* RSS3 traded at $2.56/kg, STR20 at $2.40-$2.41 FOB
* SIR20 done at 107.25-108 cents/lb; Bridgestone buys
* Qingdao rubber stocks slip below 300,000 tonnes (Adds fresh Bridgestone deals)
By Lewa Pardomuan
SINGAPORE, Aug 21 (Reuters) - Tyre grades from Southeast Asia changed hands for October delivery this week, but a drop in China's rubber inventory has yet to trigger an expected wave of buying from the world's top consumer, dealers said on Wednesday.
Tyre grade prices had plunged to multi-year lows on concerns about global economic growth and uncertainty over demand from China, which makes up 35 percent of global rubber consumption.
The Thai RSS3 grade was traded late on Tuesday at $2.56 a kg, free on board, down from $2.58-$2.60 last week. Another Thai grade, STR20, was sold at $2.40 to $2.41 a kg FOB, versus $2.54 including freight to China.
"Some of the STR20 cargoes have been sold to China. There will be some buying on dips as usual, but I am not suggesting it's going to be strong," said a dealer in Thailand, the world's largest producer.
"Even though stocks in China have dropped below 300,000 tonnes, they are still substantial."
Some cargoes of Indonesia's SIR20 were sold to Bridgestone Corp, the world's largest tyre maker, for nearby shipments, and Malaysia's SMR20 was traded to unspecified buyers at prices slightly higher than STR20.
Rubber stocks at Qingdao, which are closely watched and make up the bulk of China's inventory, have fallen to 298,300 tonnes from 313,100 at the end of July, but are still above the usual level of 250,000 tonnes, dealers said.
A drop in Qingdao is usually seen as a bullish signal for the market as it raises the prospect of more imports. But it could also indicate local tyre makers are still reluctant to buy from overseas markets despite signs the economy is improving.
"Actually, this should be bullish but the market doesn't seem to reflect it," said a physical dealer in Singapore, who trades Indonesian and Malaysian grades.
Physical rubber prices have tracked the fortunes of benchmark Tokyo futures, which in turn are dictated by the currency and equity markets. The Tokyo market shrugged off declines in China's rubber inventory.
The most active January rubber on Tokyo Commodity Exchange fell to its weakest in nearly two weeks at 257.9 yen a kg on Wednesday after the Nikkei slipped on concerns the U.S. Federal Reserve would soon start tapering its monetary stimulus.
Indonesia's SIR20 was sold to Bridgestone on Wednesday at 107 U.S. cents a pound ($2.34 a kg) for October and 106.50 cents for November and December. Late on Tuesday, the same grade was sold to the tyre maker at 107.50 U.S. cents a pound for September and at 107.25 cents for October shipment, FOB.
There were also deals to other buyers at 107.25 and 108.00 cents a pound overnight.
"China is also buying SIR20 via dealers in Singapore. But these days, you can't really feel their presence. Also, the Tokyo market is extremely volatile," said a dealer in second-largest producer Indonesia.
SIR20 was traded at 110 to 110.25 cents a pound last week.
Malaysia's SMR20 changed hands at $2.43 a kg FOB, versus $2.50, including freight to China last week.
Tyre grade prices are likely to hold at the current levels next week, given the volatile Tokyo market. (Editing by Clarence Fernandez)