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Most likely a question without an answer:(8 posts)

Most likely a question without an answer:Leisure
Apr 7, 2002 3:21 AM
But just in case, does anyone know or have heard anything off hand about what sort of "grade" of rubber gets used in some of the tires we run? I've got Axial Pros like every other rider here, and wonder how Michelin would qualify it against their automotive tires (you know, H-rated, Z-rated, etc.) And what do Conti and others use?
Just a guessDave Hickey
Apr 7, 2002 6:43 AM
I'd guess they would be rated pretty low. If I'm not mistaken, the rating on tires is based on speed. A Z-rated tire is good up to 200mph.
Comparing apples and rutabagasElefantino
Apr 7, 2002 9:34 AM
I"m not sure about grade, but in the case of auto tires, the ratings are based on treadwear, traction, temperature and speed.

Bicycle tires are usually "graded" by TPI, or threads per inch.

At least that's the only rating I know of. Good question, though.

I would assume:Alexx
Apr 7, 2002 12:30 PM
Using the automotive "treadwear indicator", where originally, 100 was an average wearing tire (today, it's probably closer to 250, but I digress...), most bike tires would rate between 10 (like, say, a Conti Sprinter, Vittoria Corsas, etc.), and maybe 50 (Tufo Specials, Specialized armadillos, etc.)
The letter is a speed rating. I belive that 80 mph is the lowest max speed rating, and most bike tire manufacturers wouldn't want to test that high.
80mph is high??cyclopathic
Apr 7, 2002 10:02 PM
more like low for recumbents or tandems
You're confused - it's not rubber gradeKerry
Apr 7, 2002 4:03 PM
Those tire grades refer to the entire construction - rubber, tread design, filler, casing material and weave, etc. They also primarily relate to the ability of the tire to withstand the heat generated at high speeds. While auto racing tires certainly are rated for traction (and therefore the "stickiness" of the rubber), road tires are not. Bike tires have the same basic construction as auto tires, but there is very little in common. "Grade" of rubber is a misnomer.
Not entirely correct!Alexx
Apr 8, 2002 3:25 AM
Road tires often DO have a traction grade, although I'm not sure if it really means anything, legally.
Bike tires do NOT have the same kind of construction as auto tires! Nearly all auto tires are of a "radial-ply" construction, whereas bike tires are nearly all of a "bias-ply" construction. Also, most auto tires are tubeless, whereas nearly all bike tires have tubes. I'm not even going to mention tubulars, either!
There are different grades of rubber, but they are not marked on the tire. That sort of thing is usually left to the chemical engineers at the tire factory.
Apr 7, 2002 7:20 PM
Are you asking about the hardness of the rubber? In that case, it would be durometer. That would at least describe in part, the stickiness and potential durability of the rubber.