Are slicks REALLY OK in the wet?

BlueEyedGirl

I'm used to mountain bikes, and started road biking last spring. Looking down at those narrow slicks is not reassuring, and I'm learning bit by bit, mainly by tagging behind real cyclists, just how much they, my bike and my brakes will actually do.

But when I ask in the shop what tyres I should get fro the wet winter, they tell me the ones I've got will be fine. This is a little scary. Will they really work in the wet??

Louisa

andrewjoseph

Yes, but be wary of leaning over too much on corners. Slicks will allow more rubber in contact with the tarmac. I only have slicks on my road bike and have ridden through very heavy rain.

HiCadence

I think it's more of a confidence issue than anything else but as long as you don't turn rediculously sharply you should be ok it's all about learning what the limits are slicks or not i had a few slides off the bike myself to know what my tires could and couldn't handle personally i use Gatorskin tires 12 months a year for the puncture protection people say they aren't good in the wet but i've yet to have a problem with them riding in the wet they are absolutly fine.

Grill

You can always use a 25c tyre instead of a 23c if it makes you feel more secure, but TBH the difference in contact patch is negligible. I've done rides on 21c tyres where it's bucketing it down and been fine. As others have said confidence is key.

Oh and don't look at your tyres as you corner, you'll likely end up there!

graeme_s-2

Your tyres will have less grip in the wet than they will in the dry, but they'll still have more grip on wet tarmac than a knobbly or heavily treaded tyre will in the same conditions.

slowbike

andrewjoseph wrote:

Yes, but be wary of leaning over too much on corners. Slicks will allow more rubber in contact with the tarmac. I only have slicks on my road bike and have ridden through very heavy rain.

Wet reduces grip - but you won't aquaplane...

I rode in on 23mm GP4Seasons this morning - constant wet road (it was raining duh!) - only issue I had was lack of braking power (forgot I wasn't on the other bike!).
As said - just slow down a bit for the corners - not least because there might be a wet metal cover waiting to whisk your wheel away ...

pirnie

I've never had an issue with 23mm Ultremo DDs in the wet, which are completely slick. I don't feel there's significantly less grip than in the dry. Do watch out for ironworks (manhole covers etc) and white lines though as they can be slippery, as well as patches of oil spilt from cars.

You won't hydroplane a bike (which is why car tyres have tread) as the contact patch is so small compared to the weight of you and the bike that water just gets forced out of the way.

Pross

Yep, tread on road tyres is just there to give an illusion of better wet weather performance but actually does nothing to help. Tread is only of use on a surface where it get get a bit of bite which is why off road tyres have tread.

andrewjoseph

Slowbike wrote:

andrewjoseph wrote:

Yes, but be wary of leaning over too much on corners. Slicks will allow more rubber in contact with the tarmac. I only have slicks on my road bike and have ridden through very heavy rain.

Wet reduces grip - but you won't aquaplane...

I didn't mention aquaplaning.

Monty Dog

A 25mm tyre will be far better in the wet than 21mm because of the shape of the contact patch and the fact you can safely run lower pressures i.e. more grip due to carcass deflection. Skinny tyres have long, narrow contact patch whereas wider tyre is shorter and broader - consequently, they will withstand greater lateral force i.e. corner better. However, if you encounter ice or diesel nothing will stop you sliding.
The tyre tread make no difference

plowmar

Was out today 09.00 to 18.00 on a charity ride and had no problems. I did however allow more distance for braking in order to initially let the pads take the wet off the rim before effecting the required braking.

Mad_Malx

I've found huge difference in tyres - original cheapos on my entry bike were horrible, when I started on road I thought sliding around was normal. I'm much happier on Conti 4 seasons or GP4000s all year round. I'm not claiming these are the best and I'm sure other good quality ones are good too. 3x the price of budgets, but I'm not going back.
As mentioned above, running at a bit lower pressure (around 85 psi for me) helps a lot too. 'Best (wet weather) pressure will depend on your weight (I'm around 70kg, probably can go a bit lower if you are less).

slowbike

andrewjoseph wrote:

Slowbike wrote:

andrewjoseph wrote:

Yes, but be wary of leaning over too much on corners. Slicks will allow more rubber in contact with the tarmac. I only have slicks on my road bike and have ridden through very heavy rain.

Wet reduces grip - but you won't aquaplane...

I didn't mention aquaplaning.

No I know you didn't. Sorry if you thought my response implied you had ... I was intending to agree with you!

Mikey41

BlueEyedGirl wrote:

But when I ask in the shop what tyres I should get fro the wet winter, they tell me the ones I've got will be fine. This is a little scary. Will they really work in the wet??

Yes, they should be fine. What is on the bike at the moment?

As others have said, a bit less speed, don't lean too much on turns and keep it smooth. Stay away from metal manhole covers and painted white lines, they'll have you off in a flash.

Best tyre I've ridden in the wet so far is the Conti GP4000S, brilliant tyre IMO.

andrewjoseph

Slowbike wrote:

andrewjoseph wrote:

Slowbike wrote:

andrewjoseph wrote:

Yes, but be wary of leaning over too much on corners. Slicks will allow more rubber in contact with the tarmac. I only have slicks on my road bike and have ridden through very heavy rain.

