Dear John Strizek,
I'm not certain yet from your email just what it is you want to do with your Raleigh Pro. Do you want to commute on it?
I owned two 52 cm Raleigh Pro Mark IV (from Carlton) bikes for many years, beginning in 1972-3, when I spent $425 for my first all-Campi "racing" bike. One had eyelets (it was stolen :-( ), and one did not. The BBs were, indeed, high, as the bike was built for some criterium racing but mostly for English-style time trialing. (That is how the guys at Collins' Cycle Shop in Eugene, Oregon, described the bike's lineage to me. Riley McLean, one of the mechanics there, had a Mark II, which was clearly a different bike, more of a stage racing design.)
The Raleigh Mark IV Pros' cornering and downhill handling left a lot to be desired, although the bikes tracked just fine on the flats. Neither of my Mark IVs handled corners or downhills as well as my 1975 champagne-green 53.5 cm Peugeot PX-10LE, which I bought for touring.
My guess on your 172.5 mm cranks is that they were sized for someone wanting more power for flat-course time trialing, where cornering might not be as big an issue as in criterium racing. But if you want to have more fun in the corners, try 170 crank arms.
I cannot imagine trying to convert my old Raleighs to fit 650B wheels--the brake clearances were closely matched to 700C wheels, as I recall. But you might be able to get a 28-32mm tire in that frame, a least on the rear. I think I managed to get fenders on one of my Pros with 25 or 28 tires, once or twice, but it was a long time ago and my memory is hazy.....
Jon
Jon Spangler
Alameda, California USA
hudsonspangler@earthlink.net
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
Jon Spangler
Writer/Editor
Linda Hudson Writing
Alameda, California USA
510-864-0370/FAX 864-2144
MOBILE 510-846-5356
hudsonspangler@earthlink.net