Resend my activation email : Register : Log in 
BCF: Bike Chat Forums


Tips on cornering

Reply to topic
Bike Chat Forums Index -> New Bikers Goto page Previous  1, 2
View previous topic : View next topic  
Author Message

Pjay
World Chat Champion



Joined: 18 Jan 2016
Karma :

PostPosted: 22:01 - 08 Dec 2016    Post subject: Reply with quote

Teflon-Mike wrote:
Pjay wrote:
You might need to rethink your logic.

Hmm.. 30 pounds per square inch... so we get one square inch of ruber contact for every 30 pounds weight....
So 'logically' the contact area, CANT change, unless you change either the Tyre pressure or the weight on the tyre... Hmmm...
Not sure how many ways I an rework the 'logic' of a simple, directly proportional three element relationship here.

May change the SHAPE of the contact area.... though..... but that's not the same thing, is it?

More rubber = more grip is the point, as long as the contact area is increased. With modern tyre profiling, there is more surface area contact when cornering, because more rubber = more grip.

I know what you were trying to say, that on perfect curve, more rubber wouldn't matter as there would be no increase in surface area contact. But more rubber does mean more grip with modern tyres as they are not perfectly round. Well sport tyres aren't anyhow.
 Back to top
View user's profile Send private message You must be logged in to rate posts

Teflon-Mike
tl;dr



Joined: 01 Jun 2010
Karma :

PostPosted: 00:25 - 09 Dec 2016    Post subject: Reply with quote

Pjay wrote:
I know what you were trying to say

No, no you don't.

Pneumatic tyres, even advanced compound profile ones, are still pneumatic; filled with air; supported by AIR PRESSURE, defined as force per unit area.

So no matter what the profile, the the area of rubber pressed against the tarmac, MUST maintain the ratio of force per unit area of Tyre air pressure needed to support the weight.

You CANNOT get more rubber pressed against the road, UNLESS you take air pressure out of the tyre or increase the weight on it.

A varying radius profile tyre, no matter how smart the geometry CANNOT defy that fundemental bit of basic physics to increase the cotact patch area as a bike leans.

AND, the contact patch area STILL does not come into the fundamental equation of 'grip', the latteral force a tyre can transmit, before slipping, which is the co-efficent of friction between tyre and surface, times the clamping force pressing the tyre vertically against that surface.

So even if the complex profile tyre DID manage to defy Newton, and Pascal, and probably a few other eminent physicists immutable 'laws', that extra contact area wouldn't automatically mean more grip!

The notion that more rubber = more grip, is at best an inordinate over simplification, tending to utter fallacy; which IF it has any seed of truth, and that in some circumstances wider tyres, or ones with apparently greater contact areas may have more 'effective' grip, must be explained by something OTHER than the contact patch area, more rubber = more grip. It simply isn't true or that simple.
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'
 Back to top
View user's profile Send private message Visit poster's website You must be logged in to rate posts

Pjay
World Chat Champion



Joined: 18 Jan 2016
Karma :

PostPosted: 00:34 - 09 Dec 2016    Post subject: Reply with quote

Teflon-Mike wrote:
Blurb

Stop being ridiculous.
 Back to top
View user's profile Send private message You must be logged in to rate posts

ThatDippyTwat
World Chat Champion



Joined: 07 Aug 2016
Karma :

PostPosted: 07:50 - 09 Dec 2016    Post subject: Reply with quote

Mike - The rubber does not deform as easily as the air (yes, 40PSI or so air), hence why multi-contour tyres do work. If you have a google around you can find papers and see how it works for yourself.
 Back to top
View user's profile Send private message You must be logged in to rate posts

andyscooter
World Chat Champion



Joined: 30 May 2009
Karma :

PostPosted: 08:33 - 09 Dec 2016    Post subject: Reply with quote

not sure if this has been added but couldn't see it


if your bike makes horrible noises and has sparks followed by pain and a sudden stop you lent over too far Shocked



hth
____________________
gilera runner vxr200 (chavped)
if its spelt wrong its my fat fingers and daft auto correct on my tablet
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

Ribenapigeon
Super Spammer



Joined: 20 Feb 2012
Karma :

