Mine are doing this at say a year and a half and maybe 750miles or so from new. I blame the high altitude sun, which is why I usually avoid skinwalls. Now they are not as bad as Cyclotourist, but given how few miles I have on them I am disappointed. My house is at 7300 feet or so and I ride them between 5800 and 9500 pretty regularly.
On Sat, Nov 14, 2009 at 6:35 PM, cyclotourist <cyclotour...@gmail.com> wrote: > This is an excellent conversation! As I mentioned, I've noticed this a > while ago, but haven't been too concerned. I'm lazy and cheap, ya' know. > The split runs completely round the tire on one side, and is barely visible > as a hairline forming on the other side. The front tire is in better shape, > but I can see the beginning of a hairline forming on one side. As noted, > high and dry temps down here in inland SoCal. That must prematurely age the > sidewalls significantly as these are maybe three years old at the most > (Nashbar's blow out sale when they were selling them for $16). I guess this > is the downside of living in the desert. Bill, do you have any problems in > AZ? The threads are in fine condition, but very exposed. I'm inclined to > keep running them, but being on the look out problems. The rear tread is > pretty worn with all the "slits" being worn down to totally smooth in the > center. Brake pads are centered properly. > > If you look at the real big full-sized photo, you can just almost make out > the threads in the casing if you squint sideways: > http://www.flickr.com/photos/cyclotourist/4103817724/sizes/o/ > > Fun with bike parts! > > > > On Sat, Nov 14, 2009 at 4:40 PM, Bill Gibson <bill.bgib...@gmail.com> wrote: >> >> 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 >> >> > > > > -- > Cheers, > David > Redlands, CA > > "Bicycling is a big part of the future. It has to be. There is something > wrong with a society that drives a car to workout in a gym." ~Bill Nye, > scientist guy > > > > -- Tarik Saleh tas at tariksaleh dot com in los alamos, po box 208, 87544 http://tariksaleh.com all sorts of bikes blog: http://tsaleh.blogspot.com --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To post to this group, send email to rbw-owners-bunch@googlegroups.com To unsubscribe from this group, send email to rbw-owners-bunch+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/rbw-owners-bunch?hl=en -~----------~----~----~----~------~----~------~--~---
