vroooom ptssssh

I replaced the fuel hose on my S1 from the pump-accumulator with a rubber hose, the original plastic hose has an inside diameter of 6mm, the new rubber hose has an internal diameter of 5mm, although it looks smaller as it is a thicker hose, will this be ok to use? car seems to run fine, just wondered if it could cause any probs? fuel pump doesnt pump faster/harder as the revs rise does it?