I have experienced conventional tread designs that worked as well as, if not better in the rain than a sexy V-shaped design.
Does the V-shaped design have any merit? Or is this just snake oil?
V-Shaped Tire Tread: Snake Oil?
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The V shape does indeed work. Some folks have confirmed it by realizing they've had the tires backwards and noticed the difference. Besides, race tires use this and they wouldn't if it didn't work.
But like you said, there are some non-directional tires that work as well, or better, in the rain than some of the directional designs. Remember - tires are a compromise, so an improvement in wet traction can mean a shortcoming in the wear or dry traction department. But the directionality only compromises the convenience of rotation.
I saw a test that was done where directional tires were run both forward and backward on a wet course to see the difference. I'm pretty sure it was Tirerack but I can't find it. Anyway, they couldn't tell the difference. But that was just wet pavement with no standing water. On standing water, I think a directional tire that clears the water out efficiently would make a big difference. The directional Michelin Pilot Sport A/S tires I got this year are more resistant to hydroplaning than any other tires I've ever used.
quote:If Tire Rack did the test, then I'll confirm that Tire Rack's test course does not use enough water to explore hydroplaning, which is where the V shape is supposed to work. But I should also tell you that the difference caused by the V shape is relatively small (my memory says that the value is 10% depending on the direction of rotation), which means the difference between a directional tire and an identical non-directional tire would be 5% - a value where some folks won't be able to tell the difference.
Originally posted by rpn453: I saw a test that was done where directional tires were run both forward and backward on a wet course to see the difference. I'm pretty sure it was Tirerack but I can't find it. Anyway, they couldn't tell the difference. But that was just wet pavement with no standing water. On standing water, I think a directional tire that clears the water out efficiently would make a big difference. The directional Michelin Pilot Sport A/S tires I got this year are more resistant to hydroplaning than any other tires I've ever used.
If I'm not mistaken, Tire Rack tests the wet traction of a tire but not the hydroplane resistance of a tire. I don't see how you really could assign a number to that unless you just drove a car through x inches of water at y MPH and steadily increased the speed until you had loss of control and then repeated the tests over and over while increasing water depth. The results would obviously be much different with, say a 50% worn tire. Also, the marketing hype is that the V shaped tread forces the water out to the front and away from the contact patch.
I will say that of the tires I've had, (Goodyear RSA's, Firestone SZ50, Goodyear GT +4, Goodyear Regatta 2's, Firestone Wilderness HT, Goodyear American Eagles, Goodyear Eagle GA's, Goodyear Eagle HP's, Cooper somethings), my current set of Goodyear Eagle F1's display outstanding hydroplane resistance, much more so than the SZ50's with their directional tread. The F1's seem much better, even with 5/32 remaining than the others (except the SZ50's) when new. I know the tires are apples to oranges in terms of performance levels but I wanted to give a range.
2 directional tires I tried got noisy in the last half of its life. Toyo T1-S and more recently Kumho MX. Very noisy! So be ware. Non-directional tires, rotated properly, will not develop saw tooth, thus not get louder as the miles pile on.
For my FWD car, I rotate with Forward-X pattern. Figure A in this page:
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=43
Figure D has to be the worst way to go in terms of tire life and noise level.
I wish there were more ultra-high performance non-directional tires. I have AVON Tech M500 (3-season), Kumho ECSTA ASX (all-season) which I like very much. The M500 cleared water better than the T1-S but not as good as the MX. So there you go.
quote:Is the "saw tooth" you refer to the same thing as "feathering" which can be caused by high speed cornering? The very directional F1's I have, have always been rotated same side front to back and they are the quietest tires I have ever owned, even half worn or so (on smoother pavement mind you). I currently have 20k + on them and the are wearing just as even as can be. I rotate every 5K. Look into Nitto Neogen and Invo, Pirelli P Zero Nero M+S, and BF Goodrich. The tires on my truck feather because I like to drive fast in curves. I've seen brand new tires ruined (pursuit courses) due to feathering which was un-related to rotation issues.
Originally posted by VelociRacer: 2 directional tires I tried got noisy in the last half of its life. Toyo T1-S and more recently Kumho MX. Very noisy! So be ware. Non-directional tires, rotated properly, will not develop saw tooth, thus not get louder as the miles pile on. For my FWD car, I rotate with Forward-X pattern. Figure A in this page: http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=43 Figure D has to be the worst way to go in terms of tire life and noise level. I wish there were more ultra-high performance non-directional tires. I have AVON Tech M500 (3-season), Kumho ECSTA ASX (all-season) which I like very much. The M500 cleared water better than the T1-S but not as good as the MX. So there you go.
