Wet Braking

[csj]

Why is it that this Valkyrie setup:




Is so much worse at stopping in the Wet than this Auto style:




like is found on my van?

In the Wet, I am thinking ten car lengths away about how I'm gonna
get stopped on the Valk. No such worry in the van.

What can I do to help the Valk STOP in the Wet.

[John Schmidt]

Often it's the tires you're running that makes the difference. Metzlers are well known for good rain performance, I have one on the front with a c/t in back. Wet or dry, it stops in a straight line and does so quite handily. I still give it extra distance and never use a cruise control or throttle lock on wet pavement. Just don't compare it to your van, that's apples & oranges. The van has four wheels grabbing pavement, the bike only two.

[old2soon]

I have O E M pads a Shinko 777 in front and the Austone taxi tire on the rear. Like John I slow down some AND increase following distance in the rain. Smooth non scary stops in the rain are normal for me. The Valkyrie has impressed me with It's stopping power in adverse conditions. The ABSOLUTE WORST tires I ever had in the rain were what came on my Phatt Ghurl-te E 3s. Long gone and NEVER to be run again by me. The ONLY tire I've had that scared me in the rain. RIDE SAFE.

[Jess from VA]

You can always stop the wheels just fine on wet pavement, but that doesn't mean you can stop the bike.  

It's all about contact patches and good tires, not the brakes.  Car tires provide a big improvement in wet braking.  

Wet pavement is not so bad, you leave a larger margin of safety between objects ahead, and more gentle pressures on the brakes (and the throttle).

But in a driving rain, I can be seen riding like an old lady.  Not only can stopping get hairy, seeing what you are running into is a problem.  I've been in a downpour that quickly turned into a 3-4 inch deep road, and was kicking up a wake.  I tried to get under an overpass, but all the space was taken up by cars and trucks.  

[Gryphon Rider]

The only time I have noticed reduced braking power in the rain was when I had DP Brakes HH pads in the front; initial bite was poor. I went back to OEM pads.

[Oldnick]

Firstly I want to clear something up. There are two types of failing to stop in the rain. One is tyre slide (which can happen with no rain, but just on the wet road), the other is that in actual _rain_ many pads just do not grip, due to, AFAIK, a film of water on the discs.

I am a little touchy about this, because on a general bike forum I asked if this still happens and was pretty much told I was talking rubbish, lectured about centrifugal force flinging off water anf finally villified for keeping on arguing, about something that I and many riders experienced in my former bike days (I have just bought a Valk trike.). Also a lot of people talked about tyre failure....in 20 winters of riding in the rain, I believe I know (a) what I am talking about and (b) the difference between the two....sorry ...rant over.

SO. I reckon you're talking of the sliding pad type and not tyres. I mean sliding tyres is pretty self-explanatory and would happen on your van as well, right ?

If I am right, I _think_ the reason that your van does not have the trouble is that its disc's not hanging in the breeze like a bike's: it's tucked under some sort of minimal enclosure and somewhatever protected by the shape of the wheel. I mean give the bike a break (hah! Brake..get it) having your disc hanging in a wet breeze would slow anyone down in their reaction times.

I am not up with technology these days, but a lot of people say some pads are WAY better than others, so I guess you need to ask the direct question "Which pads grab the disc better in the rain?"

.....and I thoubght the rant was over....:

Nick

[Red Diamond]

Try this comparison, a 700lb bike versus a 4000lb van.

[Oldnick]

Try this comparison, a 700lb bike versus a 4000lb van.

Yeah and the van stops better! Please check the post

[Blackduck]

Bit lost on this, the Valk brakes will lock up wet or dry if you hit them hard. ( last thing you want)
Nothing wrong with the brakes.
Tyres, road surface and how you apply the brakes have more to do with stopping.

[Oldnick]

Bit lost on this, the Valk brakes will lock up wet or dry if you hit them hard. ( last thing you want)
Nothing wrong with the brakes.
Tyres, road surface and how you apply the brakes have more to do with stopping.

Bacvk in the day, when I was biking, in the rain the discs would simply glide when asked to stop. This was  not tyyres on road (I mean I could still hear a ZZZZ when that happened, damn it) but pads just not grabbing
: they just "float" on a molecle of water and there ids NO stopping power.....serious ice-skating. NO FRICTION.

If the stock Honda pads work then great. But BITD,  I tried a few pads and they all skated. I hear things have improved and it's worth chasing pads. I read one reply here that OEMpads were pretty good, so maqybe the OP needs to look at those.

Beleive me I learned to stop on slippery tyres (and how NOT to ) and the non-existant  disc brake in the rain was a diifferent thing! You applied brakes and nothing happened.  Place your finger on a wet counter top and push.  What you feel is the brake feeling, not the tyre feeling.....nothing

If that has improved with SOME pads then I will be a happier man.

