Knee Pain- Setback post/bike too small? (pics)

[zackw419]

So I'm completely new to cycling. Bought this bike on craigslist. Been experiencing knee pain (mostly in front and under the kneecap). I realized if I shift my butt back basically to where I'm barely sitting on the back end on the saddle the knee pain goes away completely. So I'm basically off the saddle in that position. I've tried adjusting the height and fore aft. But the only thing that makes the pain go away is shifting my sitting position basically back-off the seat. So I'm wondering if this frame is too small.. its 56 and I'm 6ft with long legs. I don't necessary feel crunched on the bike upper body wise. Its just my knees. I've looked into setback seat posts but I'm wondering if there wont be one far back enough to do the job. The crank arm length is 170

here's a pic, what do you guy think? I'm sitting on the seat normally (not shifted back) in this pic.


View: https://imgur.com/a/MowyMhH

 

[CXRAndy]

A quick setup is to place your heel on the pedal and when its at the bottom of rotation, your leg should be locked out or just about to lock out. This will put you quite close to ideal seat height.

If you have to raise the seat, this will also move the saddle back too.

Frontal knee pain is generally associated with seat too low.

 

[PaulSB]

Agree with the above post. Before you start mark the current seat post position by wrapping electrical tape round it where the post enters the tube. This means you can always return to where you began.

The image suggests your seat needs a significant raise. I'd guess 2-3cm to start and then vary by mm until you have your leg correctly extended.

 

[mudsticks]

Wot they say.

Looks very much like the seat being too low could be the cause of your knee pain.

Good news in a way - relatively easy to sort it out 👍 👍

 

[Sillyoldman]

And do the set up with your cycling shoes on not just socks (it looks like you only have socks on) as the sole makes a difference.

 

[CanucksTraveller]

Put your saddle up.

Also, change your gears down, aim to spin the pedals quickly and easily at about 80rpm, pushing too big a gear is a common new rider's cause of kneecap pain. Some beginners feel that the act of pedalling should feel like a hard, pushing workout. It really shouldn't. It should be nice and easy, working your heart and lungs more than your quads, knees, calves etc.

If you can count one second per revolution of the pedals, that's you pedalling / pushing way too hard. Change down.

 

[SkipdiverJohn]

Some beginners feel that the act of pedalling should feel like a hard, pushing workout. It really shouldn't. It should be nice and easy, working your heart and lungs more than your quads, knees, calves etc.

In real-world cycling, there are plenty of opportunities to give your leg muscles a workout, such as climbing short gradients, but it's not a good thing to be grinding high gears throughout your ride. Not only is it asking for sore knees, but it's more fatiguing to overdo the gearing.
There's a balance between cadence and effort, where you can ride the most mileage and feel the least knackered at the end of it. That is the style of riding to adopt, and it varies a bit between each individual rider.
If you spin your legs at a silly rate, it's fatiguing as half your energy just goes into moving your legs not the bike. Your knees shouldn't hurt, but it's inefficient. Low cadence, high effort, will be efficient in the sense you are not spending much energy just whirling your legs around in relation to the power you produce, but it's punishing on your legs and knees. Avoid the extremes of both cadence and torque input.

 

[wafter]

Some good advice above, but equally I've been in exactly the same situation as you (long legs for height, frontal knee pain, shifting saddle back sorted it). I'd start by ensuring the saddle height is correct by using the "heel on the pedal with a straight leg" test then take it from there.

IME if you've got long legs for your height you'll be better off with a frame that's arguably a bit on the small side to get the shorter reach required for your smaller upper body, while saddle height and layback are easier to address on a smaller frame than changing reach to the bars on a larger frame.

All that said you do seem to be quite far back already - where is the saddle relative to the seatpost currently, and is there any amount of setback in the existing post?

I find saddles a swine to setup with measurements since unlike bars there's no definitive point to measure to across bikes (needs to be where your "sit bones" are, but this is often hard to define).

 

[T.M.H.N.E.T]

Some good advice above, but equally I've been in exactly the same situation as you (long legs for height, frontal knee pain, shifting saddle back sorted it). I'd start by ensuring the saddle height is correct by using the "heel on the pedal with a straight leg" test then take it from there.