You can call it by many names, saw-toothing, feathering, cupping... It happens on any tire that is not rotated properly or frequently enough. I drive my car pretty aggressively, especially while cornering. But to reverse the rotation every other time helps even out the wear patterns in many ways, thus giving the longest life for a non-directional tire.
There is no 15" of the Nero, or that would be my #1 choice. For me, Kumho ASX was the best.
I also rotated the directional tires at 5,000 miles or less. But it didn't prevent the saw toothing. The AVON Tech M500 (non-directional), on the same car, the same driving style, the same rotation intervals are quieter than new, even after 15,000 miles so far. I expect another 15,000 miles and by the looks of it, it is going to stay quiet.
quote:Not so fast. Cupping is quite different, as it's an accumulation of 'random spotting' wear from worn or binding suspension parts (and possibly imbalance). Then one can have feathering or saw toothing across the tread (inside to outside, usually caused by improper toe-in or hard cornering) or along the circumference (hard acceleration and braking or insufficient rotation). Is that a decent generalization?
Originally posted by VelociRacer: You can call it by many names, saw-toothing, feathering, cupping... It happens on any tire that is not rotated properly or frequently enough.
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quote:I've given up on symmetrical tread design, especially the V-pattern, because they they all turned out to aggravate tramlining to the point oif being noticeable or even or annoying. In theory, a wedge-shaped grooves should help evacuate water from under the tire better than other patterns. On a dry road surface, no tread shape or even having a tread pattern makes sense (other than in regard to noise). The road's surface texture (or lack thereof!) is what provides "bite." A slick (not any bald tire, Jethro!) is stickiest on dry.
Does the V-shaped design have any merit?
I think we can argue the point to death. The end result is that you have to find out which tread pattern and tire design best suits your vehicle. Obviously, my experiences won't be the same as yours. And your experiences may be vastly better than mine.
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I just read that nonsense that I wrote up there. I meant to say "they all turned out to aggravate tramlining to the point of being noticeable or even annoying."
The best tire choice is always a compromise and will depend on vehicle, driving conditions, driving style and personal preferences. Given my circumstances, my crititeria for tire choice are
- predictable behavior under extreme directional changes (accident avoidance)
- road holding on wet and dry
- stability (runs and brakes "straight")
- puncture resistance
Were I to live elsewhere, drive a different car or on different roads, other criteria would come into play.
I don't care much about wear, because I don't get ever more than 12k miles out of a set of tires anyway. ![[LOL!]](/forums/graemlins/lol.gif)
quote:The point I want to make is that there isn't enough water on Tire Rack's test track and it is much closer measuring dry traction than I think it ought to be. Put another way, you can sense and measure the affect of hydroplaning resistance has on tire traction at much lower speeds and much lower water depths than one might think.
Originally posted by wantin150: If I'm not mistaken, Tire Rack tests the wet traction of a tire but not the hydroplane resistance of a tire......
I bow to CapriRacers engineering experiance. Guru's like that keep this board credible.
Directional V-directed tread designs are not SNAKE! Who told you this?? Goodyear's(GY) German Eagle F1 GSD3 is V-directional and this is a significant part of earning its rating as one of the best (if not the best) for hydroplane and rain traction/handling. GY's Assurance Triple Tread & Michelin(MN) Hydroedge also (other choice examples) also feature this. The proliferation of directional all season (ie MN/BFG Traction TA) to UHP tires having V treads being there for no reason. They work, although some are better than others.
I can not elaborate further, but also the addition of Silica based tread compounds have also revolutionized wet traction safety ![[Smile]](images/icons/smile.gif)
Side note? Was GY's Aquatred I the "pioneer" of directional treads for street applications?
Side note? Was GY's Aquatred I the "pioneer" of directional treads for street applications?quote:I recall a "Gatorback" tread design that was earlier, based on F1 race tires. "Gaterback" was not the name of the tire, but a popular name because the design looked that way. What was "unique" was that the Aguatred used a channel in the middle of the tread. This was actually an outgrowth of a "twin tire" idea someone had. Others had used the channel concept before, but Goodyear popularized it.
Originally posted by outrun: ....Side note? Was GY's Aquatred I the "pioneer" of directional treads for street applications?....
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