Offset question....

[mattyb]

I am looking to make sense of the "offset" in plus size rims. Does a higher offset (45 as compared to 40...) "tuck" more. I am looking at 18's with 40 series tires. Offset may become an issue. Can you guys help. Also, I am looking for pics of EP's rolling on 18's with 40 series tires. Can you guys post or email me any? Thanks....

[YooShin]

Here is a good start:

First decide what wheel size you want. If you want 18"s then you'll need to figure out what tire size to fit. To keep the stock overall wheel/tire diameter you would need to go with a 225/35 18 tire. Sounds big and they are. They will most likely rub with a drop of more than 1.5" check out this site to figure out the tire/wheel sizes that you will need:

http://www.1010tires.com/TireSizeCalculator.asp

This site will also explain the offset. Quick and dirty, offset is the distance of the mounting surface from the center of the wheel. a 45 mm offset means that the mounting surface is 45mm from the center toward the front of the wheel. That means there is 140.25 mm behind this point and 50.25mm forward. The stock offset is 42mm. you should be safe with anything between 33mm and 48mm with a wheel width of 7-8 inches.

[cpu519]

Let's see if this clears up your question about offset. Offset is the distance from the mounting surface to the centerline of the wheel, as stated by YooShin. Stock wheels have a 45mm positive offset. This means the centerline of the wheel is 45mm INBOARD of the mounting surface, toward the middle of the car. A wheel with less offset moves the centerline of the wheel outward towards the fender lip. Take two wheels of equal width, one with a deep dish and another with a shallow dish. The deep dish wheel has the lip closer to the fender, this wheel has less offset. The wheel that is farther inside the wheelwell has more offset. Check this site from the Tire Rack (http://www.tirerack.com/wheels/tech/offset.htm) for more details about offset.

This site has a wheel tire calculator (http://www.geocities.com/gmfwd/pages/tirecalc.html), enter your wheel and tire specs and it calculates everything.



hth

[glw]

what is the stock wheel width? i can't seem to find it anywhere... that is important, too.

[YooShin]

Stock Wheel width is a road swallowing 6 inches. One of these days Honda will fit some meater stockers. I at least wish we got the wheels and drop that the Honda FP package comes with for the Honda Civic. Those wheels are alot like the CTR.

cpu519: You explained it alot clearer. I guess I was trying to picture the explaination as I was writing it.

[cpu519]

When I was into American cars and Mustangs, offset wasn't used to describe wheels much, so I didn't really understand it either. I was used to using backspace measurements instead, the distance from the mounting surface to the inside edge of the rim where the tire bead sits.

[03hatch]

will +44offset be fine?