Might depend on the geometry of the bike. Most track bikes have a higher bottom bracket and because of that some prefer a slightly shorter crank. But unless you're worried about pedal strike, I'd say run the 175s. Shouldn't be a problem if you're careful on corners. (I've never once had a real pedal strike. A few times, on clips and straps, the edge of the strap just barely brushed the ground. That feedback alone was enough for me to just gauge it from then on).