PostPosted: 20:10 - 09 Dec 2016    Post subject: Reply with quote

Its worth pointing out that roundabouts are an area to be more carefull on this time of year as they get scoured smoother than other areas of roads so the OP is right to be a bit more cautious on them.
 Back to top
View user's profile Send private message You must be logged in to rate posts

onlyJaz
Scooby Slapper



Joined: 24 Sep 2016
Karma :

PostPosted: 13:11 - 12 Dec 2016    Post subject: Reply with quote

Thanks for all the advice guys Thumbs Up

Another question, and I figure it's on the similar topic of "rear-wheel" worries so I didn't see a point starting a new topic...

On the dual carriageway, I sh*t myself every time I change a lane in the rain because of the white painted lines between each lane. I know these are slippery especially when wet, so when I need to change a lane I try to do it as confidently as I can whilst being reasonably cautious but inside I have the fear of slipping and being at the mercy of the headlights of the car behind me! (Dramatic much)

Now obviously I will be buying new tyres seeing as the advice above has told me how crap YBR originals are but will my bike be feeling more stable in the dual carriageway situation after that or is this a normal part of riding and I should just get used to it?

Or am I overthinking it, that it's unlikely to slip easing into another lane at 50mph?
____________________
Yamaha YBR 125
 Back to top
View user's profile Send private message You must be logged in to rate posts

Pjay
World Chat Champion



Joined: 18 Jan 2016
Karma :

PostPosted: 13:13 - 12 Dec 2016    Post subject: Reply with quote

Going over them to change lane isn't a problem, just don't pull the front brake on one.
 Back to top
View user's profile Send private message You must be logged in to rate posts

Hawkeye1250FA
World Chat Champion



Joined: 14 Oct 2016
Karma :

PostPosted: 13:25 - 12 Dec 2016    Post subject: Reply with quote

Just do your change of directions (and revs) smoothly and you'll be fine.
 Back to top
View user's profile Send private message You must be logged in to rate posts

Teflon-Mike
tl;dr



Joined: 01 Jun 2010
Karma :

PostPosted: 14:15 - 12 Dec 2016    Post subject: Reply with quote

In the UK, road markings are made of 'gritted' bitumen; I believe they use ground glass in the 'paint' strategically to give them 'grip'; thy are NO-WHERE near as 'slippery' as so many suggest or make out.

Was suggestion that in some continental countries, they used plastic based 'gloss' paint like you'd use on your wainscoting decorating the living room, that may be a little lethal... but in this country, road markings are often more grippy than some of the more polished bits of tarmac they use!

More dangrouse bits are actually the 'black' bits of 'over banding' they stick along tarmac patches or over the gaps between sections, which are 'un gritted bitumin'...

ANYWAY... the nadgery bt is that the lane markings are so often so over painted, that they get built up into a ridge, that can sometimes be half an inch taller in the middle then the surface!

It's that discontinuity n the surface that's more often to blame for a 'wibble' when you go over them, the tyres tryng to shift to the angle of the 'hump', than any actual loss of traction from the being 'slippery'.

Relax; loose grip on the bars, TRUST THE BIKE, it will find its own way over, you don't need to wrestle it! You are more likely to do more harm than good trying to force it to go where you think it should than letting it sort itself out.

Just don't be 'daft' and try crossing them whilst accelerating or braking... but even then TBH, on a little YBR you probably don't need to be too concerned....

I've had big bikes get a bit 'skittery' and 'maybe' break traction when nailing it to make an over take, crossing the white line; but that's not really because the lines 'slippery', but because the 'bump' has lifted the wheel and unloaded it whilst applying excessive torque the tyre.. but even then.... little 'skit' as the bike sorts itself out, and back on track soon as its over the hump and sorting itself out.

You are VERY unlikely to encounter that sort of situation on a YBR Wink

Like everything else; just relax, keep calm, be 'smooth', and trust the bike.

