Studs on winter tires

[y_p_w]

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Kind of like regular tires not providing as much dry traction as slicks, so they're a problem right ? (ignoring how slicks might do in the rain).

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Just as an aside, anyone know what crampons are? They're spikes mounted on a boot that bite into ice or hard-packed snow, and are used by climbers in winter conditions. What they do is dig/cut into the ice, providing an anchoring point and superior traction. Walk on them on dry pavement or maybe granite (very common in climbing areas) and they don't bite and can severely reduce walking traction.

Tire studs aren't quite the same, but I don't see any benefit where they're not used on a surface (like ice or hard-pack snow) where they can consistently "disfigure" the surface. Tire studs might chunk off a piece of asphalt here or there, but I don't imagine they actually create tiny little form-fitting holes to anchor the stud against the pavement, like they would on ice. However - if someone is worried about running into a patch of ice where you can lose control quickly, perhaps the tradeoff of a minor loss of dry traction is acceptable.

I'm just thinking - tire studs would probably increase traction if someone was driving on a wooden surface (like a pier or platform). Of course enough driving of that type would destroy the wood over time. I don't think anyone loses any sleep over cutting the surface of an icy road.

 

[bluemax1]

Coming from a background in amateur rallying beginning in the late 80's (and an avid track nut), I've always been a tire afficionado whether they're summer/track performance tires or dirt/gravel rally tires or winter studded or non-studded tires.

first off to answer the original question, yes studs do compromise the dry handling properties of the tires. They have been shown in testing to increase braking distances and reduce lateral traction. The person saying they can't understand it from the standpoint that the rubber of the tires appears to be contacting the ground normally even with studs isn't taking into account the tire dynamics involved under traction related conditions.

The rubber is an elastic substance whose grip in part depends on conforming to the road surface's imperfections. Under the stress of braking the rubber that has conformed to the surface irregularities maintains an interlock while the rubber deforms somewhat elastically (stretching) as the car is decelerated. The metal stud do not form to the surface and because they protrude from the tire surface, they increase the likelihood of the rubber interlock releasing as the rubber around the stud deforms from the horizontal load caused by braking or turning whilst the metal stud itself does not deform and instead skates on the hard asphalt surface.

It is important to also note that studded tires significanrtly improve ice traction only within certain parameters. They also improve snow traction only on packed snow (there is little to no improvement in deep or powdery snow) or hardpacked snow with ice on top or below.

It might interest some folks to know that studded tires provide the greatest increases in ice traction when the ice is nearest the melting point (the melting point itself is dependent on the ice with 32f being the the freezing/melting threshold if the ice consists of pure water/snow and a commensurately lower temperature if the ice is a salt-mixed freeze).

What is even more interesting (and few people are aware of this )is that studs will actually decrease ice traction if the temperature is significantly below the freezing point of the ice. The reason for this is that the ice becomes so hard that the studs cannot dig/chip into the ice properly and the they skate on the ice the way they would on a concrete/granite surface. The studs work best when the ice is softer and near the freeze/melt threshold when ice is generally the slickest and most hazardous without studs.

All this info should be accessible on the internet somewhere if you look hard enough (some of it is from testing done by the Alaskan Transportation Bureau or whatever they're called).

Studded tires also tend to lose a lot of studs if they are driven for extended periods on dry pavement (possible to lose 1/4 to 1/3 of the studs in a single dry winter). Hard driving such as hard acceleration and braking also exacerbates stud loss.

All that said though, studded tires will provide the ultimate traction on ice and hardpacked snow when the temperatures are within 40-50f of the freeze/melt threshold (as mentioned earlier, it's not a set temp as it is dependent on the ice's composition and freezing point).


