Doing the Philly ride this year and hopefully will be able to do the 100 mile ride. This year hasnt started out well, I was going to be riding for a friend of the family and since the start of they year has grown to 4

Will I be able to do the Philly-100m on a fixed gear? Itll be with 48/15 gearing if that helps (or should I ride the geared bike?)