Tandem Cycling - Wet weather tires?

I'm asking this in this forum because I have a lot of respect for the posters here, and because we have double the reason to want our tires to stay stuck to the road. This wish was just emphasized to me when friend of mine went down on a very slick straight road, just from front wheel steering input. Very slick wet nasty black tar. He was on Gatorskins. He did get injured, but not too badly.

What tires have the best traction on wet roads? Is there any data to be found anywhere?

For instance, I ride Vredesteins but I won't ride the Vredestein SE that Performance sells, because they are horrible in the wet, while Tricomps are good. I don't notice the difference in the dry, perhaps because I don't push it to a 45° lean angle. But it seems that there is a wide variation in bike tire stiction in the wet, wider than in the dry. I've experimented a bit, and find that my Tricomps will just hold while going slowly on wet, painted track banking. Other tires will not (ouch).

I think it's well established that slick tires are best, and that it's unwise to reduce tire pressures in the wet. For the physics of it, I ran across this website:
http://www.stevemunden.com/leanangle.html

What information and experience do you have?

It isn't about the tire as much as it is about the road. If it is asphalt and hasn't seen a lot of (or any) rain it is going to be slick not matter what tires you have. A light rain just brings up the oils to the surface. A tar road is even worse if it is missing the usual rock base from use. You are then riding on one of the slickest road surfaces around when it is wet for a bicycle. A heavy rain on the other hand will tend to wash the oils away after a short while and the road will be a little safer to ride on.

It isn't about the tire as much as it is about the road. If it is asphalt and hasn't seen a lot of (or any) rain it is going to be slick not matter what tires you have. A light rain just brings up the oils to the surface. A tar road is even worse if it is missing the usual rock base from use. You are then riding on one of the slickest road surfaces around when it is wet for a bicycle. A heavy rain on the other hand will tend to wash the oils away after a short while and the road will be a little safer to ride on.As a PNW rider, I've ridden thousands of miles in the rain. So I know about wet being slicker than dry and the various stages of slick.

I'm asking for the experiences and thoughts of others as to what tires seem to do better in the wet. My guess would be that tires with softer rubber are better, but which? Softer tires in winter might not be too bad for wear, as the lower traction must also reduce wear? I have rain tires for my single, but how about for a tandem? I'm thinking about Panaracer Paselas for a foreign trip involving some cobbles and other possibly indifferent road surfaces, possibly also wet. I also have a negative thing about heavy tires that ride like bricks. Opinions?

My friend went down in heavy rain, after several days of heavy rain. In this particular instance, the edge/shoulder of this road has been broken and cracked for many years - we knew where all the cracks were and habitually avoided them. But the County decided that a good repair would be just to hot tar the whole edge/shoulder and leave it that way. Didn't work too well.

).

I think it's well established that slick tires are best, and that it's unwise to reduce tire pressures in the wet. For the physics of it, I ran across this website:
http://www.stevemunden.com/leanangle.html



Agreed, on the slick part. Given that a bike tire can't hydroplane (at achievable speeds) more contact patch = more grip. Tread if it does anything reduces the size of the contact patch.

However, I'm not sure that its well established that reducing tire pressure a bit in the rain is a bad idea.

It makes intuitive sense to run a little lower pressure in the rain in that it increases the size of the contact patch.

It has been, and in my experience continues to be, common practice to run lower pressure in crits when it's raining.

I didn't read the whole article linked, but scanning it, I didn't see it addressing tire pressure for wet cornering.

Agreed, on the slick part. Given that a bike tire can't hydroplane (at achievable speeds) more contact patch = more grip. Tread if it does anything reduces the size of the contact patch.

However, I'm not sure that its well established that reducing tire pressure a bit in the rain is a bad idea.

It makes intuitive sense to run a little lower pressure in the rain in that it increases the size of the contact patch.

It has been, and in my experience continues to be, common practice to run lower pressure in crits when it's raining.

I didn't read the whole article linked, but scanning it, I didn't see it addressing tire pressure for wet cornering.The equation for side force from the article is F = μ*m*g. There's no area term because area makes no difference. I understand that conventional wisdom is to run wider and or lower pressure tires in the wet, but there's no scientific basis for it. If it were true that surface area affected frictional force, we could also corner faster in the dry with wider/lower pressure tires, but that is not the case.

Of course there may be tire/pavement interactions which simple physics theory does not explain. Have you noticed that you are more competitive cornering in the wet with reduced pressure than with full tire pressure?

