Need help with wheel and tire size

[Drache]

Ok so as many know I bought a car that has 18" wheels and low profile tires. Tire size currently being 245/45R18.

Now I've also been invited to race my car this year in the yearly drag racing event along with both my cousins. The kicker being I don't want to certainly burn off the tires I use to drive. So normally that would mean buying a set of rear wheels and tires for the car. The wrecking yards had no tires matching what I have now. So it's new only.

Now 18" was a little big and they rub when dealing with sharp corners on the front and rub deal with bumps in the back. So it's either buy a set of wheels and tires for the back to use while racing, or buy a whole set of smaller wheels and tires like I planned for driving, and use the wheels and tires I have on there now to race with.

My wheels I think are bolt pattern 5x4.5.

So now I just need to figure out which ones to get... 15x6, 6.5, 7, or 8.

Overall I think the height of my wheels and tires is 26". I'd like to drop that a little but I can't go too low since the oil pan on my transmission along with my headers and engine oil pan all hang REALLY low.

 

[70DartMike]

You should be 5 x 4.5",which both Dodge/Plymouth and Ford have a lot of wheel options.

 

[Drache]

You should be 5 x 4.5",which both Dodge/Plymouth and Ford have a lot of wheel options.

If you measure from the center of one bolt to another then my digital calibers gave me far short of 4.5" but I'll go double check with a tape measure.

 

[6pk2goDemon]

Yes, those wheels should be 5 on 4.5......Measure like this

 

[70DartMike]

What are the front brakes? The pre '72 disc was small bolt pattern which is 5x4", the '73+ is big bolt pattern, which is 5x4.5".

 

[Drache]

Yes, those wheels should be 5 on 4.5......Measure like this

Ok now THAT makes sense for the 5 bolt. Not from center to center but outside edge to center!

That would give me the 4.5" then!

Now I feel like an idiot....

 

[Drache]

Ok so now I can drop down to the 15 I'd like. So which width should I go for?

6
6.5
7
8

And thus what tire size?

 

[Oklacarcollecto]

Ok so now I can drop down to the 15 I'd like. So which width should I go for?

6
6.5
7
8

And thus what tire size?

Wheel width also depends on backspacing.

 

[Drache]

Wheel width also depends on backspacing.

And how do I factor that in?

Crappy part is I cant tell what my current wheels are for offset. Guess I'll have to take the car to a tire shop tomorrow.