Extruded running base is created by heating and melting polyethylene pellets. The result is a base that is essentially one piece and is not very porous (not as may tiny holes as sintered bases).
Sintered running base is created using the polyethylene pellets. However, instead of being melted pellets are forced together under high pressure. This results in a porous base (one with lots of microscopic holes in it).
Pros and cons of extruded running base
#1: Cheaper to manufacture.
#2: Cheaper to repair.
#3: Easier to maintain.
Waxing an extruded base won’t make as much difference as waxing a sintered base will. Therefore it is not necessary to wax as often. For example an un-waxed extruded base (EB) will actually be faster than a an un-waxed sintered base (SB). A waxed SB on the other hand will be faster than a waxed EB. So if you want to wax less often and still maintain a reasonable speed of base then extruded is the way to go.
#1: Won’t hold wax well.
#2: Not so fast.
#3: Less durable.
Whom suits more
Freestyle riders: aren’t typically too worried about speed so that’s not really a downside. Riding a lot of rails and other obstacles there is a higher chance of damage – the EB is cheaper and easier to repair, so might be a better option. If you’re hitting big features, and mostly ride the jump line as opposed to the jib line, you might still appreciate having a sintered base, rather than an extruded base.
Beginners: are probably more likely to cause damage (if trying new things, or if there are exposed rocks or roots in the terrain – e.g. late or early season). Also, quick acceleration is not necessarily a desirable feature for a beginner.
Pros and cons of sintered running base
#1: Holds wax well.
#2: High speed.
#3: More durable.
#1: Need to be waxed well in order to be fast.
#2: More difficult to repair.
Whom suits more
Freeriders, advanced riders, racers and boardercross: Those who enjoy and search out speed, the backcountry, powder etc will definitely want a sintered base. If rider is more advanced (except perhaps if only ride jibs in the park) then it’s probably worth to go with sintered base.