Hello I will help you with your question,
Yes the 20 mm width increase is well within the range of a normal fitted rim.
You don't know the rim width?
If you tell me what the rims are from I might be able to find the width.
Let me know how I can help you
You will have no problem mounting the tires on these rims. The ABS system may not have to be told of the change but if you get unintended ABS activation just find an AC Delco shop to enter the new tire size but with the shorter sidewall offset by the wider tread the circumference should be close enough to keep the computer happy.