All thing being equal,would a studded tire really

[weebl]

Originally Posted By: rpn453
Originally Posted By: SubLGT
Yes! At temperatures above approximately 5F. But at temperatures below approximately 5F non-studdable winter tires will begin to show a moderate advantage over studded tires when braking on ice. As temperatures rise to 30F, non-studdable winter tires rapidly lose the braking advantage they had at sub 5F temperatures.

Look at the graph and chart in this Russian test of winter tires at various temperatures: http://www.zr.ru/a/16906/

At -19C (-2.2F) the best studless tire requires 9.8m less to stop on ice than the worst studded tire. A significant advantage for the studless tire.

At -1C (30.2F) the best studded tire requires 58.3m less to stop on ice than the worst studless tire!! A monumental advantage for the studded tire.


Great link! It doesn't surprise me that the studless tires are better in the cold, because I do notice the studs don't dig into cold ice as well as warm ice, but it does surprise me that the difference is significant. However, it surprises me even more how big the difference is at warmer temperatures.

Leaving out the indecipherable Russian tire brand and comparing the Continental CWV2 and Michelin X-Ice North studded tires to the Blizzak WS-60, Nokian Hakka R, and Michelin X-Ice2 studless tires, the average braking distances are:

At -19C:
Studless - 31.3m
Studded - 37.4m (19% longer than studless)

At -13C:
Studless - 34.7m (1% longer than studded)
Studded - 34.4m

At -5C:
Studless - 54.9m (88% longer than studded)
Studded - 29.2m

At -1C:
Studless - 82.3m (149% longer than studded)
Studded - 33.1m

The studded tires are far more predictable, with the worst average stopping distance being only 28% longer than their best. The worst average stopping distance of the studless tires is 163% longer!

This is why it annoyed me when Tire Rack published the test that showed the studded Winterforce performing poorly compared to studless tires, while saying that they simply chipped the ice. If they had run that test at a variety of warmer temperatures, especially on wet ice, I think this Russian test makes it obvious that the Firestones would have been far superior to the others. The Norwegian test I posted accounts for temperature by performing "16-20 brake tests and the test series was repeated three times on different days and in different temperatures."

The studded continental performed much better than the studded Michelin at all four temperatures. For studless tires, the X-Ice2 was the best in the colder tests, the Nokian Hakka R was best in the warmer tests, and the Blizzak was the most consistent, taking the middle spot at all three temperatures. The Hakka R was probably the best overall of the studless tires, but not by a lot.

Even if the stud performance suffers a bit in cold weather because they chip the ice, at least they're doing something good for the next guy by roughing it up instead of polishing it!


If that's not proof for studded tires, I don't know what is. I've never run studded before, but the even slower response than last year in "clearing" the roads here (if you can even consider them cleared) has got me to thinking about studded for my next set in 4 to 5 years. The noise will be a hard sell to the wife, took my persistence and a guilt trip when we were expecting our first before she reluctantly agreed to winter tires. Got her around to the point where she asked me to find the best ones for the van this year.

 

[Craig in Canada]

Originally Posted By: weebl

If that's not proof for studded tires, I don't know what is. I've never run studded before, but the even slower response than last year in "clearing" the roads here (if you can even consider them cleared) has got me to thinking about studded for my next set in 4 to 5 years. The noise will be a hard sell to the wife, took my persistence and a guilt trip when we were expecting our first before she reluctantly agreed to winter tires. Got her around to the point where she asked me to find the best ones for the van this year.


Typically on my BMW I was running "performance" snow tires in the Toronto area. On this car I've had original Arctic Alpins and Dunlop Wintersport M3. I've driven other identical models with Pilot Alpin, Pilot Alpin 2 and Pirelli Snowsport 210s.

When I was shopping for snow tires last year I had particularly unhappy with the winter grip from my Dunlops and the past couple of winters had put me in a number of very dangerous icy conditions along with patches of ice hiding under other material suddenly reducing traction levels from "usable" to non-existant. I was planning to go to "full snows" instead of performance snows and I was actually looking at getting studded Hakka 4s.

