Wall Street was set for a lower open on Friday on doubts about the strength of the economic recovery, after data showed new orders for durable goods unexpectedly fell in August.

New orders for long-lasting U.S. manufactured goods dropped by their biggest amount in seven months, following a plunge in commercial aircraft orders, a government report showed on Friday.

This means a lot of (the economic rebound) is still being driven by the government, said Doug Roberts, chief investment strategist at Channel Capital Research.com in Shrewsbury, New Jersey.

In essence, this is a bit of a reality check.

Shares of Research In Motion Ltd fell about 14 percent in premarket trading after the BlackBerry maker reported second-quarter revenue on Thursday that missed estimates and gave a disappointing outlook.

S&P 500 futures fell 2.8 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures shed 21 points and Nasdaq 100 futures fell 3.5 points.

Friday brings more data that could reflect the health of the economy, including readings on consumer sentiment and home sales.

The final Reuters/University of Michigan reading of consumer sentiment for September is expected at 9:55 a.m. A Reuters poll of economists showed the gauge is expected to rise to 70.3 from a reading of 65.7 in August.

U.S. new home sales data is due at 10 a.m. Economists look for sales to have increased to an annual rate of 440,000 units in August from 433,000 in July, which was the highest in 10 months.

Unilever NV agreed to pay $1.87 billion for Sara Lee Corp's personal care brands. Sara Lee, whose shares jumped 7.5 percent before the bell, said it is still looking to sell the rest of its household goods business and will launch a $1 billion share buyback program.

A pledge from world leaders at the Group of 20 nations summit to keep emergency economic supports in place until a robust recovery takes hold helped stem recent fears that government efforts to support financial markets would end anytime soon.

The G20 rich and developing countries, holding a two-day summit in Pittsburgh, will aim to implement new rules by the end of 2012 to improve bank capital and discourage excessive leverage.

The world's central banks said Thursday they would scale back infusions of U.S. dollars into their banking systems.

U.S. stocks fell on Thursday on weak housing data and investor worries that the officials may curb economic stimulus efforts too soon.

(Additional reporting by Chuck Mikolajczak; Editing by Padraic Cassidy)