Braking in the wet

[TOTO]

This really only applies to dosk brakes. Water accumulates on the rotors. Some folk like to VERY GENTLY apply the brake every so often to wipe the water off. I've never really seen the point, because how long will it take to get wet again?

But, it does raise a VERY important point. In rain, the rotor gets a film of water on it. When you first apply the brake, for a very small time, it will not be very effective, because the water holds the pads off the rotor. It is only a fraction of a second, but it can seem a long time when that truck is looming up. A classic novice mistake is to panic, "oh shit my brakes aren't working" and squeeze harder. Much harder. then the water is dispelled the brake grips fully, and you can imagine what happens next. Get used to braking with a steady measured squeeze, even if for a moment it doesn't seem to do much.

+1

I think thats a valluable advice, I had a situation like that and applied the Newbie Grip of death and almost fliped forwards, but that was on my second day, now I follow what youve just said.

[discotex]

what's the safest thing to do if you start aquaplaning at highways speeds?

If you see standing water then slow down. Aquaplaning is a function of speed and the ability of your tyres to clear water.

Other than that don't do anything. You're basically on ice but it's only for a fraction of a second if you're lucky.

[discotex]

Anyway afterwords I decided that it would be a good idea to go to an empty carpark and practice braking in the wet.

Good shit mate. I can see you're not going to be a fair weather rider (or pussy as I like to say haha).

Went to the empty carpark 2 hours ago and started practicing stopping - front brake only , back brake only, 2 brakes at the same time. It was not as slipery as when It just started to rain , actually I can Say that I had more grip when it was soking wet that when it just started raining.

Yep.. The most dangerous times on the road are 30mins from sunrise/to sunset and 30mins after rain. The sunrise/sunset is because of sunstrike.

As Ixion explained it takes a while for all the oil/tar/misc shite to be washed off the road. It's super slick after a week of dry summer weather.

1. Half wet surface is most likely to lock the back wheel than fully soakeing wet surface.

2. Pumping the Back brake seemed to help me not locking the back, not sure if its always like that but this is what I observed.

Total and utter waste of time. Here's why..

Your back brake is at best providing 20% of available stopping power. Without human ABS you might lose a little but losing 30% of 20% is a bad trade to having to concentrate on your rear brake and risk affecting your 80% front.

My riding style in the wet is to use the back brake under 15km/h as locking the front at low speed in the wet is very easy with twin discs. Above 15km/h I forget the rear completely. On a sportsbike it will lock long before it does anything about slowing you down. I focus on being very smooth on the front and be ready to release at the first sign of a slide.

3. If you lock the back brake at loower speed you slide less than if you lock the wheeel at higher speed

4. Locking the back wheel standing straight is more managable than if you are a bit on an angle.

5. If you lock the back wheel and you are holding the front hard and keeping it straight, even if the back slides like a russian gymnast on ice skates it will eventually come back , even if still locked till the end (I'm sure ppl can disagree here )

Yep.. Best not to lock it at all but the rear is pretty manageable. If you get it too far out you do risk a highside if you let go of the pedel. This is another reason why I forget about the rear in the wet. Worrying about a highside takes my focus away from the front.

6. The tires still have about 80% traction compared to dry road so leaning over in a corner is a matter of confidence, where as in the first 15 min of rain I'd say you have maximum 60% (estimation)

Well yes you're right. Look at MotoGP/WSBK for proof. Lap times don't drop that much in the wet. But... Bins happen more.

Again Ixion rightly pointed out that although much of the surface will give you up to 80% grip there is a load of stuff out there that will drop that to 10%. Leaves, tar snakes (try Mt Eden rd in the wet), diesel, painted lines, dog shit, metal road joiners/grates, etc, etc, etc. Hard to see them all in the wet if you're at 80% speed around a corner.

7. people walking their dogs are quite entertained watching a biker skidding around in the carpark

8. Doing the wet weather excersisses boosted my confidence, now I have some Idea about what to expect.[/B]

The best thing is now you will probably brake harder or swerve harder in an emergency situation as you've got past the fear of braking in the wet. Just don't let it make you ride without a safety margin.

Interesting that you found the stock tyres to be ok. Personally I suspect they have a bad rep that might be unfounded if people practised more in the wet. Wet vs dry performance vs longevity is always a trade off so testing your tyres and adjusting your riding style to your tyre style might be safer than just getting new tyres Cheaper too.

[Crasherfromwayback]

1. Yes. The first bit of wetness is very slippery because of shit (rubber, oil, dust) mixing with the water. This (a) more slippery than plain water and (b) the sipes in your tyre can't easily pump it away. After a bit the shit gets flushed away .