It isn't about the tire as much as it is about the road. If it is asphalt and hasn't seen a lot of (or any) rain it is going to be slick not matter what tires you have. A light rain just brings up the oils to the surface. A tar road is even worse if it is missing the usual rock base from use. You are then riding on one of the slickest road surfaces around when it is wet for a bicycle. A heavy rain on the other hand will tend to wash the oils away after a short while and the road will be a little safer to ride on.

I agree, debris and fluids are the bigger problems. Road surfaces themselves are fine when wet, it's the other stuff that make it slippery

I've found antifreeze to be just as bad as oil. Of course you're avoiding the paint too, especially if wet. There are different theories on tread patterns. I remember Avocet doing tests years ago that indicated smooth tires were best because water clearing properties of treads were insignificant compared to the contact surface. Like any slippery conditions, your best bet is to avoid changes in direction if possible until clear of the area. The good thing about wet is that it helps to clean the road of all the fluids that can make a dry looking road slippery.

Fresh tar also oozes oil which is the kiss of death. FWIW, I almost went down on my horse on a patch of fresh, slick asphalt in the dry. Of course steel horseshoes don't help.

I am interested in the options also.
I just installed Vittoria Rubino Pro in 28 mm and while they ride better than Panaracer Pasela in 32mm width they do not have the same traction as Pasela in the wet. I should have taken a hint that the traction on Rubinos was not good when my rear tire was skipping while I was going uphill standing up on a 5-6% grade on last Sunday ride(wet road). When making a slight turn the rear tire lost traction and the bike just went under me and I crashed. A friend of mine was just ahead of me on the same turn and he was fine, he was on GP4000 in 25mm.
I commute on Paselas and never had traction problems in the wet like I did on new Rubinos. I also ride a cyclocross bike with Ritchy and Michelin Jet cyclocross tires in 30mm and I never had traction problems riding on wet pavement on that bike.
I went down before in the wet making a turn a few years back and it was on Vredestain Forteza SE in 23 mm.
I think it does depend on the compound of the tires, but I'd like to hear what others have to say.

The equation for side force from the article is F = μ*m*g. There's no area term because area makes no difference. I understand that conventional wisdom is to run wider and or lower pressure tires in the wet, but there's no scientific basis for it. If it were true that surface area affected frictional force, we could also corner faster in the dry with wider/lower pressure tires, but that is not the case.



This simply does not comport with experience. A wider tire has to give more grip than a narrower one, ceterus peribus. Otherwise, why do they put wider tires on sports cars? Certainly the fact that a Corvette can pull over 1g on a skidpad with 340mm wide tires, while an economy car does .7g on 130mm wide tires is in part the result of the different size of the contact patch.

Are you suggesting that you could put tires half as wide on a Corvette, and expect the same skidpad numbers?

This simply does not comport with experience. A wider tire has to give more grip than a narrower one, ceterus peribus. Otherwise, why do they put wider tires on sports cars? Certainly the fact that a Corvette can pull over 1g on a skidpad with 340mm wide tires, while an economy car does .7g on 130mm wide tires is in part the result of the different size of the contact patch.

Are you suggesting that you could put tires half as wide on a Corvette, and expect the same skidpad numbers?

I'll take a stab at this. I think the calculations are correct from an physics standpoint. For this equation the assumption must be made that the materials themselves will withstand the force generated. However in the case of a rubber tire the frictional forces can be higher than the cohesive strength of the rubber compound.

High horsepower cars use soft rubber compounds with high coefficient-of-friction compounds that are easily abraded, hence the need for wider tires to reduce the force. I'm not an engineer, so I could be wrong, but I think this the essence of it.

It's the heat. That's the reason they use wide tires on HP autos and race cars. High performance car and moto tires have a temperature at which they produce the highest adhesion. That's the reason you see racers working to keep their tires warm when they're under the flag. So tire width is calibrated to HP to produce the appropriate surface tread temperature under high performance use.

The lower g's pulled in the economy car example also may be due to tire distortion as well as heat. Cars run with the tire stresses in a different direction that 2 wheelers. Motorcycles are a better example. If you've ever followed a street motorcycle cornering at high speed while running old-fashioned rectangular street tires, you'd see that they also get tire distortion which limits cornering ability. It would be interesting to take low angle video of bicycles cornering at the limit with tires of the same make, but different widths. My guess would be that narrower tires will have less distortion, just from what I've seen when "road racing" street motorcycles in the Alps.

Motorcycle racing tires are triangular in section. I suspect the reason that bicycle tires are not triangular has to do with cost, rolling resistance, and the fact that most of us don't push it like motorcycle racers, riding mostly straight and looking more for good tire wear.

I'll take a stab at this. I think the calculations are correct from an physics standpoint. For this equation the assumption must be made that the materials themselves will withstand the force generated. However in the case of a rubber tire the frictional forces can be higher than the cohesive strength of the rubber compound.

