I would think you'd have the opposite effect?
With the 175's, 65 RPM was all I could maintain and it took a conscious effort. 68 RPM and my feet were coming off the pedals.
With the 170's, I'm aware that I'm spinning faster, but I don't feel like I'm "spinning out". I kind of expect to increase my cadence somewhat, through "repetition".
I messed up my back though, so I'll be off the bike for a few more days. The 165's should be in the shop tomorrow. I guess they'll be there a few more days!