Home Forum Bike Forum How quickly can you unclip?

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• How quickly can you unclip?
• epicyclo
Subscriber

I’ve always been of the opinion that attaching yourself to the pedals is more likely to result in landing on your head. Well not always – I formed that opinion after waking up one nice sunny afternoon in the middle of the road and no idea how I got there, and eventually coming to that conclusion.

Let’s say you are doing 50km per hour downhill (abt 30mph)

That’s 50,000m per hour, or

50,000/3,600m per sec = 13.89m per sec

According to the Human BenchMark site the median for clicking a mouse is 215 milliseconds. I suspect unclipping from spds would take a mite longer, but let’s use that figure.

So distance travelled before unclicked is 13.89 x 0.215 = 2.98metres.

Let’s assume you have hit something that stops your front wheel so now you are rotating around it.

Where will that 2.98m put your head by the time you unclick or let go the bars?

(I assume letting go the bars would happen about the same reaction time unless a decision was made to hold tight.)

Presumably it will be a complex action, and I’m trying to work out the scenarios.

1. Your body will pivot around the ankles until it hits the bars because your arms aren’t strong enough to resist the forward motion, then the bike will pivot around the front axle if your brakes are on, or will it pivot around the contact patch? Anyhow maybe you have released by this point but your body is rotating.

2. Your arms are stiff enough to resist the impact (calculation suggests unlikely), so the pivoting starts immediately.

Anyone care to model this? I don’t have the mathematical capacity – I’ve run out of fingers & toes on my Irish digital calculator (even assigning binary to them).

Are you really that bored.?

dabble
Member

Like that*

*clicks fingers

float
Member

30mph off road is bloody quick

makkag
Member

epicyclo
Subscriber

float – Member
30mph off road is bloody quick

I did say downhill.

But work it out for half the speed if you like.

makkag – Member

Should have unclipped then 🙂

cynic-al
Member

The chance of hitting something at 32mph that stops your front wheel dead are utterly minimal, unless it’s jumped out at you as fast.

You won’t be able to pull your hands off the bars due to the forces, but they will compress a bit.

scaredypants
Subscriber

I came off a road bike once, bottom of a gentleish hill

Seems the front brake came loose from the frame as I was slowing down, ran round with the wheel until the cable pulled taut and, err, stopped

I didn’t even blink* in time, let alone unclip

* as far as I know – don’t remember the crash at all

irc
Subscriber

Let’s assume you have hit something that stops your front wheel so now you are rotating around it.

I’ve always found looking where I was going prevents the issue from arising.

robsoctane
Member

Op: ride, don’t think – it all comes natural with some practice. Those who worry don’t get there in a hurry – and all that. 😉

crikey
Member

Er, is it me, but a scenario as described above would be just as bad on a bike with flat pedals as one with spds?

Just to push the point home; try imagining a situation at 50 kmh where your front wheel stopped with a flat pedal bike…. A running dismount at 30 mph?

Good luck with that Mr. purple bleeding face.

epicyclo
Subscriber

robsoctane – Member
Op: ride, don’t think – it all comes natural with some practice….

Unlike many STWers I’m not a riding god with super powers. I do things like hit an innocent puddle at speed only to find that since I last went over it the river has scoured out the bottom, thus my wheel gets instantly stopped, or I get forced aside in a race and hit a rock offline with the same results, and other such incidents.

Thus I think about such things.

crikey – Member
Er, is it me, but a scenario as described above would be just as bad on a bike with flat pedals as one with spds?

That is one of the things I’m trying to work out. Stopping that quickly rarely has a comfortable outcome.

bruneep
Subscriber

If the op wasn’t a regular, I’d think this was a spam post that makes no sence what so ever.

STATO
Member

i have 2 questions…

1. Why would you need to unclip in instant you hit something? nothing stopping you unclipping mid air.
2. If you hit something that stops your wheel instantly then as you say you will immediatley fly over the bars. What difference does it make if your clipped in? your head its still going to be doing 30mph at whatever stopped you.

Anyway, your very likley to wrench your feet out the clips (multi-release cleats anyone) if your doing 30mph and your bike is doing 0mph. Much more safe than toe straps of old.

crikey
Member

Thus I think about such things.

We really, really need a shaking head at the silly person smiley.

cynic-al
Member

Manual the puddle.

What forces you off line in a race? Is the race the puffer?

epicyclo
Subscriber

STATO – Member
1. Why would you need to unclip in instant you hit something? nothing stopping you unclipping mid air.
2. If you hit something that stops your wheel instantly then as you say you will immediatley fly over the bars. What difference does it make if your clipped in?

1. That’s the point, you react a given time after the incident so you are clipped in until that point.
2. I’m trying to work out how having your legs attached affects the position of your body in that 215 milliseconds.

As a rough model, I’m considering the body as the sum of 3 hinged masses, head, thorax, legs (ignoring arms for now).

crikey
Member

You bloody loony.

Think about the weights involved and where those weights are. You are a big blobby 70-80-90 kgs and you will revolve around your stopped front wheel whether you are clipped in or not.

What happens in those 215 milliseconds makes no bloody difference at all.

You are either dim as a dim thing or trolling at the very limits of trollability.

epicyclo
Subscriber

cynic-al – Member
Manual the puddle.
What forces you off line in a race? Is the race the puffer?

Obviously if you know there is an existing danger you’ll approach it differently.

