A protest and website petition is due to be launched this week by city group GoBike for a segregated diversion route so riders are not forced to switch to other transport if the national cycle network route (NCN) past the SEC conference venue is shut during the 12-day event.
The move came as Scottish Government-funded development body Cycling Scotland stressed that "every journey cycled will make a difference in cutting emissions" in the face of the "appallingly clear" climate emergency.
GoBike campaigns lead Iona Shepherd estimated thousands of people a day used the cycle route along the north bank of the Clyde, which she predicted would be closed because of its proximity to the SEC, where the event opens on November 1.
Glasgow City Council has already announced the closure of surrounding roads, including the Clydeside Expressway.
Ms Shepherd said: "It looks like the route between the Riverside Museum and the Squinty Bridge is going to be closed to walkers and cyclists.
"That part of the NCN is like the motorway for cyclists.
"It’s an east-west link and the most-used route, particularly for commuters but also for a lot of leisure cyclists.
"What they [the council] should be doing is properly consulting on the diversions and ensuring active travel [walking, cycling and wheeling] takes precedence over cars on roads nearby which could be used for an efficient diversion, which I’m almost certain they won’t do.
"We are going to have so many delegates and protesters visiting the city who need to get around.
"If they are all having to use taxis because there is no safe way to cycle, or if the bus routes aren’t up to scratch, then we’re basically doing the very opposite thing we should be doing during a conference in which we are trying to come up with solutions for saving the planet.
"We’re going to be creating carbon emissions as a result of closing active travel routes.
"It’s more than ironic – it’s devastating they would consider doing that.”
Cycling Scotland chief executive Keith Irving said: “Closing roads for the summit offers the opportunity to trial a different approach which prioritises public and active transport.
"The diversions could also become permanent cycle routes, offering the opportunity of a long-term summit legacy for Glasgow.”
Duncan Dollimore, head of campaigns for lobby group Cycling UK, said: “When the world comes to Glasgow to discuss tackling climate change, it would be bizarre to see less cycle lanes rather than more.
"If any have to be closed, they must be replaced with safe, direct alternatives, showing Glasgow is leading the way towards carbon free transport.”
A spokesperson for the city council-led Get Ready Glasgow group said: “Exact dates on the period of road closures are still to be confirmed.
“Cycle paths and footways will also be affected and could be closed to the public at certain times.
"If this is the case, then alternative routes will be available and signed appropriately.
"These measures are needed to facilitate the safe delivery of the event and maintain the safety and security of participants, citizens and visitors.“