Road grip cornering at speed

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SWSteve

Guru
Location
Bristol...ish
I love screaming downthis, if I could ever do it on a closed road and use the full width I would be the happiest man in all of zummerzet. The first corner is a bit tough as it's blind, but you can still nail the second at 30+
 

Powely

Well-Known Member
Getting a good lean on a corner is a lovely thing, there is a roundabout on the way home depending on my route with a good camber. Got to admit I love hooning it around there when it's clear at 30mph or so.

I wouldn't trust my brakes, myself or drivers to hit a roundabout at 30mph! :/
 

Hacienda71

Mancunian in self imposed exile in leafy Cheshire
I quite often hit 40 mph plus on technical twisty descents in the Pennines. Tbh I am less worried about grip at those speeds and a damn site more worried about picking the right line into a turn so I don't run out of road.
 
D

Deleted member 1258

Guest
Quite right. For the vast majority of cyclists the risk isn't to lose grip in a corner due to speed it is either choosing the wrong line or gravel/pothole/cats eye/manhole cover/oil

Yes a few weeks ago I nearly dropped the best bike turning off the A444 into Atterton Lane, a patch of gravel on the corner and a momentary wash out on the front had me looking for a soft spot in the scenery, fortunately it slid for a moment then gripped.
 

Nomadski

I Like Bikes
Location
LBS, Usually
Most people would run out of bottle before the tyres lose grip on a properly set up road bike.^_^

Only problem is, once your committed to a high speed corner its more dangerous to brake than it is to steam ahead!
 

Wobblers

Euthermic
Location
Minkowski Space
If its clean tarmac and the right tyre pressures and good rubber than it's pretty much true. However it only takes a tiny bit of diesel, oil etc for that statement to go out of the window.

No and again no!

Tyre grip is limited by physics. A tyre will start to slip when you apply a force on it which is greater than the weight it is bearing. Put simply, the force needed to keep you turning in a circle will equal your weight when you're inclined at an angle of 45 degrees - assuming perfect tarmac. Above that point, you're going to start sliding whatever, and tyre pressure won't make a jot of difference. Most times you'll get less, substantially so if it's wet.
 

nickyboy

Norven Mankey
No and again no!

Tyre grip is limited by physics. A tyre will start to slip when you apply a force on it which is greater than the weight it is bearing. Put simply, the force needed to keep you turning in a circle will equal your weight when you're inclined at an angle of 45 degrees - assuming perfect tarmac. Above that point, you're going to start sliding whatever, and tyre pressure won't make a jot of difference. Most times you'll get less, substantially so if it's wet.


Oh dear I was hoping we could have a nice discussion without the physics.......

You have missed out the coefficient of friction between rubber and asphalt which will effect your statement. Eg. a bike running on steel rims will lose grip at much lower centrifugal forces than one with a rubber tyre. Rubber tyres and asphalt typically has a coefficient of friction of about 1.5 (up to 1.7) so you can actually lean over quite a bit more than 45 degrees....if you have the cohones to do it! Clearly any imperfections in the road surface reduce this coefficient substantially.
 

byegad

Legendary Member
Location
NE England
My experience in using Kojaks on three wheels was that they are made from a very hard rubber! I found them pretty poor for grip on chip and seal even in bone dry conditions and frankly awful in damp or wet conditions. Replacing them with Marathon Racers gave me much more grip in all conditions.
 
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