Seat hieght - % or deg

BigG67

I've been fretting over my seat height and as I'm on a integrated seat mast it's a BIT of an issue.

Using the 109% of inside leg it all seems fine - 86.5cm x 109% = 94.2cm....tick.

But I then got some knee pain and looked into possible causes (other than my old age ) and a low seat matched the symptoms, though there are many other possible factors.

So Mrs B took some photos of me last night on the turbo actually cycling and at the bottom of the peddlel stroke - when the crank is in line with the seat tube - my "angle of dangle" is 50deg not the recommended 30deg.

Stationary I can easily make the angle right by dropping my heel down a touch but it looks like I lift my heels when I peddle.

All this is confusing enough but I took some stills off the TdF last night and the winner also had a 40/50deg angle in his peddle stroke.........any advice?

a_n_t

can I enquire as to your knee pain symptoms?

Having some problems myself [pain in the back of the knee] which is meant to be seat too high but to be honest I feel like I want it higher!!

Monty Dog

Did you measure your inside leg measurement as crotch to floor not as per a pair of torousers? Stand against a wall, push a book between your legs and mark the top point with a pencil on the wall - this is your inside leg measurement. In terms of your knee pain - is it front, rear, inside or outside - the position of the pain is indicative of the type of problem. As Ant says, pain at the back of the knee is typical of hyper-extension, whereas inside or outside pain is often due to poor foot and pedal alignment - too low a saddle can cause your knee to track sideways which causes similar problems.

scherrit

Looking at your static knee angle is not all that useful which is why a decent bike fitter should look at your knee angle side-on at low load, and at higher load (say time trial effort).

A knee that looks as if the saddle is too low at "pootling" load may look and (work fine) under a bigger load as the rider drops their heel a bit. Riders vary in how much (and possibly even whether) they drop their heels under effort, so you need someone to have a look at you on the trainer from the side when working at a decent level.

Good luck,
S.

BigG67

a_n_t wrote:

can I enquire as to your knee pain symptoms?

Having some problems myself [pain in the back of the knee] which is meant to be seat too high but to be honest I feel like I want it higher!!

It's the classic IT band issue with pain on the medial side of the kneecap. Bit of physio cleared it up but I can tell it's still there.

BigG67

Monty Dog wrote:

Did you measure your inside leg measurement as crotch to floor not as per a pair of torousers? Stand against a wall, push a book between your legs and mark the top point with a pencil on the wall - this is your inside leg measurement. In terms of your knee pain - is it front, rear, inside or outside - the position of the pain is indicative of the type of problem. As Ant says, pain at the back of the knee is typical of hyper-extension, whereas inside or outside pain is often due to poor foot and pedal alignment - too low a saddle can cause your knee to track sideways which causes similar problems.

Yep this was the way I measured it and double checked to make sure...on different days..I didn't want what seems to have happen, happen....

See above for the pain and it could be a lack of float as I have very splayed feet, to the extent that if I align my cleats to where my feet naturally hang my heels catch on chain stays...

BigG67

scherrit wrote:

Looking at your static knee angle is not all that useful which is why a decent bike fitter should look at your knee angle side-on at low load, and at higher load (say time trial effort).

A knee that looks as if the saddle is too low at "pootling" load may look and (work fine) under a bigger load as the rider drops their heel a bit. Riders vary in how much (and possibly even whether) they drop their heels under effort, so you need someone to have a look at you on the trainer from the side when working at a decent level.

Good luck,
S.

As I said I can get the static angle right and know that it's not that realistic, I've got a decent DSLR and set the Mrs up with a high shutter speed and lined the chain ring up with a line at right angles for her to shoot from.

BUT

Worth another try with heavier load, I kind of just spun on the turbo. But 20deg differnce seems a lot....

a_n_t

BigG67 wrote:

It's the classic IT band issue with pain on the medial side of the kneecap. Bit of physio cleared it up but I can tell it's still there.

ah right, not what i have then. I've just tried the 109% method and my saddle should go up another 20mm, kinda flies in the face of "rear knee pain"

a_n_t

upped my saddle by 15mm, 60 hilly miles at the weekend and the knee was fine :?

BigG67

I'm off for a full Bikefitting.com experience at Rock & Road in Bridge of Allan on Friday...either it'll tell me everything is fine or

over-the-hill

BigG67 wrote:

I've been fretting over my seat height and as I'm on a integrated seat mast it's a BIT of an issue.

Using the 109% of inside leg it all seems fine - 86.5cm x 109% = 94.2cm....tick.

Is that to the pedal or the ground?

proto

What do you mean by the 'angle of dangle'?

If you mean the angle the upper and lower leg deviates from 180° at the bottom of the stroke then current thinking suggests (according to an article in C+ earlier this year) this should be between 25° and 30°, but more usually near the 25° (it depends on upper/lower leg length raio).

cougie

What was the height of your other bikes - can you measure your old bike ?