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cycle-ergo.com question
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postoak Offline
Running Like a Top

Texas
Posts: 304
Joined: Mar 2014
Post: #1
cycle-ergo.com question
cycle-ergo lists forward lean angle, knee angle, and hip angle. What I can't make sense of is hip angle. It seems to me that if it is the angle between the top of the thigh and the body that it is always going to be greater than 90 degrees but the numbers given are always smaller than 90 degrees.

So just what angle are they measuring?
11-12-2017 12:29 AM
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Cormanus Offline
Moderator

Queensland, Australia
Posts: 10,722
Joined: Dec 2013
Post: #2
RE: cycle-ergo.com question
It's always going to be less that 90º, isn't it, unless you're leaning backwards?
11-12-2017 12:56 AM
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alprider Offline
1st Service Completed

CH
Posts: 217
Joined: Aug 2017
Post: #3
RE: cycle-ergo.com question
Or play with the options like seatposition legs ....there and you will understand it....
Or short : the angle between legs and upperbody its not the same like angle upperbody and bike......

Or take too a chopper and a sportsbike and observe what happend with the numbers
(This post was last modified: 11-12-2017 05:30 AM by alprider.)
11-12-2017 04:50 AM
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postoak Offline
Running Like a Top

Texas
Posts: 304
Joined: Mar 2014
Post: #4
RE: cycle-ergo.com question
(11-12-2017 12:56 AM)Cormanus Wrote:  It's always going to be less that 90º, isn't it, unless you're leaning backwards?

Can you explain? I have always taken the hip angle to be the angle between the line formed by the front of the body and the line formed by the front of the thigh. Why did I assume this? Because it makes sense to be interested in that angle. It would be one measure of how folded up your legs are and the knee angle would be another.

But I realize now I was wrong as the illustrations clearly show this angle being greater than 90°.

So what is the hip angle? I thought it might be the angle between the back and the back of the thigh but that doesn't match the drawings either.

alprider - I took your suggestions and played around with seat position and legs on a cruiser and a sportbike and still don't get it. Can you just come out and tell me what this angle represents?
11-12-2017 09:17 AM
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Cormanus Offline
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Queensland, Australia
Posts: 10,722
Joined: Dec 2013
Post: #5
RE: cycle-ergo.com question
postoak, my mistake. I didn't give it enough thought. I've looked again more closely this morning and I can't figure it either.

My first thought, like yours, is that the hip angle is the angle between the top of the thigh and either the front or back of the body. I thought it's actually most likely to be the angle between the femur and the spine. On any of those premises, with my 5'8" and 30" inseam, when I look closely, any of those angles are greater than 90º.

I did a whole lot of Google searching about what hip angle means. It seems to be important in bicycle and horse riding, but I couldn't find a decent definition without delving into detailed academic papers which I couldn't find the motivation for.

So then I played around with the arm straightness function on cycle-ergo. As you'd expect, as the arms bent more and the angle got smaller, the hip angle also decreased. But I couldn't see any angle on the representation that explained it.

All of which left me wondering exactly what they're measuring. Of course, the explanation may lie in the nature of the graphic, but I somehow doubt that. So, I've written to them to ask how they calculate hip angle. I'll report back.
11-12-2017 04:42 PM
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Cormanus Offline
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Queensland, Australia
Posts: 10,722
Joined: Dec 2013
Post: #6
RE: cycle-ergo.com question
I got a response from cycle-ergo.com which said:

Quote:It can be considered to be angle between femur and spine. I basically position a stick figure on the bike, then render a body around it, but the angles are of the [invisible] stick figure's joints.

That must mean the graphic does not accurately represent the angles as it certainly appears to me that the hip angle on the 2013 CB1100 for a 5'8" person with a 30" inseam is greater than 90º and not the 81º stated.

That makes sense if the body is rendered over a stick figure after the measurement.
11-28-2017 06:32 PM
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postoak Offline
Running Like a Top

Texas
Posts: 304
Joined: Mar 2014
Post: #7
RE: cycle-ergo.com question
Very interesting, thanks for checking on that. I emailed them and asked them to update their faq with that information but they never responded to me.
11-28-2017 08:20 PM
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Nortoon Offline
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Ottawa, Ontario, Canada
Posts: 731
Joined: Jan 2015
Post: #8
RE: cycle-ergo.com question
The angles and explanation may not make sense. But I knew before buying my CB1100 EX that the riding position was not going to be as comfortable as my CB500XA. The handlebars on the EX are a little farther forward. That results in leaning a little more forward which can be harder on the lower back on long rides. And my knees and hips are a tucked a little tighter, even though the CB1100 is a bigger motorcycle. There are times when I get back on the CB1100 that I get a pain in my hip as a result. I have to stand on the pegs moto-cross style for a short stretch to get rid of the kink.

Bar backs and a taller seat are on my wish list.

2017 CB1100 EX
11-28-2017 11:00 PM
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