The Minion DHR II is a complete redesign - acceleration, cornering and braking have all been improved TR - Tubeless Ready - sealant required DD - Double Down construction features two full 120 TPI casing layers reinforced with a butyl insert TERRA - 3C Maxx Terra is softer and offers more traction than 3C Maxx Speed, yet provides better treadwear and less rolling resistance than Maxx Grip