 Although much less common, some road bicycles do incorporate suspensions, particularly the Soft Tail variety mentioned above.One example is Trek Bicycle Corporation's s.p.a (Suspension Performance Advantage) rear suspension, offered on some of their Pilot models, but the system was removed for the 2008 model year.Virtually all bicycles produced by Alex Moulton bicycles also have very effective full suspension, due to the low unsuspended mass of the small wheels and high pressure tires, a characteristic of the unconventional design of these bicycles.