Nick

[Daniel Meyer]

I ride in the rain all the time. The valk brakes are outstanding, wet or dry. (I run stock pads/rotors). Excellent grip and feedback. No less authority.

I should also note that they stop just fine covered in fork oil.

If you're really aren't gripping when wet, somethings off in the way you have it set up. Bad caliper, pads, or something.

[csj]

Well I was about to agree with Oldnick;

they just "float" on a molecule of water and there is NO stopping power.....serious ice-skating. NO FRICTION.

but then Daniel ( I recognize that dirt encrusted fender ) says that his bike grabs well
no matter how wet the calipers and disks get.

I don't believe there's a problem with my setup. LOTS of stopping power when dry,
but 6 to 10 car lengths to get stopped when REALLY wet.

I'm stumped for the moment.

To add some info, I've got a Shinko bias on front ( grips the road as well as any
Metzeler I've used ) and a Falken radial car tire on back. I'm quite confident
that both tires are Not slipping, good grip, no out-of-round.

 ???

I get my brake pads from a local bike wrecker, and they're not Honda, but I can't say
exactly what make. Honda pads are available close by, but they're more than twice the cost.

[Paladin528]

Ok here is my theory which is related to the cause of the buzz on the front brakes.  When the disc is dry and the wheel is rotating there is a slight drag on the brakes.  Very slight but it still causes friction.  When you apply the brakes what you are actually doing is converting the energy in the bike to heat which causes the rotors and pads to get hot. The air inside the cross drilled holes also gets hot. When the brakes are applied that hot air becomes trapped in the hole between the pads and expands.  When the hole rotates away from the pad that pressure buildup is rapidly released with a pop.  Many rapid pops become a buzz.
Now add water to the mix. Water trapped in the same hole heats and converts to steam with a higher pressure. This causes a "lubrication" effect by causing the fad to "float". Requiring more pressure on the pad to stop the bike.
And yes the bike rotor is far more exposed to the elements.

Ps. All of this is alleviated by using the OEM pad which has 3 pucks instead of 2.

[knockdolian]

My theory is, a van/truck has more tread pattern on the road x4 plus more weight which will resist skid. also there is x4 brakes. Bigger callipers usually servo assisted. As mentioned a locked wheel wont stop the bike. I have locked up in the wet. Not fun !!       

[Valkpilot]

I get my brake pads from a local bike wrecker, and they're not Honda, but I can't say
exactly what make. Honda pads are available close by, but they're more than twice the cost.

I'll theorize that this is part of the problem.  The cost difference you describe is typical of organic pads vs sintered metallic pads (OEM type.)

Organic pads are inexpensive and easy on rotors, but need to be heated up to have the same stopping bite as sintered metallic.  A positive aspect of this is that the braking feel is "softer" and it requires a lot more lever pressure to lock up the brakes.  But, riding it the wet, it's hard to heat them up enough to produce the same stopping effectivness.

That said, many people on this forum use organic pads without mentioning the issues you are having, but perhaps they appropriately compensate with slower speed and extended following distances.

[Jess from VA]

It's also worth mentioning that many never ride in the rain if at all possible.

I will save a buck when I can.  I would not save a buck with brake pads.

Just like I don't run Crisco in my crankcase, or Hawaiian Punch in my master cylinders.

Good tires are the number one most important thing on a bike.  Good brakes are probably a close second.

My OE Honda pads last a long time. 

[Daniel Meyer]

Well I was about to agree with Oldnick;

they just "float" on a molecule of water and there is NO stopping power.....serious ice-skating. NO FRICTION.

but then Daniel ( I recognize that dirt encrusted fender ) says that his bike grabs well
no matter how wet the calipers and disks get.

I don't believe there's a problem with my setup. LOTS of stopping power when dry,
but 6 to 10 car lengths to get stopped when REALLY wet.

I'm stumped for the moment.

To add some info, I've got a Shinko bias on front ( grips the road as well as any
Metzeler I've used ) and a Falken radial car tire on back. I'm quite confident
that both tires are Not slipping, good grip, no out-of-round.

 ???

I get my brake pads from a local bike wrecker, and they're not Honda, but I can't say
exactly what make. Honda pads are available close by, but they're more than twice the cost.

Yeah, try some OEM pads. I've run aftermarket pads on other bikes with success, but for the Valk, the aftermarket pads I've tried suck so bad I pulled 'em and tossed 'em immediately.

[csj]

Right, OK. Next pad change it'll be the OEM. All the opinion and theory points
to it being the pad Material (not heating up enough) and Architecture (three sections req'd).

