Is the treadwear rating the moulded number following the size and ending in a V? If so the Dunlop Direzza is 85 and is the same for S1, M1, M2 and H1 which seems a little at odds with the actual wear rate I have experienced.
And Ray, I have such a pile of used 205/50 x15 Direzzas that I had to climb up to see the numbers so curry remained undisturbed!
That's the speed and load rating. I think V means rated to 240kph and 85 is somewhere around 500 kgs. A Google search will give you the exact figures.Originally Posted by Howard Wood
Also, apparently treadwear ratings often aren't consistent between brands so it is hard to compare.
Last edited by Paul Wilkinson; 04-02-2014 at 08:50 AM.
Thats the problem CobraV8, they are cheap(as far as performance tyres go) around $1000 a set for 4 new(unless corrected) but i believe the wear rate is very high? i have never raced on them so relying on supplied information!! others may have a better idea. I believe race class's like Central Muscle are marking the tyres and regulating there usage to stop the more wealthy racers fitting a new set every race?
Come to think of it the Wear rating is for the American market and although this will capture most tyre manufactures there are probably some that won't. The words "Wear rate 80" "Temperature 120" etc should be molding into easily readable words on the side of the tyre!!
Dale M
Oh boy. So like bra sizes, it rather depends on who the manufacturer is as to what the numbers really mean?... Ironically, I know more about bra sizing than tyre wear numbering.
Don't know much about bra sizes but even the 2K cup guys are spending $1,000 on tyres to be competitive. I know I have spent it.
Graeme
Tire Sidewall Branding lesson 101. A hugh amount of information is available from the sidewall branding but not all information is equal. Depending upon where and which market the tires are manufactured for then there are several different brandings applied i.e. Europe ECE , America DOT , Asia CCC etc so expecting all tires to be DOT marked or not and as such , street legal or not , is a misconception. Race tires will have no such branding but the cheater style tires may have DOT or similar branding but are essentially race tires with lighter all-round construction, minimal tread grooves etc. and not realistically street legal. Similarly the UTQG labeling ( Treadwear, Traction, Temperature ) give an indication of similar performance of like branded tires , but given that all manufacturers use different combinations of products to produce their tyres and perform their own controlled testing and branding then not all similarly branded tyres will perform the same.
The point I’m trying to make is that if you ask 5 different “ tire experts “ the same question then you are likely to get 5 different answers and possibly not any of them are wrong.
Maybe the trick with the ERC series is to go around the paddock at the next meeting having a quick look at the tyres being used and make a list of all of them. Then make that the list of acceptable tyres for the series (assuming you don't find anything unacceptable). Then anyone wanting to run anything different can apply to have another tyre added to the list - a couple of minutes on the internet should show whether it is in the spirit of the series and if it should be accepted. That way no-one turns up saying 'but it is a WOF-able tyre so I should be able to run it'. That conversation has been had well upstream of purchasing. Set a criteria e.g. min 4mm tread covering 3/4 of the tyre or whatever is desirable so there is a good basis upon which to reject or admit new tyres....
Thanks Parnelli.
You have pointed out the problems, but what's the solution?
Supply your car/tire inspector with a durometer, worst case scenario some 'old' race tires might pass.
$1000 a set sounds like the right money.
The Kumho V700 that CMC ran at one point lasted well, ( have been told nearly a season)
It seems that restricting tyres on some treadwear number may well be a real can of worms Tony. We are still waiting to hear back from Dunlop regarding a treadwear number for the Direzzas (probably one the most popular DoT/road legal race tyres in NZ) or even if such a number/ rating exists. It seems that this number is primarily a US market initiative and may not be available for tyres not used in that market and at best seems to be somewhat arbitary.
Given that there were a number of competitors using the Hankook at last year's Festival and Ray appears happy to allow them in his series maybe that ship has already sailed. I am finding the combination of purchase price, performance and a wear rate which seems at least no worse than other DoT tyres to be a fairly compulsive argument.
Interesting diversion. Thanks Parnelli - I think I now know who you are!!!
The last thing I want to do is over complicate what we have , which is currently very simple. If I look under a car and see tread, then I assume that all is reasonably OK. If what I see is just two grooves and no tread pattern , then it suggests to me that maybe it is more of a race tyre than a road tyre.
That is about as simplistic as it gets without getting bogged down with numbers, lists, acceptable and exceptions.
As I said earlier, with a speed bar in place which only affects maybe 5 people (two are 'rebuilding') then a slight performance improvement for the majority is not going to make too much of a difference. As Pointed out earlier by Dale, over the last 25 years or so, there has always been 'the tyre of the moment' which has gradually improved lap times. I think the first race I entered in NZ, the winning Lotus Cortina at Pukekohe had a fastest lap of about 1:20.