Studs are legal in Ontario north of a line about 1-1.5h north of my location. They must be used only from Nov-April and must be lightweight Nordic stud systems to be used at all. I was seriously considering getting them and "taking my chances" on getting a ticket. I didn't think that police would actually be standing outside their cars listening for studs to drive by, then running the plates to see if I had a primary or secondary residence north of the cutoff line or not. I ended up not going with studs and getting Hakka RSis instead. Because of that, we had absolutely no snow all winter (practically a record) and I drove around on dry pavement all winter

I still give serious considering to going ahead with studs next time.

 

[Jim 5]

I've had pure winter tires over the years with and without studs. I'm a convert, and I'll never go back to studless. Studs are legal where I live. We have plenty of days around freezing temperature where the studs really bite into the ice when the ice has some melting snow/water on top. This is where "ice tire" (and all tires for that matter) seem to have the least traction.

The other benefit is that in my unscientific testing is that when your blizzak type tires have a few seasons on them, they turn into more of an all-season tire. The studs don't ever seem to wear out, and their advantages don't detriorate over time once the soft part of the blizzaks is worn off.

 

[SubLGT]

Originally Posted By: Rand
They should do a followup with 10,000 miles on all the tires and see how much studded degrades vs studless. would be interesting for sure.
....................


These reports are available from the Swedish National Road and Traffic Institute (VTI):

2004-09-10 Friction on ice for new and used winter tyres

2004-06-28 The friction on wet smooth ice for new and used winter tyres. An investigation concerning the influence of age, tread depth, tread rubber hardness, stud protrusion and stud force.

2003-11-11 The correlation between grip on rough ice of winter tyres and their age, tread depth and tread rubber hardness

2003-09-09 The friction on smooth ice for new and used winter tyres

http://www.vti.se/default____2782.aspx


English summary of report # 2004-06-28 The friction on wet smooth ice for new and used winter tyres. An investigation concerning the influence of age, tread depth, tread rubber hardness, stud protrusion and stud force:

"No significant influence of age on the ice grip on wet smooth ice of fully studded winter tyres with stud protrusion over 1 mm.
The ice grip for non studded winter tyres deteriorates with age and increasing rubber hardness.
Fully studded tyres with stud protrusion over 1 mm are superior to non studded winter tyres on wet smooth ice.

The aim of the investigation, which is sponsored by the Swedish National Road Administration and of the Norwegian Public Road Administration, is to investigate the correlation between ice grip on wet smooth ice of winter tyres and their age, tread depth and tread rubber hardness and for studded tyres also stud protrusion and stud force.
The investigation is part of a series of tests comprising the study of ice grip on three different ice surface conditions: Wet smooth ice, smooth ice at -3ºC and rough ice also at -3ºC. The tests on the two last mentioned surfaces were carried out in 2001 and 2002 and have been reported in VTI meddelande 923 (2003) and VTI notat 34-2003.
The tests in this part investigation were carried out on wet smooth black ice. This type of surface is one of the most dangerous with respect to traffic safety that has justified the development of studded tyres.

The investigation comprises 23 studded and 42 non studded winter tyres and four summer tyres mainly of the in Sweden popular brands Gislaved, Michelin and Good Year primarily of size 195/65-R15. The tyres were manufactured from 1981 to 2003 and the majority had been run in ordinary traffic. Some of the older tyres had only been used at earlier tests on ice and had been stored at VTI. A smaller number of new tyres produced 2001–2003 were also tested including four summer tyres used as reference to the winter tyres.
The results of the investigation, which show similar trends as in the two earlier studies can be summarised as follows:

• No influence of age on the ice grip on wet smooth ice could be found for the fully studded (100–110 studs) winter tyres with stud protrusion 0.9 mm and higher. Stud protrusion and stud force determine the ice grip in this category. The ice grip was also superior compared to non studded winter tyres and studded tyres with less stud protrusion.

• The studded tyres with stud protrusion less than 0.9 mm had as a group the next best ice grip in the age range 0–5 years. Then they were equivalent to the older non studded winter tyres.

