How far can you lean your bike over in a bend?

bernithebiker

.....without striking the pedal....?

Ever wondered? No? Fine, this thread is worthless to you! Move along!

Yes?

Your answers are here!

https://www.youtube.com/watch?v=kDvXX_xiRGo

ugo.santalucia

I have a cross frame, 170 mm cranks and 28 mm tyres, so generally speaking I don't have to worry too much about it

fat daddy

at the sort of corner speeds to lay my bike over that far that it hits the inside pedal if I was pedalling ... .I have stopped pedalling a while ago and that leg is firmly in the 12oclock position .... so no worries here, I haven't got the balls to have that foot down and lent over that far

imposter2.0

Lots of hits for your YT channel in all these threads, fair play

bernithebiker

Imposter wrote:

Lots of hits for your YT channel in all these threads, fair play

Well obviously the real aim is to draw traffic to the website for cycle tours, but if it's useful and or entertaining then so much the better!

(As with most people I hate the sound of my own voice though!)

lakesluddite

Given the state of the re-surfaced roads around here, and the amount of left over gravel that accumulates on corners - about 5 degrees from the vertical is all I dare usually!

thefd

Is someone having a pee just off camera?

bernithebiker

TheFD wrote:

Is someone having a pee just off camera?

Might be the dog?!

bbrap

LakesLuddite wrote:

Given the state of the re-surfaced roads around here, and the amount of left over gravel that accumulates on corners - about 5 degrees from the vertical is all I dare usually!

There is a bend in the road near me which has a fair camber and a dip (which makes it a bit like the end of a velodrome) which I can crank over about 40 degrees if I'm going fast enough and in the right direction. The buggers have just thrown loose chippings and tar all over the place making it extremely scary to navigate. All the loose stuff has accumulated in the dip making it like trying to ride through a sand pit.

stanthomas

Well that was a waste of a 60 seconds.

Some years ago, TT racer Simon "Ronnie" Smith rode a motorbike in a large circle, going progressively faster until he fell off. It's amazing just how much grip tyres have and how far they will go over when only cornering loads are being put in.

And I remember a Michelin video a few years ago where they put a guy in motorcycle leathers on a bicycle to test the wet grip of whatever tyres they were flogging at the time. So I was hoping for something similarly entertaining in the linked video. Just standing beside a bike and stating the bleedin' obvious is plain lame.

bernithebiker

stanthomas wrote:

Well that was a waste of a 60 seconds.

Some years ago, TT racer Simon "Ronnie" Smith rode a motorbike in a large circle, going progressively faster until he fell off. It's amazing just how much grip tyres have and how far they will go over when only cornering loads are being put in.

And I remember a Michelin video a few years ago where they put a guy in motorcycle leathers on a bicycle to test the wet grip of whatever tyres they were flogging at the time. So I was hoping for something similarly entertaining in the linked video. Just standing beside a bike and stating the bleedin' obvious is plain lame.

I think you may have slightly missed the point?

I didn't mention tyres once. It has nothing to do with tyre grip. If you strike your pedal hard in a bend, you're going down, no matter how grippy the tyres are.

Another test, in a similar vein, would indeed be to test tyre grip in bends, and at what point they start to slip, but that's not what we're doing here.

bompington

True, but anyone who has cycled for more than 10 minutes knows how to set the pedals when cornering hard. I personally am much more interested in overall grip: I would guess that I, like most of us, am a long way back from the edge when it comes to cornering on a dry, good quality surface - but I have certainly lost it a few times on gravel, ice or (scariest) diesel.

bernithebiker

bompington wrote:

True, but anyone who has cycled for more than 10 minutes knows how to set the pedals when cornering hard. I personally am much more interested in overall grip: I would guess that I, like most of us, am a long way back from the edge when it comes to cornering on a dry, good quality surface - but I have certainly lost it a few times on gravel, ice or (scariest) diesel.

I think we covered the bit about setting your pedals too? For tight bends, you're going to have to keep your inner crank up at 12 o'clock, I would hope we're all kind of born with that type of common sense.

However, there are times, especially if you are racing, where you will be pedalling through bends. Everyone will have pedalled through open bends at some point, albeit at shallow angles of say 10 to 20'. (Perfectly safe).

