J30 front 5 lug machining and abs ring

[zer0c123]

Question for anyone that has sucessfully performed the J-30 front 5-lug conversion on the S13.

1. Did anyone have to machine out the bore of the j30 hub to get the s13 bearing to fit right? I'm not talking about the groove for the snap ring.

Based on my research, all the forum posts say that you have to machine out a new groove for the snap ring because the S13 bearing is taller than the j30.

I took my parts to a machine shop to have the groove cut out and s13 bearing pressed in. For a check, the guy measures the outside diameter of the s13 and j30 bearing. He notices that they are 0.007” difference in which the s13 bearing is bigger in diameter. In addition, he roughly measures the bore of the j30 hub with a caliper. I say roughly as he couldn’t find the right size bore gauge, so he was only able to measure from the top with a Vernier. I don’t recall the bore diameter, but he did say I was looking at a 0.013” inference fit to press S13 bearing into a J30 hub and that’s not a good idea (even if I put the bearing the freezer). He suggested that he could counter bore the hub by taking off 0.005 – 0.007”.


The machinist knew what I was doing for the 5 lug conversation, so he didn’t want to proceed with cutting groove and pressing in the bearing until I researched further. I read tons of forum threads across google and only one thread mentions boring the hub down a little to get the s13 bearing in. All the other threads just mention you machine the groove and install the bearing. *

2. For those that do not have abs, do you need to cut off the j30 abs ring? All the threads mention cutting it off. I personally want to keep it because the ring acted as a mounting point for me to put pipe around the hub to push out the old bearing.

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