As far as Kevlar goes, it isn't as abrasion resistant as Cordura. It is a stronger thread, but won't last as long when sliding down the road. It is great for stopping bullets.
When Kevlar is woven with other fibers it adds strength to the end product that will make a very good piece of protective motorcycle gear. Many "Kevlar pants" use raw Kevlar and may actually be less effective at protection than heavy Nylon. Kevlar is also quicker to degrade when exposed to sunlight (UV).
From
Aerostich's site:
"We still choose Cordura, not Kevlar. Here's why:
Its advantages don't make up for it's disadvantages. In pure, undiluted form, Kevlar is lighter than Nylon and has greater tensile strength than Nylon. It won't melt like Nylon after touching a hot muffler (or from the friction generated heat of a high speed slide on hot pavement). Unfortunately, it's expensive and difficult to work with, which limits design and construction possibilities. Believe it or not, pure Kevlar fabric actually is much less abrasion resistant than Cordura Nylon. This quality is not important for bulletproof vests. Kevlar fibers have far less elasticity than Cordura Nylon fibers, a crucial handicap. In a crash, even the smoothest pavements have a rough aggregate surface that causes abrasive pulling. Nylon's stretchy fibers will elongate, ride over the surface irregularities, then snap back into the weave (like a tree bending in a strong wind), but Kevlar fibers quickly reach their tensile limit and snap."
From
Motoport's site:
"Kevlar
Dupont strikes again
In order to give it the proper motorcycle abrasion strength Kevlar must be woven together with other threads, like Dynatec and or Lycra, ei Schoeller's Keprotec.
These are the only suits approved for road racing other than leather. Some gear manufacturers use small portions of pure Kevlar as a gimmick. Quality full suits of it can be found. This gear is lighter, offers greater protection and it breathes. It slides on pavement the same way as leather and dissipates friction heat better than leather. Due to its' innate toughness during construction and the fabrics limited availability it is not widely marketed so it will take a bit of looking to get one."
On the other hand, Nylon gear will melt when sliding down the road. It can melt right into the skin and be very challenging and painful to deal with. Aerostich, which uses Cordura Nylon, clearly states that a non-synthetic layer should always be worn between their suit and the skin.
Motoport's
Air Mesh Kevlar pants may seem a little pricey at first glance, but they will do the job better than race leather. Check out the Jean cut, Police cut and Ultra II pants for a variety of styles to choose from. Probably cost about twice what you are looking at elsewhere, but will be custom made for you and last multiple times as long.
I've had the Ultra II Air Mesh pants and jacket for a few years now and can't say enough good things about them. Looking back I have spent much more on gear that I wore out and/or didn't like over the decades than I paid for this set.
I can put these on over my office clothes, or just wear them over my briefs. They breathe well, offer great protection, will probably last forever, and the manufacturer will repair or replace them if damaged. I bought these specifically to be my "everywhere" riding pants.
If money is tight buy a set of zip-on overpants and always always wear a cotton layer under them.
Then, do your own research and save up for some premium gear that best fits your application.