IME if you've got long legs for your height you'll be better off with a frame that's arguably a bit on the small side to get the shorter reach required for your smaller upper body, while saddle height and layback are easier to address on a smaller frame than changing reach to the bars on a larger frame.

All that said you do seem to be quite far back already - where is the saddle relative to the seatpost currently, and is there any amount of setback in the existing post?

I find saddles a swine to setup swith measurements since unlike bars there's no definitive point to measure to across bikes (needs to be where your "sit bones" are, but this is often hard to define).

The small frame point is oft misunderstood. I've had countless people telling me I need a bigger frame because of the amount of seatpost I require but nobody saying that ever takes the triangle into account. When a dimension is lengthened the other two (seat tube and downtube) are also affected.

I've had identical bikes in different sizes where the difference in actual TT length is less than 10mm, but when saddle height and fore/aft are set appropriately, reach increases significantly on the bigger frame size. Conventional internet "wisdom" would suggest a shorter stem, but this in reality is misplaced as the physical frame length hasn't changed

 

[Fab Foodie]

The small frame point is oft misunderstood. I've had countless people telling me I need a bigger frame because of the amount of seatpost I require but nobody saying that ever takes the triangle into account. When a dimension is lengthened the other two (seat tube and downtube) are also affected.

I've had identical bikes in different sizes where the difference in actual TT length is less than 10mm, but when saddle height and fore/aft are set appropriately, reach increases significantly on the bigger frame size. Conventional internet "wisdom" would suggest a shorter stem, but this in reality is misplaced as the physical frame length hasn't changed

Bingo!
You have to consider the relative positions of the 3 contact points, all else is mostly irrelevant. If you're using muscles to keep position on the bike you're wasting energy.
I have the similar problem to the OP but for the opposite reason. I am short of leg and long of back and only 5'9". On a 'standard' sized bike properly 'sized and set-up' I always end-up pitching my weight forward onto the bars and constantly need to shift my weight back on the saddle just as the OP describes. This is due to my centre of gravity relative to the contact points which I need to move rearwards to counterbalance my long body.
In his excellent (I think the best) article on bike set-up, this idea of being balanced on a bicycle is well described (forget the crank length nonsense). https://www.peterwhitecycles.com/fitting.php
If you stand straight, bend at the waist and start to reach forward your arse moves rearwards as a counterbalance over your feet. This is how you should be on a bicycle* at such a seated position over the pedals that you can easily rest your fingertips on the bars with your torso counterbalanced.
I found on standard bicycles that despite fitting the most set-back post I could find I still needed to sit on the rear of the saddle to find the optimal position for pedaling and all-day comfort.
In the end I bit the bullet and went for a custom frame in order to get a more laid-back seat-tube angle as my primary goal. Unfortunately, this was not clearly understood and I ended-up with a lovely frame, but the same problem. So I went back to the frame-builders and had a long and at fitrst mildly heated discussion with Brian Rourke about what I wanted and why, and we he started to talk in terms of being balanced so that you can simply rest your fingertips on the bars THEN we understood each other. I ended-up taking a saddle on a set-back seatpost on a broom handle to show him where my seat needed to be relative to the Bottom bracket compared to the bike they built and HOORAH, I have a bike with a longer than average top-tube BUT where I sit perfectly on the saddle behind the BB to simply touch the bars with my fingertips.
The best fitting bike I ever owned apart from my 1950's Holdsworth made in a time when seat-tubes were very laid back and riding styles were different even when racing.

OK, long-winded experience, but part of this is that not only does raising the saddle lengthen your effective leg length/knee bend so does moving the seat backwards and both give a different sense of balance/comfort/efficiency.
The cheapest and most set-back post I could find at the time was this one, the same as the Velo Orange version and designed to work with Brooks saddles, but works brilliantly with all regular saddles. If the post length is long enough it's a cheap option to try....
https://www.planetx.co.uk/i/q/SPHOGS/holdsworth-gran-sport-seatpost