White lines AREN'T the evil zero friction snakes of death they are so often made out to be.
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'
 Back to top
View user's profile Send private message Visit poster's website You must be logged in to rate posts

Pjay
World Chat Champion



Joined: 18 Jan 2016
Karma :

PostPosted: 14:25 - 12 Dec 2016    Post subject: Reply with quote

Tef mate, you do talk some shit.
The white lines are never more grippy than the tarmac ffs.
Infact, go out and pull your front brake on one in the wet.

https://www.youtube.com/watch?v=EDsMIXhgGPw
 Back to top
View user's profile Send private message You must be logged in to rate posts

Yorkshire Geek
Scooby Slapper



Joined: 02 Jun 2015
Karma :

PostPosted: 20:50 - 12 Dec 2016    Post subject: Reply with quote

Pjay wrote:
Tef mate, you do talk some shit.
The white lines are never more grippy than the tarmac ffs.
Infact, go out and pull your front brake on one in the wet.

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

Actually Tef is not really wrong. They do use glass beads to increase skid resistance in road marking paint where high SRV values are needed and they're nowhere near as slippy as people think. That's not to say NO white lines (especially outside the UK where BSEN 1436 doesn't apply) can be slippy, but well specced ones are definitely a lot grippier than you'd expect.

Disclaimer: I'm not a polymer chemist who designs paint but my fiancee is.
 Back to top
View user's profile Send private message You must be logged in to rate posts

ThatDippyTwat
World Chat Champion



Joined: 07 Aug 2016
Karma :

PostPosted: 20:55 - 12 Dec 2016    Post subject: Reply with quote

Yorkshire Geek wrote:
Actually Tef is not really wrong. They do use glass beads to increase skid resistance in road marking paint where high SRV values are needed and they're nowhere near as slippy as people think. That's not to say NO white lines (especially outside the UK where BSEN 1436 doesn't apply) can be slippy, but well specced ones are definitely a lot grippier than you'd expect.

Disclaimer: I'm not a polymer chemist who designs paint but my fiancee is.


Well, despite the design and regs calling for it, someone's sure as fuck not putting grippy shit in them around here, like a fucking ice rink if you happen upon one in anything other than a totally straight and upright position. Easily on a par with the giant swaths of overbanding they seem to like using.
 Back to top
View user's profile Send private message You must be logged in to rate posts

Pjay
World Chat Champion



Joined: 18 Jan 2016
Karma :

PostPosted: 21:35 - 12 Dec 2016    Post subject: Reply with quote

Yorkshire Geek wrote:
Pjay wrote:
Tef mate, you do talk some shit.
The white lines are never more grippy than the tarmac ffs.
Infact, go out and pull your front brake on one in the wet.

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

Actually Tef is not really wrong. They do use glass beads to increase skid resistance in road marking paint where high SRV values are needed and they're nowhere near as slippy as people think. That's not to say NO white lines (especially outside the UK where BSEN 1436 doesn't apply) can be slippy, but well specced ones are definitely a lot grippier than you'd expect.

Disclaimer: I'm not a polymer chemist who designs paint but my fiancee is.


Of course they are supposed to put glass in them to make them a bit more grippy, but they are not more grippy than tarmac.
Aside from that, I've slipped a few times on them when coming to a stop at lights, so know first hand that in North London at least, they dont add enough of it, the video I posted also shows how slippery they are.
 Back to top
View user's profile Send private message You must be logged in to rate posts

M.C
Super Spammer



Joined: 29 Sep 2015
Karma :

PostPosted: 01:27 - 13 Dec 2016    Post subject: Reply with quote

onlyJaz wrote:
Thanks for all the advice guys Thumbs Up

Another question, and I figure it's on the similar topic of "rear-wheel" worries so I didn't see a point starting a new topic...

On the dual carriageway, I sh*t myself every time I change a lane in the rain because of the white painted lines between each lane. I know these are slippery especially when wet, so when I need to change a lane I try to do it as confidently as I can whilst being reasonably cautious but inside I have the fear of slipping and being at the mercy of the headlights of the car behind me! (Dramatic much)

Now obviously I will be buying new tyres seeing as the advice above has told me how crap YBR originals are but will my bike be feeling more stable in the dual carriageway situation after that or is this a normal part of riding and I should just get used to it?

Or am I overthinking it, that it's unlikely to slip easing into another lane at 50mph?

