Vintage Velo: Shimano Deore XT indexed thumb shifters

by Gus Alexandropoulos

Possibly no single bike component did more to popularize mountain biking than the Shimano Deore XT indexed thumb shifters. Before they hit the market in 1986, mountain bikers shifted gears with simple friction shifters. While these shifters were very reliable and compatible with any wheelset, attempting to shift gears accurately while riding over bumpy terrain was difficult to master: missed shifts were common. But with the introduction of Shimano’s indexed thumb shifters, new riders could shift reliably even under load or during hill climbs. Shimano had released index shifting to the road market the previous year with its Dura-Ace group, but it had met with resistance from many riders. It seemed that quite a few in the tradition-steeped peloton felt friction shifting was what “real” cyclists used. Mountain bikers, on the other hand, who were less constrained by past traditions, eagerly accepted the benefits of the indexed thumb shifters. They realized that the new gear allowed riders to focus more on riding than trying to avoid a momentum-robbing missed shift constantly; riding was suddenly even more fun. As indexed shifting proved itself quickly on the trails, the Deore XT thumb shifters performance also helped legitimize index shifting on the road. By the late ’80s, it was almost impossible to buy a new road or mountain bike without indexed shifting – something that may have taken longer if not for the introduction of XT “thumbies.”