Bike and car parts seller Halfords saw the fall-off in like for like (LFL) sales accelerate in the final quarter of 2010 in its retail estate, and the group now expects full year profits will be at the lower end of market expectations. In the 13 weeks to 31 December retail revenues fell by 6.6% on a LFL basis, taking the decline in LFL sales in the 39 weeks to the end of 2010 to 5.2%.Total revenues fell 6.3% from the final quarter of 2009, while over the 39 week period retail sales were down 4.7% in a year earlier.There was a big decline in cycle sales, which were down 16% in the final quarter on a LFL basis, as fewer children's cycles were given as presents and premium bikes were affected by the slow-down in Cycle-to-Work sales."Looking forward, we are confident that the fundamentals of the bike market remain sound," said David Wild, chief executive officer of Halfords.The Nationwide Autocentres chain, acquired in February 2010, did better, however, with LFL sales up 1.6% in the final quarter and unchanged over the 39 week period.Retail customer numbers increased by 3.1%, while the average retail customer transaction values increased by 1.4% in the final quarter.151 centres have now been re-branded as "Halfords Autocentres" and 7 new centres have been opened.Guidance that full year gross margins will be broadly flat has been maintained.