Wet reduces grip - but you won't aquaplane...

I didn't mention aquaplaning.

No I know you didn't. Sorry if you thought my response implied you had ... I was intending to agree with you!

Ok

Initialised

The winter before last I was cornering at ~18-20mph on knobblies, I lost grip, went over and fractured my humerus. A year or so prior to that I had a similar fall after swerving to avoid a cyclist on the 'wrong side' of a narrow path, that was on semi slicks, a few cuts and bruises that time.

Point is that when cornering on a smooth surface you'll have more grip and there fore more control as you tilt into a corner since the tyre will be conforming to the road surface rather than resisting the turning action.

On 28mm tyres with minimal tread I don't find a problem with met metal.

roger_merriman

slicks as others have said are fine, like for like they do have more grip than nobblies, though worth noting that MTB tyres tend to be a lot bigger, with low pressure, soft compound rubber.

As long as you don't push the limit road bikes are fine, they don't handle well on the limit tending to snap away.

hangeron

This is th only pic I could find of Ratto leading the Vuelta downhill in the rain yesterday

TheHound

It really depends on the road surface.

If you're on an F1 track with near perfect Tarmac beneath you then by all means slicks are fine. But for normal roads out about the country then tyres with a tread are better as there is more intetaction with the imperfections on the road surface.

Mad_Malx

TheHound wrote:

It really depends on the road surface.

If you're on an F1 track with near perfect Tarmac beneath you then by all means slicks are fine. But for normal roads out about the country then tyres with a tread are better as there is more intetaction with the imperfections on the road surface.

No, because on a hard surface you are reducing the contact area. Think about running wearing football boots, or even with a softer tread like wellies. On mud or turf, great; the surface moves and the tread sticks in. On a solid suface, less of your sole in contact with the floor, and you slip. I think climbers (I'm not talking about hill walkers) have the same debate.

BlueEyedGirl

Thanks, guys, this is all very re-assuring. Just in time, too, today, the first rain in months....

OnYourRight wrote:

Treads on car tyres give somewhere for water at the contact patch to go, allowing the protruding tread blocks to grip dry ground (it’s much more complicated than that: see pages 59–69 of this PDF; but that’s the gist of it).

Since road-bike tyres have a smaller, more rounded contact patch with much greater pressure than car tyres they cannot aquaplane. Therefore they don’t need tread patterns.

That said, loss of grip on two wheels is often catastrophic, and slick tyres give little warning before they lose traction (by contrast treaded tyres start ‘walking’ – operating at a high slip angle – giving the rider feedback about traction). So I fully understand your fear about losing traction. I’m scared stiff sometimes.

The compound used in the tyre makes a great difference in wet grip, so one slick tyre can give far greater grip than another. What tyres are you using now?

On the front I have a Giant FlatGuard PR3, on the back a Mavic Aksion, both 700 x 23. I have a pair of Michelin Pro3 Race available, same size, which i could use if better, but the sidewalls are an awful colour for my bike!

jezzpalmer

TheHound wrote:

It really depends on the road surface.

If you're on an F1 track with near perfect Tarmac beneath you then by all means slicks are fine. But for normal roads out about the country then tyres with a tread are better as there is more intetaction with the imperfections on the road surface.

That's wrong I'm afraid, a slick will always have more contact area than a cut/treaded tyre with the road surface, tread is only there to channel/clear water out of the way to prevent aquaplaning; unlike a car, due to the high contact pressure of a road bike tyre it's virtually impossible to aquaplane so there's no need for tread.
Slicks still deform around the imperfections, and will create more grip than on a smooth surface. As mentioned previously reducing tyre pressures (and/or running wider tyres) in the wet helps facilitate this by increasing the contact patch, as well as allowing more compliance in the sidewall which help dampen the lateral forces, helping to prevent the tyre from breaking free on the reduced friction that a wet surface presents.

Obviously on gravel and muddy surfaces this changes and tread is welcome, but then that's an issue for the MTB forum.

TheHound

I'm wondering where you guys are getting your sources? Or whether it's the usual road cycling myths that's the reason for sky coming along and destroying the peloton with actual science?

Look at a gecko's foot. It's not perfectly smooth for running up walls.

I've had a look around and can't find any actual science to suggest that in real world conditions with imperfect road surfaces, slicks are better than treads. It's all just anecdotal. I'm happy to be proved wrong.

jezzpalmer

A geckos foot works because it has massive surface area from the large number of 'hairs', and makes more surface contact. if you assume their normal foot is a slick, then you removed 30% of those hairs (to make it treaded) it would have 30% less surface area and less grip.

This is not a sky myth, as long as you're not auqaplaning the bigger the surface area in contact = more grip. In motorsport (unless rallying on gravel/loose surfaces) the only reason to run a treaded tyre is to clear water out of the way to prevent aquaplaning, though tread blocks also help the tyre generate heat by moving around, the heat that the water is dispersing.

if anything a textured road surface offers bigger surface area as the tyre deforms and stretches against the various faces of the stones embedded in the asphalt. And is why the rolling resistance of a tyre is higher on a textured surface than a glassy smooth one.

