Cyclist gathered at Centurion Way on Friday over fears it could be re-routed due to a major housing development.
The public right of way looks set to be moved under plans for Whitehouse Farm with an access road built on neighbouring playing fields at Bishop Luffa School.
Headteacher at Bishop Luffa School Nick Taunt assured the group he knew of no plans to close Centurion Way outright, but he would be unhappy with a path cutting through what would become part of the replacement school site.
He said: “In terms of protection, in terms of safety, it’s not sensible to have a public right of way so close to a school.”
He added the school was ‘neutral’ about the development and had made a ‘quite a generous offer’ to share the new playing fields for community use.
Campaigners were joined by John Grimshaw, who oversaw the path’s construction in 1994 and said the route would be a key link into the South Downs National Park after an extension at West Dean.
He said: “I’m very concerned about how the development and the school and everything will integrate.
”Obviously we’re trying to make things better for cyclists year on year.”
The group, led by city councillor Sarah Sharp, intend to submit their own alternative plan to keep the route in place.