I have never used a truer on my foam tire. I have always just used the foam tires right ouot of the box. Is it really worthwhile to true the tires and if so where do you find how data on how much to cut them down? Also, on Ebay there are simple "trackside" truers for sale made by "Cobra". Does anyone know if these are any good?

any truer is better than running out of the box. a smaller tire is less prone to chunking and traction rolling. also the tires willl last longer because there is less sidewall to get ripped from the rim when the car weight shifts to make a turn.

Thanks for the info.