Get a Grip Cornering

[andrew_s]

Slick tyres do give more cornering grip. It can be demonstrated in the lab by having someone on a bike on a tarmac covered plate whose angle can be changed. Generally, the angle gets up to about 45 degrees before the tyres slip.

The advantage of a fine tread on the shoulders isn't that there's more absolute grip, but that you can feel the loss of grip approaching as the individual tread blocks start to slip and regrip. By contrast, a slick tread just lets go with no warning.

 

[Ajax Bay]

It can be demonstrated in the lab

Thank you, @andrew_s and for your insight into the possible 'warning' benefit of fine tread on the shoulders.
Has this work been done, do you know (ie increasing angle to point of slip, and with different tyres (compound, tread/fine tread/slick, width, wet/dry)?
Or is your 'can' a (asserted) 'could'?
It's a brave/confident woman/man who leans at more than 30 degrees - roughly 22mph going a 20m radius bend (excuse mix of units).

 

[Smokin Joe]

Slick tyres do give more cornering grip. It can be demonstrated in the lab by having someone on a bike on a tarmac covered plate whose angle can be changed. Generally, the angle gets up to about 45 degrees before the tyres slip.

The advantage of a fine tread on the shoulders isn't that there's more absolute grip, but that you can feel the loss of grip approaching as the individual tread blocks start to slip and regrip. By contrast, a slick tread just lets go with no warning.

Bearing in mind that the fine tread on the edge of a cycle tyre is smoother than a well worn child's nail file I think you'd have a job feeling any movement on the "Individual tread blocks".

Tread on a roadbike tyre is for show alone, it does nothing.

 

[nickyboy]

Bearing in mind that the fine tread on the edge of a cycle tyre is smoother than a well worn child's nail file I think you'd have a job feeling any movement on the "Individual tread blocks".

Tread on a roadbike tyre is for show alone, it does nothing.

What????

Next you'll be telling me that cycling in shorts in cold weather doesn't wear out your knees out and SPDs don't let you pedal on the upstroke

 

[raleighnut]

Thank you, @andrew_s and for your insight into the possible 'warning' benefit of fine tread on the shoulders.
Has this work been done, do you know (ie increasing angle to point of slip, and with different tyres (compound, tread/fine tread/slick, width, wet/dry)?
Or is your 'can' a (asserted) 'could'?
It's a brave/confident woman/man who leans at more than 30 degrees - roughly 22mph going a 20m radius bend (excuse mix of units).

Totally agree, I used to be a demon cornerer/descender but 45 degree angle of lean no way.

 

[si_c]

Totally agree, I used to be a demon cornerer/descender but 45 degree angle of lean no way.

I've leant over that far once or twice. Ate pavement each time.

 

[nickyboy]

I got the bike out this morning and lent it over to see what the maximum lean was before the inside pedal touched the ground. A bit of trig and the answer was around 21 degrees of lean

Of course we lean in with the inside pedal "up" rather than "down" but it shows perhaps how little we lean into corners in reality. Certainly looking at a 21% lean angle it looked pretty frightening

 

[DaveReading]

"Lean angle is limited by the available traction that must be assessed from velocity and appearance of the surface. For good pavement, this angle is about 45 degrees, in the absence of oil, water, or smooth and slick spots"

Jobst Brandt

http://www.sheldonbrown.com/brandt/descending.html

 

[Ajax Bay]

From the JB article Dave quoted (above) "For smooth tires on pavement, slipout occurs at slightly less than 45 degrees from the road surface and is both precipitous and unrecoverable." ie more than 45 degrees lean (although not clear what science ie testing of different tyre material with different coefficients of friction this may be based on).
"This effect is more naturally apparent to riders who exceeded these limits early in life and have added the experience to expected natural phenomena."
Love it. Early confirmation that if you try to go round a corner too fast in your youth, and lose it, you take that experience with you to inform your appetite for fast cornering as an adult.

A bit of trig and the answer was around 21 degrees of lean

OK, @nickyboy . On my bike with a BB centre height (above ground level) of 300mm, a crank length of 170mm and distance from centre line to pedal edge of 170mm, if one was to corner with the inside pedal down, the arctan is 1.3 (17/13) giving an angle of 52 degrees from horizontal or 38 degrees of lean. YLMV. Certainly I have, perhaps foolishly, pedalled through a corner and grounded (touched) the inside pedal. I had not lost traction (on tarmac) so was over at circa 38 degrees (recovered btw). Have been more circumspect since.