• The ice grip on wet smooth ice for non studded winter and studded winter tyres with stud protrusion less than 0.9 mm deteriorated with increasing age and tread rubber hardness primarily during the first 5–8 years. The variation in ice grip was large especially for the non studded winter tyres, both the new and the older ones.

• Increasing tread depth in the
investigated range from 6 to 10 mm gave a positive effect on the ice grip for the studded tyres probably due to a co-variation between tread depth stud protrusion and stud force. The correlation was weak however. For the non studded winter tyres no correlation could be found between tread depth and ice grip on wet smooth ice in the investigated range from about 3.5 to 10 mm.

• Increasing tread rubber hardness diminished the ice grip for non studded winter tyres and studded tyres with stud protrusion below 0.9 mm. For studded tyres with stud protrusion 0.9 mm and more no clear correlation between hardness and ice grip could be found. As the hardness of the tested tyres increased with increasing age especially during the first years of use it seems as expected to be the primary reason for deterioration of ice grip with age.

• The ice grip increased with increasing stud protrusion and stud force. The stud force tended to increase with increasing stud protrusion. Worn tyres had normally lower stud force than new tyres with the same stud protrusion.

• The tested summer tyres had as a group the lowest ice grip.

• There was a large variation in results for the non studded tyres of the same age that could not be explained by the studied variables age, tread depth and tread rubber hardness. The explanation lies probably in tread pattern and other rubber characteristics than hardness.

An unexpected strong reduction of braking or cornering performance during maximum braking or cornering is seen as a serious accident risk factor especially as the yaw stability of the vehicle is seriously reduced if the friction of the rear wheels is drastically reduced during a rear wheel skid.

As a measure of stability in braking performance a braking stability factor has been defined as the ratio between the locked wheel friction and the maximum braking friction. As a measure of yaw stability a steering stability factor has been defined as the ratio between the 20 degree side slip angle lateral friction and the maximum lateral friction.

The braking stability on wet smooth ice was acceptable for all tested tyres.
The steering stability on wet smooth ice was fully satisfactory for all the tested studded tyres i. e. they had values over one. The non studded tyres had significantly less good steering stability somewhat deteriorating with age. The mean value was about 0.8. New tyres with soft tread rubber were best with values close to one.

The steering and braking performances of the tyres were measured in a special climate controlled enclosed high speed flat bed test facility developed by the VTI.
Very good correlation has earlier been found between results from the facility and lap time results from ice track circuit tests with cars as well as pure braking and cornering tests with cars on ice tracks.
The results from the tests are intended for use by ordinary consumers as a guidance in estimating the performance of used tyres for example when buying used tyres or deciding whether their own used winter tyres are good for another season. The results can also be used as support for decisions concerning possible changes in present tyre regulations. Furthermore researchers in the subject area could use the results. "

 

[SubLGT]

Originally Posted By: rpn453
[............Leaving out the indecipherable Russian tire brand ........


The "indecipherable Russian" is not a tire brand, but "average braking distance"

 

[rpn453]

Originally Posted By: SubLGT
The "indecipherable Russian" is not a tire brand, but "average braking distance"

No wonder they seemed so average! I always do a double or thicker border over results like average or total values on my spreadsheets, so that thought never even crossed my mind!

 

[rpn453]

Originally Posted By: Rand
They should do a followup with 10,000 miles on all the tires and see how much studded degrades vs studless. would be interesting for sure.


Yep. More info on the subject is always interesting to me! As SubLGT has shown, studded tires remain effective on ice as long as the stud protrusion is good, and I think that element depends heavily on driving style. On one extreme, my mother corners, accelerates, and brakes very conservatively, even though she drives pretty fast on the highway. Her studs seem to flatten out over time and lose effectiveness. At the other end of the spectrum, my buddy drives around the city in winter like he's in a rally race. His studs seem to get sharper and protrude more over time until the tips eventually break off after a few seasons. My conclusion is that mildly aggressive acceleration, cornering, and braking may be good for keeping the studs effective.

