# Running directional tires backwards



## civdic (May 13, 2009)

I was out for a group ride last night and I noticed one of the senior riders had his rear Corsa CX tubs glued on backwards. I asked him about it and he said they perform better in the rain especially when the roads are slippery. The front tire was on pointed in the right direction.

He told me the directional thing is BS especially on a tire with a tread pattern like the Vittoria's. 

I've seen backwards tires before but I thought it was just a mistake. Anyone else run tires backwards?


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## AndrwSwitch (May 28, 2009)

Road tires are not directional.

I know they have arrows on them and they say they are.

But they aren't.

Tires with a significant tread, especially ridden on dirt, sometimes perform differently in different directions.


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## danl1 (Jul 23, 2005)

Whether these are meaningfully directional is one topic - but I agree that it's not really going to matter. 

The real issue here: He got it glued on, then realized they were backwards. The rest is all rationalization to shut you up.

Consider the facts - he contradicts himself twice: Once by saying it's BS (but that he does it that way because makes a difference) and another time by having one wheel each way.


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## civdic (May 13, 2009)

If it doesn't make any difference why put any arrows on the tires? Aesthetics?

I doubt he did it by mistake. He said he doesn't do it with his Conti's. Just the Vittoria and the Velolex's. He says he keeps the front wheel directional.


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## iheartbenben (Mar 18, 2011)

FWIW I run my MTB slicks in reverse to get more "bite" in the dirt with they directional "V" pattern turned backwards.

I imagine the same principle would apply.


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## kbwh (May 28, 2010)

*chuckle*

(See below. That lining up of the label with the valve stem on a tubular tire actually cracked me up. Big time.)


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## QQUIKM3 (Apr 20, 2008)

*Busted. .*



civdic said:


> He told me the directional thing is BS especially on a tire with a tread pattern like the Vittoria's.


You cought him doing something retarded, and he's not too quick in his feet. Vittoria wouldn't bother putting arrows into the mold to go on a tire if it weren't for a reason. The moron glued them on wrong. Probably doesn't even have the lable lined up with the valve stem either.


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## civdic (May 13, 2009)

QQUIKM3 said:


> You cought him doing something retarded, and he's not too quick in his feet. Vittoria wouldn't bother putting arrows into the mold to go on a tire if it weren't for a reason. The moron glued them on wrong. Probably doesn't even have the lable lined up with the valve stem either.


Careful with the retarded comments. On a tubi you don't have a choice where the label and valve stem line up.


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## danl1 (Jul 23, 2005)

civdic said:


> If it doesn't make any difference why put any arrows on the tires? Aesthetics?
> 
> I doubt he did it by mistake. He said he doesn't do it with his Conti's. Just the Vittoria and the Velolex's. He says he keeps the front wheel directional.


I won't say it 'doesn't' matter, but it's whatever is below trivial.

I can't find it now, but I recall an interview with a Continental rep that when asked about the directional arrow, said something to the effect of "It matters not-at-all. We just got sick of answering the same stupid question over and over again, so we put an arrow on the sidewall."


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## stevesbike (Jun 3, 2002)

if you're running a CX in the rain the last thing you're going to be worried about is whether you glued it on the right direction. You're likely going to be thinking "guess this is why they come out with the SC" as you slide across the road...


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## cxwrench (Nov 9, 2004)

QQUIKM3 said:


> You cought him doing something retarded, and he's not too quick in his feet. Vittoria wouldn't bother putting arrows into the mold to go on a tire if it weren't for a reason. The moron glued them on wrong. Probably doesn't even have the* lable lined up with the valve stem either*.


brilliant comment of the day, possibly the week...


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## forge55b (Jan 30, 2011)

cxwrench said:


> brilliant comment of the day, possibly the week...


I thought I was reading that incorrectly so had to check to make sure it wasn't glued on clinchers.


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## Fixed (May 12, 2005)

*No!*

OMG no, they are going to explode and kill you! 

The reverse osmotic hysteresis of the subvalent tire molecular compound is atomically linked to the Avogadro's Constant. You should not do this. Sheldon Brown said so.


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## danl1 (Jul 23, 2005)

danl1 said:


> I can't find it now, but I recall an interview with a Continental rep that when asked about the directional arrow, said something to the effect of "It matters not-at-all. We just got sick of answering the same stupid question over and over again, so we put an arrow on the sidewall."


Here's one version - I assume CC isn't lying when saying they discussed with Conti:


> We were staring at the tread and riding and staring wondering how this tread was supposed to grip better than a traditional "slick" tread. In our riding, we didn't notice any better or worse grip. So we asked. We were told that the little side tread shapes are for show. Slicks grab better and bikes don't hydroplane, but there are people who just refuse to believe that slicks are better. So Continental puts a little side pattern on to make a good show to allay the concerns of the doubters who want tread. After riding the tires for a few months, we can see that almost all of the wear happens in the middle of the tread and very little of the side pattern gets touched.
> 
> Because the middle is where the wear is, Conti' has molded two little wear indicators into the middle of the tread. When these are gone, it's time to toss the tire. If it's hard to see by looking at the tread, you can find it by scanning the sidewall for "TWI." The marking is on both sidewalls, so it should be easy to find. Also on the sidewall is a directional arrow. Our assumption was that the arrow, when at the top of the tire, should point forward. *We asked for confirmation, and found we were right, to a point. It can also read properly if it's pointing forward at the bottom of the tire. The arrow is there for the people who want such things; the tread is not directional. *


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## AndrwSwitch (May 28, 2009)

I think the tread pattern is kind of cool. I don't know if I'd miss it if it were gone, but it says "GP4000" to me.

