The cranksets on my tri-bike are 170. I have this bike for around 3 years. But recently I build a road bike and found a very good deal on eBay for the cranksets, but they are 172.5. Currently I’m using the road bike for climbing and group (cyclists) rides.
I want to know if there’s a standard calculator to know if I have to use 170 or 172.5 cranks (my height, inseam, etc…)?
I doubt you can tell a difference between a 170 and a 172.5. Thats only 2.5mm or a .015% increase in length. A few people advocate that the standard cranks are not long enough for people with long or longer legs. Thats a formula somewhere on the net that basis the crank length on leg length. With my 37" inseam my cranks are supposed to be 205mm or so. I use 180’s on all my bikes.