DiscoDunc
Member Since: 08 May 2006
Location: Bristol
Posts: 16390
  
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what are the std fit Wrangler All Weather tyres rated at ? Duncan
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 2nd Oct 2012 4:11 pm |
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AJS4X4
Member Since: 30 Mar 2008
Location: Surrey
Posts: 3224
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General at are the same at 74db. 
Duratrac is E fuel and E wet grip............General AT is F fuel and F wet grip which is not as good as Duratrac, very  on that.......looking into this one at present.
We are going to have some interesting results with Tyre Labeling. 
Spent a day in class over in Spain last week, trying to make others understand the facts etc.
We will have a short video on our web site very soon to explain how it all works.
Have seen some funny results with some of the Chinky tyres available, seems to me as they make it up as they go along. 
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| 2nd Oct 2012 4:25 pm |
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methley
a.k.a. Big Hairy Ski Monster
Member Since: 07 Oct 2008
Location: Marshfield, South Glos
Posts: 2433
 
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AJS4X4 wrote:...Have seen some funny results with some of the Chinky tyres available, seems to me as they make it up as they go along.
Presumably these are what the "plebs" buy are they  Andy
Fridge Slide for sale https://www.disco3.co.uk/forum/post2064622.html#2064622
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| 2nd Oct 2012 4:29 pm |
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christophe
Member Since: 18 Apr 2006
Location: Up in the North...of small Luxembourg
Posts: 88
 
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AJS4X4 wrote:christophe wrote:Mr. AJS 4X4 can you easily get the duratracs in England. Here in Luxembourg and around it seems that they will only be available in November the earliest and I really should replace my actual tires soon. The Duratrac is my first choice so I am looking at all the options.
Thanks.
255/55x19 Duratrac's in stock as I type. 
Great! I might be pushing a bit but would you be willing to ship a set of 4 to Luxembourg if I decide to go for it and have no other option nearby?  By the way, what is your price for the Duratrac?
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| 2nd Oct 2012 4:29 pm |
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LT
Member Since: 31 Dec 2005
Location: South West
Posts: 23519
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AJS4X4 wrote:General at are the same at 74db.
Duratrac is E fuel and E wet grip............General AT is F fuel and F wet grip which is not as good as Duratrac
I find that very surprising. The Duratrac is a pretty aggresive tyre, in my experience more so than photos portray. Certainly much more so than the AT.
If the above is correct, then Goodyear have done an amazing job and I'm tempted to get a set for the winter.
I'd like to know how the tests are conducted.
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| 2nd Oct 2012 4:35 pm |
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LT
Member Since: 31 Dec 2005
Location: South West
Posts: 23519
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christophe wrote:AJS4X4 wrote:christophe wrote:Mr. AJS 4X4 can you easily get the duratracs in England. Here in Luxembourg and around it seems that they will only be available in November the earliest and I really should replace my actual tires soon. The Duratrac is my first choice so I am looking at all the options.
Thanks.
255/55x19 Duratrac's in stock as I type.
Great! I might be pushing a bit but would you be willing to ship a set of 4 to Luxembourg if I decide to go for it and have no other option nearby? By the way, what is your price for the Duratrac?
Are they not currently available in Germany? With the Duratracs having the mountain snowflake, it seems odd that the UK would have them and Germany doesn't.
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| 2nd Oct 2012 4:42 pm |
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AJS4X4
Member Since: 30 Mar 2008
Location: Surrey
Posts: 3224
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Even more fuel for the "which is the best tyre" boys.
Good looking tyre the Duratrac but very lumpy on price at present.
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| 2nd Oct 2012 4:45 pm |
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AJS4X4
Member Since: 30 Mar 2008
Location: Surrey
Posts: 3224
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LT wrote:
I'd like to know how the tests are conducted.
You and me both.
All this is going to do is put prices up IMHO.
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| 2nd Oct 2012 4:49 pm |
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LT
Member Since: 31 Dec 2005
Location: South West
Posts: 23519
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Testing Rolling Resistance
A tyre is mounted to a specially designed two-metre drum. It is then rotated with a defined load and pressure.
The test engineers have the torque required to rotate the drum before the tyre is fitted, so they are able to calculate the torque of the tyre by subtracting the new level required when the tyre is mounted against the level when it is not.
It is through calculating the difference of the drum's torque with or without the tyre that they can record what is known as the 'Rolling Resistance Coefficient'. This is what is used to work out the correct grading for the new tyre label.
Testing Wet Grip
There are two tests that engineers are required to carry out to come up with the wet grip rating.
First of all they need to carry out a wet braking test. This measures the performance of a tyre when a vehicle is braking on a wet surface. The distance that the car travels when slowing from 50mph to 12mph is recorded.
They also carry out what is known as a skid trailer test. This calculates the friction between the tyre and the road surface. For the tests to be valid, it must take place when the vehicle is travelling at 40mph.
Once they have both results, they combine them to create the Wet Grip Index (WGI) - this shows the percentage of improved ability compared with an independent reference tyre.
Testing Noise Emission
This test is done to find out the external noise of a tyre in decibels (dB).
The actual test consists of a microphone being set up on the edge of a track to measure the sound level of a test vehicle - the microphone is required to be 7.5m from the centre of the track and sit at 1.2m above the ground. When passing, the vehicle must be travelling at 50 mph with the engine turned off for the test to be valid.
The rolling resistance and noise levels seem straightforward enough. But the wet grip test must be susceptible to variants?
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| 2nd Oct 2012 4:59 pm |
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AJS4X4
Member Since: 30 Mar 2008
Location: Surrey
Posts: 3224
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Well done.
Sometimes things can make your eye's bleed, I have just had a metal picture flash in my mind of what the testers look like.................someone help me. 
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| 2nd Oct 2012 5:06 pm |
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grzesiul
Member Since: 11 May 2008
Location: UK
Posts: 6294
 
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19" LTZs should be available now from Silverline sweet rubber
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| 2nd Oct 2012 5:08 pm |
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AJS4X4
Member Since: 30 Mar 2008
Location: Surrey
Posts: 3224
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Sorry I can't "HEAR" you.
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| 2nd Oct 2012 5:16 pm |
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LT
Member Since: 31 Dec 2005
Location: South West
Posts: 23519
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Dunc, back on topic.
In real life, I couldn't tell any noticeable difference in noise between 19" Goodyear Wrangler HP AW which are rated at 70db and 19" Pirelli ATR which are rated at 72db when fitted and run on my D3.
So if the GG AT and Goodyear Duratrac are both rated at 74db, then you'll easily be able to live with the 4db increase in noise over your HP's.
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| 2nd Oct 2012 5:40 pm |
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AJS4X4
Member Since: 30 Mar 2008
Location: Surrey
Posts: 3224
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Anyone will find it very hard to hear any difference between these db levels.
What we now are starting to see one manufacturer challenging another one as one or the other disagrees with the others findings.
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| 2nd Oct 2012 6:18 pm |
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