FiftyOne Custom models are handmade in Dublin using a proprietary construction process. First, the tubes are cut to each client's predetermined length and mitred with a diamond-tipped hole saw. The tubes are then inserted into the jig to check their fit. The tighter the fit, the stronger the joint and the joints are sanded by hand to achieve the tightest fit possible. After removing the tubes from the jig, the frame builder prepares the surface to ensure a good bond. In step one of a three-step process, a high-strength adhesive is used to bond the tubes and infrared is used to aid the cure.
Before the joints are wrapped with prepreg, a fillet is built up around them that adds additional strength and ensures a smooth transition from one tube to next, avoiding acute angles in the fibers and removing potential weak spots. Once the joints are wrapped, the frame is vacuum-bagged and cured under pressure. The temperature, pressure and duration of the cure vary depending on the carbon used. FiftyOne can vary lay-up and use different weights of carbon fiber depending on the rider's size and riding style, and this also means the ride characteristics of the frame can be fine-tuned. Meticulous attention to detail is a crucial part of every custom FiftyOne bike.