But aside from a triple crankset, cyclists haven't had many choices for lower gearing.  The smallest chainring that can be mounted on Campagnolo's 135mm crankset bolt circle is a 39; 9-speed cogs max out at 28, 10-speed at 29.  How to get lower gearing if you don't want a triple?  French component maker TA has for years offered a wide array of cranksets with very small bolt circles--they still make cranksets with a 110mm bolt circle that allows chainrings down to 34t.  (For more info on TA from the Classic Rendezvouz web site:  http://www.classicrendezvous.com/France/TA_main.htm)  But what if you're putting together a cutting-edge machine?

Component maker FSA has stepped into this arena with their Carbon Pro Compact, a 110mm bolt circle crankset that would look at home on any high-end bicycle. 

Front view	Back View	Spider and crankarm are separate	Spider is machined from a solid piece of carbon fiber
Spider view.  A hefty lockring holds it all together	Ramps and pins aid shifting Note: Photos show 46/36 rings; we are testing the 50/34 model	Front-side machining of the spider and FSA's alloy crank bolts	We counted 16 layers of carbon fiber in the spider.
	FSA's cranks mounted on the Campy Only Teschner  The 50-tooth ring doesn't look that much smaller than a typical 52- or 53-tooth design

FSA's Compact crankset shares some features of their more standard "Carbon Pro Road Racing" model, which uses an alloy spider and carbon arms.  The Compact design, as shown in the photos above, replaces the spider with carbon fiber, and slims the bolt circle down to 110mm.  FSA's own rings (equipped with ramps and pins for better shifting) are fastened with allow chainring bolts (Campagnolo offers alloy bolts only on the Record crankset).  Two ring sets are available (both in 9- and 10-speed:  46/36 "cyclocross" and 50/34 "road".  Both are available with splines to fit ISIS or ShimaNO--a tapered crankset to fit a standard Campagnolo bottom bracket spindle is not available.

FSA's web site advertises the crankset at 521 grams.  We measured the weight of the crankset and the matching alloy crank bolts at 532 grams (18.8 ounces).  That's only 32 grams more than a Record carbon crankset and well within the realm of lightweight components we would consider using on our own bicycles.  Visit FSA's web  site for the official word on the Compact.

Our Road Test

Is there a compact crank in your future? Campagnolo and several other component makers are guessing that you--and many other riders like you--will soon be riding a bicycle with smaller chainrings and lower gears.

As we noted above, "compact" cranks have been around for years. Most current cranksets, which generally feature a 52- or 53-tooth large chainring and a 39-tooth small chainring, are primarily an artifact of the racing scene, where higher gears for sprinting are generally more important than low gears for climbing. Indeed, Campagnolo's cranksets featured an even narrower range of gears well into the 1980s--the classic Super Record/Nuovo Record crankset was limited to a minimum 42-tooth chainring.

Nowadays, however, cyclists (who are on average older than they were 20 years ago) are demanding lower gears. Look around the paceline at the next century or double century, and you're likely to see a fair number of triple cranksets, which offer the lowest gears of all.

Compact cranks, then, fill a gap between cranksets appropriate for strong riders and triple cranksets, which still (even Campagnolo admits) carry the "granny gear" stigma.

Using the Compact

For the past year, we've been riding with a compact crankset from component maker FSA on one of our bicycles. (FSA provided the crankset to us for testing; Campagnolo does not provide equipment for testing.)

Our FSA crankset features chainrings of 50 and 34 teeth--in both cases a few teeth smaller than possible with a standard crankset due to the use of a 110mm bolt circle (Campagnolo's standard cranksets use a 135mm bolt circle).  Our FSA crankset, incidentally, was shipped out with 46/36 rings;  we asked for 50/34, which FSA promptly sent to us.  The 34t ring came with ramps and pins, indicating that it should be a middle ring on a triple crank, but it works fine as part of a double crank. We haven't seen the need to change it out for a double-specific ring.

FSA's crankset features carbon fiber construction in the arms and spider and alloy rings. For our test machine, FSA provided a "Platinum Pro" bottom bracket (ISIS splined,not tapered) with a titanium spindle. Crankarms fasten to the bottom bracket with alloy bolts. (Scroll down for more on the bottom bracket.)

To shift the chain, we're using a Campagnolo triple-compatible front derailleur and a long-cage Daytona/Centaur rear derailleur.

The 50-tooth big ring means that our top-end gear is somewhat lower than with a standard bike (about 104 gea-inches with a 13-tooth rear cog, compared with 110 gear-inches with a 53-tooth chainring). At the low end, the 34-tooth small chainring lets us get a low gear of 33 gear-inches with a 28-tooth cog, compared with 37 gear-inches for a standard rig.

How Does It Work?

We have taken the Campy Only Teschner on numerous rides with the FSA crankset--since we installed it, the Teschner has become our "extreme event" ride of choice, due to the lower gears offered by the compact crank. In our experience, we've experience the benefits--lower gears without the need for a triple crankset--far more than the downside of a slightly smaller large ring. The compact crankset has helped us crest many a long, steep climb; we have yet to feel that we couldn't go fast enough at the top end.

Campagnolo recommends a compact-specific derailleur for their compact cranksets. In our experience, we have had virtually no problems using a "standard" triple derailleur. Campagnolo's compact front derailleur has a sharper curve in the outer cage that better matches the smaller big ring; we would be hard-pressed to say that it's a truly necessary feature. Shifting between the large and small rings is just as smooth as a standard setup.

A few items to keep in mind:

Our Teschner uses a clamp-on front derailleur mount (non-Campy, unfortunately--Campagnolo does not offer this part). This made it easy to move the derailleur lower down on the seat tube to match the smaller chainring. If your frame has a braze-on derailleur mount, you may want to have your LBS check to see if it has enough adjustability.

While not a compact-specific issue, our FSA bottom bracket seized up after about a year's use. We took the bottom bracket out of the frame and found that the left-side bearing was no longer turning. We sent it back to FSA and they promptly replaced it.