Re: DOT street and strip tires

MO,

Running a four-speed would be so much fun; wish I had a manual in one of my cars...not enough room in the stable though.

As to the sidewall letter ratings...the “ads” for tires should tell you the compound and “traction” rating but if not then the following from the UTQG (Universal Tire Quality Grade) from the DOT (Dept. of Transportation) is the “formal” explanation;

Based on national highway testing, the basic street tires have ratings in the 400-600 number range generating our typical 40-60K tread wear mileage and “performance” tires can range down to 0 or 00 under street conditions which reduces mileage from 3000 or so...unless you really burn ‘em up on the rough street/road surface. According to the information I have read, a 400 rating will last twice as long as a 200...linear ratings.

There are other tire ratings which can get confusing (unless you spend a lot of time & money ordering tires!) -

Traction Grade – for example, a street purpose tire with AA traction means the tire will pull over .54g’s on asphalt and over .41g’s on concrete. Contrastingly, a sticky Drag Radial with a B traction rating is rating for “less traction” because this rating system is under normal street and all-weather conditions which includes rain/wet surfaces which is how the DOT (Dept. of Transportation) rates tires. Thus the Drag radial has the best traction on dry street or strip conditions with much less mileage and fails miserably under wet/dangerous street conditions; therefore the “WARNING” label or disclaimer associated with Drag Radials and all such racing tires.

Temperature Resistance – Since temperature of a tire increases with speed, the DOT lists A,B,C as tire “speed ratings.” All U.S. tires must meet the minimum of “C” or better; capable of 85-100mph without suffering any tire damage. “B” rated tires are safe up to 100-115mph. “A” rated tires push the envelope over 115mph.

I have not personally “tested” my Stickey Mickeys yet on my 340 Dart but I hope to this coming week after I R&R the broken third member...

Take care,

Gary P.

Reading The Sidewall

Every tire has a tire wear rating as part of the UTQG (Universal Tire Quality Grade) as required by the DOT. This rating is based on the tests performed by the National Highway Traffic Safety Administration (NHTSA) over a specific 400-mile loop, driven for 7,200 miles in west Texas. These numbers range from 600+ down to 0. For comparison sake, a typical street tire has a treadwear rating in the 400-600 range. These tires last a long time, providing a comfortable ride in all weather conditions.

The axiom is that every time you double up on the treadwear rating, the tire will last twice as long: a 400 lasts twice as long as a 200, for instance. A BFGoodrich Radial TA (the classic muscle car tire) has a treadwear rating of 400. The ultra-high performance street version of the TA, the G-Force TA KDW, is rated at 300, and the ultra-sticky G-Force TA Drag Radial features a 00 treadwear rating. While these standards have left some room for interpretation, a 00 rating means that the tire did not last the entire course, and that is performed under street conditions, not racing.

If you look at the rest of the UTQG scores, there will be some puzzling grades, such as the traction grade. The G-Force KDW is listed with AA traction, which means on asphalt the tire will pull over .54 G, and over .41 G on concrete. The Drag Radial on the other hand, with its sticky compound, is rated with a B grade. This is because drag radials are not designed for wet traction, and that is what the DOT traction test is based on.

“The only difference between the ‘traditional tread’ and the ‘new tread’ of the BFGoodrich g-Force T/A Drag Radial tire is the look. The ‘traditional tread’ five-rib g-Force T/A Drag Radial tire appeals to muscle car owners, while the ‘new tread’ directional g-Force T/A Drag Radial tire appeals to new performance owners,”- Andrew Koury, BFGoodrich Tires Ultra High Performance Brand Category Manager.

The other main grade is temperature resistance. This is actually a fairly important detail for a drag tire. The temperature of a tire increases as speed and time at that speed increases. These are portrayed in A, B, and C. This is different from the speed ratings, which measures speed. All tires in the US must be rated at a C or better, which means the tire is capable of 85-100 MPH without damage. B rating is 100 to 115, and A is over 115 MPH. Of course, while a drag radial is capable of handling well over 100 MPH, it is not capable of these speeds for

From: MO

Sent: Thursday, March 16, 2017 6:50 PM

To: The 1962 to 1965 Mopar Mail List Clubhouse

Cc: 62-65-mail-list-club@xxxxxxxxxxx

Subject: Re: DOT street and strip tires

I did not see any explanations on what the letter rating ( tire wear, traction, speed rating etc. ) means Wouldn't the traction rating indicate how soft the rubber compound would be? I would think, the softer the rubber compound, the less tread life...........................MO

On Wednesday, March 15, 2017 at 11:19:02 AM UTC-5, 62-65-mail...@xxxxxxxxxxx wrote:

I have not, but the protections in place through the Department of Transportation won't allow a new tire to be manufactured and sold in the US without meeting basic safety standards. You can see these ratings of the tire on the sidewall. https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=172

As for "recommended for automatic transmission" I don't see how a tire would know the transmission style. It's more likely a computer programmer's way of linking together all parts for a specific vehicle, that is 1999 Dodge trucks with automatic transmissions. In other words, more marketing than technical. In any case, almost all vehicles sold in the US are now automatics. Which is too bad for many reasons, like the left leg exercise automatic drivers miss out on. :)

Thanks,
Gary H.
> -------Original Message-------
> From: MO
> Has anyone here tried the "Nitto " brand tires ? How you like them ?
> Quality any good? ... These are somewhat lower priced than the "name
> brand" ones.
> I like that they have a little more rain grooves in them.   I
> notice that some tires from Summit say they are recommended for
> automatic transmission. Guess they are trying to say they get too
> much traction for a 4 speed
> driveline?.......................................MO
>

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