Max

 

[CapriRacer]

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jmacmaster said:

........If studs keep the rubber from gripping the hard surface of dry pavement as much as the rubber would grip dry pavement without studs, then the same thing should happen with studs on an icy road, because both dry pavement and an icy road are hard surfaces. Yet, studs increase traction on ice. In fact, as CapriRacer says, stude provide "a tremendous improvement in pure ice traction". So I conclude that on ice, the rubber grips as much as if there were no studs. I still say that its a myth that the studs make the rubber stand up off the pavement to some extent and that if you look at a studded tire on a vehicle the rubber is solidly planted on the pavement and is on the pavement just as much as for a tire without studs.....

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Unfortunately, actual traction tests don't support this.

Here's where I think the flaw in your logic is: Dry pavement has a great deal of macrotexture, where ice does not. Plus, ice melts at higher pressures - and while I am not 100% sure of this, I seem to remember a study where ice was observed changing phase (becoming water) due to the footprint pressure. In essence one of the problems of ice is that you are riding on a partial layer of water.

I think this also explains Bluemax1's comments about studs not working as well in colder temps - the pressure of the studs is partially melting the ice.


YPW said:

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.......Even CapriRacer (whose reputation on tires is pretty good) claims that the difference on dry pavement is minor and probably not detectable by most people who don't use ten-tenths of the capability of their tires.......

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Thanks for the vote of confidence, but I want to make sure this is understood:

I would not consider the decrease in traction "minor". However, most people don't drive near the limit of adhesion and are never in a position to correctly assess the traction of their tires. (This comment is directed towards those who say "I've been driving for 30 years and never had a problem".)

Having said that, I want to put this in perspective - most people DON'T ever drive near the limit of adhesion and WON'T experience the loss of traction - BUT, there IS less traction and in an emergency situation you could come up short!!

This is more of a cautionary note. DO NOT think that getting studs is 100% the answer. There is a compromise and you have to be aware of it.

If I were in a position where I was considering studs, I would carefully assess how often I needed them. If it is only once or twice a year, then I would "opt out" - and call in "sick" (as in "I am sick and tired of the other drivers and their less than skillful driving.")

But if encountering ice was the norm - sure - studs is the way to go.

This should not be a "one size fits all" - but, once you've made the commitment (in other words installed the tires - with or without studs), then you have to be aware of what your limitations are.

Hope this helps.

 

[D-Roc]

Good points, bluemax1 and Capriracer- I'm beginning to come to the conclusion that studs while they would have their benefits will probably not be the best choice for me. I will check out the Alaska Transportation website.
Thanks

 

[rpn453]

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Good points, bluemax1 and Capriracer

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Yes, those were very good posts.

Edmonton weather is similar to Saskatoon weather, so I'd run studs there. The only time I'm driving at the limits of my tires in dry/wet weather is when I'm driving overly aggressively and fully aware of it. I don't do that on my studs in order to preserve the stud life. But in slippery conditions, I'm constantly driving at the limits of my tires. For that reason, I like my studs. But as long as you're at least running winter tires, I don't think you're making the wrong decision.

Despite the reduced traction, I'd bet that my studded tires would stop me 50 feet sooner from 70 mph on dry pavement than your non-studded winter tires.

 

[bluemax1]

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Unfortunately, actual traction tests don't support this.

Here's where I think the flaw in your logic is: Dry pavement has a great deal of macrotexture, where ice does not. Plus, ice melts at higher pressures - and while I am not 100% sure of this, I seem to remember a study where ice was observed changing phase (becoming water) due to the footprint pressure. In essence one of the problems of ice is that you are riding on a partial layer of water.

I think this also explains Bluemax1's comments about studs not working as well in colder temps - the pressure of the studs is partially melting the ice.

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Yes, you are correct. The hard studs sink into the ice due to the greater pressure focused on the small surface area of the studs. The ice changes phase from solid to water and the studs sink in and 'bite'. They also have the ability to chip into (and chew up) the ice, and as a side effect, actually increasing traction for other vehicles with non-studded tires as well (this was from testing conducted by either the Finnish or Alaskan Department of Transportation. can't remember which because it's been years since I read it). The studded tires chew up the ice making it less slick for vehicles without studded tires (what they call the difference between rough ice and 'glare' or smooth ice.