Thank-you for the great stuff. Learned a bunch. Got a solution to go with.

[Gavin_Sons]

I use organic pads and they work just as well as the oem. Wear out faster yes, dirtier yes, but they are easy on the rotors. I have been in some vey heavy rains for several hours and have never came across this problem with the brakes floating on a molecule of water. These brakes float and lightly touch the rotor at all times, unless you have bent rotors. If you have that much trouble stopping I suggest buying new rotors and pads.

[Oldnick]

Ok here is my theory which is related to the cause of the buzz on the front brakes.  When the disc is dry and the wheel is rotating there is a slight drag on the brakes.  Very slight but it still causes friction.  When you apply the brakes what you are actually doing is converting the energy in the bike to heat which causes the rotors and pads to get hot. The air inside the cross drilled holes also gets hot. When the brakes are applied that hot air becomes trapped in the hole between the pads and expands.  When the hole rotates away from the pad that pressure buildup is rapidly released with a pop.  Many rapid pops become a buzz.
Now add water to the mix. Water trapped in the same hole heats and converts to steam with a higher pressure. This causes a "lubrication" effect by causing the fad to "float". Requiring more pressure on the pad to stop the bike.
And yes the bike rotor is far more exposed to the elements.

Ps. All of this is alleviated by using the OEM pad which has 3 pucks instead of 2.

I can tell you that idea of steam is wrong, sorry. My old bike, like most bikes in those days, did not have drilled discs. They would not grip in the wet, buyt bad! I had them drilled in the hope that it would allow water to be takern into the holes. It made no difference for better or worse.

Everything tells me that pad compounds and builds have improved...if you get the right pad. If you get some "cheap" pads of unknown make, you may get various problems like heat fade, poor wet stopping etc. Over to the buyer.

Nick

[Oldnick]

Well I was about to agree with Oldnick;

they just "float" on a molecule of water and there is NO stopping power.....serious ice-skating. NO FRICTION.

but then Daniel ( I recognize that dirt encrusted fender ) says that his bike grabs well
no matter how wet the calipers and disks get.

I don't believe there's a problem with my setup. LOTS of stopping power when dry,
but 6 to 10 car lengths to get stopped when REALLY wet.

I'm stumped for the moment.

To add some info, I've got a Shinko bias on front ( grips the road as well as any
Metzeler I've used ) and a Falken radial car tire on back. I'm quite confident
that both tires are Not slipping, good grip, no out-of-round.

 ???

I get my brake pads from a local bike wrecker, and they're not Honda, but I can't say
exactly what make. Honda pads are available close by, but they're more than twice the cost.

If people are saying that the Honda stuff is OK in the wet, maybe you need to pay that cost .

It is 100% not your tyres. If your front tyre skids, you are very likely to bite pavement, or at least need new undies. As I say I know both feelings: tyre skid (with attendant complications ) and brakes just not biting.

I wonder if a lot of guys have simply only ridden with good, modern pads and do not know what you are experiencing. Back in the 70s and 80s nearly everyone knew that "non stop" feeling. I basically used to rely on my rear drum to slow me until the front disc grabbed.

Nick

I still reckon you need to ask "Which pads work in the rain?" and stress that you mean _in the rain_ and that it's not tyres.

[Oldnick]

My theory is, a van/truck has more tread pattern on the road x4 plus more weight which will resist skid. also there is x4 brakes. Bigger callipers usually servo assisted. As mentioned a locked wheel wont stop the bike. I have locked up in the wet. Not fun !!       

It is not tyre skid we're talking about here, so tyre size and number are not the issue. As you say, skidding a tyre is a definite and memorable experience and can be quite exciting. DAMHIKT.

If you experience the non-stop effect that I reckon the OP is talking about, you would then know that _20_ discs would make no difference. For some long, scary time there is NO brakinbg friction...ever been ice skating?

The only way we could test a car vs a bike's disc brakes' effects when truly wet would be to expose car discs, not hide them in a wheel hub, then see what happened. AFAICS car brake discs only get slightly damp. It would be interesting to see what happened to a car's disc brakes immediately after actually driving through water. That would be a test.

Actually, I find that car discs can be a bit grabby in the wet, until they heat up and dry....I reckon I would not want that on a bike!

Nick

[Oldnick]

I ride in the rain all the time. The valk brakes are outstanding, wet or dry. (I run stock pads/rotors). Excellent grip and feedback. No less authority.

I should also note that they stop just fine covered in fork oil.

If you're really aren't gripping when wet, somethings off in the way you have it set up. Bad caliper, pads, or something.

That's good to hear...right from the horse's mouth.