I tested that theory on my tires last year. Before last winter my Cooper Weathermaster S/T2 tires had about 15k miles on them with 10/32 tread depth and the studs were barely protruding from the rubber. They had seen a lot of highway use and had been babied in the city most of the time, except for occasional angry clutch drops that did them absolutely no favors. So I began driving more aggressively with them (but without the clutch drops). By the end of the winter, with about 20k miles on them, the studs on the front tires were back to being sharp with good protrusion, to the point that I was occasionally getting some oversteer around slippery corners. Those are now on the back and I'm hoping to work the other pair back into shape this winter.

Another key for keeping studs in proper condition is to always maintain the same rotating direction of a studded tire, whether they're directional or not. This is a recommendation I found in a technical document from Continental regarding their European factory-studded tires, and they felt strongly enough about it to mention it twice on the same page. The experiences of my friends who use directional studded tires and have seen excellent stud life seem to support that recommendation.

 

[SubLGT]

Originally Posted By: rpn453
........So I began driving more aggressively with them (but without the clutch drops). By the end of the winter, with about 20k miles on them, the studs on the front tires were back to being sharp with good protrusion,.........


Did you get better stud protrusion because you wore down the rubber faster than the studs with the agressive driving?

 

[Craig in Canada]

The studs don't need to protrude from the rubber. In the contact patch the weight of the car forces the stud into the road/ice/whatever.

Protrusion anywhere else around the tire is undesirable (as far as I know), pointless and no indication of any kind of performance. These are "studded" tires, not "spiked" tires.

In reading various tire manufacturer materials on modern studded tires, they are specific to talk about how the stud material is engineered to wear at the same rate as the rubber compound etc...etc....

 

[Jim 5]

Originally Posted By: SubLGT
Originally Posted By: rpn453
........So I began driving more aggressively with them (but without the clutch drops). By the end of the winter, with about 20k miles on them, the studs on the front tires were back to being sharp with good protrusion,.........


Did you get better stud protrusion because you wore down the rubber faster than the studs with the agressive driving?


That is how I have understood it.

 

[rpn453]

Originally Posted By: SubLGT
Did you get better stud protrusion because you wore down the rubber faster than the studs with the agressive driving?


That's my theory!

 

[rpn453]

Originally Posted By: Craig in Canada
The studs don't need to protrude from the rubber. In the contact patch the weight of the car forces the stud into the road/ice/whatever.

Protrusion anywhere else around the tire is undesirable (as far as I know), pointless and no indication of any kind of performance. These are "studded" tires, not "spiked" tires.

In reading various tire manufacturer materials on modern studded tires, they are specific to talk about how the stud material is engineered to wear at the same rate as the rubber compound etc...etc....



Properly studded tires always protrude a bit, and it seems that the more they do (up to a point, I'm sure), the better they work on ice. They may get noisier though and be more likely to break off. The studs on my "rally-style" buddy's car are always so spiky that it hurt my finger to press on them with any force, and that little Acura 1.6EL has always been the most impressive vehicle on ice. He had Hankook W404s and now W409s. Maybe it wasn't just his driving style that caused it; the specific tires, studs, or installers could have been partially responsible for that too. They were the proper stud size: TSMI #12. If they had been a larger size, they'd have been bronze in color rather than silver.

It's really not unique to him though. I've seen some very spiky studs on the tires of a few other buddy's vehicles: W409s on a '93 Camry, Hankook Dynapros on a '04 Mazda Tribute, and Cooper Weathermaster S/T2s on an older Hyundai Elantra. I was thinking it may have been unique to the Hankooks until I thought of that Elantra that my buddy's ex had.

 

[rpn453]

Originally Posted By: Craig in Canada
In reading various tire manufacturer materials on modern studded tires, they are specific to talk about how the stud material is engineered to wear at the same rate as the rubber compound etc...etc....


I was thinking: maybe factory-studded tires would wear more evenly since the stud specifications would be more strictly controlled. I've seen two sets of the Nokian Hakka 5 in the wild and the studs had good protrusion without being overly spiky. I have no idea on the tire mileage though. Is it unusual that I would examine and touch studded Hakkas in a parking lot?