It's interesting to note that a lot of tubulars don't have any tread pattern at all.


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## Kerry Irons (Feb 25, 2002)

*Imagining*



iheartbenben said:


> FWIW I run my MTB slicks in reverse to get more "bite" in the dirt with they directional "V" pattern turned backwards.
> 
> I imagine the same principle would apply.


Yeah, but the principle with treaded tires is that the contact surface deforms and so the tire can grip better against the soft and deforming surface. Last I checked, the road surface will NOT deform and so tread on road bicycle tires is meaningless.

And per many other commentors: the reason they put arrows on the tires is so their customer service department won't get flooded with calls and e-mails asking which way the tires go. Engineers have a sense of humor too you know.


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## Shiftracer (Jan 18, 2008)

Contrary to popular opinion...and Sheldon Browne...under certain circumstances siping on road tires makes a difference. Whether for bikes or cars, siping is intended to break the surface tension on the pavement to allow the rubber to contact the surface. Siping is directional to help then guide the water away from the contact point. Cross-hatched or herringbone patterns (like the Corsa CX) do something similar but without guiding the water away. For cars, it's mandatory as hydroplaning on asphalt surfaces is a proven fact. For bikes with their dramatically narrower profile, it's a bit of a different story. Normally the pavement itself acts as the siping...not allowing a sheet of water to build up under the tire. The exceptions occur where the asphalt disappears: Paint stripes, metal utility covers, and other very smooth surfaces that occur in our roadways. Anyone who's raced an urban crit in the rain on slicks, and where the corners have painted crosswalks, has likely experienced at least some uneasy moments. I'm not saying all siped tires will let you corner in the rain like it's dry. Compound also enters into the equation. The best all-weather tires also have a shoulder compound that's formulated to perform better in the wet. A properly engineered siped wet weather tire will outperform a slick in the conditions for which it was intended.


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## Kerry Irons (Feb 25, 2002)

*Pretty much wrong*



Shiftracer said:


> Contrary to popular opinion...and Sheldon Browne...under certain circumstances siping on road tires makes a difference. Whether for bikes or cars, siping is intended to break the surface tension on the pavement to allow the rubber to contact the surface. Siping is directional to help then guide the water away from the contact point. Cross-hatched or herringbone patterns (like the Corsa CX) do something similar but without guiding the water away. For cars, it's mandatory as hydroplaning on asphalt surfaces is a proven fact. For bikes with their dramatically narrower profile, it's a bit of a different story. Normally the pavement itself acts as the siping...not allowing a sheet of water to build up under the tire. The exceptions occur where the asphalt disappears: Paint stripes, metal utility covers, and other very smooth surfaces that occur in our roadways. Anyone who's raced an urban crit in the rain on slicks, and where the corners have painted crosswalks, has likely experienced at least some uneasy moments. I'm not saying all siped tires will let you corner in the rain like it's dry. Compound also enters into the equation. The best all-weather tires also have a shoulder compound that's formulated to perform better in the wet. A properly engineered siped wet weather tire will outperform a slick in the conditions for which it was intended.


There is absolutely nothing even remotely approaching hydroplaning on bike tires. You can look up formulas for hydroplaning (function of tire width, load, and pressure) and you would find that bikes would need to be going well over 100 mph to trigger hydroplaning. The siping and various rib, file, etc. tread patterns are for looks. Metal and paint surfaces are more sliperly due to there being nothing for the tire to deform around and grip compared to asphalt or concrete. Tire tread improves traction when it can deform the contact surface and obviously this does NOT happen on pavement.

Tread compound, casing flexibility, and tire pressure are what influence grip on a road tire, not tread or tread pattern.


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## Pitts Pilot (Dec 5, 2011)

It matters which way you put them because they look stupid the wrong way. This can be avoided by getting tires with no tread, as road tires need none. As far as improving the Corsa CX performance in the rain, I did ths by putting a GP4000s where the Corsa was. It does, however, bug me that my current favorite has a tread. Maybe I'll try the Pro4.


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## erickB (Jan 3, 2012)

well its a coincidence tha every road tire that i know put the direction arrow in the way that guiding the water away from the center of the tire, i now aquaplaning it´s not going to hapen in a bike, but maybe helps to get water away and get a litle more grip


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## Kerry Irons (Feb 25, 2002)

*Nope*



erickB said:


> well its a coincidence tha every road tire that i know put the direction arrow in the way that guiding the water away from the center of the tire, i now aquaplaning it´s not going to hapen in a bike, but maybe helps to get water away and get a litle more grip


If there is no hydroplaning then "getting water away" means nothing. The tread pattern on a normal road bike tire is for cosmetics and maybe to lighten the tire a little. You need to reread some of the comments from the tire companies noted above.


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## AvantDale (Dec 26, 2008)

From Michelin:

The oval shape of a bicycle road tire contact patch permits effective water evacuation to help keep the tire from hydroplaning.

The footprint of a 23mm tire (approx. 7 sq. cm) is so small that the bike would need to be traveling at about 120MPH in order to hydroplane.

Nevertheless, some road tire models are designed with specific tread structures – primarily for cosmetics or to comfort the consumer. Sometimes tread features can help provide a harder rubber compound a better mechanical link with the road surface, for better grip.



Michelin Bicycle USA - A better way forward®


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