will difference in tire diameter cause hicas to act up?

[6902brad]

just did the 5 lug swap with the z32 breaks on my s13. I used the 2007 350z wheels Staggered 18x8 +30 with 225/40/18 in the front and 18x8.5 +33 with 245/40/18 in the back. I used 300zx rear hubs in the back. my problem is that when i get going down the road, it feels like hicas is active engaging in the back, and the back feels extremely feathery or loose. It feels this way when i turn the wheel even just a little bit. could it be that the difference in tire diameter sizes causing just enough wheel speed difference to engage the hicas making the back of the car to feel really loose????? the hubs i used in the back came off a 93 300zx from the parts yard. The bearings seem to be in pretty good shape with an extremely small amount of play in them.
Modified by 6902brad at 5:18 PM 10/28/2007