I have a 91 Volvo 240, looking to drop it 1.5". Im putting 17x10 rims on. Does anyone know a lot about off settings?

 

17" rims on a 240 will ride AWFUL with the prehistoric suspension design of the 240, and the size tires that fit on 17x10's will likely scrape everything in sight. your steering will feel like sludge.

about the only 17" tire that has a chance of fitting is a 225/45-17, and those have a MAX rim width of 8.5", nominal rim width is 7.5"

 

Which do you recommend, rim and tire. Size, width, offset etc.

 

whats the goal here? cosmetic or performance/track handling ?

I ran 205/55-16 on my 740 turbowagon, with hte Volvo Hydra rims, whihh are 16x6.5 and I think ET25. they fit perfectly. i was running stock height, with IPD overload springs in the rear, bilsteins with IPD sway bars. car handled great, especially with a bit of a load, but the ride on the local surface streets around here was mildly harsh especially when empty.

tires, I used Michelin Primacy, then later Premier A/S... long wearing, quiet, good traction matched to the 740T's mild power, and excellent in the rain. no surprises if you push them to the limit, they let you know well before they slide. Never did drive that car enough on snow to know how they were there.