Car Modification: The Thing You Need to Know When Choosing a Sport Rim

I did some researches during the time I chose my sport rim for my Celica. When you plan to go for flush or hellaflush, you will need to t...

I did some researches during the time I chose my sport rim for my Celica. When you plan to go for flush or hellaflush, you will need to take into consideration of the front and rear spacing of the rim to clear off your wheel arch. So the offset and width of the rim are very important when you choosing a rim.

Here are some rims size information for Toyota Celica which I researched and how to calculate the front and rear spacing based on the rim offset and width. The important note here is to clear the inner wheel arch spacing because if the rim offset is selected wrongly it will hit the suspension and inner wheel arch. However it is important for you not to only consider about the inner wheel arch spacing as well, if the wheel offset is towards to negative, the rim will poke out of the wheel arch and the wheel will poke out. Thus negative camber and tire stretch may be needed.

The calculation is pretty straight forward. You may follow below steps to calculate the rim front/rear spacing.

Let's take wheel size 10" as an example:

1. Convert your rim from inch to mm. (10" * 25.4mm = 254mm)

2. Divide the rim size to 2. (254mm / 2 = 127mm)

3. Then add/subtract the rim offset. If the offset is positive then you need to subtract while if the offset is negative you need to add. (127mm + 42mm = 169mm rear spacing, 127mm - 42mm = 85mm front spacing)

You would ask, why you subtract for positive offset and add for negative offset. This is because we are calculating the spacing left of the front and rear of the rim but not the position of the center core of the rim. If you are calculating the center core of the rim, then you need to reverse the formula.

Some fail examples. Poke, Hellaflush and sunk.