I went through my bookmarks and dug up an old thread on street-stud class ice racing. The poster "Mike Kamm" seems to have quite a bit of experience with racing in that sort of class. It sounds like more stud protrusion increases traction, but decreases stud/tire life, so they typically use one size larger than the tire recommends. It also sounds like hard use increases protrusion by pulling the studs out a bit, so I guess aggressive driving brings out the studs by doing more than just wearing the rubber down around them.

Originally Posted By: Mike Kamm
I am from the Adirondack Motor Enthusiast Club [A.M.E.C.] located in upstate New York. www.icerace.com I have read this thread with much interest as we too run a Street Legal class which uses street studded tires. Our street stud class is about to start our fifth season of racing.

First I'd like to say that we don't have very many unhappy competitors. In fact it's our biggest growing class. But that is probably more due in part because we don't require roll cages for this class, and the cars are unmodified in this class. It is very cheap to get into and more than half of the cars in the class are driven to and from the races.

I agree with NINE_CA that keeping the studs in the tires is an ongoing problem, and we only allow a one size up stud from what the tire calls for. My experience has shown that going two sizes up or more shortens tire life even more. I do prepare my tires with the Loctite 496 like in the article referenced earlier in this thread. What happens is the stud holes in the tire tear and once the stud falls out, that stud hole is ruined. We usually run about eight race days with two races per day. I have never used more than 6 tires for the season. I'd like to offer one additional tip about studding the tires. If you have the tire dealer install the studs in the tires for you, you had better run them on the street [like NINE_CA said] or they will fall out the first time you step on the accellerator. But yes, after getting chewed up on the street, they will be far less effective. Best bet is to buy your own stud gun and prepare the tires yourself as referenced in the article earlier. But nothing is fool proof when it comes to street studded tires. It is a class where you really need to like to work on your tires if you want to win.

I read some references in this thread about to the thought that studded tires would offer more consistent traction throughout the race and be less sensitive to the polishing of the ice that occurs later in the race. I can tell you that the studded tires we use definately do suffer from late race traction loss and I have learned to slow down more for the corners later in the race. Many novices go off on the last two laps, as they don't realize this.

Our studs aren't allowed to protrude more than 1/16". Our tech inspector came up with that spec so the studs would stay in the tires longer and to keep speeds down somewhat, as we don't require roll bars in this class. Here's the sticking point with the 1/16" rule. If you run the correct studs [in my case the blue #11 studs in my Hakka 2's] when new, the stud tips will not protrude at all. So you are not competitive. If you go one size up [like I have] with a silver #12 stud, the tires will be legal at tech inspection in the morning, but after only a couple race days they start to loosen somwhat and "grow" a bit. They ususally end up at about 1/8". This is clearly illegal [for our rules] but most everyone seems to end up there using one size up studs. The only time anyone had gotten DQ'd for excessive stud length has been greedy racers who show up with two size over studs [gold #13's in a Hakka 1 or 2] and are blatantly cheating. So as you can see. teching for stud lengths is an inexact science. I made some "go" and "no go" stud length gauges up to check tires, but never use them because there are times when my tires are a bit over spec.

All in all, we all enjoy ourselves and the best drivers usually end up in the top five no matter what tires they have.

Incidently, we tried starting up an all rubber to ice class about six years ago and couldn't get more than three or four cars to run it. I think that is because no one bought Hakka Q's or Blizzaks. They all ran their old Hakka 10's without studs. On glare ice the races were so slow it was almost laughable. So then we started the current Street Legal stud class and it has taken off like wild fire. We now average 20 car fields. Funny thing is, over the last couple of seasons, there has been a group of SL racers who choose to run the Blizzaks and Q's in the studded SL class. So this year, we have created a second division for unstudded drivers called the SLU class. Go figure.


Street Stud Class

 

[Craig in Canada]

Interesting article. If I do ever purchase studded tires, I would definitely want something factory-studded to make sure that everything was just right.

I don't understand all of the factors at play in the stud arena, but it sounds like there's a lot of variables. If you're counting on "technology", like the Hakkas, you want to make sure that they get it all right.

 

[rpn453]

Originally Posted By: Craig in Canada
Interesting article. If I do ever purchase studded tires, I would definitely want something factory-studded to make sure that everything was just right.


