ive taken another look, and the .acd file isnt even in the cars folder.Rename your data.acd file. AC prioritizes that file over the data folder. That's the only reason AC wouldn't "read" the file.
If that's not the problem, then whatever you're editing in tyres.ini isn't what you think it is.
also, in the tyres.ini file, i am changing the width value, for instance WIDTH=235