As said mate Tardis is an excellent product for removing Tar, it literally melts the tar off when sprayed directly on so you cant really use it wrong apart from leaving it on too long or not rinsing it off after properly
As far as break dust bonded to the wheels goes a dedicated wheel cleaner will get the results you want, if they are bad or were not sealed before winter then you might want to spray the cleaner on undiluted and let it go to work before aggregating it with a good wheel brush! Then wipe down with Tardis, then get the clay bar out, and finish with couple coats of wheel seal! See how easy it is to keep them nice after that lol