Same here. I'm considering buying a set of factory studded ContiWinterViking2 tires for my mother's car. In her winter size (195/65R15 - $131), they're actually cheaper than many inferior studdable tires after factoring in the cost of studding. The prices vary a lot depending on size though, and there are even multiple tires in different load ratings in certain sizes, with significant price differences.

Factory Studded ContiWinterViking2 at Canadian Tire

Here's the Canadian version of the Continental document I mentioned earlier. It has some good info. My buddy talked to a Continental rep when he got his non-studded but studdable Gislaved Nord Frost 5s a month ago through an online distributor and apparently it is nearly impossible to acquire the proper factory studs in Canada so he went with a TSMI #11, as recommended by the rep. He found it difficult to find any studded tire in Canada in a 245/40R18. Hakka7s were over $2200 after tax in that size and needed to be special-ordered with at least a month wait.

Continental Stud Specifications

 

[mikiee]

Someone needs to invent a studded belt that you drive onto, then you hook it around the tire, similar to putting on chains. That way you only use it when you need to and remove for good weather.

 

[SSGSTbirdtoyman]

I have a real world test result regarding this topic

I drive a 2010 Mazda CX9 AWD and put on 4 new Hankook ipike RW11 studded snow tires and they work great. Indeed the new studded tires seem better than the older studded tires of 20 years ago or even 10 years ago. I read most of the test reports and I have no trouble stopping when dry or on wet roads at all. And in the ice traction is incredable.

Just last week we had a snow fall here in the NW and after it rained on a Sunday night and part of Monday it snowed and all the water on the roads and the new snow turned mostly to ice. I work a late swing shift and by midnight it was around 27f degrees and a long and steep hill is on my way home, well I went out at lunch and tested the roads and watched vehicles (mostly 4X4s, SUVs and Crossovers) attempted to get up this steep hill of ice. I should have brought my video camera but none of the vehicles (with whatever tires they had) could make it up this hill, most made it from 10 to 30% then slid back down. I had no trouble from this point and I gave it a shot at climbing the hill and presto- did great made it to the top with minimal slippage.

Mentioned my experience on the hill to a co-worked who drives a 2008 Subaru Outback with new Blizzak WS70s and he said it should be no problem either. Well he gave it a shot when it was time to leave at around 3 AM and he got a good start, and I waited at the bottom and could hear his tires spinning and he made it about 75% up the hill but then slowly slid sideways and then he just gave up and did a u turn and drove back down and he had to drive home the long way around this hill to get home. I again had no problem with traction or my studded tires in this thick ice scenenario.

So from this real world little test I would say that yes good studded tires do help.

 

[Ursae_Majoris]

Originally Posted By: rpn453

Leaving out the indecipherable Russian tire brand and comparing the Continental CWV2 and Michelin X-Ice North studded tires to the Blizzak WS-60, Nokian Hakka R, and Michelin X-Ice2 studless tires, the average braking distances are:


They are not brands, they are averages for studless and studded tires.

Also the article said that studless tires do not work as well in warmer temperatures since a thin layer of water forms on top of the ice and studless tires can not "stick" to the ice. In addition, it was not just ambient temperatures that affected the performance. Studded tires will perform better on sunny cold days (below the "break-even" range" of 13-15C), than studless.
Colder days produced hard, rough ice, when was easier for studless tires to stick to, but harder for studs to bite into.

Article conclusion--select tires based on the prevailing winter conditions in your area: frigid winters with hard-frozen roads--choose studless; gentler winters, frequent thaws, followed by roads covered with ice--chose studded tires.

PS Nokian modified their Hak R and Hak R SUV tires after these test tires. Rough water channels were retaining snow and tires were sliding. Nokian did their original test on the warm tires (stored and changed in the heated garage), Russians did theirs in the cold with cold tires. Warm tires shed snow better.

Nokian wend back and polished their tire molds, so water channels would shed snow easier. Tires produced after the end of April 2008 have the improved design.

 

[rpn453]

Originally Posted By: Ursae_Majoris
They are not brands, they are averages for studless and studded tires.


You just had to rub it in, huh?

 

[Ursae_Majoris]

Sorry, I missed SubGL's post about the same.