Only wiki but it's the gist of it.
http://en.wikipedia.org/wiki/Racing_slick#Bicycle_tires

In contrast, many bicycle tires made for street use are slick. Aquaplaning does not present a problem for bicycles due to their narrower width, higher pressure, lower speed, and circular cross section (due to the need to lean the bicycle in turns), the bicycle tire can penetrate the water layer to contact the road much more easily; in practice, grooved bicycle tires do not outperform slick tires on wet roads. However, many low and medium performance bicycle tires have substantial tread depth, because the bicycles are designed with off-road excursions in mind, in dirt, gravel, or sand the tread pattern provides significantly improved traction. In addition, high performance bicycle tires, although designed for road use only, often have a very fine tread pattern, which appears to provide no difference in performance versus a slick tire and is only there for marketing purposes and as a tire-wear indicator. This is clear not only from direct testing of tires, but also from the fact that the texture of the road is itself coarser than the minimal tread pattern on these tires.[5] Some grooveless designs have small "holes" or dimples embedded in the tread as a tire-wear indicator. This is similar to automobile tire-wear indicator bars, which contact the road when the tire is worn to a low tread amount, making the tire noisy on the road.

And another bit taken from the same page explaining why car tyres are treaded to prevent aquaplaning.

Slick tires provide far more traction than grooved tires on dry roads, due to their greater contact area but typically have far less traction than grooved tires under wet conditions. Wet roads severely diminish the traction because of aquaplaning due to water trapped between the tire contact area and the road surface. Grooved tires are designed to remove water from the contact area through the grooves, thereby maintaining traction even in wet conditions.

sungod

beat me to it

gecko's feet stick to smooth surfaces by using the val der waals force, rather than the physical deformation and friction which are the dominant factors determining grippiness of rubber on tarmac depends

the racing world doesn't choose slicks for anecdotal reasons, f1 racing cars etc. use slicks because in the dry they grip better and waste less energy, in the wet they would aquaplane so if the roads are wet they have to switch to tyres with a water dispersing pattern

slicks don't squirm, the contact is stable, the rubber only needs to deform enough to grip the relatively smooth road surface

knobbly tyres squirm and can even tear loose on tarmac surfaces at speeds where a slick would be fine, i've experienced the latter first hand

unlike with car tyres, slick road bike tyres are also best in the wet, the rounded profile and high contact force prevent aquaplaning (at road cycling speeds)

TheHound

I'm not really willing to take Wikipedia as evidence.

I'm looking for actual research done in this area. Cycling is full of myths about this or that being better, then when someone actually looks into it in depth it turns out wrong.

bill_gates

What are the best tyres for winter training then? I've started reading some on the Continental blurb on GP4000S versus Gatorskins, etc. What do most folk choose?

frisbee

TheHound wrote:

I'm not really willing to take Wikipedia as evidence.

I'm looking for actual research done in this area. Cycling is full of myths about this or that being better, then when someone actually looks into it in depth it turns out wrong.

This article is old and about car tyres but it is relatively easy to understand.

http://deepblue.lib.umich.edu/bitstream/handle/2027.42/49006/ptv6i1p11.pdf;jsessionid=DC792FCE04E6B185BCDFF64FB230B16D?sequence=2

It talks about long, thin contact patches as a method of reducing the depth of the water film between the tyre and the road. As you don't need grooves to disperse water you may as well maximise the rubber to improve grip and also make a more durable tyre.

awavey

sungod wrote:

the racing world doesn't choose slicks for anecdotal reasons, f1 racing cars etc. use slicks because in the dry they grip better and waste less energy, in the wet they would aquaplane so if the roads are wet they have to switch to tyres with a water dispersing pattern

is now a good time to mention Michelin have actually developed a "slick" wet tyre for motorsport the only way you can tell the difference between it and the proper dry slick is the colour of the sidewall.

the profile of a bike tyre is so narrow it will just cut through the water building up in front of it (its that water build up that leads to car tyres aquaplanning), the tread blocks really are just there for providing more grip on loose surfaces.

I guess it just doesnt feel intuitive that a slick road bike tyre will be ok in the wet.

jezzpalmer

awavey wrote:

is now a good time to mention Michelin have actually developed a "slick" wet tyre for motorsport the only way you can tell the difference between it and the proper dry slick is the colour of the sidewall.

Yeah, the intermediate that the prototypes (not sure about other classes?) ran at LeMans, now that was a weird concept.
Not entirely sure how successful it was, will be interesting to see if they take it next year.

andrewjoseph

TheHound wrote:

I'm not really willing to take Wikipedia as evidence.

I'm looking for actual research done in this area. Cycling is full of myths about this or that being better, then when someone actually looks into it in depth it turns out wrong.

Put a knobbly cx tyre on your bike and see how far over you can lean in the dry, let alone the wet, compared to a slick.

I ride mtb and road. I don't ride slicks for mtb or knobblys for road. There is a logical reason for this.