Using SI hubs on EX spindles

Originally written; September 9, 2007

Revised June 2, 2008

To start off;

I've got 90/91 4-door EX spindles, brakes, and hubs on my 89 hatchback. The reason is that it allows you to use the larger brakes that are also used on the DA Integra's.

That's all fine and good, but one of the hubs were out of true (I had to have the rotors turned on the car in order to have them run true). So, I wanted to replace the hubs with new ones.

Well, Honda no longer sells EX hubs! (bastards!!)

That leads to the question as to if it's possible to use SI hubs.

I'd like to thank dr_latino999 and steronz of Honda-Tech for their input!

Let's compare the two different hubs

Here is a photo showing the two different hubs next to one another. The rusty one is the EX hub. The shiny new one is an SI hub (still available from the dealer)

Here are the dimensions off of the EX hub;

And here are the dimensions off of the SI hub

So what does it mean?

Item #1    The diameter where the press into the wheel bearing is the same.

Item #2    The spacing of the wheel studs is the same.

Item #3    The offset of the flange for the rotor is the same.

Item #4    The fact that the over-all diameter is different, it isn't critical and doesn't matter.

Item #5    The 2.25" dimension is for indexing the wheels and is the same on both hubs.

Item #6    The 2.525" dimension on the EX hub is different from the 2.395" dimension on the SI hub. This dimension is for indexing the rotor and it's debatable as to if it's important or not. It could be said that the brake rotor is already indexed due to the wheel stud and the two philips screws, but it bothered me.

What is the solution to item #6? (if you care)

You need a spacer ring (collar) that has an inside diameter of 2.395" (to fit the SI hub) and outside diameter of 2.525" (to fit the brake rotor).

Doing simple math (2.525 minus 2.395, divided by 2), you can figure out that you need collar that has a wall thickness of 0.065". The height of the collar should be about 0.56".

OOPS!!!!!. That height of 0.56" is just a major error and it was pointed out to me. It should be something like 0.2", but there isn't any way that I can give an exact number due to having sold the car!

Here is a photo of the collar that I made of aluminum;

Now if you look close you will notice that it's cut, much like a piston ring. The reason is that by making it that way, I only had to worry about the wall thickness (which is critical). I didn't have to worry about the inside or outside diameter due to it's being able to spread as required.

Here is a photo of the hub, rotor, and spacer installed.

So there you go. It really does work.

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Wes Vann