DETROIT (BLOOMBERG) - Mr John Hughes is busier than ever and still fretting about making ends meet.

That's because his Detroit-based cycling shop has plenty of customers, just not enough bikes.

Like many Americans, Michiganders stir-crazy with quarantine turned to cycling as one of the few socially distant ways to enjoy the nicer weather, and each other.

But the same virus that created new enthusiasts wreaked havoc with traditional supply chains.

Global auto manufacturers forked over extra cash to airlift parts stranded in China during coronavirus lockdowns.

Small bicycle shops like Mr Hughes' had to get in line. Now they're suffering inventory shortages at the peak of the riding season.

Mr Hughes sold out of 90 per cent of his bikes within three weeks of reopening in early May.

"Everyone wants a woman's beach cruiser. If you have that, they're worth more than gold."

Coming from Detroit, Mr Hughes could be forgiven for not anticipating the pandemic-driven cycling craze.

The city was built on automobile riches, and evidence of car culture is everywhere, from the hospital system and football stadium named after Henry Ford, to the now-cancelled Woodward Dream Cruise, an annual summer parade of 50,000 muscle cars, hot rods and vintage American rides.

But if Detroit was built on the combustion engine, bicycles have marked its rebirth.

The wide, flat streets are rarely filled with cars even in non-pandemic times, making them ideal for urban explorers on two wheels.

The Slow Roll, a Monday-night ritual where Detroiters of all ages and backgrounds come together to tour the city by bike, has been around for a decade.

After the city emerged as a Covid-19 hot spot this spring, the Slow Roll was suspended in favour of "solo rolls," and even more people took to the now socially-distant pastime.

Amid the shortage of new bikes, people are digging two-wheelers out of their garages that haven't been ridden in years.

At Mr Hughes' two shops, repairs are up 50 per cent, and the work he's doing is much more extensive.

"The bike I'm working on right now is probably from 1965," he says.

"Repairs that would normally take 15 to 20 minutes, or 45 minutes, they're taking 2.5 hours."

One thing Mr Hughes did spot was the potential for a supply squeeze on parts - he ordered two years' worth of tyres and tubes just as China was shutting down.

It has been his saving grace: Although sold out of almost all of his new and used bikes, his shops are still crammed with bikes to repair.

Hehas hired two extra people, and even closed up for a couple days in June so he could make headway on the repairs.

But at this rate, he could come up short in July and August, months he usually needs to make money to get through the winter slowdown.

He's worried that the repair work he's doing now won't be enough to cover late summer, when he runs out of parts.

"Right now is awesome but, is it gonna be awesome in a month or two when you're not able to get anything?" he says.

"Maybe it'll be the first time in my entire life when I'll have a vacation in summer."