I have only ridden my Valk trike at very low speed so far (not registered yet) and in the rain they were not good. I need to get up to speed and see how they go. If they are no good I will grab some Honda pads and see if that helps. AFAIK the rotors are stock.

HAH!I reckon there is a story behind that fork oil thing!

Nick

[WintrSol]

It would be interesting to see what happened to a car's disc brakes immediately after actually driving through water. That would be a test.

Nick

Perhaps you don't get flooding the way we do here, between multiple rivers. I've actually done this test with 4-wheel disc brakes, and it does get exciting for a while, until the water spins off the rotors. Not the same as having them out in the direct rain, but, for a brief instant, you do get minimal braking, until the pads start to heat up. Different compound pads require more or less heat to function well, so if you have heat-activated brakes, you won't like riding in the rain.

[Oldnick]

It would be interesting to see what happened to a car's disc brakes immediately after actually driving through water. That would be a test.

Nick

Perhaps you don't get flooding the way we do here, between multiple rivers. I've actually done this test with 4-wheel disc brakes, and it does get exciting for a while, until the water spins off the rotors. Not the same as having them out in the direct rain, but, for a brief instant, you do get minimal braking, until the pads start to heat up. Different compound pads require more or less heat to function well, so if you have heat-activated brakes, you won't like riding in the rain.

Thanks for that. It puts to flight all the guys who said I was talking carp, because the pads would squeegee the water off the disc  instantly and I was just plain imagining things!

Nick

[Oldnick]

Bit lost on this, the Valk brakes will lock up wet or dry if you hit them hard. ( last thing you want)
Nothing wrong with the brakes.
Tyres, road surface and how you apply the brakes have more to do with stopping.

Yeah it seems a crap-shoot on what pads you get. Some pads are good, others bad in the wet. This one is not a tyre issue. You ride along in the rain, apply brakes and there is _nothing_ for a sometimes scary time and distance. Not spongy levers or anything, brakes work fine in the dry. The pads just skate over the discs until the water has gone. It can take 2 seconds or so and is a horrid feeling.

Nick

[Bighead]

I only use OEM pads and have had no issues wet or dry. Other than not being able to see real well when wet enough

[WintrSol]

So the takeaway here, is that OEM pads work well at lower temperatures than many other brand pads. Good to know.

[Oldnick]

So the takeaway here, is that OEM pads work well at lower temperatures than many other brand pads. Good to know.

mmmm...not sure about a temperature...there may be other reasons. I feel that this is an important topic and needs checking. What makes a good wet weather pad?

Nick

[Oldnick]

Hezoos! We sound like we are standing around discussing "feminine products"... dryness.... slip.... bleed may well even appear.

I guess it's a matter of importance where it matters.

Nick

[WintrSol]

So the takeaway here, is that OEM pads work well at lower temperatures than many other brand pads. Good to know.

mmmm...not sure about a temperature...there may be other reasons. I feel that this is an important topic and needs checking. What makes a good wet weather pad?

Nick

I don't know what else could be a factor; all pads experience the same mechanical conditions, and none *should* absorb water, which leaves the temperature of the surface, which is a known variable when it comes to brake effectiveness. Try racing pads, and just try to stop in street conditions.

[Oldnick]

Yeah you are propably right. It does seem weird that a pad would absorb water. It still puzzles me. It's such a dramatic difference between pads that work and pads that are horrible.

Nick

[Michvalk]

Are you absolutely certain that both calipers are working as they should? If only one caliper is working, you could get reduced braking in the wet. (One caliper is not enough) Wouldn't hurt to go through the braking system, to make sure everything is like it should be. It wouldn't surprise me to hear that the fronts got rarely used on a trike.

[Oldnick]

I doubt there is any problem. This trike is bike front end based as in the entire front of the bike is still there with the engine, as distinct from the OzTrike style, which have very low front wheel loading with the engine slung back behind the back wheel. So the front wheel plays quite a large part in the braking effort. The brakes were completely professionally overhauled not long before sale and the previous owner spoke to me specifically about the fact that you _can_ lock up the front wheel if you hit the brakes too hard...probably by a sudden grab rather than squeezing. So far the trike, with me on it, has not gone over about 10kph, because it's not rego'd, so brake testing is moot. I'd ride it up and down the front road a few times (semi rural) but the exhaust note is 115-120dB and I just _might_ p off a neighbour enough for them to complain. But I and many others had the rain -no-brake on bikes, years ago, from new. It looks as if th3e pads are the answer.

BTW guys, I would be interested in comment. I reme mber that it was commonly believed by quite knowledgabe people that bikes that had non-stainless steel discs did not have the trouble...interesting.

Nick