Vietnam is another option, but Mr. Cusick estimates that finding a new supplier will be a six- to eight-month process. He would have to send the company bike specs, get samples back and visit to make sure standards are up to snuff.

“It takes a long time to get that thing rolling,” Mr. Cusick said.

China dominates the American bike business: 96 percent of imported bicycles with small wheels come from the country, trade data shows. China also produces a large share of bike accessories, including 80 percent of imported coaster brakes and about 70 percent of bike signaling equipment. Taiwan, Vietnam and China produce virtually all imported rubber tire tubes.

The cycling industry’s reliance on China is not unique. China dominates entire import product categories, including clock and watch batteries, women’s clothing items and footwear components. Practically all imported photograph albums come from China, and most toys are made there.

Many of those items have yet to be hit with tariffs but are in line if Mr. Trump goes through with his threat to tax nearly all Chinese goods. The final list is much more consumer facing than the products that have been hit up to this point. Goldman Sachs analysts think that July is the earliest that round would take effect.

Mr. Trump indicated on May 27 that added tariffs were still in the pipeline.

“We’re not ready to make a deal,” he said, speaking in Japan. “And we’re taking in tens of billions of dollars of tariffs, and that number could go up very, very substantially, very easily.”

If companies selling consumer wares face higher tariffs and cannot pivot out of China to avoid the costs, customers could pay the bill. Walmart recently warned that shoppers would see higher prices on furniture, clothing and accessories because of the duties on Chinese imports. Target, Macy’s and Wayfair have also indicated that prices could rise.