Braking Distances

[Stevebrooke]

Following on from my thread about wet weather confidence and not wanting to get it too clogged up, here's another question.......

If there is 85-90% of the available tyre grip available in the wet then surely I only have to increase my safety margin by 10-15%?

I bet I'd be failed for not keeping a safe distance if I didn't open a gap of at least half as much as I would need in thr dry!!!!!

And I'm not aware of any motoring literature that doesn't increase considerably the recommended braking distances in the wet.

 

[skippy]

Most modern rubber delivers the goods in the wet unfortunatly the tarmac don't not to mention white lines, manhole covers, cats eyes and various slippery substances unleashed from the road surface by a good shower of rain and reduced friction on your braking surfaces hence the need to increase distances by more than you would think.

 

[RHINO]

Lumpy

That will mainly be weight transfer causing that, my Avons are fine under braking with the footprint spreading under weight transfer but lateral traction is poor as well as acceleration in the wet..

 

[bishbosh]

Go on and test yourself

The other week I was riding home on a dry sunny Friday, quiet b-road, so I thought what is my stopping distance from 60mph if braking briskly but not full anchors. So I using a tree as a marker I stopped the bike, looked round and the tree was a long way back; result, you have to ride well within yourself and the bike for safe stopping distances in the dry, let alone the wet. My advice, go and find a dry quiet country road and do some stops at 40/50/60 - I guarantee rule of double the speed, quadruple the stopping distance is very true. Another point is that no matter who you are, Schumacher included, you will take between 0.6 to 1 second to respond to an unexpected hazard, so if you only leave a 1 second travelling gap you are relying on your brakes being better that the person's infront.

 

[CbrDavE]

Having put a car down a ditch at 40mph on a wet and muddy corner that I've since been round at 80mph, oh!..er! did I say 80 officer, I mean 60.
You just cant consider water on the road, you have to think about what other shit/oil goes down as well.

Does the Blackbird with its linked breaks have any advantage to the average Joe riding non-linked breaks, dry or wet?

I think Yes, because the bike will proportion the front to rear better than most riders can!

What's your views..... :dunno:

 

[BrisbaneBlackbird]

Deformation of the tyre

One reason hard braking distance increases in the wet is attributed to exactly the same reason bikes brake so well in the dry - when you look at the profile of the front rubber it is almost circular with a small strip in the middle touching the blacktop when riding (straight)

So when you brake (and particulary hard braking) the weight transfer onto the front rubber deforms the tyre - kinda squishes it flatter - so then theres more rubber in contact with the black stuff - so in the dry this helps braking and i was taught always apply a little rear pressure, then a little front - then bring it on - the idea is to make the bike dig in a little before applying to much stop.

The flipside is in the wet as the tyre squishes, the grooves (that help disperse the water) close up considerably (because they radiate out from the centre of the tyre kind-of) and thus leave you with a racing slick. Course this is good in the dry!

Then combine this with linemarking that has no permeability(so the water covers the entire surface - unlike bitumen where there are lots of little pockets for the water to drain into) and away you go

Grab your front rubber both hands and press thumbs in about 50mm apart - look what happens to the groove.!

Edit - of course all the previous comments are also 100% valid as well

Ken

 

[Rods]

Most modern rubber delivers the goods in the wet unfortunatly the tarmac don't not to mention white lines, manhole covers, cats eyes and various slippery substances unleashed from the road surface by a good shower of rain and reduced friction on your braking surfaces hence the need to increase distances by more than you would think.

exactly what i was going to say.

 

[Theoldgit1]

What you also need to take into consideration is that wet = cold, cold tyres, cold fingers and your reactions will be slower anyway.
Rain is always the same temperature, it's the surrounding physical effects that make it feel warm or cold.

 

[Stevebrooke]

After all, it's better to be overly cautious than wrong!

Interesting quote from a man of your calibre, Clive.

That is one of the reasons I was given by my examiner for failing the IAM test initially.

 

[ianrobbo1]

dont hold your breath waiting for a bite Steve,!!

 

[Centaur]

Not biting today

Must be too sunny or not enough water or summat!

 

[Stevebrooke]

dont hold your breath waiting for a bite Steve,!!

I wasn't expecting one Ian. Serious posts only. So what are you doing here :k

 

[Theoldgit1]

I'm sure I read somewhere that the old braking distances are still relevant even though vehicle braking ability has improved as the original figures were based on "thinking time"/reaction time. Which apparently is still the same....

So the 2 second rule/4 second rule for the wt would still apply no matter how good the brakes are.
It's what I stick too anyway, even though I have Carbone Lorraines Best on the bike.

 

[grant57]

pads

Try EBC HH pads, even better than Lorraines!!