I'm with you there. Yes...happy New Year to you too.

2."pumping" has a mixed press, Basically it just helps avoid too heavy an application, and thus lockup. But on the other hand you lose a lot of braking time, because , in effect you are only breaking half the time. There is a more sophisticated approach called pulse or cadence breaking which in theory overcomes this. On a rear wheel I'm not convinced it's worth bothering. In theory ther eis also a risk of a high side by locking and then releasing the wheel.

'Pumping' is absolute shit. I'll be an absolute wanker here (what's new you and hundreds of other say) and state that I've NEVER been out braked racing in the wet. You can stop really well in the wet with ONLY the front brake if you apply it PROGRESSIVELY and gently. Every split second you spend 'off' the lever is a split second that could/will save you life.

almost all modern road bikes, IMHO have back brakes which are far too powerful. There is no justification for a disk brake on a road bike, except maybe a heavy crusier.

Sorry. Can't agree with you here Ixion. Most sport bikes have rear discs so ineffectual that they might as well not be there. That is because the weight transfer to the front during braking is so pronounced that they know it's trouble if they're strong.

..

cool. practice is always good.
I rode home yesterday in rather dismal conditions. had pretty low visibility.

I was more concerned about stading water on the motorway, having never really encountered it before. I've ridden a few times in heavy rain but never really come across more than patches about half a metre in diameter that were easily avoidable. going along the wellington motorway there was almost two lanes covered in parts.
what's the safest thing to do if you start aquaplaning at highways speeds?

Relax your grip on the bars and make sure the bike is dead upright and pointing straight ahead!

I was told that you should lightly apply the brakes occasionally in the wet to help to keep them a bit drier, so when you need to use them they won't need to scrub off a surface of water first and they don't work so you apply more brake but then they dry and grab suddenly. not sure if that was understandable... or correct, just what I was told.

No need with modern discs Love. When they (discs) were made of mostly stainless they were near dangerous in the wet. Now they're fine. You have moto-x bikes to thank for that.

This really only applies to dosk brakes. Water accumulates on the rotors. Some folk like to VERY GENTLY apply the brake every so often to wipe the water off. I've never really seen the point, because how long will it take to get wet again?

How much water stays on a disc rotor at even 30km's per hour Ixion?

. Much harder. then the water is dispelled the brake grips fully, and you can imagine what happens next. Get used to braking with a steady measured squeeze, even if for a moment it doesn't seem to do much.

I'm with you here though...the gentle squeeze rules.

If you see standing water then slow down. Aquaplaning is a function of speed and the ability of your tyres to clear water.

Other than that don't do anything. You're basically on ice but it's only for a fraction of a second if you're lucky.

Keep cool above all else.

[DingoZ]

Cheers for the post...

Most valuable to read and learn from others experimenting. Have done the same sort of thing, local carpark, pouring with rain. Even had 4 or 5 people out walking their dogs, with umbrella's and raincoats on standing off to the side, having a good ole time watching me zip up and down the car park....

Best thing that I was told and practice every time....Both brakes progressively every time.....

Then again get the chance to ride in the wet most times anyway, living in Welly......

[C_A]

If you see standing water then slow down. Aquaplaning is a function of speed and the ability of your tyres to clear water.

Other than that don't do anything. You're basically on ice but it's only for a fraction of a second if you're lucky.

yuh. I do this. Was jsut as a 'worst case' scenario. Guess it's jsut like riding a dirtbike on mud or somethign.

[TOTO]

...

Again Ixon rightly pointed out that although much of the surface will give you up to 80% grip there is a load of stuff out there that will drop that to 10%. Leaves, tar snakes (try Mt Eden rd in the wet), diesel, painted lines, dog shit, metal road joiners/grates, etc, etc, etc...

Thanks Disco for the coment.

About the metal joiners , there is metal joiner on the harbour bridge on the south side and they are aboy half a metre long. One day on the rain I had to switch from higher gear to lower hear and I happened switch exactly when I was on top of that metal joiner. The lower gear bit in and because of the slightly higher revs the back tyre slid maybe 20cm sideways. The scariest 20cm in my life. I never change geard on that spot anyomore during the rain. sort of like a heads up... for that spot.

[Ixion]

Sorry. Can't agree with you here Ixion. Most sport bikes have rear discs so ineffectual that they might as well not be there. That is because the weight transfer to the front during braking is so pronounced that they know it's trouble if they're strong.

That is why I say they are too powerful. What is the point of having that heavy , and expensive disk brake, and all the hydraulic plumbing, when the maximum amount of grip you are going to be able to put through the tyre could be delivered by a bicycle brake ? The GSXR1000 has (I think) a 220mm rear disk. That's far bigger than is needed for traffic light stopping. But far more than the rear tyre will handle under serious stopping.

