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Lost my brakes in the rain

  • Thread starter Thread starter BluePlateSpecial
  • Start date Start date
Wow, a brake thread that I bypassed.

Disc brakes by their design and operation are not inherently affected by water since the water is flung from the Disney by centrifugal force. Add slot or holes and there is even an improvement over the first clearing first revolution.

But these last few posts have hit on the reason, the fiber reinforcement of the brake pads.

Asbestos is a hygroscopic fiber, as are some of the non-asbestos fibers also used in organic classified friction material compounds. When they absorb water, disc or drum, it takes heat energy today them before they loose the water film on the rubbing surfaces that prevents normal coefficient of friction.

The removal of asbestos from highway use varied all over the world. And Japanese auto and bike manufacturers continued to use the asbestos materials (legally) into the 80's and 90's, well after those of us in the USA and other countries banned it's manufacture. Not the use, just making them!

Asbestos and other fibers in organic compounds are only about 15 percent of the matrix, it's not a big block of fibers as some think. While some carbon is in the compound initially, it's the carbonization of the matrix at the rubbing surface by normal braking temperatures that turn this thin layer into a carbon matrix. That is why "bedding or burnishing" the brakes is so important, even with semi-metallic compounds. Also brake fluid has the same effect on friction material as water does, it may alter the friction or it may not. All depends on the friction compound. If you experience a wet fade issue, change the pads to a different material.
 
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jabcb said:
Given all of the idiot drivers on the road, a half second can be the difference between an accident & a close call.
Its also worth remembering that many of those idiot car drivers have antilock brakes & can stop quite quickly in the rain despite being totally clueless.

There is even some evidence that LED stop lights reduce accidents, and LED stop lights are only about 140 milliseconds faster than conventional incandescent bulbs.
Click to expand...

It takes me a half second to get the weight transferred to the front wheel so I can really pull on them anyway. The brakes are dried out and working hard before that. Anyone who tailgates in the rain on a motorcycle is a fool, plain and simple.

None of this equates to five times the stopping distance wet as in dry. That is still pure fiction.
 
I have old brit bikes with drum brakes from late 50 early 60 thought they where ok. In 81 I bought the 1100e thought it will never get any better then this, many miles in the rain,I don't get it either.
 
tkent02 said:
I even sent an hour googling it. Couldn't find any reference to GS brakes sucking in rain. Found one article about the disc brakes on the GT 550, which took a little while to come on, but it went on to say that's just how disc brakes on all bikes were, before the mid 70s.

Disc brakes on cars were the same way at first.
Click to expand...

I had a 76 550 GT. I don't remember any problems with braking. But the TT 500 I had previously needed a brick wall to stop it.....
 
The last paragraph in 3.2.1, page 31 discusses their finding that sintered (full) metallic pads have comparable friction in both dry and wet condition whereas "organic" suffered wet fade. The issue is their investigation (and table) classifies materials as organic and metallic, way to simplistic for a valid study.

You have to differentiate between the fibers and organics of a particular formulation. A semi-metallic compound, which will have organic components that are not hygroscopic, will have the same wet fade resistance as a sintered product. So will an organic if all of its components are not hygroscopic. Most ceramics are of this nature, a compound that uses potassium titanate fibers in place of asbestos or other non-metallic reinforcement fibers.
 
TooManyToys said:
The last paragraph in 3.2.1, page 31 discusses their finding that sintered (full) metallic pads have comparable friction in both dry and wet condition whereas "organic" suffered wet fade. The issue is their investigation (and table) classifies materials as organic and metallic, way to simplistic for a valid study.

You have to differentiate between the fibers and organics of a particular formulation. A semi-metallic compound, which will have organic components that are not hygroscopic, will have the same wet fade resistance as a sintered product. So will an organic if all of its components are not hygroscopic. Most ceramics are of this nature, a compound that uses potassium titanate fibers in place of asbestos or other non-metallic reinforcement fibers.
Click to expand...

Fully agree especially given the fact that a plethora of recipes have emerged since this work was done. If you dig further into the Australian study they question the validity of their wetting methods as inadequate representation of real world conditions. The other point of note is the double force pull required.
From the OP's point of view what are the chances that a leak fix and new pads of the same material will give him acceptable performance in the wet. I'm not convinced.
 
Brendan W said:
From the OP's point of view what are the chances that a leak fix and new pads of the same material will give him acceptable performance in the wet. I'm not convinced.
Click to expand...

I don't have a clue what's wrong with the OP's brakes. Probably they haven't been opened up and cleaned out in 35 years, pads are contaminated, lines are shot, seals are hardened and cracked, just generally messed up brakes which happens with decades of neglect.

Whatever caused his problem, it is NOT normal operation for early GS brakes.
To say it is normal, that they are supposed to suck is completely irresponsible.
 
