I have a 69 convertible mustang all new suspension front and rear with drums on back and disc on front want to measure for bigger tires and rims to fill the wheel wells and looking at 17 in but not sure how to measure for height and width with out making rim size mistakes. Any help or suggestions would be very helpful in advance.

 

There is a lot of info on this forum about tires and wheels. It kinda depends if you want to do the research yourself or just have someone tell you what will fit. There on tire size calculators online that tell you the dementions of any given tire size. That helps on tire selection.
if you don't want to do the research, I would start asking the company you are going to buy the wheels from. If they don't know, try someone else. I bought my wheels from National Parts Depot, and they were helpful on rim selection. Have dealt with Performance Tire before too...helpful .
the other thing you can do is go to car show and look, guys might not know the back spacing , but you can look at tire size, How clearances are and rim sizes. Generally bigger rim sizes give you a thinner side wall. My opinion is thinner sidewalks give you a more modern or resto-mod look., wider sidewalls are more old school, stock look. Wanted the old school look on mine 67, but because there are more size options for
15 in rims, I went with 15's on the back and 14's on the front. ( you don't have to worry about rotating them either!!) I think the look cam out pretty good, and if you don't know, most will never notice the two sizes.

 

Are you looking for a staggered set or a set that is the same all around? 17x7 or 17x8 depending on the offset will work for you for sure, just depends on how large of a tire you use.

 

Thanks for the info guys think in going to go staggered

 

You should be able to fit a 9" wide wheel in the back with the correct offset.

 

You could run a 17 x 7 on the front with -6 to 10mm offset. You can view wheels within those specs at this link. That would pair with a 235/50-17 tire.

For the rear, you could run a 17 x 8 with -6 to 25mm offset. 17 x 8 wheels within those specs can be found at this link. That would pair with a 255/45-17 tire. Or you could fit a 17 x 9 wheel on the rear with 0 to 20mm offset. 17 x 9 wheels within those specs can be found at this link. The 17 x 9 would also go with a 255/45-17 tire.