All of my bikes, from “newest” to most vintage are set up with vintage cranksets. I prefer the quality of the finish and materials as well as the reliability of the chainrings and crankarms to newer models. Of course, there have always been lower end models in any product line, but even low budget vintage cranksets are often superior to their modern day counterparts.
Even my 1990’s Terry ( a NOS frame which I built up with vintage components) features an early ’80s Shimano 600 crankset that has simply never worn out over decades of use. This model is a triple, with separate drilling on the inside of the spider which allows the 30T inner ring to be installed. Some triple cranksets are equipped this way, rather than reducing the bolt circle diameter (“BCD”) of the spider.
Vintage cranksets are often beautifully made, using a square taper connection to the bottom bracket, and featuring a variety of crank arm lengths, generally ranging from 160mm to 175mm, and bolt circle diameters which vary from the tiny Stronglight 49 & T.A. models 50.4mm diameter used on touring bikes up to 144mm used on high end racing bikes which need larger rings.
Selecting the right vintage crankset for your bicycles involves many considerations which include: crank arm and chainring material (steel vs. alloy); chainring spider design (5 arm vs 3); chain-line and spindle length, crank arm length, torque settings for the attachment bolts, the attachment to the spindle ( square taper ISO vs. JIS, or cottered), number of rings (1,2 or 3); and the all important measurement – bolt circle diameter (BCD), which determines the smallest ring you can use. Other ancillary considerations include whether or not to use elliptical chainrings, threading characteristics of the crankbolts and bottom bracket, and what kind of pedal threading you have on the crankarms.
The smaller the BCD, the smaller the chainring you can use with the crankset. This is very important. Cyclists who need lower gearing want cranksets with smaller BCDs, so that they can ride steep hills and haul stuff, whether it be a change of clothes, a touring kit, or the week’s groceries. Unfortunately, many off the shelf cranksets feature large bolt circle diameters, often 130 which can only accept a 38T ring as the smallest. While this shortcoming can be overcome by a triple crank with a smaller inner ring BCD, many cyclists including myself prefer the simplicity of a double crank. There are many examples of older triple cranksets, but plenty of vintage double cranksets are designed for a wide gear range. How did they do it? A smaller bolt circle diameter is the answer.
This T.A. Cyco-touriste crankset shown above is one way to achieve a wide gear range using a two ring crankset. You’ll see that there is a large tooth difference between the outer and inner rings. That means it is necessary to use a front derailleur specifically designed to handle the big shift between the inner and outer rings, such as the Simplex Super LJ shown above, which has a large inner cage plus a relatively steep angle on its parallelogram, plus a long cage rear derailleur.
If you are using a single chainring, you can’t go wrong with a Stronglight 49D which can accomodate virtually any chainring size that is made. Older French bicycles sometimes featured reverse threading for all the BB components, as on my 1947 Camille Daudon. French cranksets generally have French pedal threading on the crankarms. However, it is not difficult to tap out French threading to English if needed, as long as you have the right tools. Velo Orange has a good discussion of this process here. There are still plenty of French threaded pedals available if you find yourself in need.
Most vintage cranksets have 5 arm spiders, but some have 3 arms, such as Rene Herse and Stronglight as well as other vintage models, as shown above. If your crank has a 3 arm spider, you’ll be limited in ring choice, since 5 arm cranks were the standard for many decades. However, 3 arm cranks are lighter weight, and can look quite elegant without sacrificing strength and reliability. And, believe it or not, cottered cranks are not necessarily low-end. Many are very lightweight and strong, as in the beautiful Favorit PWB set on my 1950’s Oscar Egg mixte, shown above.
While much is written, studied and debated regarding the right crank arm length for your cycling endeavors, I hold to the most logical analysis: shorter cranks for shorter cyclists. As Georgena Terry has quipped, if we were all 3 feet tall, we would design bikes suited for our bodies’ geometry. Isn’t that obvious? Apparently not, but I encourage riders to experiment with a variety of crank arm lengths, as well as to research the health risks associated with riding too long crank arms for one’s height.
Most off the shelf crank arms come in the 170 mm length. But there are many lengths available, ranging from the shorter 152mm arms up to 185mm or more. Shorter arms are ideal for bikes with lower bottom bracket heights (which I prefer), and for most of my bikes I use 165mm. For me, this length offers a comfortable cadence, and minimizes pedal strikes while cornering.
Spindle length is important because it determines whether you can use a double or triple crankset. The longer the spindle, the greater the clearance of the chainrings from the chainstays. However, you also need to make sure that your chainline is proper given the crankset and spindle you have chosen. Ideal chainline is when the chain follows a straight line back to about the middle of the rear cogs when it is inbetween the two rings (or on the middle ring if a triple). While chainline can be adjusted by rearranging the spacers on a rear axle, it’s also important to make sure that you are using the correct spindle length to insure the best placement for the chain. You can also add spacers to the drive side BB to move the chain out a few millimeters, which is especially helpful if chainstay clearance is a problem. Park Tools has a good discussion of chainline concepts here.
Crankset selection can seem daunting, but it is important to remember that most vintage cranksets, whether square taper or cottered, will be an attractive and reliable addition to your current ride.