Some customers of our René Herse cranks have noticed that their brand-new cranks show traces of having been mounted on a bottom bracket. Did they receive used cranks by accident? No, the cranks are brand-new.
As part of our quality control, we mount each crank, with the chainrings the customer ordered, on a bottom bracket. We want to make sure that the chainrings don’t wobble. Our tolerances for chainring “runout” are tighter than most in the industry, but when you have a flexible frame, the frame flex and runout of the chainrings can add up. Having your chain rub on the front derailleur can be annoying.
In making the new René Herse cranks, we found out why this design has not been copied more widely. It offers many advantages over other cranks, but it is much harder to make. Conventional cranks have a large bolt-circle diameter and four or five beefy arms, so you can pull even a slightly out-of-round chainring into shape. With three lightweight arms and a small bolt-circle diameter, very small irregularities are translated into a noticeable wobble on the outside edge of the chainring. Thus, the manufacturing tolerances have to be much more precise. To make sure that every crank meets our standards, we check it after it is assembled. Then we send the new cranks to the customer.
100% quality control used to be common among high-end makers. In the days when Campagnolo still gave a lifetime warranty on their products, they also mounted every crank before it left the factory. Mike Kone, who used to own Bicycle Classics and who has handled more “New Old Stock” Campagnolo parts than almost anybody, noticed mounting traces on every “NOS” Campagnolo Nuovo and Super Record crank.
Today, many companies leave the quality control to their customers. If something is not up to standards, the customer can return it for a free replacement. That is a lot cheaper than actually checking your products. And since not every customer will send back a sub-standard product, you have fewer rejects.
When we design our products and check their quality, I often ask myself the question: “What would René Herse have done?” Herse was known as a perfectionist. He did not send out a product without being sure that it performed as intended. It is our goal to live up to his standards.