High horsepower cars use soft rubber compounds with high coefficient-of-friction compounds that are easily abraded, hence the need for wider tires to reduce the force. I'm not an engineer, so I could be wrong, but I think this the essence of it.We can tell the bicycle tire tread compounds are sufficiently strong to resist the forces involved by noticing that front tires will last 1000s of miles without significant loss of tread.

Continental Winter Contact tires are impregnated with some kind of abrasive compound in the rubber, designed for patchy winter ice conditions. Last I checked not marketed in USA, maybe that has changed.

I am interested in the options also.
I just installed Vittoria Rubino Pro in 28 mm and while they ride better than Panaracer Pasela in 32mm width they do not have the same traction as Pasela in the wet. I should have taken a hint that the traction on Rubinos was not good when my rear tire was skipping while I was going uphill standing up on a 5-6% grade on last Sunday ride(wet road). When making a slight turn the rear tire lost traction and the bike just went under me and I crashed. A friend of mine was just ahead of me on the same turn and he was fine, he was on GP4000 in 25mm.
I commute on Paselas and never had traction problems in the wet like I did on new Rubinos. I also ride a cyclocross bike with Ritchy and Michelin Jet cyclocross tires in 30mm and I never had traction problems riding on wet pavement on that bike.
I went down before in the wet making a turn a few years back and it was on Vredestain Forteza SE in 23 mm.
I think it does depend on the compound of the tires, but I'd like to hear what others have to say.Thank you! Since I started this thread, I've done quite a bit of web research on tire compounds and reviews of wet weather performance. I've compiled the following list of tires from this research:

Avocet FasGrip SL K
Michelin Pro3 Grip
Vittoria Open Pave Evo CG
Vittoria Diamonte Pro Tech
Vittoria Rubino Pro Tech
Vittoria Revo KXS
Continental GP4000S - note this is the "S" or Black Chili rubber version, not the standard 4000
Schwalbe Ultremo
Continental GP4Seasons - good wet stiction, but high rolling resistance so may be appropriate for rough roads.

The particular models indicate special tread compounds. For instance, the Vittoria Corsa Evo is reportedly bad in the wet. The "Tech" in the Rubino model indicates wet weather compound as well as sidewall reinforcement.

Unfortunately, few of these tires come in widths that we normally associate with tandeming. The Rubino Pro Tech does. And some come with sufficiently high pressure limits to make them entirely feasible.

Thank you! Since I started this thread, I've done quite a bit of web research on tire compounds and reviews of wet weather performance. I've compiled the following list of tires from this research:

Avocet FasGrip SL K
Michelin Pro3 Grip
Vittoria Open Pave Evo CG
Vittoria Diamonte Pro Tech
Vittoria Rubino Pro Tech
Vittoria Revo KXS
Continental GP4000S - note this is the "S" or Black Chili rubber version, not the standard 4000
Schwalbe Ultremo
Continental GP4Seasons - good wet stiction, but high rolling resistance so may be appropriate for rough roads.

The particular models indicate special tread compounds. For instance, the Vittoria Corsa Evo is reportedly bad in the wet. The "Tech" in the Rubino model indicates wet weather compound as well as sidewall reinforcement.

Unfortunately, few of these tires come in widths that we normally associate with tandeming. The Rubino Pro Tech does. And some come with sufficiently high pressure limits to make them entirely feasible.

Thank you! That was a very valuable information.

It's the heat. That's the reason they use wide tires on HP autos and race cars. High performance car and moto tires have a temperature at which they produce the highest adhesion. That's the reason you see racers working to keep their tires warm when they're under the flag. So tire width is calibrated to HP to produce the appropriate surface tread temperature under high performance use.

The lower g's pulled in the economy car example also may be due to tire distortion as well as heat. Cars run with the tire stresses in a different direction that 2 wheelers. Motorcycles are a better example. If you've ever followed a street motorcycle cornering at high speed while running old-fashioned rectangular street tires, you'd see that they also get tire distortion which limits cornering ability. It would be interesting to take low angle video of bicycles cornering at the limit with tires of the same make, but different widths. My guess would be that narrower tires will have less distortion, just from what I've seen when "road racing" street motorcycles in the Alps.

Motorcycle racing tires are triangular in section. I suspect the reason that bicycle tires are not triangular has to do with cost, rolling resistance, and the fact that most of us don't push it like motorcycle racers, riding mostly straight and looking more for good tire wear.

The back and forth motions you see cars and bikes doing are to keep tires clean, speed builds heat. The triangular shaped tires are very old school. Michelin Pro Grips might be a good choice if you like Michelins