I go offline to allow faster riders past and sometimes don’t see the hidden traps.

However I’m talking about a theoretical situation – can we concentrate on what happens after, not the lack of prescience/skill/luck that causes it?

epicyclo
Subscriber

That’s offensive crikey.

I’m not trying to prove any point. I’m trying to work out the trajectories.

I’m interested in why and how things happen.

crikey
Member

It’s not offensive; it’s accurate.

Junkyard
Member

the force will unclip you and you wont really have enough time to react

In the scenario you decide i doubt there is very much difference between clipped in and flats as you will either
1. be catapulted off the bike at great force
2. rotate OTB instantly and have a face ground interface

I go for one if the wheel stops dead as the more likely
Flats may [ probably do] let you get your feet off slightly quicker but with those forces i doubt there is any real tangible difference

M1llh0use
Member

Last time it happened to me I was doing about 10 mph and face planted into a puddle whilst still holding onto the bars and clipped in.

Was still laughing about it half an hour later!!

jam bo
Subscriber

The chance of hitting something at 32mph that stops your front wheel dead are utterly minimal, unless it’s jumped out at you as fast.

I cut a really fast corner on dartmoor once chasing sharki down.

Perfect granite wheel trap hidden in the grass stopped me dead in my tracks, had perfect handlebar bruise across my chest and ended up in a bush on the other side of the trial.

robsoctane
Member

epicyclo – Member
robsoctane – Member
Op: ride, don’t think – it all comes natural with some practice….
Unlike many STWers I’m not a riding god with super powers. I do things like hit an innocent puddle at speed only to find that since I last went over it the river has scoured out the bottom, thus my wheel gets instantly stopped, or I get forced aside in a race and hit a rock offline with the same results, and other such incidents.

Thus I think about such things.

That’s where you are going wrong – don’t THINK, feel!

Honestly, you fret too much! 🙄

crikey – Member
Thus I think about such things.

We really, really need a shaking head at the silly person smiley.

crikey
Member

Hmmm, bit too stern that one. I’m thinking more of a kindly old lady shaking her head at the silly boy kind of thing…

brakes
Member

this is where eggbeaters would be good, the force would probably snap the axle

samuri
Member

Your feet will be pulled out of the pedals with the force of the initial impact.

I’ve no idea of the forces involved but I’ve come off my bike loads of times and always come out the pedals without me doing anything. It’s never caused me any issues.

The vast majority of mtbers ride clipped in nowadays, if they caused harm during accidents we’d know about by now.

warton
Member

How quickly can you unclip?

I doubt theres more than 1/10 second difference between clip and no clip getting my foot off the pedal.

messiah
Member

God unclips me… it must be some kind of higher force anyway because I never have to think about doing it… it just happens.

robbo
Member

The original question ‘how quickly can you unclip?’ is wrong. It should be how quickly can you put your foot down if you need to? And that is exactly the same whether you are clipped in or not as its the same movement. If you are nervous clipped in just practice until it makes no difference. Stop overthinking and start enjoying it…

My last crash was a high speed lowside on flats and was sliding along the ground with my bike before I had even had a chance to move my feet.

I see flats as more of a low speed benefit, being able to dab a foot quickly without having to unclip seems more useful and frequent than the high speed stuff.

JoeG
Subscriber

I’ve run clipless for many years with regular (not multi-release) cleats. I can’t ever recall a crash where I remained clipped in. Since I can’t claim to have cat like reflexes, I have to assume that the cleat/pedal system has been designed to release if sufficient force is applied even in directions other than that used to unclip.

If you are really concerned about it, use multi-release cleats or dial the release tension down to the minimum.

skaifan
Member

The answer is: “Imhotep is invisible”.

ontor
Member

I cut a really fast corner on dartmoor once chasing sharki down.

Perfect granite wheel trap hidden in the grass stopped me dead in my tracks, had perfect handlebar bruise across my chest and ended up in a bush on the other side of the trial.

I have never had so many OTB crashes anywhere, as I have riding dartmoor. If it’s not a granite lump it’s a bog or as it was yesterday: an innocent looking patch of mud, just like the others I’d ridden through, but Hub-deep as it turned out.

cloudnine
Subscriber

Are we talking 29er clipped in OTBs? The larger circumference will give you that matrix neo slow motion type reflex… you not only will have unclipped, you will also had time to pull the uzi from your leather padded shorts and have shot 2 hikers before doing a forward front somersault and landing drop knee style. You also need to determine what tyre pressure you are running and whether tubeless or not.
I don’t know how you guys dream up these crazy scenarios.

smell_it
Member

I have to congratulate the OP for hand wringing of the highest order, having come off a bike at those speeds I can honestly say my choice of pedal was the least of my concerns. What tyres for bed wetting anyone?

ononeorange
Subscriber

Can I just point out that for at least 10 months of the year where I live that the mud is sufficient to allow a maximum speed of approx 4 mph only? If you’re that concerned, maybe move to a mudfest part of the country.

Oh and in answer to your question, I reckon when things do suddenly go pear-shaped at speed I can unclip and fall off in less than a nanosecond.

Does that help?

CaptJon
Member

I’ll always remember a mate at school was showing off his wheelie skills. He hoofed the front wheel up, began to pedal but over-rotated and fell off the back. However, he kept his riding position exactly and the bike was on top of him, supported by his hands on the bars and feet on the pedals. He used flats.

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