These are tests, and just tests, i.e. FMVSS 105, 121, 122, 135, etc. They are not true real world situations and never will be. But they are designed around worst case beliefs based on current tests and practices. Not defending them as I've a history complaining about some of the methods NTHSA has set up.
 
I don't believe I've anywhere said they are supposed to 'suck', whatever that means. I did try to google 'GS sucks wet performance' and similar to yourself found little to support my case but lots of other racy stuff.
I think it irresponsible to let someone ride off into the rain thinking he's fixed a problem when you have direct personal experience, backed up by contemporary research that his problem may be something other than the majority opinion and that pad material could solve it and restore his brakes to a 'nonsucking' condition. Is that the right term? "
 
tkent02 said:
I don't have a clue what's wrong with the OP's brakes. Probably they haven't been opened up and cleaned out in 35 years, pads are contaminated, lines are shot, seals are hardened and cracked, just generally messed up brakes which happens with decades of neglect.
Click to expand...

Just to bring you up to speed, this is what the OP told us way back at the start of this;

"Actually I rebuilt the brakes earlier this year right before I got the bike back on the road. New pads, new pistons and seals in the calipers and new SS lines front and back and I disassembled and cleaned the master cylinders."
 
Brendan W said:
I don't believe I've anywhere said they are supposed to 'suck', whatever that means.
Click to expand...

NO, not you. The other guy was saying that they are Death on Wheels, that it would take five times the usual stopping distance in rain, and he was lucky to have survived riding in wet conditions, all kinds of dramatic and false bullsh:t, and implying that not being able to stop in rain is normal for the early GSes. The rest of us on this forum mostly have said we had no such braking problems.

Really irresponsible thing to post when we have lots newbys trying to decide if they should fix their unmaintained and non functional brakes or just keep riding with them as they are.
 
Brendan W said:
Just to bring you up to speed, this is what the OP told us way back at the start of this;

"Actually I rebuilt the brakes earlier this year right before I got the bike back on the road. New pads, new pistons and seals in the calipers and new SS lines front and back and I disassembled and cleaned the master cylinders."
Click to expand...

Well whatever he did, he did some part of it wrong if it caused him to fall down riding around in his neighborhood. Brake fluid coming out? That's not supposed to happen.
 
tkent02 said:
Anyone who tailgates in the rain on a motorcycle is a fool, plain and simple.
Click to expand...
Agreed.

Tailgating when its dry isn't too smart either.
The Fifth Gear TV show has a bike vs. car brake test at around 3:30 sec in: http://www.youtube.com/watch?v=xckqNulY10o

Back in the day there were plenty of articles complaining about wet disk brake performance on the Suzuki GT-series two strokes. Had a GT380 back then. Subsequently had a Honda CB650SC, and if my memory is correct the wet disk brake performance was much improved over the GT380.
 
jabcb said:
Agreed.

Tailgating when its dry isn't too smart either.
The Fifth Gear TV show has a bike vs. car brake test at around 3:30 sec in: http://www.youtube.com/watch?v=xckqNulY10o
Click to expand...

A lot if riders think they can stop quicker, becuse of the forces on the body, it feels like it. It just ain't so. My mom thought her Jeep braked better than my 535i for the same reason. It pitches down so hard it really felt like you were stopping. We went out and had a stopping contest, we drove side by side, about 70 or so mph. She slammed on the brakes first, I braked when I saw her brake, she went twice as far.

Interesting stuff.
 
tkent02 said:
A lot if riders think they can stop quicker, becuse of the forces on the body, it feels like it. It just ain't so. My mom thought her Jeep braked better than my 535i for the same reason. It pitches down so hard it really felt like you were stopping. We went out and had a stopping contest, we drove side by side, about 70 or so mph. She slammed on the brakes first, I braked when I saw her brake, she went twice as far.

Interesting stuff.
Click to expand...

I think the only way to out brake a car with a bike is to have soft compound, race type tires and absolutely no anti lock brake system.
On the average, you probably will not be able to out brake a car. A pick up truck with hard rubber truck tires and all terrain tread, yes you can. :)
 
earlfor said:
I think the only way to out brake a car with a bike is to have soft compound, race type tires and absolutely no anti lock brake system.
On the average, you probably will not be able to out brake a car. A pick up truck with hard rubber truck tires and all terrain tread, yes you can. :)
Click to expand...

Possibly for a normal car with cheap brakes. Outbraking a BMW with an M in the model name is another thing altogether.

It just isn't going to happen.
 
tkent02 said:
Possibly for a normal car with cheap brakes. Outbraking a BMW with an M in the model name is another thing altogether.

It just isn't going to happen.
Click to expand...

The common econo box, you have a shot. :)
 
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