[Closed] presumably a bicycle is more stable when pedalling than freewheeling?

I’m going to say no-it probably makes no difference for a normal rider with no balance issues.

I am not a scientist.

No difference, and cornering with outside pedal down and weight upon it will lower the centre of gravity.

It might be, because the pedalling force is acting on the trail effect presumably harder than the drag when going downhill.

But your issues are clearly medical, and it could well be covid-19. I think I probably had it largely asymptomatically but I've had a bit of slight dizziness and some other mild symptoms that I would not really think about otherwise. We're still learning about the longer term implications of even mild or asymptomatic cases.

Sounds more like labyrinthitis but I'm no doctor.

Doesn't pedaling introduce two destabilising forces 60-100 times a minute? Maybe large rhythmic inputs are less upsetting than tiny, natural unpredictable ones.

I haven't had a test for Covid but had fairly broad spectrum bloodwork and all was fine.
started with intermittent fatigue, headache, body aches and pains , slight nausea and dizziness as well as constantly twitching calf muscles. Seems to be improving but 3 months now . Not had a cough or any respiratory issues. ...anyhow ..back to bicycles!

That's a good point ONZA ......Funnily enough ..when off road it's less of an issue ...perhaps as I'm less anxious re the dizziness/ slighly unstable feeling and traffic.

Definitely more stable when freewheeling - pedalling makes it wobble!

it is a weird one ..as indicated before ..I actually feel less affected when riding hard on lumpy uneven /loose surfaces than freewheeling along a smooth road . Perhaps , as suggested ..I'm more sensitive to the occasional irregularity than when it's constant and full on .

Not the same thing I think...

Motorbikes and cars are generally more stable in the corners with a balanced throttle, so a little power on to avoid any engine braking or big change of speed, mostly to avoid big weight transfers.

With a bike there’s no “engine braking” because of the freehub*

In fact pedalling I suspect makes it worse as the rider is a big fraction of total vehicle weight, so waggling** your legs up and down and back and forth constitutes a big weight transfer!

*yes, fixies are different
**pedalling. 😉

I find pedalling can make it easier to ride no hands on some bikes. I've always assumed this is because the slight waggling of the bike from pedalling overcomes any stiction in the headset make it easier to control the steering with your weight.

I can't see it making a difference with hands on bars.

On very slippery downhill tracks off camber roots etc it's better not to peddle as the weight transfer is enough to upset the ballance and cause a fall.

started with intermittent fatigue, headache, body aches and pains , slight nausea and dizziness as well as constantly twitching calf muscles.

Sounds a bit familiar. Stress and/or vit D deficiency possibly.. ?

What sockpuppet said.

If you're feeling dizzy, a doctor is more likely to help than a physicist.

Funnily enough ..when off road it’s less of an issue …

Is this road bike vs mtb?

Big mtb tyres will have a lot more inertia and therefore give that stable feeling, compared to some lightweight 23c slicks.

An accelerating body is more stable than a decelerating one, so if you are losing speed freewheeling it will be more unstable.

Seen a doc + my family has 3 docs incl my bro.Nothing obvious at the mo.
Bike involved is a big tyred surly rigid.
Had the unstable feeling in other situations also but when balancing high up on a large 29 plus (freewheeling) it is often more noticeable.

An accelerating body is more stable than a decelerating one

The gyroscopic effect of the wheels turning contributes to a bike's stability. I wonder if the legs and drivetrain also contribute.

The gyroscopic effect of the wheels turning contributes to a bike’s stability. I wonder if the legs and drivetrain also contribute.

Extremely unlikely. Your legs are not spinning in circles at high speed. Your feet follow circles, but your knees do not. If there's any detectable effect, I would expect the reciprocating motion to be destabiizing, not stabilizing.

Leaving the stability of the bike out of it, I find it much easier to control the bike when coasting because you can choose how you weight the pedals. The examples of DH racers being extremely fast despite broken chains support this view.

The examples of DH racers being extremely fast despite broken chains support this view.

On almost all bikes the suspension will work better without a chain. Probably more importantly, having no means of pedaling probably elicts a desire to take greater risks to carry speed through obstacles.

I'd expect freewheeling to be more stable, at the same speed, but freewheeling is usually at faster speeds.

If you're having balance or dizzyness issues, where you're looking might be significant. Head down when freewheeling?

On almost all bikes the suspension will work better without a chain.

I think this effect is massively exaggerated. The point, however, is that that spinning your legs does not seem to affect stability enough to make any difference.

There’s physics and there’s biodynamics.

When you’re pedalling you’re constantly making adjustments, your whole body is moving and flexing. When you’re freewheeling you’re not, so those constant adjustments are no longer hidden within other motion.

As for the accelerating/decelerating thing, it’s more about the effect of the two wheels’ relative forces through the steering axis: braking with the front will have a jackknifing effect whilst rear braking will tend to straighten the steering; and since a bicycle is normally rear-wheel drive, the implication is that acceleration (from the drivetrain rather than gravity) should destabilise it.

On almost all bikes the suspension will work better without a chain. Probably more importantly, having no means of pedaling probably elicts a desire to take greater risks to carry speed through obstacles.

Dunno about chainless DH but I know I ride a lot more smoothly on my SS where I get past pedalling/spin-out speed fairly easily and focus on unweighting where needed and getting speed from small downslopes on the trail. Not being able to pedal frees up that focus easily.

Interesting Q though..

and since a bicycle is normally rear-wheel drive, the implication is that acceleration (from the drivetrain rather than gravity) should destabilise it.

This is true (unless assuming the whole thing is 100% 2D, upright etc? But in reality I'd say it's true). A normal steering geometry gives a relationship between speed and trail that meas some bikes gain more stability at higher speeds. Generally though we might say 'stability' in terms of steering geometry and since a bike stays upright through steering and the position of your c of g, at a constant speed the bike won't be any more or less stable when pedalling. I can see how the pedalling motion encourages or naturally includes the corrections that keep us upright though.

at slow speeds, trackstands, slow tight corners, etc chain tension has quite an effect. At higher speeds freewheeling is more stable, certainly when traction is an issue, roots/ice/offcamber/other slippery stuff, you dont want to be pushing any drive thru rear tyre or introducing any minute wobble.

Sorry I don't want to derail your thread but the symptoms you describe (bar the muscle twitching) are pretty much how I've been feeling for the past 3+ weeks. Still waiting on bloods results from the Drs. Not had anything that was obviously Covid. Feeling a bit more human today but it's been scaring me with its persistance.

Mat ..as previously mentioned ..it's been 3 months now ..nothing horrendous but i began to worry I had something sinister . Still could be I guess but now seemingly heading in the right direction recovery wise. Some symptoms like the aches , nausea and fatigue have improved a lot . Now it's more the occasional mild headache and unsteady feeling so fingers crossed I'm on the mend but slow progress. Hope you feel a lot better soon .