Hello dear forumers, I have an Audi a6 tdI 2003. The specs of the tires that are on my car at the moment are 235/40/R18. I want to fit a new tires with specs of 245/40/R18. Would it be possible that the new ones will fit ? Cheers in advance.

 

Plug those figures in here: http://www.sjdsm.com/tech/tire_size.htm, and you'll note a couple problems.
One, with that much change in height, you may have clearance problems, but at least now you'll be able to measure it out.
Two, you will be reading .5 miles per hour faster than you are really going at 10 mph. More at 35, 60, and 75.
I'd suggest changing the wheel size (go to 18 or 16) and adjusting the aspect and rim diameter to ensure fit and no speedo change.