Not surprised by the high BB, since it seems most early 70's high end Raleighs (stiil Carltons really at that point) had 172.5 cranks, even my 1969 Raleigh Pro, despite being only a 21" frame. Since a 650B bike will typically be used for touring/commuting, the short and steep geometry typical of the Raleigh Pro is less than ideal, despite the high BB. My 1969 is not excessively short or steep, but from your description, it seems the Pro geometry had already changed a lot by 1971. In 1969 mine still had eyelets, which would be desirable on a 650B bike, don't know about your 1971.
Regards,
Jerry Moos Big Spring, Texas, USA
john strizek <lyonstrings@yahoo.com> wrote:
Dear Mr. Moos I find the bottom bracket heigth on my '71 Raleigh Professional is higher than the norm. they came with 172.5 cranksets as a standard rather than the typical 170s. The ride is to me a bit "twitchy." I attribute the high bottom bracket height and the twitchyness to being a criterium style. The stays are also shorter than I usually ride. I attribute the short stays for needed responsiveness in a short course in a pack. The longer crankarms would give an easier leverage in coming out of a corner, although it is slightly at odds with a leaned over criterium turn. I might suggest a criterium bike or a cyclo-cross bike with a high bottom bracket for a 650B or 26" conversion. Of course with the smaller wheel you then have the consideration of brake reach. A set of wheels with disc brakes or drum brakes could then solve the brake reach concern. Another possibility is using a drop bolt in front and a long drop bolt in the rear.I have used the drop
bolt and the drum brakes for such a solution in brake reach.Happy trails,john strizeksacramento causa