No problem going over them (no one post the video of alpha coming off on a tar snake Very Happy). However watch out for bus lane lines, they always seem to be painted on really thick and can be slippy. Same with direction arrows on roundabouts etc.
 Back to top
View user's profile Send private message You must be logged in to rate posts

mas101
Borekit Bruiser



Joined: 26 Sep 2016
Karma :

PostPosted: 09:46 - 13 Dec 2016    Post subject: Reply with quote

Teflon-Mike wrote:
Pjay wrote:
You might need to rethink your logic.

Hmm.. 30 pounds per square inch... so we get one square inch of ruber contact for every 30 pounds weight....
So 'logically' the contact area, CANT change, unless you change either the Tyre pressure or the weight on the tyre... Hmmm...
Not sure how many ways I an rework the 'logic' of a simple, directly proportional three element relationship here.

May change the SHAPE of the contact area.... though..... but that's not the same thing, is it?


I think the two of you are slightly at cross purposes.

The point about bigger tyres not increasing grip is valid - the whole aquaplaning issue, and the pressure/contact area is also correct.

However, that isnt the whole story - it is sort of assuming a static situation.
Things change as soon as you apply control inputs. The tyre contact patch is where forces are applied so as soon as you start talking about cornering/braking/etc then you are increasing the forces applied by the tyres and the contact area will change (or you crash Razz)

Thats where tyre profile and size can make a difference because the tyres ability to increase contact patch size to produce more grip does matter.
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

Pjay
World Chat Champion



Joined: 18 Jan 2016
Karma :

PostPosted: 10:15 - 13 Dec 2016    Post subject: Reply with quote

mas101 wrote:
Thats where tyre profile and size can make a difference because the tyres ability to increase contact patch size to produce more grip does matter.


Which is what I said, even gave a picture explaining the profile.

I also said I know what he was getting at with the whole pressure/tyre thing, but he said I didn't.

He wont be wrong of course, he will just batter you with walls of text until you fuck off.
 Back to top
View user's profile Send private message You must be logged in to rate posts

mas101
Borekit Bruiser



Joined: 26 Sep 2016
Karma :

PostPosted: 10:54 - 13 Dec 2016    Post subject: Reply with quote

Pjay wrote:
mas101 wrote:
Thats where tyre profile and size can make a difference because the tyres ability to increase contact patch size to produce more grip does matter.


Which is what I said, even gave a picture explaining the profile.

I also said I know what he was getting at with the whole pressure/tyre thing, but he said I didn't.

He wont be wrong of course, he will just batter you with walls of text until you fuck off.


Well I was trying to do the being reasonable thing, but since this is the internet I should have sworn a bit and given details of my extensive (in)experience and question both of your parentages.

tef wrote:
You CANNOT get more rubber pressed against the road, UNLESS you take air pressure out of the tyre or increase the [s]weight[/s] forces on it.
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

Pjay
World Chat Champion



Joined: 18 Jan 2016
Karma :

PostPosted: 11:06 - 13 Dec 2016    Post subject: Reply with quote

He was just looking at a consistently curved surface, in which case he would be right.

Anyhow, that wasn't the point I was making, I just attacked his 'More rubber does not equal more grip' statement. That just isn't the case.

He should have added, 'Unless you can get it onto the tarmac' and then I'd have nodded and scrolled on by.
 Back to top
View user's profile Send private message You must be logged in to rate posts
Old Thread Alert!

The last post was made 7 years, 129 days ago. Instead of replying here, would creating a new thread be more useful?
  Display posts from previous:   
This page may contain affiliate links, which means we may earn a small commission if a visitor clicks through and makes a purchase. By clicking on an affiliate link, you accept that third-party cookies will be set.

Post new topic   Reply to topic    Bike Chat Forums Index -> New Bikers All times are GMT + 1 Hour
Goto page Previous  1, 2
Page 2 of 2

 
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum

Read the Terms of Use! - Powered by phpBB © phpBB Group
 

Debug Mode: ON - Server: birks (www) - Page Generation Time: 0.09 Sec - Server Load: 0.41 - MySQL Queries: 17 - Page Size: 117.11 Kb