dolfinack

Hey ho peeps. So I've been fiddling with the new bike for a week or two now to try to get the seat height right for me. Went with the whole measure by having a straight leg when your heels on the pedal deal, and that seems to work well.

But then.... been glued to this Tour thingy on the telly, and those guys REALLY don't seem to have the same fit. Their knee angle seems huge at the bottom of the stroke. Like about 30-35 degrees? To my simple brain this means I have my seat relatively way higher than them? If I lower my seat any further my legs are in some serious fatigue pain rather soon. I thought the idea was to have an ever so slightly bent leg at this position. (I know they're pros and might do things a little different to a 75 miles a week guy like me )

What gives?

daxr

No end to the debate on seat height, but if you look at all the different ways of doing it you should be able to pick one that's comfortable for you.

I like to keep my foot pretty horizontal through the stroke, so on the bottom of the stroke I have a flat foot and a noticeable bend at the knee. This leads to a saddle height two centimeters or so lower than other methods, but it works very well for me.

I can set it by the heels-on-pedals method as well, where you have someone hold the bike up for you as you sit in a normal riding position, except that you center your heels on the pedals and pedal backwards. If you feel your hips rocking, lower the saddle just until you don't feel any rocking. Then raise the saddle back up about a centimeter, and that's about right too. The more someone rides, the less likely they are to vary much from the above method.

Szczuldo

It's an illusion brought on by the minuscule time their legs spend at the point of most extension and the frame rate of TVs.

ZG2NYC

Bike fit in boulder - at 6 minutes he talks about angles. May or may not agree but he calls it "neutral":

https://www.youtube.com/watch?v=8kgpkZfjhmc

johnny99

Andy Pruitt, perhaps the most famous bicycle fitter in the USA, recommends a knee angle of 30 to 35 degrees at the bottom of the pedal stroke:
https://www.ultracycling.com/equipment/bikefit.html

sakonnetclip

Funny, I was thinking the exact same thing watching the Tour today.

My second thought was that most of us haven't seen video of ourselves riding, but rather we look at our leg angle from a static position on the bike.

-spence

dolfinack

Thanks for the replies chaps. Even when the boys in the TdF where pedalling slowly i'm pretty sure it looked like they had a "large angle". Couple of you are saying its pretty normal, obv they know what they're doing! But why do so many direct noobs like me to the nearly straight leg if 30-35 is recommended... It's all a little contradictory. And the angle you see in the mirror from static testing is bound to be the same as riding, no? Interesting ain't it?

johnny99

Some reasons why newbies' seats are too high:
1. poor fitness
2. poor posture on the bike
3. slow pedal cadence
4. don't ride uphill very much
5. don't ride long enough to experience crotch pain

daxr

I've never heard anyone say the leg should be straight or nearly straight at the bottom of the stroke. If you try it that way, first you have a substantial "dead spot" in the rotation where you have no power. Second, you'll find that your leg really doesn't want to do that and instead will maintain a bend while you rock your hips to make up the difference - very inefficient and almost impossible to do at a high cadence.

One of the old pedaling styles popularized by Anquetil (if I have my history right) used a high saddle and toes-down. Obviously that worked well for him, but less so for most. Hinault had a similar style, and I've read that it was at the root of his long-standing knee problems.

umd

You're doing it wrong. The fit rule of thumb to have your lef straight with your heel on the pedal gives you about a 30 degree angle when the ball of your foot is on the pedal, i.e. when you are pedaling. You don't want your leg to be straight during your pedalstroke unless you want to destroy your knees.

ZG2NYC

^^+1 There ya go.

dolfinack

ya ya thats what I said in the OP. I use the heel and it works well.

About 1min 20secs here https://www.graspr.com/videos/Part-2-...tisportcast-tv Thats a weeny angle at the bottom of the stroke, and is identical to many other videos by pro fitters I've seen. This angle is way smaller than the tour guys I watched yesterday.

Its all very confuzzling. Perhaps what some people call 30 degrees is not what I would call 30. I guess I'll just play about til I feel good - I reckon its pretty swell at the mo. Ta very much everyone, have a good 'un.

umd

umd

It's hard finding a picture from a race where they are truly at the bottom of the pedalstroke. Here is one example I found from the tour of California. I believe they are coasting, so the knee will unbend a little more than normal while pedaling but you can see there isn't a huge angle there. You can adjust the angle a lot with the position of your ankle. If you fit for a 30 degree bend with your foot flat and you pedal toes down then you will have a greater angle, and conversely if you push your heel down you will have less of an angle.

DaveSSS 

The picture above shows exactly what I suggest. The leg is fully extended with the foot horizontal at the bottom of the stroke, but during normal pedaling, most people will raise the heel by 2-3cm, which is all it takes to create the 30 degree angle. These riders are coasting with the leg fully extended, not pedaling normally.

johnny99

Some people pedal with their toes pointed down at the bottom of the pedal stroke. Other people have their feet level at the bottom. A good bike fitter will fit you based on the way you move on the bike, not based on static body measurements.