Yes, Doug, I will be happy to do that. In fact, last night I went downstairs and disassembled the entire wheel. later today I will take a hacksaw to the rim at several points and try and photograph close in the cross-section cuts. I'll post those pix. Unfortunately, I don't own a point-to-point device to measure the wall thickness, but I'll try and reference scale the pix somehow.
________________________________ From: dougP <dougpn...@cox.net> To: RBW Owners Bunch <rbw-owners-bunch@googlegroups.com> Sent: Tue, December 6, 2011 8:18:15 AM Subject: [RBW] Re: Near-Catastrophic Rim Failure Ray: Is it possible for you to measure the thickness of the failed area? Even a rough idea such as "half of original; quarter; or thin as a soda can" may be helpful when the rest of us check our rims. Given the dimensions that Grant lists, I should pay a lot more attention to rim wear. My replacement cue has been when they're been banged up enough they won't true up. The current Mavic A719s on my Atlantis rarely need any attention but the braking surfaces have noticeable wear (now that I'm looking). After reading Grant's dimensions for the upcoming Stouty rim, I checked Mavic's website for comparables on the A719. They only list weight (565 grams for 700). tire width (28 to 47), but not rim width or height. IIRC they used to have more detail. The next level down for touring is the A319 @ 595 grams. So Grant's 650 gram is right on target. Most of us are going to mount tires in the 600-900 gram range so another 50-100 grams of rim is worth it for a stronger, longer wearing rim. dougP On Dec 5, 11:08 pm, Grant Petersen <gep71...@gmail.com> wrote: > Many of you will remember, and all of you can relate to Keith > Bontrager's maxim from the late '80s: > > Light Strong Inexpensive: Pick Two > > It works to some extent with all bike parts, but even IT can't come to > the rescue when the thing is just too light. > > Do you know the thickness of the braking surface on a typical road > rim? It's about 1.2mm. Some are 1.1. That's what fails when rims wear > out and blow out. Well...1.1 or 1.2mm looks like nothing, which you > consider the abrasion they're subject to and can't possibly avoid. > (Disc brakes have their own set of problems, so let's stay on track.) > > It used to be common practice to inspect brake pads AND rims, but > raise you hand if you can remember the last time you did that. > > How much should a non-racing 700c rim weigh? How thick should the > braking surface be, and how tall? How wide should it be? > Reasonable answers, kind of, could be: Weight: 500g. Thickness of > braking surface: 2.5mm. Height: 11mm. Width: 24mm. > But a rim with those specs would weigh about 800g. I believe this > because we're having a NOBS rim made to our specs, and it has 1.6mm > braking surface, 10.5mm brake surface height, is 25.4 (1) mm wide, and > weighs about 650g. It's wider than 24, but way thinner than 2.5, and > the 10.5<11. I think this is a totally reasonable rim, in every way. I > wanted 2mm of braking surface, but that would have meant zero buyers, > so we settled on the world-record 1.6, bringing the weight down to a > near world record 650g, and even though I think it's a perfectly > fantastic rim for general nonracing use---touring, trails, commuting, > all purpose riding when there's not a timer or a finish line with a > banner---I believe we'll end up selling it mostly to guys who weigh > 300 pounds and are sick and tired of wheel problems...because most > riders like the idea of stout stuff, but don't really want the weight > that comes with it. > We'll continue to offer other rims....but this new rim will be the way > to go when you truly, really, want a durable rim and wheel. > (Anyway....the new stouty won't be available for many months). -- 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. -- 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.