The pressure from the footprint of the tire can (and does) cause a phase change from ice to water in the same fashion that skis and snowboards work. The pressure on the surface causes the snow/ice to form a thin layer of meltwater upon which you slide/hydroplane. This is the main reason for siping and why dedicated winter/snow tires have a lot more sipes in the tread design than normal summer or all-season tires. The siping uses capillary action to draw the meltwater away from the contact surface of the tire to prevent the slippage/hydroplaning.

However, in extreme cold (when the temperatures drop below -30 to -40f) The ice is so cold, it doesn't readily melt from the pressure, this means the tires are less prone to drastic slippage on the ice and the studs also do not provide the 'bite' that they do when closer to the freeze/melt threshold. In those temps (which occur in Alaska and have also occurred a few years ago in MI), the studies showed that non-studded tires actually provided better traction with shorter stopping distances than their studded counterparts. Under those conditions, what mattered most was the rubber composition (ability to retain softness and conformability to the road surface) and the tread pattern.

One of the major reasons not to drive dedicated summer tires in the winter is not only their lack of snow/ice traction due to the tread pattern not being designed for it, but simply because the rubber compounds are not made for those temps. Even on perfectly dry asphalt, in the cold temps of winter, the rubber compounds of dedicated summer tires (which are formulated to handle heat) turn into hard hockey pucks and lose their ability to conform to the road surface thereby greatly reducing their available traction (they're also much more susceptible to cracking).


Max

 

[D-Roc]

What about with the truck I have- Dodge Cummins. Are the studs going to last? Lots of torque going to my wheels, even going easy on the fuel. Would I end up with less studs at the end of the winter?

 

[1sttruck]

If you run studs on concrete highways you can wear both out, but one will last longer than the other. Studs last lots longer on ice and snow, and work best if they protrude at least 1/16in or so.

The 'claw marks' on our steep concrete driveway are pretty much gone now, left from the studded tires on the Honda Civic as it would fight for traction getting up out ice covered driveway. We donated the Honda back in 2000. If studs can chew into concrete and leave marks that last for years, they can also bite into 'hard ice'.

 

[jmacmaster]

I've done a lot of internet research and read numerous studies on the use of studs, and have done so every couple of years during the past 6-8 years.

Most of the arguments against studs are myths or mere speculative theories that are not supported by the studies, or by experience in the use of studs. A good example of the myths is the claim that driving on dry pavement results in the loss of a lot of studs, up to between 1/4 and 1/3. This is simply not true. I've driven two vehicles exclusively on studded snow tires for at least 15 years, and during the approximately 33 years before that I drove between 40 and 60 percent of the time on studded snows. I have never experienced much stud loss. My two current vehicles are going into their 5th and 6th winters on the same set of studded tires, and neither set shows stud loss. And most of the time where I live the roads are bare in the winter. In addition, I've never read a study supporting the excessive stud loss claim.

As to the claim that the studs keep the rubber surrounding them from gripping the surface the way the rubber would grip were the studs not there, consider the percent of the tire patch that is in contact with the ground that consists of studs. It is a miniscule percent. The vast amount of the tire patch on the ground has no studs in it. So even if this theory is true, it apllies only to a very small amount of the rubber that's in contact with the ground and thus traction loss would be very small. Furthermore, if the theory is true on dry pavewment it should be true on ice, and its been proven that studs increase ice traction, so the theory is suspect. This is a good example of speculative theory not borne out by studies and experience.

Obviously, studs grip soft ice better than they grip hard ice. There may be studies that show this. So what? The fact is that the studies, and experience, also show that studs significantly increase traction on hard ice. I'd like to see a study showing otherwise. And as to studies, I'm only interested in neutral, nonpartisan, impartial studies by orgazizations that haven't made the study results match a hidden agenda of the organization, such as organizations and government entities that are against studs because of the damage that they do to pavement. The best studies that I've seen are out of Canada and the northern Scandanavian countries (at least one of which REQUIRES studs in the winter).

