ST vs LT Tires -- I'm confused
I've moved up from a TT to a 5'er. Years ago I replaced the TT tires with Maxxis ST based on just about universal recommendations. Had them for 3 yrs without a single problem of any type. Now I'v...
Forum Discussion
Me Again wrote:Francesca Knowles wrote:elkhorn98 wrote:
I think people need to read the thread on testing requirements by the dot.
Here ya go- existing rules, as can be seen at this NTSB link:
NTSB wrote:
ST tire high speed performance test requirements.
S2Application. This standard applies to new pneumatic radial tires for use on passenger cars manufactured before 1975, new pneumatic bias ply tires, T-type spare tires, ST, FI, and...
§ 571.109Standard No. 109; New pneumatic and certain specialty tires.
CFR Title 49 571.109
S5.5High speed performance.
S5.5.1After preparing the tire in accordance with S5.4.1, mount the tire and wheel assembly in accordance with S5.4.2.1, and press it against the test wheel with a load of 88 percent of the tire's maximum load rating as marked on the tire sidewall.
S5.5.2Break in the tire by running it for 2 hours at 80 km/h (50 mph).
S5.5.3Allow to cool to 38° ±3 °C (100° ±5 °F) and readjust the inflation pressure to the applicable pressure specified in Table II.
S5.5.4Without readjusting inflation pressure, test at 121 km/h (75 mph) for 30 minutes, 129 km/h (80 mph) for 30 minutes, and 137 km/h
(85 mph) for 30 minutes.
So why don't they test ST tires at they full mythical inflated ratings rather than at 88%?????
Chris
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