LONDON (Reuters) - Standard Chartered (>> Standard Chartered PLC) boss Peter Sands has his work cut out to convince investors he can turn around the Asia-focused bank after three profit warnings, new troubles in the United States and a 30 percent share price drop.

Sands, who begins a three-day road show for investors in Hong Kong starting on Tuesday, is under pressure to show a restructuring plan he unveiled a year ago is still relevant and goes far enough.

The former McKinsey consultant, 52, was widely praised for Standard Chartered's 10 years of record earnings. He is the longest serving CEO of a major British bank and next week will celebrate eight years in charge.

But the good times came to a halt in summer 2012 when the bank paid $667 million (419.43 million pounds) for violating U.S. sanctions on Iran.

The bank's bad debt outlook will be a key topic for investors attending the meetings. Bad debts more than doubled in the third quarter from a year ago as falling commodity prices hurt corporate borrowers in Asia.

If the bad debt spike signals a new trend, shareholders will want reassurance the bank is adequately protected.

Indonesian businessman Samin Tan, who owes the bank $750 million, is in talks to sell assets to help repay the debt, Reuters reported last week.

But losses on that loan would show how the bank has made some bad bets. Investors typically hold Standard Chartered shares to get emerging market exposure without many accidents.

"It's not priced for perfection, but there's little tolerance ... and it wasn't convincing on the last call why they are missing (expectations)," said Colin McLean, managing director of SVM Asset Management, which holds the bank's shares.

Standard Chartered shares, which traditionally trade at a premium to rivals, were last at 0.8 times book value, compared to 1 times for rival HSBC (>> HSBC Holdings plc) and 1.2 times for Lloyds (>> Lloyds Banking Group PLC), after the stock crashed to a five-year low last month.

Other problems include losses in Korea, falling investment banking income, a shareholder backlash over pay and U.S. authorities looking anew at potential sanctions violations.

Some investors have called for Sands or Chairman John Peace to step aside or set out clear succession plans.

Sands has said he will step up his restructuring effort and cut $400 million more from costs next year.

(Editing by Jane Merriman)

By Steve Slater