I recently bought a 58cm trek 5900. It came with a no setback seat post and a 90mm stem. By moving the seat back to where my knees are about 2cm-3cm behind the pedal axels I effectively position myself where my view of the front hub is blocked when on the hoods. I have ridden the bike about 300 miles so far without any physical complaints. I actually think I climb better. Should I get a longer stem and move the seat to a KOP position or is this a minor issue that is subjective as long as there are no knee or back problems? I know as a rule reach should not be adjusted by seat position,but it just worked out without any further changes.Thanks.

After many years of riding with my knee approximately over the pedal spindle, I moved my saddle back about 2cm to improve my climbing (in the Colorado mountains) with no ill effects. I also shortened the stem by 1cm and changed to short reach Salsa Poco handlebars to maintain the same reach.

If you can tolerate the longer reach with the saddle back 2-3cm, it probably means your stem was way too short to start with. If you have a no-setback post, you must have the saddle slammed all the way back. I'd get a new setback seatpost like the ITM Millenium to center the saddle on the post. In general, no-setback posts are not appropriate for road bikes.