knee angle question
 

I have been riding for about 6 months. Almost exclusively climbing, simply because of where I live. I took my bike in to have my shifter fixed and they told me my seat was too high. They measured my knee angle at 10 degrees and they said 30 degrees would be better. My first ride with the lower seat position proved uncomfortable. My lower back hurt and I felt weak in that position. I am 6'3" with slightly long legs. I naturally have more strength in my hamstrings than quads.

Should I give the lower seat position a chance? Or is it possible that my body will be better in the more agressive set up that I am used to?
Thanks.

Hard to say for sure. I like the "be able to lock the knee with heel on pedal when fully extended" as a starting point.

Got any pics?

I will try and get a pic. I think your rule though is closer to a 10 degree bend than a 30 degree bend.
Thanks for the response.

Probably so. The problem with measuring the degree bend in your knee is that it is very sensitive to whether you pedal heel up, heel down, or heel parallel. I would estimate that in my "normal" pedaling style my knee is about 10-15 degrees off 180.

In general, if you are changing your seat height (or any other adjustment) it's best to do so slowly/incrementally, say by 5mm at a time anyway, to give your body time to adjust. If you make a big adjustment, even if it is "correct," it may feel "wrong."

It does depend...

Myself I have to have more knee bend or my knees and back ache....

With the greater knee bend, I find it allows me to drop my heel a touch when pedaling, especially when trying to power over climbs seated...Also, find it activates my quads more and provides more well rounded power.

When I first dropped the saddle I did find it odd, but after a bit I noticed the improvements...

Impossible to answer without seeing your posture. Not sure why you feel you naturally have more strength in the hamstring, perhaps because your seat was too high for a long time. You'd be served to develop your quad strength as super-strong hamstring and weak quad/hipflexor will eventually cause lower back pain.

Thanks for the response and info. I have known that I am hamstring/glute dominant long before I got into cycling due to years of weightlifting and collegiate track and football. I threw that in there referring to the hamstring involvement with hip extension on the downward pedal as oppossed to the its involvement with knee flexion on the upward pull. I know my body but I really am just guessing as it pertains to cycling and whether or not a higher seat is more suited to my natural strengths and tendencies. If I understand correctly, lowering the seat will cause the knees to track over the toes further resulting in more quad involvement. Thanks again.

If it hurts, move it back where it was, and, then, try lowering the seat a little at a time. Big changes in riding position can be very disruptive.

This......

Yeah, basically right. I have a suspicion that your hams are super-tight(can you touch your feet?). Tight hams can **** with your back and the classic cyclist flat lower-back(posterior tilt of pelvis and no lordosis) can really be exaggerated. Do you feel the reach for the bars has changed? Perhaps raising them up for the time being and working on flexibility/ab strength? For sure you'll get faster(way more efficient) by steadily engaging the quads. :thumb:

If your hams are very strong - then a high saddle position is better. The hams are used on the "upstroke" (i.e. when pulling up at the back), and a more upright position allows a stronger pulling motion.

The quads are used when mashing down - which is the strongest motion for most cyclists. A lower saddle position allows a stronger downstroke, so your LBS probably wanted to put you in the 30-degree position assuming that you would mash down, as most riders do.

I'm surprised that your quads aren't your strongest muscles - all that time in the gym must have included plenty of squats, which build quads and glutes.

Hey thanks for putting thought into this. Actually my hams are very flexible, I can touch my head to my knees with legs completely straight. And my pelvis has a nice anterior tilt. As far as reach what I noticed is that before the change my hub was way in front of my handle bars. With the seat dropped I can not see my hub, which I understand to be ideal...

I guess the message I am hearing is that I should return the seat to where it was and make small adjustments allowing time to adapt to the changes, and the result will be more quad activation and more efficient riding.

Thanks everybody, keep it coming.

Have a look at this...

At 6'3" and with long legs - you'd be a candiate for this...


I'm 6'7" and can't believe the difference it made to my riding...

Adrian.

I've always been told the angle of your knee should be between 25-30deg at the bottom of the stroke with your foot at your normal pedaling angle (do you point down, up or not at all).

Also, your knee should never go past your toes... In fact, with your pedals at 3 and 9 you should be able to drop a line (plumb bob) from your knee cap and it should bisect where the pedal axle is (or just behind)...never in front.

Also, also, if your seat is too low you'll probably cop some pretty severe pain in the front of your knees if you're doing some reasonable distances...

I have always liked Sheldon Brown's dictum, which is to keep raising your seat gradually until no rocking of your hips. That way you get the optimum seat height.

I recommend that you read Sheldon Brown's primer on approriate seat height.