Lots of potential possibilities...
- They manually entered their FTP into trainerroad or wherever (ie they made it up and didn't achieve it in a test
- They might be better at performing an FTP test (either ramp or 20 min or whatever) than they are at riding in certain zones that are being ridden in your outside group rides
- The power source they use indoors measures high (either poorly calibrated or just a trainer that is 'off')
- They might weigh a lot more than you so their watts/kg is not as good
- They are holding back during the group rides
- As you mentioned - fit can play a role. Having higher handlebars can make it easier to push bigger watts. But that comes at a cost of having worse aerodynamics
- They might have equipment that isn't very aerodynamic
Matt
- They manually entered their FTP into trainerroad or wherever (ie they made it up and didn't achieve it in a test
- They might be better at performing an FTP test (either ramp or 20 min or whatever) than they are at riding in certain zones that are being ridden in your outside group rides
- The power source they use indoors measures high (either poorly calibrated or just a trainer that is 'off')
- They might weigh a lot more than you so their watts/kg is not as good
- They are holding back during the group rides
- As you mentioned - fit can play a role. Having higher handlebars can make it easier to push bigger watts. But that comes at a cost of having worse aerodynamics
- They might have equipment that isn't very aerodynamic
Matt