My criteria for tire replacement is whether the carcass fabric is compromised or not; no bulges or cuts in the sidewall. Cork life will reglue the stray fabric edges, and seal exposed threads, but I hope to wear out the tread first, which is always a satisfying proof of much riding. Confidence in tires is important.
On Sat, Nov 14, 2009 at 4:58 PM, EricP <ericpl...@aol.com> wrote: > > The last set of tan sidewall Pasela tires did the same thing. Like > Angus said, it seems to be where the glue line is. My opinion was the > glue was too strong and not letting the rest of the sidewall flex. > This set also had about 2,500 to 3,000 miles on them. So it was time > to change anyway. > > My own tires were/are 700x35 and run at about 60 pounds (front) and 70 > to 80 (rear). May still be underinflation for my weight at the > time. > > Still have a pair of blackwall Pasela tires that sit in reserve. If > the present Schwalbe Marathon Supreme tires get tiresome then will try > them. > > However, have to admit that since going to 40mm wide tires, even 35 > seem pretty skinny. > > Eric Platt > St. Paul, MN > > On Nov 14, 5:18�pm, R Gonet <richard.go...@earthlink.net> wrote: > > Nice analysis, Jim. �It would be interesting to ride the tires until > > they fray to see how long they would go, but I tend to replace tires > > on my cars and bikes before I need to. �I think the newer tires are > > safer, it gives me peace of mind, and it's a small luxury that I can > > indulge in. �Kind of like buying new sneakers before your old ones are > > worn out. �This also offsets other riskier, even dumber, behaviors > > that I engage in. > > > > Thanks for the post. > > > > Richard > > > > On Nov 14, 4:57�pm, CycloFiend <cyclofi...@earthlink.net> wrote: > > > > > > > > > on 11/14/09 12:50 PM, R Gonet at richard.go...@earthlink.net 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 > > > cyclofi...@earthlink.net > > > > > "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- Hide quoted text - > > > > - Show quoted text - > > > -- Bill Gibson Tempe, Arizona, USA --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. 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