There are quite a few videos out there of club racers, pros, striking their pedals in bends, simply because they're pushing the envelope that bit harder to win a race. Another situation that springs to mind is on a large roundabout, where you need to apply some power to escape a blind granny in a Metro.

Overall grip is a much more complex test which is why they are hard to find. You can do lab tests to see at what force and angle a tyre starts to slip, but in the real world, so many other variables are at work (constantly changing forces through the tyre, surfaces that do not offer linear grip, wind, temperature, braking or accelerating, etc. etc.) that you can't say,
"Right, with this tyre, you can lean at 41', at a speed of 35km/h in a bend with a radius of 15m."

Unfortunately, the only thing that can give you this answer is your brain and your ass!

sloppyschleckonds

step83

LakesLuddite wrote:

Given the state of the re-surfaced roads around here, and the amount of left over gravel that accumulates on corners - about 5 degrees from the vertical is all I dare usually!

Lots of that round here recent rains washed a load of sand an general crud onto some of the fast downhill sections and bends. Nothing quite matches the feeling of inhaling ones saddle via the anus when you take a bend at full tilt to discover a fine coating of sand all over it.

cycleclinic

lent so far over in race when I pedal out of the bend I get pedal strike but I have always held it. shorter cranks would help.

chippyk

bernithebiker wrote:

There are quite a few videos out there of club racers, pros, striking their pedals in bends, simply because they're pushing the envelope that bit harder to win a race. Another situation that springs to mind is on a large roundabout, where you need to apply some power to escape a blind granny in a Metro

It was an old granny in a Metro that knocked me off on a roundabout. Stunk of piss she did.

bernithebiker

ChippyK wrote:

bernithebiker wrote:

There are quite a few videos out there of club racers, pros, striking their pedals in bends, simply because they're pushing the envelope that bit harder to win a race. Another situation that springs to mind is on a large roundabout, where you need to apply some power to escape a blind granny in a Metro

It was an old granny in a Metro that knocked me off on a roundabout. Stunk of wee-wee she did.

Well there you go, had you seen the video before you might have escaped her!

stanthomas

bernithebiker wrote:

stanthomas wrote:

Well that was a waste of a 60 seconds.
...

I think you may have slightly missed the point?

I didn't mention tyres once. It has nothing to do with tyre grip. If you strike your pedal hard in a bend, you're going down, no matter how grippy the tyres are.

I routinely wack a pedal down. My standard Domane, which has a much lower bottom bracket, really catches me out. I've had the rear wheel off the ground and hoping sideways. But so far, touch wood, I got away with it.

And I my critique stands - lame video stating the bleedin' obvious. Might have been entertaining if he'd demonstrated his ability to put the inside pedal down when it was at 12 o'clock thru a bend. :P

bernithebiker

stanthomas wrote:

I routinely wack a pedal down. My standard Domane, which has a much lower bottom bracket, really catches me out. I've had the rear wheel off the ground and hoping sideways. But so far, touch wood, I got away with it.

I would try to avoid doing that it I were you, it will end in tears.

stanthomas wrote:

And I my critique stands - lame video stating the bleedin' obvious. Might have been entertaining if he'd demonstrated his ability to put the inside pedal down when it was at 12 o'clock thru a bend. :P

That you think the video is 'lame' is fine by me, it's a free world, after all......

..but bleedin' obvious? So you knew that pedal strikes would happen at about 30'? (Not 25 or 35?)

And that the precise angle A for your bike is;

tan A = (Q/2 + Pw) / (BBh - Cl)

?

If so, I'm impressed, it took me a while to work it out.

47p2

I've never had pedal strike, I fitted a clinometer to my bike to prevent this happening. I calculated that 31° is the point my pedal would make contact with the tarmac should I be silly enough to have the crank arm in straight down position at the time of leaning the bike over. I keep a close watch on the clinometer and usually don't allow myself much over 28° before backing off a bit.

fat daddy

where did you fit it ?? .... Chainreaction, wiggle ... none of them stock clinometer mounts

and do they do a Bluetooth one .. something I can sync with strava so I can best someone elses lean ?

47p2

I fitted it on the rear seat stays, just above the brake caliper and below the seat post clamp. Oddly enough I sometimes have a stiff neck when I return from some of the twisty bendy routes I traverse

bernithebiker

47p2 wrote:

I've never had pedal strike, I fitted a clinometer to my bike to prevent this happening. I calculated that 31° is the point my pedal would make contact with the tarmac should I be silly enough to have the crank arm in straight down position at the time of leaning the bike over. I keep a close watch on the clinometer and usually don't allow myself much over 28° before backing off a bit.

