I think the 50 is too large for a gym bag. For me at least. The keepall 45 may be perfect or the speedy 40.
I'd be afraid that the lockers at the gym may be too small to fit the 50 but if your gym has large lockers then def go for it.
I'd be afraid that the lockers at the gym may be too small to fit the 50 but if your gym has large lockers then def go for it.