Can I increase my tire size by 1 inch?

Right now my car has P205/50/R16 tires. I want to buy some new rims and tires and I was was wondering if I could upsize to 17 inch rims and tires. If so, what size tire would I have to go with so it doesn't interfere with my speedometer? I have a 2005 Ford Focus ST

225/40/R17 is the same height and only 3/4 inch wider. https://tiresize.com/height-calculator/

You can, 205/45/17 would be virtually the same diameter, maybe an 1/8 of an inch more, but that's an awful lot of trouble to go to just for a tire change.

Mhmm.

The specific see your models, the size of the tire is accord with the car

The overall diameter is what counts. Right now you have 16 inches (the rim) plus 205 mm (the tire, each side being 50% of the 205 mm width)
So you are adding one inch of rim width. One inch is 25.4 mm. 205 mm minus 25.4 mm is 179.6 mm. Call it 180 mm. So now you have 17 inches of rim and 180 mm of tire. Half that Is 90mm so for 205 mm wide tires, to get 90 mm sidewalls you need a 45 series tire. Go with 205/45 --17. If you go with wider tires you might find they rub when you turn the wheel. To be sure, talk to a tire store.

Steven,

You can certainly mount a 17 inch rim and tire package on your 2005 Ford Focus ST. You will want to limit your search to 17x7 sized rims with a 40 to 42mm offset and a 4-108 bolt pattern. Top the wheels off with a set of quality 205/45-17 sized tires and you will be good to go.