It was accompanied by a fall in car traffic, which the group said made it easier to provide more space on roads for bikes.
The group’s latest annual traffic counts showed more than one in four vehicles heading into the city centre in Tuesday morning’s rush hour were bikes.
They also accounted for nearly a quarter of the traffic in both directions.
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The figures were recorded from 8-9am on Lothian Road in the west end and Forrest Road, which links The Meadows cycle paths with George IV Bridge.
Spokes said cycles comprised 26.6 per cent of city-bound vehicles and 10 per cent in the other direction.
It said the total number of bikes had increased by 7.2 per cent since last May to 553.
They have also gone up by 51 per cent from 366 in the first count in 2007.
The group said car traffic had fallen to its lowest level since then, by 4.6 per cent since last year and 23 per cent over the ten years.
Three in four cars had lone drivers.
A Spokes official said: “This is a success for the council, which has a bold local transport strategy target to cut car use.
“The long-term trend of rising cycling and declining city centre car commuting in our counts ties in with trends in the 2011 census.
“Once again most cars - 76 per cent - have only one occupant, a huge waste of precious road space in the heart of the city.
"The new council should take every advantage of this great legacy from the last administration to speed up plans to boost cycling, as well as walking and public transport.
"The continuing decline in car numbers makes it much easier than ten years ago to re-allocate road space."
Spokes said this should include segregated cycle lanes on “scary” Lothian Road.
It said: “There are few roads in the city which would benefit so strongly from such a scheme, and, as shown by the London superhighways, there is almost certainly a big pent-up further demand from people who’d like to cycle but don’t feel safe until they have the right conditions.”
John Lauder, director of cycle route developers Sustrans Scotland, said: “Edinburgh is leading the way as Scotland’s cycling city.
“While much more needs to be done, Spokes research showing this significant increase in cycling confirms what we have seen on the national cycle network throughout Scotland, where annual trips rose to 121 million in 2015.
“Edinburgh’s previous administration has set things in motion for cycling.
“Sustrans Scotland is keen to work with the new administration to keep up this momentum.
“More cycling is better for health, better for the environment, better in tackling congestion and air pollution."
Keith Irving, chief executive of official development body Cycling Scotland, said: “Spokes have provided a valuable record of the increase in cycling in Edinburgh over many years, demonstrating that central and local government investment is delivering results.
"Cycling Scotland’s ambition is to extend this type of modal share monitoring to more places so we can plan for and track the ongoing increase in cycling.
“Everyday, more people are cycling in Scotland.
“One in ten journeys [the Scottish Government’s national target by 2020] to some campuses, schools and workplaces are already taken by bike.”