bfg drags and black sticky buildup

[jbaker]

running a set of 275/60/15 bfg drag radials. there is about 1/16th
of tread left. after being at the track and looking at them, it appears that there is a black material built up on the tire .
it can be scraped of if warmed up a bit with a hair dryer and becomes tacky. i susspect this is either rubber of the track or rubber of of the tire itself. why is this building up on the tires?
anyone seen this before, and how do i eliminate it?

thanks jerome bake

 

[UNGN]

That's most likely melted rubber bits from the tires and the track. To get rid of it, pump them up to 36 psi and drive it around for a few days. It should all go away (except for in the grooves, if there are any left).

It's building up, most likely because your track doesn't sweep the burnout area enough and uses a ton of VHT to compensate. After your burnout, you roll through the unswept rubber and VHT and now it becomes part of your tire.