The Schwalbe Jumbo Jim is consistently one of the lightest and lowest rolling resistance fat bike tires on the market. Schwalbe has now upgraded the Jumbo Jim with their new Addix SpeedGrip rubber compound which replaces the fast rolling PaceStar compound on older models. Jumbo Jim's combination of smaller open spaced center tread blocks and larger shoulder knobs allow the tire to be used in all 4 seasons from fast rolling hardpacked Summer singletrack to freshly fallen snow. Addix SpeedGrip Jumbo Jim''s retain the low rolling resistance of the PaceStar tires but gain a more supple ride quality, better grip, and increased durability. Like previous Jumbo Jim tires, the Addix SpeedGrip tires feature Schwalbe''s durable SnakeSkin sidewall and easy to seal TubelessEasy bead.