https://www.bikeradar.com/news/trek-redesigns-fuel-ex-29-brings-isospeed-to-dirt-with-procaliber-hardtail-2
First look at Trek's 2016 XC and trail line
fuel extrekredesignsbringsisospeed
https://www.cyclingweekly.com/products/new-trek-domane-is-lighter-and-faster-with-a-simplified-isospeed-system-and-improved-aerodynamics
Trek says the fourth generation is the fastest Domane it has ever made, but claims it still has the same cushioned ride
new trekdomanelighterfastersimplified