And as to studs biting into ice, but not biting into pavement, as claimed in a prior post, this is another example of speculation not borne out by fact. Studies have clearly shown that studs damage pavement. That's why many states forbid studs. If the pavement is damaged, obviously the studs are biting into it.

You can mythologize, speculate, and spin untested theories all you want, but the fact is that experience and neutral, nonpartisan studies show that studs significantly increase traction on ice (including hard ice) and hardpacked snow.

 

[y_p_w]

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And as to studs biting into ice, but not biting into pavement, as claimed in a prior post, this is another example of speculation not borne out by fact. Studies have clearly shown that studs damage pavement. That's why many states forbid studs. If the pavement is damaged, obviously the studs are biting into it.

You can mythologize, speculate, and spin untested theories all you want, but the fact is that experience and neutral, nonpartisan studies show that studs significantly increase traction on ice (including hard ice) and hardpacked snow.

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I don't think there's anyone here who disputes that studs will greatly improve traction on ice. However - it's just common sense that a metal stud on pavement is going to negatively affect dry traction. To what degree (and why) seems to be a good topic for discussion. There's also no dispute that metal studs do damage road surfaces. But do they damage it in a way that they can use the result to improve traction?

I've got a tungsten carbide cleat right in front of me. I went to a bit of my driveway and tried jamming and dragging it. What happened was it didn't bite in, but left a little scratch mark. There's you're damage. What's likely to happen when a tiny 2mm stud manages to break off a piece of concrete (like Donner Pass near Lake Tahoe)? Is it going to be a nice round hole about the size of the stud, or maybe a big chunk that gets kicked into the air? Apparently studless ice tires were developed in Japan after studs were banned. They measured high levels of concrete **dust** on winter highways.

There's no dispute that tire chains damage pavement over time either. I can't think of anyone who would believe that a tire chain would be a benefit on dry pavement.

 

[ITSMR2U]

When all is said and done, and you're driving home on the freeway in the dark, and that wet look on the road is really black ice, it might be nice to have studs on all four wheels. Twenty years of company cars in the northwest and I would never be without them!

 

[1sttruck]

"Apparently studless ice tires were developed in Japan after studs were banned. They measured high levels of concrete **dust** on winter highways."

The had to as winter road maintenance increased by almost a factor of 10, as the studless tires were polishing the roads. Studies have found that studded tires keep some texture on the ice, and when the percentage of studded tire vehicles drops below something like 20% the road traction drops quickly.

As I've mentiond several times in other threads, look at ice racing rules; with studless tires tape your lights, bring a helmet and you can race, while even production studded tires need a roll cage and racing harness in addition to the other requirements. Lots more traction with studs.

I run studded tires and still carry chains. People rag on me about using studded tires and I tell them that I live on a hill at the mouth of the Columbia River Gorge. It's not uncommon to have snow and ice on top of the hill and the roads next to the river to be dry. With studded tires I can drive up and down the hill, and not worry as much about the ice patches scattered around, while with chains I'd need to put them on and take them off and put them on at least twice a day just to get to work, and twice for each time that I need to run an errand.

If people don't want to use studs it's fine, just please stay home if you can't stay in your lane or stop when you need to.

 

[y_p_w]

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I run studded tires and still carry chains. People rag on me about using studded tires and I tell them that I live on a hill at the mouth of the Columbia River Gorge. It's not uncommon to have snow and ice on top of the hill and the roads next to the river to be dry. With studded tires I can drive up and down the hill, and not worry as much about the ice patches scattered around, while with chains I'd need to put them on and take them off and put them on at least twice a day just to get to work, and twice for each time that I need to run an errand.

If people don't want to use studs it's fine, just please stay home if you can't stay in your lane or stop when you need to.

