Possible Clues:

• 'At last, a scratcher on the wheel (6)'
• Re the task on the wheel
• Wager about right length of planking
• A street scraper on the wheel?
• Bit of a wheel to scratch the street
• Does it take a bit of a wheel to scrape the street?
• Section of wheel rim; line of plating (along ship)
• Is there such a street scraper on the wheel?
• There's a street scraper on the wheel
• A street scraper on the wheel