Bicycle Mechanics - Kevlar Woo Woo... oh really?

I just put on a brand new set of Vitorria Kevlar tires.

After 20 miles, I noticed that the rear tire had several gashes in it. Upon inspection, I found shards of glass had shredded the tire.

Upon changing the tire, I found that the glass had penetrated the kevlar belting as well and cut the tube.

So much for Kevlar being "all that". It didn't even stop a tiny crystal of broken beer bottle from going through the tire. Another important point is that the mileage on the tire was so limited that the glass didn't 'work' its way though the ply, it just cut straight through.

These tires have a light grey colored riding suface. My friend in tire maintanance for a major freight hauler told me that colored tires are not as durable as black tires. He says that the secret is in the carbon content in the rubber. It takes at least 25% carbon content to make a tire road worthy for automobiles and trucks. 25% or more carbon means the tire will be black.

No more fancy colors for me. Oh, and forget paying extra for Kevlar too.

Mike, did these tires actually have Kevlar belting? I'm sure you know that most tires that say Kevlar are just referring to the bead. If they are Kevlar you should email Vitorria about them. I got two new tires from Hutchinson that way. Just a thought.:)

Originally posted by Dirtgrinder
most tires that say Kevlar are just referring to the bead. If they are Kevlar you should email Vitorria about them. I got two new tires from Hutchinson that way. Just a thought.:)

You are kidding me. I assumed the when a tire is a kevlar tire, it is kevlar belted. What good would kevlar do for the bead? Nothing special... unless maybe it was a folding tire which this was not.

Anyway, YES, I plan to write to Vittoria.

Mike,

I can personally recommend Vredestein's Puncture Resistant System, It does make a heavier tyre, but having ridden over 2000 miles on a pair, with daily trips over broken glass without a puncture I'll pu up with that. I'm not sure which of their road tyres use it, but it might be worth a look. DG's right about the number of tyres that boast 'Kevlar' when all your getting is the lighter beading but no belting. I'm also unconvinced by claims made for kevlar in dealing with glass - It might help a bit, but I don't think Kevlar's strength is in dealing with slow moving sharp objects.

Richard

I have shreded kevlar belted tyres on the first ride as well. At £18 a go its really frustrating. The surviving Panaracer tyre has given me 2 years trouble-free use.
Kevlar or Aramid fibre belts dont extend up to the sidewall, so these are still vulnerable to shredding. Even the belts are not puncture proof, just more resistant.
I always regarded kevlar beaded tyres as a racing speciality. The usual "kevlar" tyre is a banded puncture resistant one.

I've used Vitoria Kevlar tire for almost two years then I change to Michelin Pro axial, thats when I got a lemon, going back to Vitoria Twin Techno as soon as my budget will permit....

Mike,
Also, with regard to Vittoria tires, the "Kevlar 3D" refers to their mixing ground up Kevlar in the tread compound for increased wear. It does not refer to a Kevlar belt. Many Vittorias actually have extremely low thread count belting; I think I have seen as low as 27 TPI.

Having said all that, I bought a number of Vittoria low end tires for $10 each for commuting. I got tired of shredding Continental Ultra 2000s and 3000s in less than 1000 miles at $20-25 a pop, including one that was ruined within 100 miles. I even tried Specialized Armadillos that DEFINITELY have Kevlar belt and are supposed to be super tough. I shredded one in less than 500 miles. I am finding that the cheap Vittorias seem to last about 1000 miles. I do go to extremes, though, using Mr. Tuffy liners AND heavy, thorn resistant tubes.
FWIW,
Raymond

Originally posted by RainmanP
I got tired of shredding Continental Ultra 2000s and 3000s in less than 1000 miles at $20-25 a pop, including one that was ruined within 100 miles. I even tried Specialized Armadillos that DEFINITELY have Kevlar belt and are supposed to be super tough. I shredded one in less than 500 miles.

You are tough on tyres, RainMan! So far, I have had very good luck with 23mm Conti Ultra2000s on the Bianchi (my "fun" bike)and 28mm Armadillos on the Capo and the Peugeot, which are my commuting/transportation bikes.

Mike, hate to be the one to break it to you but kevlar will not stop a cutting type of "weapon". It is designed to stop blunt force objects, not sharp edge objects.

Here is a good example: A pilice issue kevlar bullet resistant vest will stop a bullet but not a knife. If a bad guy shots a police officer with a gun his vest will stop the bullet. But if the bad guy attacks the officer with a knife it will go right through the vest adn into the officers body.

So the kevlar tires will stop flats from happening from blunt force applied to the tires. Such as really rough spots or constant pounding on non sharp objects, tree roots, round and flat rocks or anything that has a dull edge on it, etc. In this manner they help prevent pinch flats too. But when you roll over any thing sharp at all it will penetrate the tire every time.

Originally posted by b_rider
Mike, hate to be the one to break it to you but kevlar will not stop a cutting type of "weapon". It is designed to stop blunt force objects, not sharp edge objects.

Unique kevlar tire liner. Protects against thorns, glass and other nasty stuff. Doubles you pinch flat resistance.

http://www.aardvarkcycles.com/tires.html

About 2/3 the way down the page.