I think you'll find your Iphone can do that.....!

47p2

iPhone isn't waterproof so unsuitable to bolt to the rear seat stays

bernithebiker

47p2 wrote:

iPhone isn't waterproof so unsuitable to bolt to the rear seat stays

The 7 is!

stanthomas

bernithebiker wrote:

stanthomas wrote:

I routinely wack a pedal down.

I would try to avoid doing that it I were you, it will end in tears.

Boys don't cry.

bernithebiker wrote:

..but bleedin' obvious? So you knew that pedal strikes would happen at about 30'? (Not 25 or 35?)

You have failed to allow for the rider and how she positions herself on the bike. The knee-out, hang-off style is an extreme case and was developed by motorcycle racers to compensate for limitations in ground clearance. Much copied by cyclists these days, although I'm not a fan of it myself 'cos bicycles don't have a ground clearance problem. Given the rider's mass is 10x the bike's, a small movement, into or out of the turn, will make enough difference that your formula is meaningless, even for those who invest in a clinometer. All you can say with any confidence is, if you take a corner with the inside pedal at 6 o'clock the pedal could hit the ground at an angle of lean that only experience, possibly painful, will tell. Bleedin' obvious.

bernithebiker

stanthomas wrote:

You have failed to allow for the rider and how she positions herself on the bike. The knee-out, hang-off style is an extreme case and was developed by motorcycle racers to compensate for limitations in ground clearance. Much copied by cyclists these days, although I'm not a fan of it myself 'cos bicycles don't have a ground clearance problem. Given the rider's mass is 10x the bike's, a small movement, into or out of the turn, will make enough difference that your formula is meaningless, even for those who invest in a clinometer. All you can say with any confidence is, if you take a corner with the inside pedal at 6 o'clock the pedal could hit the ground at an angle of lean that only experience, possibly painful, will tell. Bleedin' obvious.

We're not talking about motorbikes, or knee down, rider mass, tyre grip, etc.

It's about pedalling through a bend, something we all do to some degree.

If you're pushing on and want to go hard through a shallow bend, you might pedal strike. My bike happens to do this at 30.9'. That angle will not change, no matter where I put my body, no matter what speed I'm doing, or what type of bend.

I am simply interested in the factors which reduce this risk, which are; Q factor, crank length, BB height and pedal width. Some bikes will be better than others, sometimes significantly so.

Using the formula I mentioned above, allows you to work out how good or bad a bike is.

It's not any more complicated than that.

rockmonkeysc

Accidentally clicked on this forum by mistake. I'll shuffle off back to the mountain bike forum but I'll leave you with this.



That's how far you can lean a bike.

bbrap

bernithebiker wrote:

If you're pushing on and want to go hard through a shallow bend, you might pedal strike. My bike happens to do this at 30.9'. That angle will not change, no matter where I put my body, no matter what speed I'm doing, or what type of bend.


It's not any more complicated than that.

I think it is more complicated than that. Your bike may touch down at 30.9 degrees to the plane of the surface of the road (flat road). However many roads have large cambers which effectively change the bit you are measuring your 30.9 from. depending on whether the camber is working for or against you in the bend will allow either a greater or lesser lean from vertical (actual vertical not 90 degrees to road surface).

bernithebiker

bbrap wrote:

bernithebiker wrote:

If you're pushing on and want to go hard through a shallow bend, you might pedal strike. My bike happens to do this at 30.9'. That angle will not change, no matter where I put my body, no matter what speed I'm doing, or what type of bend.


It's not any more complicated than that.

I think it is more complicated than that. Your bike may touch down at 30.9 degrees to the plane of the surface of the road (flat road). However many roads have large cambers which effectively change the bit you are measuring your 30.9 from. depending on whether the camber is working for or against you in the bend will allow either a greater or lesser lean from vertical (actual vertical not 90 degrees to road surface).

True, but an off camber of say 3' just adds 3' to your nominal flat figure, and vice versa if the road is 'on-camber' (is that a word?).

A bike that is bad for pedal strikes will still be worse than a good one, regardless of camber.