Whether it's an off-the-shelf product or somebody's home brew, I'm curious who may have (or "has a friend" who) tried one to either "rejuvenate" an older race tire or to get better bite from one with a rubber compound that's on the hard side to start with. Thx

Years ago tried it. I wouldn't waste the effort. I was on a tight budget and spent money trying it to no avail.

Apparently, the go cart guys are the tire softening experts. You might try some of their web boards to see what they say. I have tried some of the commercial products myself, but they didn't do anything for me. And in fact, too much will make the tires 'greasy'.

Many years ago, I looked at using some of this stuff since track prep at these little tracks was about nonexistent. Super Stock guy I know had sent off some of the tire softener available at the time to be checked. His brother worked at a high end race shop and had access to a lab.

Diesel fuel and WD40. So me being the experimenter, I give my tires a good painting of straight diesel fuel and leave them sit for a few days. Made sense, knowing how tires are made.

Actually helped, but only for a few runs. Went away pretty quick. I didn't experiment with mixing WD but have to assume that would have made the diesel penetrate deeper.

Junior dragsters back in the day used diesel and trans fluid. Mineral spirits and trans fluid too. Spray and wait a half hour until it evaporated.
Some guys would Saran Wrap the tires after spraying.

That was at the tracks where they didn’t prep the track on a consistent basis.
At some tracks that prep’d properly we stopped spraying the tires and actually staged in the bald spots - too much traction actually slowed down the slower cars.

In the past you could buy some stuff from you local speed shop to help out your traction on a bias ply. Would fill a container and put your tire in and keep turning it now and then. I never used it much on my Challenger tires always had slicks on the Challenger. I would go and help out a friend I worked with that had a 1968 Camaro LS7 10 second street car. That car with bias ply L 60s would hook hard and never lose traction at the track or on the street. He did a lot of testing at the track using the juiced tires so he could be competitive street racing. Wish I could remember what the produce was from back then. Today you can buy good sticky tires and just put them on the car without having to juice anything.

OK, folks, thanks for the replies. My takeaway from this is the results are "iffy" and the process is "messy".

Those formulas are spin offs of rubber rejuvenators and are applied to rubber rollers on machinery. They soften the rubber but are greasy. No for the track or street. For a harder tire, VHT, Pimp Juice or Stripper Glitter are what you are looking for. A little longer burnout than usual. Too long and the traction goes the other way.

When I raced go Karts we used wd40, let it soak in, helped for about 3 laps, oval clay track, by that time I was so far ahead it took them 15 laps to catch up to me.

It seems to me that straight Clorox bleach was used by many Pro racers back in the day, pour it in front of the tires and do a hard the burn out and stage it
I do remember a racer using something else in front of me that made spider web looking stuff blow out of her rear wheel wells during the burn out. I got some of that sticky crap on the side of my car when I did a burn out right after her
Didn't and does VHT still make some liquid traction compounds?
it would be interesting to find out what some of the "street racers" on T.V. use to make their "pimp juice"

Rather than treat the tires, the OP could treat the track like the Street Outlaws would do. TrackBite is still available in gallons. Pour it in front of the tires and spin through it. www.summitracing.com/parts/pji-sp-162

I always thought that I might rig up a windshield washer tank and pump with the stuff and plumb it in front of the tires so that I could lay it down without getting out of the car of having a helper at the line. Never did try it, though.

Like the FAST guys do.

This stuff:

https://www.summitracing.com/parts/pji-sp-162

I also keep a gallon of Pimp Juice in the trunk. Rather than pour it out in a puddle I prefer a thin path in front of each tire. A good hard inaugural burnout gets the party started.

Pimp Juice, Stripper Glitter and Devil's Glue are what the no prep and back of the track racers use. I've personally seen the Devil's Glue used with success on the street. It's crazy the 60' times guys are running on and unprepped street with a small tire and this stuff!

Had an old set of drag radials I treated w/ WD-40. Roll it on w/ a paint roller and let them sit over night. Made them real sticky and worked great for about 2 passes...then they were hard/dry again and wouldn't hook.