175 sounds quite big for you. I have 35" inseam and usually ride a 175. I currently have a 172.5 on my roadie only as it was going spare. I think I prefer the slightly shorter one.

I'm sure a 170 will be ok for you

Bump

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USAT L2 TriAUS L2 UC Irvine head coach "The human foot is a masterpiece of engineering and a work of art."
Leonardo da Vinci

I have a similar inseam at 6'0" and went from 175 to 172.5 and am happy with the change. I would say to do it. It does help with hip angle in a lower position. On a TT bike, I would consider 170.0. I have a size 12 foot, so I don't want to go much shorter than 172.5. (I don't know if foot length matters in all that equation – not interested in debating crank length and think that there is a point where they can get "too short.") I would definitely switch to 172.5. It's a subtle change but it does feel better for me, and I live in a hilly area with lots of climbing.