[discotex]

yuh. I do this. Was jsut as a 'worst case' scenario. Guess it's jsut like riding a dirtbike on mud or somethign.

You should be sweet as then. Chances are if you didn't see it and slow down it can't be bad enough to cause a problem.

Or, if it's deep enough you could just speed up

This guy's going too slow:

[YOUTUBE]http://www.youtube.com/watch?v=JLaIv5LTrlc[/YOUTUBE]

This guy has it nailed:

[YOUTUBE]http://www.youtube.com/watch?v=Y5fZdesf0QM[/YOUTUBE]

[Crasherfromwayback]

That is why I say they are too powerful. What is the point of having that heavy , and expensive disk brake, and all the hydraulic plumbing, when the maximum amount of grip you are going to be able to put through the tyre could be delivered by a bicycle brake ? The GSXR1000 has (I think) a 220mm rear disk. That's far bigger than is needed for traffic light stopping. But far more than the rear tyre will handle under serious stopping.

Lol...we've had 'chats' regarding disc brakes in the past Ixion.

Disc brakes offer better 'feel' than bicycle brakes at no more of an 'expense' than a drum. They also don't 'lock' up like a drum brake when the shoes are worn due to them going over center.

[discotex]

Thanks Disco for the coment.

About the metal joiners , there is metal joiner on the harbour bridge on the south side and they are aboy half a metre long. One day on the rain I had to switch from higher gear to lower hear and I happened switch exactly when I was on top of that metal joiner. The lower gear bit in and because of the slightly higher revs the back tyre slid maybe 20cm sideways. The scariest 20cm in my life. I never change geard on that spot anyomore during the rain. sort of like a heads up... for that spot.

Yep that's exactly the sort of thing to watch out for. Getting onto the North Western from Newton Rd is super dodgy as you have to turn across it.

Your mention of changing gears reminded me of something else to be wary of in the wet... Don't change gears while leant over in the wet. Unless you change ultra smooth you're risking a lowside.

[sugilite:Me]

On a hot mix surface - 1st few spots, exercise caution, though still surprisingly grippy, as road starts to get wetter and water spots start to join up to form a fully wet road 'DANGER' use extreme caution, VERY slippery. Road fully wet, back to exercizing caution with more grip than you may think being available, just hold plenty in reserve and watch the following distances.

[Ixion]

Well, I'm not (necessarily) arguing for a drum brake . Actually, an argument could be made for no rear brake at all. Many sprotsbike riders say they never use it anyway. So why cart around 20 or 30 pounds of dead weight?

But taking the GSXR1000 as an example. That 220mm disk is going to provide far more braking force than the tyre will transmit, in any serious braking (because, as you say, of the weight transfer forward). In fact, if the rear wheel is in the air, the rear tyre will transmit NO braking force.

So, why such a large (and heavy) brake ? A chain is only as strong as its weakest link, so there is no point in having a brake that can provide more retardation than the tyre can transmit. And on a sportsbike, that's not very much.A 125mm disk would still probably be too much for the tyre .

[Crasherfromwayback]

Well, I'm not (necessarily) arguing for a drum brake . Actually, an argument could be made for no rear brake at all. Many sprotsbike riders say they never use it anyway. So why cart around 20 or 30 pounds of dead weight?

But taking the GSXR1000 as an example. That 220mm disk is going to provide far more braking force than the tyre will transmit, in any serious braking (because, as you say, of the weight transfer forward). In fact, if the rear wheel is in the air, the rear tyre will transmit NO braking force.

So, why such a large (and heavy) brake ? A chain is only as strong as its weakest link, so there is no point in having a brake that can provide more retardation than the tyre can transmit. And on a sportsbike, that's not very much.A 125mm disk would still probably be too much for the tyre .

Good argument mate...but the problem with it being that in the dry you may well want to stomp on it (the rear brake) to get the bike sideways etc.

Like everything motorcycle...it's always a comprimise.

[xwhatsit]

How about a cable/rod operated single pot rear disc? Don't have awful hydraulic systems weighing a tonne and requiring lots of maintenance, and getting in the way of proper feel and linear application.

I still have that momentary Jesus H. Christ moment when first applying front brakes in the wet, despite a change to some modern pads. Hadn't heard the comment regarding old stainless steel discs; I'd say that's the issue with mine. Not really an issue, I've learned to brush the water beforehand, as written above.

Rear drum brake still works perfectly, day, night, wet, dry, hot, cold. Relining the shoes was cheaper than new pads for the front disc. Don't remember having to rebuild it, or bleed the hydraulic fluid. Funny that.