Jun 26, 2002 4:53 AM
|I have a buddy who has kevlar tires on his KHS. In the past month he has had seven flats in his rear tire. Yesterday's flat was attributed to a wee bit of steel he rode over. Taking the tire off was the most painful part of the entire ordeal. Scratch that, reverse it. Putting the tire back on was a bit worse. My question is, is it possible that his tire is a little too small for the rim or is it difficult because it's kevlar? Is there a way to make changing these flats any simpler?
ml - the only easy day was yesterday.
|let me elaborate...||mlester|
Jun 26, 2002 5:08 AM
|It took us 20 min to get this tire off and 15 to get it back on yesterday...the guys at the LBS know him as "the guy with the tires..." Are all tires as equally difficult or is it just the Kevlar?|
|re: Kevlar tires||brider|
Jun 26, 2002 5:33 AM
|Seems to me you've run up against the tolerancing ghost. Basically, you've got a rim that's on the large end of the manufacturing tolerance, and possibly a tire that's on the small side as well. Some manufacturers tend to go on the small side (don't know which ones off hand). I've found Quick Sticks tire levers to really help with those stubborn tire/rim combos.|
|belts and beads||DougSloan|
Jun 26, 2002 5:41 AM
|There are Kevlar belted tires, and tires with Kevlar beads; some could have both.
I don't think either one necessarily causes the problems you describe with mounting. I've seen Kevlar bead tires and wire bead tires that are hard and easy to mount. Some tire/rim combinations just are difficult, and it's not always consistent with a certain model.
My Campy Nucleons seem to be particulary difficult to mount, but some tires, like Vittoria Open Corsa's, go on ok. Others are darn near impossible.
The Crank Bros. tool helps a lot with the hard ones. Park Tools has a shop tool that is great, too.
|second the Crank Bros. speed lever. (nm)||JL|
Jun 26, 2002 5:55 AM
|third the speed lever. A real bargain @ $7 (nm).||dsc|
Jun 26, 2002 11:03 AM
|belts and beads and Vittoria Rubino Pro?||PdxMark|
Jun 26, 2002 6:29 AM
|I bought Vittoria Rubino Pro TT tires a couple years ago thinking they had a kevlar belt. Studying the packaging closer after installation it looked like there is not actually a belt, but rather bits of kevlar mixed into the tire rubber. It seemed odd, becuase it's hard to imagine how bits of kevlar could possibly help prevent flats, but despite "kevlar" being plastered all over the packaging, there seems not to be a kevlar belt... Here's the summary from their web site...
The aramid fiber reinforced rubber makes our treads strong, cut resistant and stiff. Aramid fibers offer solutions to rubber weaknesses. They lasts longer, grip better and resist cuts and wear. Aramid fibers are also lighter than rubber and therefore lower tread weight.
Kevlar 3D Compound will be replaced by Aramid 3D Compound from this year on.
|Two quite different products.||Spoke Wrench|
Jun 26, 2002 5:50 AM
|Actually, there are two quite different products that people commonly refer to as "kevlar tires."
The first is kevlar belted tires. These have a kevlar belt running under the tread. It's purpose is improved puncture resistance. The price you pay is a less supple tire with slightly higher rolling rresistance.
The second is kevlar beaded tires. These replace the steel wire beads with foldable kevlar. As a general rule, their weight is quite a bit lower than the same tire with a steel bead so they are generally marketed as a high performance tire.
There are certain words that only bike mechanics are allowed to say. I think that my vocabulary has been expanded about equally while mounting examples of both types of tires. Repeated flats on a difficult to mount tire, whether wire or kevlar bead, is usually due to pinching the tube during the mounting process. Life is too short to waste part of it struggling with bike tires that are that hard to install.
|I try to avoid Kevlar tires||pmf1|
Jun 26, 2002 6:23 AM
|The belted ones are kind of heavy and not really any more puncture resistent than a high quality non-belted tire. Personally, I think its the quality of the rubber that makes the difference. Buy cheap tires and you get more flats, go through more tubes, waste more time and in the end save no money. Keep your eyes open and snatch a bunch when they go on sale. |
I've had good luck with foldable tires from Michelin, Vredstein or Hutchinson. Had bad luck with Conti GP, but recently bought some Conti 3000 to see if they have changed (haven't used them yet). Vittoria tires are nice, but not long lasting (at least the Open Mario ones I got on sale last year).
Wire or kevlar beaded tires are generally harder to mount than foldable tires in my experience. Some rims are difficult too. My wife has a set of Spinergy Spox and I can't get anything except Vredsteins on them. I dread it when she gets a flat. Its a good idea to carry some tire levers in your bag.
Jun 26, 2002 6:46 AM
|The only reason I went to clinchers in the last few years was so I could use kevlar casing or belted tires because of severe glass problems in my current location. I used to ride Michelin Axial Selects but they changed the construction so I went to other tires.
If you can find them, the Schwalbe Blizzard Neo Pro's (they have a kevlar belt) are worth trying. For me, the Neo Pro's are better tires than GP 3000, Vredstein Fortezza's and Axial Pro's. Subjectively they feel light and responsive, seem to have low riding resistance and are better than the Axial Select resisting glass cuts although I will note that the belt's fairly narrow. The ride cannot compare to the Vred's but few tires can. I've switched both my road bikes over the the Neo Pro's although I still run Vred's on one of my extra wheel sets.
FWIW, I've not tried any Hutchinson or Vittoria clinchers to date.
|I try to avoid Kevlar tires||commuterguy|
Jun 26, 2002 7:31 AM
|I commute on Performance Forte Pro Kevlar belted and beaded tires. After a lot of experimenting, I have found that they are quite flat resistant, compared with other tires (even expensive ones). It's true that the ride isn't that supple, but that's a tradeoff I'm happy to make, given how unfun it is to replace a tubes on cold, dark and rainy nights. (Another drawback: my rear tires rarely last more than 1200 miles.)
Regarding the original question: these tires mount very easily on Mavic Open Pro rims. So much so that, until reading this post, I assumed that Kevlar-beaded tires were an inherently easier mount than their steel-belted counterparts.
Jun 26, 2002 8:08 AM
|Wire (steel) beaded tires are the hardest to mount. I have not found a tire that cannot easily be mounted on a Mavic Open Pro rim. |
Ever tried Mr. Tuffy tire liners? I tried these once and got a flat on the first commute using them. Bad luck? I guess, but I took them out the next day.
Jun 26, 2002 7:31 AM
|I have a set of Hutchinsons that were extremely tight and very difficult to get the bead over the rim. After fighting with it and getting tube and the final bead onto the rim, it inflated fine and tube was undamaged and not pinched by the bead. I rode the bike a few times and then once about 70 miles later the tire sidewall burst above the bead exposing the kevlar strands and blowing the tube out.
Because the tire was so tight there must have been tension pulling the bead away from the rubber carcass. Finally, under pressure under inflation the whole thing went.