Colin531's Frame Alignment Check ( Amended Title )

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mill4six
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Colin531's Frame Alignment Check ( Amended Title )

Post by mill4six »

Not unusual in a cyclist I know, but I mean literally leaning to the left. As I look down at my front wheel I can see the whole of the right hand side but none of the left. I can adjust my posture so that the tyre appears central and aligned with the stem but it feels unnatural. The bike handles fine like this and I've no niggles or pains but who is unbalanced, me or the bike? If the bike, how? The forks are ancient, much abused rock shox Judy, nothing's been seriously crashed and I can't think of any reason for it :?
Last edited by Graham on 13 Sep 2020, 10:33am, edited 1 time in total.
Reason: Title changed for "Too Good to Lose"
Malaconotus
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Re: left leaning tendencies

Post by Malaconotus »

mill4six wrote:Not unusual in a cyclist I know, but I mean literally leaning to the left. As I look down at my front wheel I can see the whole of the right hand side but none of the left. I can adjust my posture so that the tyre appears central and aligned with the stem but it feels unnatural. The bike handles fine like this and I've no niggles or pains but who is unbalanced, me or the bike? If the bike, how? The forks are ancient, much abused rock shox Judy, nothing's been seriously crashed and I can't think of any reason for it :?


Coasting or pedalling? Standing up or sitting down?

When I stand up, I tend to favour the left leg being down and the right one up. This induces a very noticeable lean to the right.
snibgo
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Re: left leaning tendencies

Post by snibgo »

When cycling in a straight line, assuming no side winds, your combined centre of mass must be above the line that joins the contact points of the tyres. If this weren't so, you'd fall over.

But the bike can lean left while you lean right to compensate. If the bike was massively unbalanced, this would happen naturally. But the bike is highly unlikely to be this unbalanced, unless you are carrying lead weights in one pannier.

So I conclude your posture on the bike is causing this. It will need muscle-work to maintain the posture, so it's probably worth curing, if you can.
alicej
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Re: left leaning tendencies

Post by alicej »

If the bike is leaning to the left then I guess you must be leaning to the right. I used to do this a lot when I rode horses, which I had to try to correct all the time because the horse wouldn't like it. But I doubt your bike minds much.

What I used to do, quite unconsciously, was tilt my head to the right. Because your head is so heavy and so high up this makes a huge difference and everything else has to adjust to compensate. It was very easy to correct but impossible not to forget as soon as I stopped thinking about it!

Don't know if I still do it on the bike because if I do it's never caused me any problems.

You could probably get twice the wear out of your tyres by buying ones which don't have a directional tread pattern and turning them round every 6 months :lol:
Malaconotus
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Re: left leaning tendencies

Post by Malaconotus »

snibgo wrote:When cycling in a straight line, assuming no side winds, your combined centre of mass must be above the line that joins the contact points of the tyres. If this weren't so, you'd fall over.


Or go round in circles.
gbnz
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Re: left leaning tendencies

Post by gbnz »

I know I lean right :oops:

My right pedal, handgrips, shoes and walking boots always wear out before there's any noticeable wear on the left hand side
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531colin
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Re: left leaning tendencies

Post by 531colin »

mill4six wrote:.............. who is unbalanced, me or the bike? If the bike, how? .................


If the bike can be ridden "no-hands" in a straight line without tucking the saddle under one cheek, then its straight enough.

BTW, I don't know if its actually possible for a rider who naturally leans to one side to ride no-hands......would be a good exercise, because to ride a straight bike in a straight line, you have to have the bike upright, ie. you have to be upright too!

BTW2....I once rode a tandem with somebody who naturally leaned the opposite way to me....it was interesting!
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fausto copy
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Re: left leaning tendencies

Post by fausto copy »

I actuallt think you're riding pretty vertically.
The effect is probably down to your being right-eye dominant.
If you close your right eye and look down, you'll probably see the centre of the front tyre.

If you know any good archers, ask them to explain it to you in more detail. :wink:
Note that's a left eye wink...
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531colin
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Re: left leaning tendencies

Post by 531colin »

fausto copy wrote:I actuallt think you're riding pretty vertically.
The effect is probably down to your being right-eye dominant.
If you close your right eye and look down, you'll probably see the centre of the front tyre.

If you know any good archers, ask them to explain it to you in more detail. :wink:
Note that's a left eye wink...


I'm very strongly left eye dominant, and fairly strongly right handed*
.....I shall give due consideration to what you say, but maybe not to-day, as its not forecast to get above freezing I may not get out on the bike.

* This makes one or two things awkward....I look behind over my right shoulder, but in order to see I must close the dominant eye....I'm not winking at you....
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531colin
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Re: left leaning tendencies

Post by 531colin »

Well, I didn't get out on the bike to-day, but I did get to spend some time in the shed assembling my new bike....and on the way I took some photos of "how to check your frame is straight" ...using that most sophisticated of tools, a piece of string. I actually used baler twine, as its free and fairly easy to photo in red.

Step one

Image

Pass your bit of string through the valve hole of the front wheel, put the valve hole at the top, tie the bottom end of the string to the rim opposite the valve, and the top end to the handlebar stem, with the string tight.

step two

Image

With the steering tied "dead ahead" and squinting from dead in front, the string line must pass dead centre over the head tube, and dead centre of the hub, with no kink at the valve hole.

step three

Image

With the bike upside-down, pass your bit of string through the front wheel valve hole, and tie a washer or anything else that won't go through the valve hole on the hub end of the string. Hold the string above and behind the back wheel, pull it tight enough to centre the steering. (My steering is centred...it must be distorted by the camera lens)

step four

Image

Squinting along the bit of string, with the steering held dead ahead, the front wheel, down tube, BB and back wheel must all be dead in line.

step five

Image

The back wheel should ideally be dead in line with the seat tube too......I wouldn't worry about a small error here in an old frame if it was OK everywhere else.
Ayesha
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Re: left leaning tendencies

Post by Ayesha »

What does it look like when you close your right eye?

Is your brain using your right eye's image in priority to your left?

Strange this is stereoscopic vision when presented with objects at different distances ( top tube, stem, front tyre, cranks and the floor ).
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[XAP]Bob
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Re: left leaning tendencies

Post by [XAP]Bob »

Is it just me or is that an asymmetric frame - just enough to allow the drive side to not be negatively dished....
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tatanab
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Re: left leaning tendencies

Post by tatanab »

mill4six wrote:who is unbalanced, me or the bike?

Does it matter?
If a particular machine suddenly has this tendency then it needs investigating. If you ride like this on every machine then it does not matter. I ride slightly one sided, possibly being right handed, and I noticed this about 40 years ago. The slight cant to one side becomes greater if I am trying hard. It is not a problem, it's just the way I am built.
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Audax67
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Re: left leaning tendencies

Post by Audax67 »

Try it on a different bike. If it doesn't lean then it's your bike that's out of kilter, if it does lean it's you.

I noticed a long time ago that my left sitbone is higher on the saddle than the right, and if I sit centered my right leg starts hurting after a bit. I've probably got a slightly shorter right leg. My bike stays upright, but my spine must twist the opposite way in compensation, which is probably the origin of the asymmetrical lower back pain that always plagues me on very long rides.

You might be experiencing something similar but leaning the bike instead of the bod.
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porky
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Re: left leaning tendencies

Post by porky »

Having spent a lot of time at the back of group rides, I have noticed that quite a few people lean to one side or the other. The bikes may be symmetrical but I'm not sure that people are.
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