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Stupid ? of the day re tire tread direction(9 posts)

Stupid ? of the day re tire tread directionvindicator
Oct 31, 2003 7:36 AM
I use Conti Ultra Gatorskins. I'm curious if there's an "official" direction these are supposed to be mounted. The "put the trademark on the drive side" adage doesn't work, as there are trademarks on both sides. The treads have little grooves in them that have two segments - one parallels the direction of the tire rotation and the other goes off at an angle toward the edge of the tire. They're slight enough that I'm sure it probably doesn't matter, but (just in case), as I'm sitting on the bike looking down at the top of the front tire, should the grooves go "fore and out" like this (I hope this comes out):
x
x
x
x
x
x
x
x
x
x
x
x
x
x

Or "aft and out" like this:
x
x
x
x
x
x
x
x
x
x
x
x
x

Strange things we wonder about, I know...
On road tires, the tread is there just to make the tire lookMR_GRUMPY
Oct 31, 2003 7:44 AM
nice. Tires that look "nice" sell better than plain tires.
no no, you need tread for days like this...rwbadley
Oct 31, 2003 8:18 AM
two days ago it was 83f here. This AM saw 'heavy frost'.

I always get the feeling tire tread is something like a fingerprint on the hand, it gives just a little extra siping for glomming onto a surface, especially uncertain road surface. After trying both, I thought the treaded tires seemed a little more secure in corners, tho I know some studies say tread doesn't make a diff, and racing slicks are indeed... well, slick.

I used to ride Avocet 20's and when I made the switch to other tires (treaded)it seemed they were more predictable corneringwise. But they could have just been better tires ;)
no no, you need tread for days like this...asgelle
Oct 31, 2003 10:08 AM
Tread pattern on tires has no effect unless the surface is soft enough for the tread to leave an imprint, such as mtb tires in sand or gravel. This is described in the rec.bicycles FAQ. However, bicycle road tires have sipes which add nothing to traction and add to tread squirm. All studies I've seen show tread doesn't have an effect. Do you know of any that show otherwise.
tread design...rwbadley
Oct 31, 2003 8:56 PM
The short answer is: no. The information I have seen shows road bicycle tire tread having minimal or no effect on outright adhesion of tire/road surface under certain conditions. This being due to an especially small contact patch of the bicycle tire.

The snow pictured and in the case of soft surface would qualify as a case where a treaded tire might indeed have advantage over a slick, tho in the case of high performance 'road' tires it would indeed be minimal. I have taken slick tires off road, and if you have the right tire pressure, they do ok.

I have seen some tire mfr sources stating that traction of cycling tires tread/no tread showing minimal effect under certain conditions. Compound of the tire being primary to the traction. To make it even more confusing, other mfr sources will then crow how their new tire tread design enhances traction etc.

For motorized sports, racing slicks indeed put the most soft sticky rubber to the ground. We could assume this would also be the case made for cycling tires. The difference comes in what purpose the tire will be put to. Our roads in Reno can be pretty ugly at times. What surface will the tire see? How long do we want the tire to last? Cost? etc...

My experience with Avocet vs Conti 3000, vs Specialized Turbo & Armadillo, vs Panaracer Stradius Pro vs Michelin (whatever they were, they were also slicks). The Avocet was a slick tire. It rode ok, it seemed to cut fairly easily. They gave me an uncomfortable lack of confidence cornering due to what I felt was an unpredictable character of drift. What must be part of the equation is drift and predictability near the limits. The Specialized Turbos rode with poor comfort but seemed to handle a little better. The Michelin lasted well, but also were low in comfort, while handling ok. The red gumwall Armadillos wore like iron, but rode like crap unless you low pressured 'em. They also liked to blow off the rims at higher pressures. The Conti 3000 I have had real good luck with. I have blasted some narly corners with utter confidence on them, and they seem to ride pretty well. Same for the Panaracers, I really have liked them alot.

The casing design will play a part in how well that rubber is kept on the road. Suspension will play a role in keeping the rubber on the road, as will frame character. Does the frame flex? Is the frame very stiff? Will it tend to hop the rear end in corners. Are the tires better at a lower pressure? How does that effect power transfer and efficiency? Does the fork behave well under load? All making for a complex issue.

Moving that aside for the moment...the difference that occurs via tread design for specific use will affect the tire treadlife, road holding under braking, cornering and adverse conditions (water, sandy etc). As the tire wears, it will change character to the rider in various ways. The 'squirm' you mention is a valid point, tho the minimal tread pattern most high pressure road cycling tires have may rule most of that out, the balance being casing deformation under load.

My own experience shows huge difference in tire character on motorcycles and bicycles. Some tires will drift in a more controlled manner rather than sticking like glue then letting loose rather more suddenly. This most likely would be attributed more to rubber compound and carcass design. Predictability may be as positive an attribute as is outright adhesion limit.

I guess it all boils down to what works for the purpose and how much money you want to throw at it. I have had some of my best luck with the cheapest tires. But on the bike I know I will ride fast down some twisty road, I certainly want to have confidence in the tire. At this time, it seems the tires I have confidence and like to ride all seem to have some form of tread design, for whatever reason...

;)
What I've heardcyclinseth
Oct 31, 2003 8:31 AM
road tires should be mounted with the psi info on the drive side. I just bought a pair of Specialized Whatevers and they have an arrow pointing in the direction of rotation.
ContisFez
Oct 31, 2003 12:26 PM
If it is truly directional, there will be a rotational arrow on the sidewall. Otherwise it really won't matter.

When it doesn't matter, I just put the label with the brand, size, and other relevant info on the drive side.

BTW, Conti GP3000 is nondirectional and has orange labels (they are different) on both sides. So I just put the one with the above info on the drive side.
Conti Attack/Force Have Rotational Arrowsmerckxman
Oct 31, 2003 1:26 PM
...on the sidewalls; not mentioned in paper instructions that came with mine.
Aft and OutKeeponTrekkin
Oct 31, 2003 8:00 PM
I have these on my commuter bike. On cars, the tread is to drain water and the "aft and out" orientation should tend to squeegee it out while the alternative would tend to squeegee it in (not what I want).

That said, my other bike has slicks and it doesn't seem any looser in the wet.

I use the aft and out method because it just might matter, not because I know it does.