Oct 8, 2001 11:08 AM
|I've used tires with and without kevlar and haven't noticed any difference flats. Is kevlar overstated or is their really a benefit? |
|belt or bead?||wherefore art thou kevlar?|
Oct 8, 2001 11:26 AM
|belt or bead?||VW|
Oct 8, 2001 11:39 AM
|Isn't there's a third variety of "kelvar" tires where the rubber compound on the tread has some kevlar in them? |
|Belt or bead? What's the difference||Mick|
Oct 8, 2001 11:55 AM
|You said there's a big difference. What is the functional difference, please?|
|well gee||Jack S|
Oct 8, 2001 12:06 PM
|a kevlar belt is a belt under the tread and is designed to prevent flats. A kevlar bead simply allows the tire to be folded and is lighter... ain't gonna do squat for flats.|
|Belt or bead? What's the difference||dsc|
Oct 8, 2001 12:06 PM
|Bead refers to the inside 'hoop' that sets the tire into the rim. A kevlar bead is flexible, vs. steel, so the tire can be folded. Also, it usually makes the overall weight of the tire lighter.
Belt refers to kevlar threads woven in with the material that makes up the tread of the tire. It is supposed to offer greater protection from flats. Think steel belted radials on your car.
Oct 8, 2001 12:46 PM
|My question is in regard to tjhe belt. Does it make a difference in flat protection? |
Oct 8, 2001 1:04 PM
|I'm running Conti Gatorskin Ultra's (25mm, wire bead) on my new Calfee tandem. I went with wire beaded for extra protection in case of a blowout. The extra rotating weight isn't as much of a factor (IMO) on the tandem.|
Oct 8, 2001 2:26 PM
|I don't believe it does. Yes we've heard all about bulletproof vests etc- where the cords are stressed (on impact) in tension, a failure mode which kevlar strand resists very well: but a bike tyre suffers under different tormentors... mainly small sharp pointed things, which seperate the kevlar pieces or strands like they never existed. If a tyre's going to be punctured by something like a nail, then nothing is going to stop it, given that the primary constituent is rubber, which cuts easily especially when the penetrating object is lubricated with rainwater. The only protection is thicker rubber which brings with it the problems of weight and rolling resistance. Ride carefully, and scan the road ahead, is my advice.
The use of kevlar rather than steel in the bead, is mainly useful because it allows tyres to be packed more neatly: it's also a little lighter. Strength or failure resistance here is unimportant as it's been shown, surprisingly, that even a tyre which has had its beads severed performs perfectly normally... ie, the bead doesn't hold the tyre on the rim.
|re: Kevlar Tires||Elefantino|
Oct 8, 2001 11:32 AM
|With regard to belts, I had many problems with non-Kevlar Contis. I switched to Kevlar belted (folding) Performance Fortes, and haven't had flatting problems since.|
|My Avocet Cross K's||Rich Clark|
Oct 8, 2001 11:37 AM
|...have 3500 flat-free miles on them. FWIW. (700x32c)
|My Michelin Axial Selects||Dan-O|
Oct 8, 2001 2:57 PM
|w/kevlar belt have ~2K mi without a flat (so far!!) I don't particularly baby them, and I'm a big guy @ 205 lbs, down from 225 last season.
Alas, they're discontinued :(
|Michelin Axial Selects||zelig|
Oct 9, 2001 12:52 AM
|Say Dan-O. Like you, I ride Selects a lot because of the amount of glass on the roads in my area and was disappointed when I could no longer find them. Apparently they're back according to the Michelin website as the 'improved' Axial Selects I don't know if they're improved and I've yet to see them at my LBS but I'm hopeful they've not become history. |
BTW, Conti just introduced two new tires you might find interesting. The Grand Prix 4 Season which is a GP 3000 with some two additional polyamide (same stuff used in their better tub casings) layers under the belt plus their DuraSkin cut-resistant layer. Kevlar bead and 220gr in 700x23. Also the UltraGatorskin which has the DuraSkin plus a kevlar belt. Only in wire bead and 280gr in 700x23. I'm going to buy some of the GP 4's next week to see how resistant to flats they are compared to the Selects and see if I can get some weight savings as a bonus.
|Put Selects on my bike...........||Len J|
Oct 9, 2001 4:41 AM
|for the trip across Alaska. Had some really sketchy roads, including gravel & "rock & seal" (as opposed to chip & seal, these "chips" were closer to boulders). No flats, Tires were bulletproof. Tradeoff was weight & rolling resistance was worse than Mich Axiel pros. It was well worth it in Alaska.
|now called Axial Kevlar||fret not|
Oct 9, 2001 4:36 AM
|that lame name game|
|thread count is everything!||Rusty McNasty|
Oct 9, 2001 6:37 AM
|If the weave of the kevlar belt isn't tight, it ain't gonna stop squat. A piece of glass, metal, orother $hit, will go right between threads, straight to your tube. Of course, the threads won't be damaged, but your tire will still be flat.
Also, kevlar in the rubber (like vittoria does) has almost nothing to do with flat prevention.
|a little better||Dog|
Oct 9, 2001 6:43 AM
|The Kevlar mesh/belt seems to help a little. I'm using Michelin Axial Selects for the 508 for that reason.
However, I'm starting to think that harder and thicker rubber makes more of a difference, and it seems that many of the Kevlar mesh tires use harder rubber, too.
The harder rubber picks up far fewer things that might penetrate the tire the next few revolutions - less stuff embeds in the rubber. But, it doesn't grip as well - not a big deal on most rides, though.