By enforcing the speed bar, those who are pushing the very limits at the front end are going to have to back off anyway, so further performance improvements in the handicaps are pointless, but as Tony and Derek prefer scratch races anyway and there is no speed bar, their lap times are still fed into the system because that is the way we do it. The tyre rules are still the same but the rules also state that if they continually break out, they may be asked to go and race elsewhere! Or, they do something to reduce their performance, either by driving more slowly, detuning the car or as in this case, using a tyre with a lesser performance.
Hi Tony and Ray , To be honest there is no Fair and Equable way to sort it out over a range of tire brands. The only honest system is for a class to specify one type of tire brand for all competitors ( V8 Utes, Supercars, Central Muscle etc ) . This is obviously no solution for a class running numerous wheel sizes because no one supplier can offer the same tire product across a range of sizes.
What’s the solution ? You don’t want to here this but it all comes back to Handicap Races. If any competitor chooses to run the latest, stickiest tires available then it is up to the co - ordinater to handicap that person accordingly. When that person realizes that spending all this extra money does not let him unfairly win races then he will realize the futility of the exercise. It really is that simple to do !
if you are running a 14 inch rim like and Alfa 105, the correct size rim for the car, you are really scatching to find tyres.
even in period correct rubber ie Avon vintage tyres most are 13" or 15" - 14" is like rocking horse doo doo
Mike L
Thanks again for the debate. Parnelli, I think you are correct as it covers not just tyres but any or all other tweaks a driver elects to use, but we adopted that philosophy 18 years ago when it was blatantly obvious that a small straight four cylinder was generally no match for a V8 or V12 monster.
When you get people jumping up and down about 100% standard cars and then blowing the wheels off much larger cars, and you find out that the internals of their car have been tweaked, illegally, it merely points to on track performance is all that really matters at the end of the day, otherwise you are going to be either totally stressed or demented or both. Live is for living, not stressing about the little things.
Agree also that with 10, 12, 13, 14" wheels the choices are limited as manufacturers go for bigger and bigger wheels on current production vehicles. Running on true period rubber isn't very easy either therefore not really feasible.
Series such as BMW E30's can run with a control tyre, weight limits, shocks/springs but it isn't so easy for the remainder but as we promote variety anyway, it is sometime easier to stand back.
We still need a definitive ruling on the Hankook. Is it road legal or not?
I agree Ray with some flexiblity in the tyre choice but I also believe that they must meet WOF regulations. I also don't see that you have the time to check every car. Running a control tyre or designated option as Dale does in HMC is a good idea but it doesn't suit the variety of cars that race. Tony you have a hurdle in front of you with this but legality is the issue of what you can use and that will change month by month.
Sorry Ray its hijacking your thread a bit but is a good subject.
Not hi-jack at all. These issues deserve an airing somewhere and maybe they'd get more traction as a stand-alone thread but it is good to get a variety of opinions from both within and outside the series. For people such as myself who tend to work from home, unlike those in workshops with people coming and going, the message boards are an essential means of communication.
I just wish there were even more contributors as if we are not careful, we get swayed by a minority. Polling our drivers is useful but the same people respond each time, which is fine by me. They all have the opportunity to be heard.
Achtung fuhrer Ray, great debate going on here, i agree with your statement! The last thing I want to do is over complicate what we have , which is currently very simple. If I look under a car and see tread, then I assume that all is reasonably OK. If what I see is just two grooves and no tread pattern , then it suggests to me that maybe it is more of a race tyre than a road tyre.
So its a easy solution and i figured this out while been on bended knees all day today because i know how you like to stand straight and tall at these events with one arm upwards, LOL! BUT all anyone needs to do is go directly to the T&C rules and the problem is solved? Currently the tyre regs read: Only tyres suitable for legal road use in New Zealand may be used. (ie. road tyres having 1.5mm minimum tread depth across 75% of the width of the tyre and around the entire circumference). Aspect ratio is restricted to 50% minimum
Its the "road tyres having 1.5mm minimum tread depth across 75% of the width of the tyre" that solves this problem and all you have to do is get an ERC SS officer to bend down and check the tyre every racer has because a Hankook 2 stripe slick and a Kumho V700 with a light tread pattern "does not" have 1.5mm depth tread across 75% of the tyre and thats pretty obvious to see!!
Dale M
Currently T&C rules quoting portions of the WOF requirements are quite some number of years out of date. The current version of the NZTA Vehicle Inspection Requirements Manual states the following:
14. A tyre, other than a winter tyre (Note 3), fitted to a vehicle capable of exceeding 30km/h, does not have a tread pattern depth (Technical bulletin 7) of at least 1.5mm (excluding any tie-bar or tread-depth indicator strip) around the whole circumference of the tyre:
a) within all the principal grooves that normally contain moulded tread depth indicators, or
b) if the tyre does not normally have moulded tread-depth indicators (such as some retreaded or vintage tyres), across at least three-quarters of the tread width.
Just thought that I would throw that into your discussion
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