There are many choices when selecting motorcycle gear, and we hear things about which materials provide best protection against road rash. I thought some research might benefit those looking for gear, or people who sometimes don't wear all their gear. The following comes from manufacturers, individual tests from advrider.com and various other sources, but they should provide some good points for discussion and probably offer good rules of thumb. Please note that abrasion resistance is only part of the story, you should also consider stitching quality and impact protection. If you have good abrasion resistance, but the stitching fails, you may end up using skin as your abrasion resistance. Also, if you have a poor fit of you gear, it may shift, making abrasion resistance worthless. Please also note that there are a couple of studies that show that price and protection aren't necessarily linked. You have to check quality, not the brand.
I'll edit this OP as I finish research and it may end up significantly changed -- there are a few good European studies still out there I'm trying to get, and I'll draw some conclusions. So far, these studies tend to be a bit old, and don't include enough information about modern, high D corduras. I'm also welcoming reference to additional studies I can report here.
How Far Something Can Drag on Asphalt Before You Hit Skin:
"Samples were stitched to a bag that held a 75-pound
sandbag inside a milk crate, then dragged behind a pickup truck..."
New 100% Cotton Denim Jeans -------------------- 3' 10"
Balistic Nylon ------------------------------------- 3' 10"
Leather, Lightweight, Nude Finish, 2.25 oz/sq. ft. --- 4' 3"
Leather, Fashion Weight, 1.75 oz/sq ft. ------------- 4' 4"
Two-year-old 100% Cotton Denim Jeans ------------ 4' 5"
440D Cordura Nylon ------------------------------- 18' 3"
Kevlar 29 Aramid Fiber, Style 713 ------------------ 22' 1"
Leather, Competition Weight, 3 oz/sq. ft. ---------- 86' 0"
Tear and Abrasion Strength:
CottonJeans ----------------- 4.5 pounds to tear 50 cycles to failure
70 Denier Standard Nylon----- 4.5 pounds to tear 165 cycles to failure
500 Denier Polyester---------- 8 pounds to tear 180 cycles to failure
200 Denier Standard Nylon---- 7.5 pounds to tear 275 cycles to failure
500 Denier Cordura----------- 22 pounds to tear 710 cycles to failure
620 Denier Cordura----------- 35 pounds to tear 1200 cycles to failure
Competition Grade Leather---- 80-110 pounds to tear 1200-1700 cycles to failure
1000 Denier Cordura---------- 110 pounds to tear 1780 cycles to failure
Kevlar----------------------- 1260 pounds to tear 970 cycles to failure
Abrasion Strength - Taber Industries:
"The specimen was mounted on a rotating platform and scuffed by two rubber-emery grinding wheels." The numbers represent the
number of revolutions until the fabric totally fails.
Two-year-old 100% Cotton Denim Jeans ---- 168
New 100% Cotton Denim Jeans ------------- 225
Kevlar 29 Aramid Fiber, Style 713 ----------- 506
440 D Cordura Nylon ------------------------559
Leather, Lightweight, 2.25 oz./sq. ft.-------- 564
Leather, Fashion Weight, 1.75 oz./sq. ft. -----750
Senior Ballistic Nylon ------------------------817
Leather, Competition Weight, 3 oz./sq. ft. --- 2600
Seconds of Drag on Asphalt Before Getting Holes:
Denim ---------------------------------0.2 to 0.5
Textile gloves -------------------------0.6
Most leather gloves---------------------1.0 to 1.8
Keprotec stretch material---------------0.9
Poor Kevlar-----------------------------1.0
Two layers of waxed cotton------------ 1.3
1.3mm thick cow hide ------------------3.8
Two layers of 1.3mm thick cowhide------18
Three layers of 1.3mm thick cowhide-----55
Two layers of Kevlar plain weave---------5.6
Suede ---------------------------------18
Boot leather (generally 2.2mm thick)-----20
Leather stretch panels------------------20.4