 

[Profpointy]

on the leaning point, by moving your arse off the bike Barry Sheene style you can move the centre of gravity in further than the actual angle of the bike hence corner faster (if there's grip) than would otherwise be possible without grounding a pedal - you quickly learn to do this on a fixie !

Regarding the tread thing - if you had rough tarmac and very blocky tread I would expect extra grip to be possible. You could make a ratchet out of ice after all where two ice surfaces would simply slide. That said I am skeptical of the grip the writer is claiming for slighly treaded tyres and the water clearance claim is simply wrong

 

[nickyboy]

From the JB article Dave quoted (above) "For smooth tires on pavement, slipout occurs at slightly less than 45 degrees from the road surface and is both precipitous and unrecoverable." ie more than 45 degrees lean (although not clear what science ie testing of different tyre material with different coefficients of friction this may be based on).
"This effect is more naturally apparent to riders who exceeded these limits early in life and have added the experience to expected natural phenomena."
Love it. Early confirmation that if you try to go round a corner too fast in your youth, and lose it, you take that experience with you to inform your appetite for fast cornering as an adult.

OK, @nickyboy . On my bike with a BB centre height (above ground level) of 300mm, a crank length of 170mm and distance from centre line to pedal edge of 170mm, if one was to corner with the inside pedal down, the arctan is 1.3 (17/13) giving an angle of 52 degrees from horizontal or 38 degrees of lean. YLMV. Certainly I have, perhaps foolishly, pedalled through a corner and grounded (touched) the inside pedal. I had not lost traction (on tarmac) so was over at circa 38 degrees (recovered btw). Have been more circumspect since.

As I am in Friday afternoon work avoidance mode I had another go at this. My schoolboy error was to not ensure that the pedal was horizontal which make quite a difference. That's because my method was to get the pedal just touching the ground then use the wheel to calculate the angle. I guess it's fair to assume a pedal will be horizontal-ish when cornering.

Anyway, I get 31 degrees as the max FWIW. Here it is. I certainly wouldn't fancy cornering like that

 

[si_c]

As I am in Friday afternoon work avoidance mode I had another go at this. My schoolboy error was to not ensure that the pedal was horizontal which make quite a difference. That's because my method was to get the pedal just touching the ground then use the wheel to calculate the angle. I guess it's fair to assume a pedal will be horizontal-ish when cornering.

Anyway, I get 31 degrees as the max FWIW. Here it is. I certainly wouldn't fancy cornering like that

View attachment 150832

In reality though you would have the pedals the other way, so as to allow you to shift your weight so the outer pedal is under load rather than the inner, which would allow an even more precipitous lean angle. I certainly wouldn't want to corner at that angle with the inside pedal down.

 

[nickyboy]

In reality though you would have the pedals the other way, so as to allow you to shift your weight so the outer pedal is under load rather than the inner, which would allow an even more precipitous lean angle. I certainly wouldn't want to corner at that angle with the inside pedal down.

Of course you're right. It's just interesting to see a bike leaning over at 31 degrees (an angle at which traction will be maintained if the road is dry) and think "blimey I'd never lean it over that much"...even with the inside pedal up. Maybe I'm getting old

 

[si_c]

Of course you're right. It's just interesting to see a bike leaning over at 31 degrees (an angle at which traction will be maintained if the road is dry) and think "blimey I'd never lean it over that much"...even with the inside pedal up. Maybe I'm getting old

The reality is though you probably corner at that sort of angle anyway without realising, just you have your weight shifted properly and you're paying more attention to where you want to go rather than the angle your bike is at. Given the speed you seem to ride at I'd have thought that was an inevitability.

 

[nickyboy]

The reality is though you probably corner at that sort of angle anyway without realising, just you have your weight shifted properly and you're paying more attention to where you want to go rather than the angle your bike is at. Given the speed you seem to ride at I'd have thought that was an inevitability.

I'm more of a straight line merchant. Going fast around bends I always seem to be envisioning the front wheel going from under me. Maybe I should pay more attention to @Ajax Bay 's analysis...get it over to 40+ degrees and rely on the immutable laws of Physics