Swiffty6

I really need this problem solved. I had a second hand steering rack fitted on my a4 avant a couple of months ago and ever since then it's been whining when driving and it sounds like a wheel bearing has gone but I've had them checked and they are fine . Both garages say it's the tyres that are making the noise because I only bought cheap ones. I had 4 new tyres fitted a couple of month before the rack and there was no noise at all until I drove away with the new rack . Can anyone shed some light on this ??