Both oils, Blue and Red have the same chemical make up although the Red High Temperature Oil is more viscous and therefore slightly thicker, meaning it will flow more efficiently in higher temperatures than the traditional Blue Scottoil. Other than that they?re the same and can even be mixed, so if you?re changing over from one oil to the other there?s no need to drain one out and start again, they?ll blend thus saving you waste. The choice of oils is dependent on the general riding temperatures you usually experience. Between 0-20 C (32-68 F) the Traditional Blue Scottoil would be recommended and for higher ambient temperatures then the Red High Temperature Oil as it will be a much better lubricant on the chain at those temperatures and will be easier to regulate through the vacuum operated systems too. The Red Oil has an operating range of 20-40 C (68-104 F). In some cases you could use the Red High Temperature Oil if your reservoir is located near to a constant hear source such as the engine, as this will warm the oil in the reservoir to the operating range more suited to the Red oil.