I'm petty sure that's the snake bite protection strip turning loose. It's a bit of fabric tape that they put just above the bead to help prevent pinch flats. I've seen it dry up and turn loose on several tires--on one Ruffy Tuffy it loosened to the point that it was rubbing the brake and bugging me so I just peeled it off. Tire is still fine and in use.
Check if the crack is actually a seperate outside layer that's coming loose before giving up on the tire. Steve Frederick, East Lansing, MI -----Original Message----- From: [email protected] [mailto:[email protected]]on Behalf Of Angus Sent: Saturday, November 14, 2009 6:12 PM To: RBW Owners Bunch Subject: [RBW] Re: increasing longevity of skinwall tires? Jim, David, For what it's worth (probably 2 cents), I believe the "cracking" is not a crack, but the last layer of material that was wrapped over the tire bead. It looks like it has started to peel off the sidewall. I've had several tires do this over the years, specifically older/ narrower Paselas. I have not had a tire fail due to this...yet. The tan sidewalls seemed to degrade faster in So Cal than they do in East Texas (smog degrades rubber faster?). There is not a lot of smog out here...heck there is not a lot of anything out here! (cept trees). Everyone makes their own choices and lives with the consequences...having a higher than normal risk tolerance (and Scottish blood) I'm riding my tires into the ground. Angus "whose All-Rounder still wears the original, circa 1998, Ritchey Tom Slick" On Nov 14, 3:57 pm, CycloFiend <[email protected]> wrote: > on 11/14/09 12:50 PM, R Gonet at [email protected] wrote: > > > I just checked my 2-year-old Jack Browns and they have that same split > > all the way around, though not as bad looking as the much older Pasela > > tan wall. The split appears to be in the outer gum wall, if that's > > the correct term, and doesn't look like it's penetrated into the woven > > layers below. I don't know if this is a safety issue or not. I've > > never heard of a tire failing at that point before, but confess to > > little knowledge on the subject. > > > By the way, it's very easy to check your tires without removing them. > > Just deflate them all the way and push the tire bead away from the > > rim, working your way around the tire to inspect the circumference > > visually. > > > Is there anybody out there who has some knowledge in this area who has > > an opinion on the safety issue? > > Hey. It's the internet. I'll hazard a guess... > > If you work from the outside in, the tire layers consist of "contact" > material (the black part of a skinwall), The underlayer (the skinwall), the > thread/casing, and a thinner layer. > > AASHTA -http://www.sheldonbrown.com/tires.html > > In the photo that David E shared > -http://www.flickr.com/photos/cyclotourist/4103817724/ > > I notice two things - first, the cracking parrallel to the rim, second the > whitish "fold marks" from running at relatively low inflation. Overall, the > sidewall looks pretty dried out - certainly drier than my tires. > > David rides in an area which has consistently high ambient temps, which I've > always found to degrade tires quickly. My experience is that the > skinwalls/sidewalls go first. > > If those were my tires (and lemme just say that I may have a higher > tolerance for risk than others here, and if you base your actions on my > opinions, I can't take liability for it....) I'd run 'em until I start to > see the beginning hints of threads fraying through. But, I'm also just odd > enough to want to see how they begin to fail. > > If the whole sidewall is cracking, I'd replace the tire. This is how you > often find old tires on garage sale bikes - unused tread but brittle, almost > "varnished" looking sidewalls. But, if the sidewall is still relatively > supple and elastic, I'd run them for a while yet. > > IF I could see through to black tube anywhere when they are inflated, I'd > pull 'em, cut the bead with a tin snip and not use them. > > Back to the photo - > The threads still have to fail, and the thread casing/underlayer in general > is probably a bit thicker than the skinwall. The threads are probably more > resistant to heat damage than the surrounding rubber composite. > > I think what may be happening is the combination of running larger volume > tires at low pressures, while the sidewall itself is drying out a bit > quicker than average. That big footprint of the tire tends to stay stuck, > while you and the bike can move quite a bit side-to-side. I would tend to > think that's why you are seeing cracking like that. > > Just one other semi-unrelated data point - > Riding with a canti brake pad out of alignment, I cooked through a brand new > WTB Velociraptor rear tire in under an hour, and the first half was > climbing. There's not a lot of material there. You might check to make sure > the edge of the pad isn't off the edge of the rim, though David's doesn't > appear to have done so. > > One more thought - > If the underlayer is really dried out, there is a possibility of the black > layer delaminating. (Kinda like a retread auto tire failure). I've > experienced this with a Specialized road tire (can't remember the name - > back in the later 90's) that used a dual durometer compound. But, even that > was happening slowly enough that I noticed it between rides. > > Hope that helps. > > - Jim "who just took his Pasela 32's outside and looke at them under strong > light and cleaned glasses..." > > -- > Jim Edgar > [email protected] > > "One Cog - Zero Excuses" L/S T-shirt - Now > availablehttp://www.cyclofiend.com/stuff > > Cyclofiend Bicycle Photo Galleries -http://www.cyclofiend.com > Current Classics - Cross Bikes > Singlespeed - Working Bikes > > Send In Your Photos! - Here's how:http://www.cyclofiend.com/guidelines --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en -~----------~----~----~----~------~----~------~--~---
