A couple good links

I just finished listening to the Spokesmen podcast #7. Recently, I recommended episode 6 and, though I don’t want to sound like a broken record, I will take this opportunity to recommend the Spokesmen once again. As always, the guys cover a wide range of topics on the roughly hour-long show. Of particular interest to readers of this blog will be the discussion, which takes place toward the end of the podcast, about carbon composite as a frame material. During part of the discussion, you will hear mention of these cut away frame pictures, which generated a lot of interest when they were first posted. I could ramble on and on about my thoughts on the subject of carbon fiber, but I think they covered it well in the podcast. I will just repeat one point that I have made before. All of the commonly used materials in the bike industry can be used to produce great frames or really bad ones. No one material is magic and each has its pros and cons. That is why the design and engineering that go into a particular bike are more important factors in its performance than just the material from which it is created.

There is one more link that I want to pass along while I am at it. Carolina Triathlon is a great bike shop here in Greenville, SC, and now they have started a blog. At this point, there is not much content, but I expect great things from these guys. If you have ever seen the downtown shop, you will know exactly what I mean; they are definitely not your average bike shop (and that is coming from someone with absolutely no interest in running or swimming). Sure, I like almost all bike shops, simply because they are full of bikes, but I think that Carolina Triathlon has done a great job of designing an environment that is truly inviting. I don’t have time to elaborate right now on why I think they stand apart; maybe that will be a topic for a future post. In the mean time, if you are interested, check out this older Brand Builder post for a little background on the shop.

I probably won’t have a chance to post again until next week, so if you are reading from the United States, have a great Thanksgiving. Just don’t forget to get in a nice long ride after the big meal.

Posted

November 21, 2006

Miscellaneous

James

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5 responses to “A couple good links”

Anonymous

November 21, 2006

You finally got me to listen to the spokesman, that and the wife and kids are late getting home.

Regarding Carbon, (composite) frames, too bad the marketing guys demand that visually acceptable weave on the outside, not much strength added there most of it is going the wrong direction. I’m more concerned as to how the bond to the alloy parts is done, and the resin to “cloth” ratio. Oh yeah, they would all be better off with a suitable coat of paint to protect the material. All old news to the sailboat industry… Rant over.

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Tim Jackson- Masi Guy

November 22, 2006

James- thanks for the mention and link love for the Spokesmen. It’s a pretty cool group. (Even if I don’t ever shut up.)

Anon- I hate the cosmetic outer weave too. It adds weight and doesn’t do anything “real” for the bike. The protection is minimal at best and the look is just “played out”. Everything from golf clubs, to fishing rods, to car hoods… it’s everywhere. The look of the actual composite material is much more techie and intersting to me- which is why we have gone that route on the newest models. Since the outer cosmetic weave is just there for a uniform appearance, it really doesn’t do much of anything for the ride and adds weight. I believe you’ll see more bikes moving away from it. Besides, the high global demand for carbon fiber is driving the cost of cosmetic weave through the roof and limiting availability.

Hope you enjoyed the podcast. Next one should be around 11/27.

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michael

November 24, 2006

Having worked on a few composite projects myself I have some insight into the issues raised. There are two distinct ways to construct a composite frame, monocoque (a somewhat inaccurate term) or tube-to-tube. Both have their pros & cons but in either case it’s important to view the material as a surface matrix and not as a volume of material. One of the problems with monocoque construction is getting the internal bladder (the thing that squishes the composite to the mold walls) to form tightly to the turns and radia inside the frame tubes so often ‘fillers’ are used to ease the transtion from one tube to another. Although it looks pretty shitty when you cut a frame in half it neither adds or detracts from the overall strength of the frame. This is determined more by how the composite fabric is ‘layed up’ and compressed/cured during fabrication. It will however add weight. Although I started out design ‘monocoque’ frames I now think that tube-to-tube offers a lighter and in many cases more cost effective way to manufacture composite frames. I am more concerned with the way we attach bottle boss’ using a pop-rivet deal which invariably splinters the composite fibers and looks ug-er-ly!

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Anonymous

November 26, 2006

Rivnuts, in aerospace they are a non starter unless isolated from the composite, crushing the fibres, breaks up the resin and bye bye strength as the fibres can slide and drift.

I think by and large the bike industry gets off easy.

I crack up when some owner writes to Leonard Zinn complaining about the galvanic problems on his “plastic” bike.

Unfortunately the UCI plays a role in frame shape, so some of the design problems are created from addressing those “rules”

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David Bernstein

November 27, 2006

Thanks for mentioning The Spokesmen. We love doing the show and it means a great deal to us when we hear from satisfied listeners!

— David from The FredCast and The Spokesmen

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