Jon- Creeeeeeak goes Pandora's box lid. There are many drivers of how and why tire/rim sizes have come to be.
One path was that bikes were designed around an outer tire diameter and as the grade of roads got better the tire's profile could narrow down. But to maintain the same outer diameter the rim has to grow in diameter. If you look at a rim diameter chart you'll see the "A, B, C and some times D" versions of the same root tire size. Each of these were regarded as the "new light weight" model at some time in the past. Since then the rim sizes took over as the control but the tires continued to shrink. Throw into this large manufacture's (can you say Schwinn) and the need to be unique in a market place and you can see easily why there are so many tire/rim sizes. many overlap in tire outer diameter with each other (a 559 tire can run from 670mm+ in diameter to less then 615mm compared to the typical 571 tire which runs 619mm or 584 tire at around 660mm). Lastly the government will influence things. The US manufactures lobbied for import tariffs based on tire sizes for many years. This, I was told, is why the 559 tires on the early flood of mountain bikes (think 1985) were labeled with uncommon (for then) sizes but were basically the same size as the traditional size. The tariff was for 26x2.125 not 26x2.0...
This is an issue for the supple chain, not just the riders. Sizes have been orphaned then resurrected but with a different rim and tire profile. When does a manufacture or shop, stop dealing with a size? I have sold bikes years ago that I don't think I could source a tire for these days (say, 700D).
As to the ride differences I won't say much. I view the tire size choice more as a fitting/design thing not a ride efficiency thing, with the goal to have a large diameter in general. But that's coming from a small guy who works with small woman often. If I were taller and had more tire size options, for a given design, I might feel otherwise. I do think the tire profile probably has more to do with perceived ride quality differences then most any other aspect.
Andy Stewart Raleigh, NC
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From: Jon Spangler <hudsonspangler@earthlink.net> To: <classicrendezvous@bikelist.org> Cc: Jerry Moos <jerrymoos@sbcglobal.net> Subject: [CR]Why 650B? Message-ID: <BD21A5D1-B744-46EF-A76B-9402CC4982DF@earthlink.net> In-Reply-To: <MONKEYFOODRGryWtIIZ00000167@monkeyfood.nt.phred.org> References: <MONKEYFOODRGryWtIIZ00000167@monkeyfood.nt.phred.org> Content-Type: text/plain; charset="US-ASCII"; delsp=yes; format=flowed MIME-Version: 1.0 (Apple Message framework v753.1) Content-Transfer-Encoding: 7bit Precedence: list Message: 4
Jerry and all,
Your post brings to mind an issue I've never been able to understand very well: why are there so many wheel diameters and and tire sizes within such a small range? It's almost overwhelming.
What makes a 650B wheel superior to a 700C or a 26" MTB wheel? Why would one want a 650B bike instead of a 26" wheeled one? The differences in rim diameter seem so small as to be insignificant, but I know lots of 650B fans here on CR and elsewhere.
Thanks in advance for this discussion.
Jon Spangler (who is off to Mac World Expo in San Francisco after this post to get help with our "vintage" Apple G4 desktop computers from 2001-2003. They might as well be 1912 Pierce Racers... :-)
Alameda, CA USA
On Jan 7, 2009, at 6:17 AM, <classicrendezvous-request@bikelist.org>
<classicrendezvous-request@bikelist.org> wrote:
>
> Date: Tue, 6 Jan 2009 21:01:52 -0800
> From: Jerome & Elizabeth Moos <jerrymoos@sbcglobal.net>
> To: <ooki1998@yahoo.com>,
> Classic Rendezvous <classicrendezvous@bikelist.org>,
> Tom Harriman <transition202@hotmail.com>
> Subject: RE: [CR]wtb- touring bikes and small bikes
> Message-ID: <376590.58913.qm@web82208.mail.mud.yahoo.com>
> In-Reply-To: <BAY140-W36B8B1FED16238504D9814F0DF0@phx.gbl>
> Content-Type: text/plain; charset="us-ascii"
> MIME-Version: 1.0
> Precedence: list
> Reply-To: jerrymoos@sbcglobal.net
> Message: 7
>
> Don't know about the Trek, but another nice thing about the World
> Voyageur is it has a high BB that lends itself nicely to a 650B
> conversion. I converted my World Voyageur to 650B because it was
> just a little too tall with 27" wheels, but the result was so nice
> that I picked up another World Voyageur that would fit me with 27"
> wheels, but I may convert to 650B anyway.
>
> Regards,
>
> Jerry Moos
>
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