DOT rule change and effect on R tires

[Eric Parham]

I read something a few weeks ago about DOT requiring an actual treadwear test for all tires, and that some minimum acceptable score would be required in order to receive a DOT rating. The implication was that most or all of the current crop of "R" compound tires would not be able to receive the DOT rating. Unfortunately, I can't seem to find the article again. Does anyone know exactly what the scoop is, and when it's supposed to take effect?

[Eric Parham]

I found this link: http://www.nhtsa.dot.gov/staticfiles/DOT/N...s/TP-139-02.pdf (http://www.nhtsa.dot.gov/staticfiles/DOT/NHTSA/Vehicle%20Safety/Test%20Procedures/Associated%20Files/TP-139-02.pdf)

I didn't find anything about a minimum acceptable treadwear rating, but I did notice new or revised test procedures for "endurance and low pressure performance" that seem to require the tires to hold up to at least 24 hours of 100% loading at 26psi plus 90 minutes of loading at low pressure or 20psi. See pages 44-49. Perhaps that's the part that the R-compound tires might have trouble with. Looks to me like it takes effect Sept. 1 of this year (for marking?) or Sept. 1 of 2007 (for performance?).

[mlytle]

I found this link: http://www.nhtsa.dot.gov/staticfiles/DOT/N...s/TP-139-02.pdf (http://www.nhtsa.dot.gov/staticfiles/DOT/NHTSA/Vehicle%20Safety/Test%20Procedures/Associated%20Files/TP-139-02.pdf)

I didn't find anything about a minimum acceptable treadwear rating, but I did notice new or revised test procedures for "endurance and low pressure performance" that seem to require the tires to hold up to at least 24 hours of 100% loading at 26psi plus 90 minutes of loading at low pressure or 20psi. See pages 44-49. Perhaps that's the part that the R-compound tires might have trouble with. Looks to me like it takes effect Sept. 1 of this year (for marking?) or Sept. 1 of 2007 (for performance?).
[/b]

great...dot catering to the morons in society who never check their tire pressures, then sue everyone when they get in a wreck.

[anrkii]

so does that mean that the tires that we currently use are out the window at the end of the year?

[pgipson]

so does that mean that the tires that we currently use are out the window at the end of the year?[/b]

That sounds like the perfect question for our tire suppliers. This rule change has been in the works for several years, so the DOT-R suppliers should have a handle on what it will mean.

Interestingly there is an article in the April isue of Grassroots Motorsports (page 171) on this topic that adresses some of the new test requirements. The closing paragraph says (in part) "...because of the unique service conditions DOT-legal competiton tires are designed for, the severity of these new NHTSA tests may reverse the trend of competition tires becoming more like their pure racing brethren, and force them into becoming more like real street tires."

And a little side thread hijack -- has anyone seen the new Nitto DOT-R tire that is molded with 6/32" tread?

[pfcs49]

wouldn't it be great if IT race tires became more like the Yokahama 008 of yesterhear?
I ran 12 events on a set of 5, drove to every event, and set lap records the first and 12th time out (1985?) Now, those were tires!