 11s and 12s. With a 52 or 53 on the front, that is, IMO, overgeared for anyone who is not a pro sprinter. I have my bikes set up with top gears of about 100" (50x13 [custom cassette] on 650B and 48x13 [screw-on freewheel] on 700C). I can spin this gear out to 35 mph or so on a downhill -- anything steeper than that, it is faster to tuck than to pedal.

I tried a retro-compact double (35-47 [I think that's right] TA crank and 13-28 freewheel). I hated it. I never seemed to have the right gear, and it did not go low enough for my purposes. I recently replaced the crank with a mountain bike triple, and it is a huge improvement.

For me and my purposes, triples are the way to go. I live in the southern Appalachians, where 6% slopes are routine and 10% is common. Yesterday, I rode a short stretch that must have been about 20%, and it had rained just enough to make the road slick. My 22" gear was not too low. If I used a double to get that low, it would either have a huge gap between the sizes of the rings or a high that was not very high.

My fitness level varies season to season and year to year. This means that sometimes I don't use the lowest gears much, but sometimes I do. And at this point in my life, I will probably never again be fit enough that a long 8 or 10% climb after 80 miles of riding (a typical feature of regional centuries) is feasible without a sub-30" gear or some walking shoes.

For those of you in relatively flat places, a compact double might be the ticket, but if you currently have a standard double, you might consider keeping it and changing to a custom cassette with a 13 or 14 high gear, like those from Harris. Bigger cogs don't wear out as fast and have more efficiency for power transfer.

And BTW, crank arm length may be something to worry about from a pedaling mechanics perspective, but changing from a 175 to 172.5 changes your leverage (and therefore your effective gear) by only about 1.5%, and the shorter crank makes an effectively higher gear (see Sheldon on the subject.

Boudicca

I have a compact double on one road bike and a triple on the other, and when it comes to hills I just prefer the triple.

In fact I prefer the triple on the flat as well because I just sit in the middle chain ring all day and never use the other ones.

dit

I built my sport tourer in about 1980. It has a 46/34 chain ring if memory serves me correctly. The 5 speed cog is a 14/30 or 32 I think. I spent hours picking my gears. It served me fine in flat and rolling country but I found some hills that I just could not ride up and some that really taxed me to the limit even when I was in shape and 40# lighter. I now live in very hilly middle TN and I NEED some lower gears and I am going to a triple with no hesitation. (except money) The only problem I had with the 'compact' gears was I used both chain rings where with the std. 52/42 I almost never used the 52 ring. Who needs 120 inches unless they are riding in the tdf with 500 other riders with oak stumps for thighs. I guess I must have started the 'compact' thing hehehe