I'd use it. Some sort of notification feature would be cool. E.g you could ask the user a radius of miles that they would want to meet and ride. Say I chose '20 miles' and then someone within 20 miles of my current location said they wanted to ride, I would get a notification saying 'John Doe is riding (destination), want to ride?'. You could add some sort of text feature too, especially if it is riding with people you don't know and you don't have their number.
Could have a 'Group Ride' feature too. Same aspect as above, except if you got the notification and you said 'I will ride' then it would add you to that ride. Then when other people get the notification they will see who is meeting at the same place at that time.
Could also give the ability to add contact details to the app. This way if that person can't get internet access or has no internet signal at their location other people can text/call that person if they don't already have their contact details, however I would recommend making this an optional choice.
If you were to do this for different sports as well you might want to add a Sport filter. That way they can choose what type of riders they want to meet with.
Would be good to see how this turns out!