I recently bought a bike that came with 172.5mm ultegra cranks - the crank is in great shape (9speed splined octalink etc) but I use a 177.5 dura ace crank on my tri bike and want to get at least 175mm. If you want to go to a smaller crank (higher cadence - theoretically better but not for me I find) I would like to swap my 172.5 crank for your your 175mm - may consider shimano 105 as well or dura ace + some $$$ but would prefer ultegra just to keep everything the same. If you like we could keep our chain rings and just swap arms or the works its up to you really. These are 39-53 rings I believe. Please contact me at bmacfarquhar@yahoo.com if interested.