triplering

Started biking about 5 months ago. Everything was going fine (riding up-to 3 hours comfortably) and then started having discomfort in left knee. Sensations vary, sometimes it feels like burning in the area of the petella and other times some low-grade pain in the actual knee joint itself (more prominent on medial side). At times the right knee flares-up as well. In any case, I'm concerned that if I continue to ride, permanent damage may result. I have adjusted the seatpost as high as it can go without my hips rocking when pedaling. I have noticed that a plumb line intersecting the middle of the pedal also intersects the middle of the knee joint as opposed to just in front of the knee cap. No fore/aft adjustment of the seat will remedy this. I ride with regular pedals and regular shoes at this time (no clipless pedals or cages). I know the best answer is to have a professional evaluate my set-up, but I hope to fix this situation without the expense if at all possible. Any suggestions greatly appreciated.

JPPLAY

Sounds like you may of torn something in your knee. I would go to a doctor and maybe get an MIR to make sure there no damage to any areas of your knee.

ConstantRider

Can you pinpoint any changes to your riding habits that brought on the pain? You mention that you ride up to three hours, but don't say how often or how hard you ride. Did you increase the frequency or intensity of your rides? Did you start doing more climbing? And did you change any of your equipment?

Spintogrin

Look, take care of this before it becomes chronic. Get a set-back seatpost so that you can get your foot where it belongs, spin don't mash and rest a bit so that you don't develope tendonitis or anything like that. Good luck

Carbonfiberboy 

Do you know at about what cadence (pedal rpm) you normally ride?

DannoXYZ 

Rocking when pedaling is not a bad thing, everyone does it to a certain amount. It actually increases when you push harder, like riding up a hill or sprinting. Your height-measurement is too vague, we need actual numbers:

1. inseam length of your legs
2. saddle to pedal distance (when pedals at bottom, crank parallel to seat-tube)

Also your seat seems to be a little too far forward, but that should cause ligament/tendon pain on the back of the knee, not on the front/top of the kneecap.

Yeah, I suspect you may be pushing too big of gears...

triplering

As far as changing riding habits, the answer is "yes". I first started riding forest roads and trails where there were hills and the gears were small. About six weeks ago I started getting the itch to try pavement and that's when I started hitting the big gears with a relatively slow cadence, say in the 60-80 range. Once I realized something was going on with the knee, I stuck with the flatter portions of the pavement and upped my cadence (in smaller gears) to 80-110. Granted the discomfort is not severe, it is enough to slow me down throught the day (off the bike) and kind of make me feel like an old man. As far as measurements go, my inseam is 29" and , unfortunately, I do not know the distance between the saddle and the pedal right off hand ( I'm here and the bike is at home). If this information fosters further discussion, great! If not, thanks for the reply from all of you.

Snuffleupagus

Get on a trainer, and spin for about 10 minutes. When you're comfortable, and in a bit of a groove, stop pedaling at bottom dead center, and have someone take a picture. Then measure your knee angle. It is possible to have your seat too high as well.

Check your cleat angle and position, the same for your seat as well. Any variance there could be the problem.

You say you're fairly new to riding on the road as well - 6 weeks - this could easily be an overuse symptom. Believe me, I know (2x knee surgeries since September). You need to knock back your volume, keep your cadence around 90ish and stick to flatter rides to avoid putting too much stress on your knees. Once you're feeling good for a couple weeks, and your position is good, you should be fine to begin ramping up your intensity.