I have had to scrap the frost off the seat (about 20F) and my boxers have started just fine with the 20W50 Mobil and 20W50 castorol syn blend. I am not planning to ride much below that. Man I hate sitting on a frosty seat. I do not believe in long warm up. 30 to 60 seconds is plenty. I have ran over 100K on several. And I hate 100F (38C) and above even more.