Tire size question

[1994gt]

Wasn't sure where to post this so I'm going to throw it up here. I just traded for a set of XXR 518 rims that are 18x8.5. The tires that are on them are 225/40/R18. They are junk and need replaced. I put them on the car and they fit fine but I'm wanting to know what size I should put on the rims? The tires that are currently on them seem too narrow for the rims if that makes sense.. Also they need what appear to be some small lug nuts. My factory 94 lugs don't even fit inside the holes. Any help you guys can give me would be appreciated.

 

[1994gt]

So after doing some research, well a crap load of research, I've read that 245/40/18 would work well. I thought about 255/40 but they will be a quarter in taller than stock. Will that make much of a difference in the speedo being off?

And i found these as a possible solution for my lug nuts.
http://www.summitracing.com/parts/gor-21183ht/overview/

am i on the right track here.

 

[familytruckster]

Quarter inch isn't bad at all. Won't make a noticeable difference.

 

[1994gt]

Which size will work best? Will I have any clearance issued with the 255's? Or should I use the 245's?

 

[Rallim]

Go with the 255's. And those nuts will be fine

 

[1994gt]

No clearance issues front or rear?

 

[Rallim]

Worst that'll happen is you might rub the control arm/sway bar at lock in the front, other then that it'll be fine.

 

[1994gt]

The rims have a 6 11/16 backspacing..roughly. And a 55 mm positive offset. I'm thinking I'll need to run spacers to use these. Am I correct?