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Who could forget this?

http://www.youtube.com/watch?v=zMzeiMJQrvk

Of course nobody expects ice (or even much snow) in Portland. I'm sure some of the cars in question had 3-season tires that had lost most of their grip in freezing temps. Studs would have likely helped, as would chains. However - it didn't look like there was much space for any of the parked cars to install chains.

If it ever does ice up here in the San Francisco Bay Area, I'll have my chains ready, as well as those Get-A-Grips and YakTraks for my feet. Or maybe I'll just take a couple of vacation days off.

 

[bluemax1]

If you want to find tesst and studies that showed that studded tires have less grip than studless tires on dry tarmac and on hard ice, like I said, go look up the Department of Transportation studies conducted in Alaska (especially about studs having less traction than studless in very, very cold temps), Finland and Sweden (although you'ld better be able to read Finnish and Swedish for the last two or have someone who can translate).

If the vehicle has low power and/or you drive very carefully, it's possible to minimize stud loss, but if the vehicle has high torque and/or is driven aggressively, you can lose a lot of studs, I've personally witnessed it. I haven't used studded tires in a few years though so it's possible (and I would hope probable) that newer studs and studding techniques would show better retention.


Max

 

[D-Roc]

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If you want to find tesst and studies that showed that studded tires have less grip than studless tires on dry tarmac and on hard ice, like I said, go look up the Department of Transportation studies conducted in Alaska (especially about studs having less traction than studless in very, very cold temps), Finland and Sweden (although you'ld better be able to read Finnish and Swedish for the last two or have someone who can translate).

If the vehicle has low power and/or you drive very carefully, it's possible to minimize stud loss, but if the vehicle has high torque and/or is driven aggressively, you can lose a lot of studs, I've personally witnessed it. I haven't used studded tires in a few years though so it's possible (and I would hope probable) that newer studs and studding techniques would show better retention.


Max

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That confirms my suspicions in regards to studs on my truck. It has quite a bit of torque and even driving carefully I would expect to lose more than a few in one winter.

 

[c502cid]

Sorry bluemax, I produce gobs of torque with both my big block chevy trucks and losing studs is not even close to reality. You obviously do not have a clue how a stud is designed, not how it is installed. All you are doing is trying to rationalize your viewpoint with myth. The absolute only way you lose a stud is when the tire is so far worn out there is no rubber to hold it in anymore. As far as tire studies go, like any study considering rubber on the road, dont you think that just for a second that each tire will produce different results, just like in a dry cornering test? If you dont like studded tires, just say so and be done with it but those of us who actually use them know better......

 

[alreadygone]

A total moron can very well shed studs doing "burnouts"!

Anyone with a brain bigger than a walnut should be able to adjust their driving habits during the time period studs are viable.

If you can't adjust driving habits for conditions, you're gonna be in the ditch so quick you're not gonna be a problem for the rest of us.

If you can adjust for conditions, should be no great inconvenience to make allowances for studs when on dry surfaces.

Bob

Bob

 

[1sttruck]

"If the vehicle has low power and/or you drive very carefully, it's possible to minimize stud loss, but if the vehicle has high torque and/or is driven aggressively, you can lose a lot of studs," I have three years of driving a Dodge 4x4 QC SB 2500 diesel with studded tires, Cooper M+S, and don't recall loosing one stud. This is with a mix of freeway as well as city driving.

Someone gave us some studded tires that we used for a season a Taurus, some of the tires had lost studs, but they were older tires. Two Taurii ran with new studded tires last season, Nokian Hakka 2s, and again as I recall none lost any studs.

 

[c502cid]

Negative on the stud loss during burnouts boys. Do any of you that dont run them have any clue at all how they install? Do you realize the shape of a stud holds them in. At least get a little educated about them before you make stuff up!

 

[alreadygone]

c502cid,

For the record, I'm probably up to somewhere around 2million plus stud installs in the past 30 years. NOTHING can be made idiot proof,,,fools are too ingenious!

Bob