Here is lovely 1975 Centurion Semi Pro. It has been well preserved over the decades by its original owner, and I am now the proud steward of this extraordinary machine.
As readers of this blog already know, I have been on a decades long quest to replace my crashed 1976 Centurion Pro Tour, a bike which was my only bike for over 20 years, and upon which I logged over 40,000 miles including tours of the Pacific Northwest, the San Juan Islands, and Canada, as well as serving as my daily commuter. The Pro Tour was my original all-rounder.
So, when I saw this baby blue 1975 Centurion Semi Pro on eBay, I knew I would be honored to shepherd this bike into its next phase.
When the bike arrived, I unpacked it like a toddler with a new toy, and when I found these interesting frame transfers, they confirmed the information provided by the seller of the bike (who was not the original owner, but who sold it on their behalf). The first human to ride this Centurion was a member of the US Cycling Federation (now known as USA Cycling), and had ordered the full Dura Ace upgrade for this bike, as well installing racing tubulars instead of the 27″ clincher rims offered as standard equipment. The original owner was also a member of the L.A. Wheelmen and had added these black and white racing flag transfers to the top tube.
While the bike clearly had a documented racing heritage, I was puzzled to find the Dura Ace crankset mounted with a chainguard. And, you’ll note that the rings are not in racing configuration, but are a compact set-up with 52 teeth on the large ring and 39 on the small ring. Both rings are Shimano Dura Ace. Don’t forget to notice the lovely Dura Ace front derailleur. The Dura Ace upgrade included: the front derailleur, the anodized brake calipers, the drilled levers and the crankset:
These Dura Ace components are in amazing condition. The drilled levers look new, but are given away by the gum hoods which have long ago lost their resilience. The brake calipers are beautifully anodized. The Dura Ace crankset with its 172.5 arms is in equally amazing condition, considering its 43 years in service.
I enjoyed seeing this unusual Huret wrap around chrome cable guide which provides shifter cable routing on both sides of the frame. This bike has zero braze-ons. While it is built with Tange Prestige #1 tubing, during this era braze-ones were rare, and most needed accessories and cable guides were handled via clamps.
The drivetrain consists of SunTour ratcheting Mighty shifters mated to the Dura Ace front derailleur and a Shimano Crane GS rear derailleur. The Crane would be needed to handle the 52/39 rings up front. The dropouts are by SunTour, and I don’t think I’ve ever seen anything as lovely as these fully chromed SunTour GS dropouts. Their unusual shape made me look up this component in the 1975 SunTour catalog. You’ll note that the design pushes the dropouts inward toward the hub. I wonder if this simplified mitering the rear stays.
The pedals also provided a surprise – they are very rare Barelli pedals, with the optional alloy cages. According to the site Classic Lightweights, these pedals “were considered the Rolls Royce of pedals. The spindle was made from Nickel Chrome Steel and they were machined for accuracy at the bearing surfaces and they came with a life time guarantee” That, and the other component upgrades help to explain why this bike weighs in at 22 lbs.
The upgraded wheelset consists of 27″ Super Champion Competition tubular rims laced to Sunshine Pro Am low flange hubs. A new set of Pararacer 20mm tubulars were installed as part of the deal. I’m not sure how well the new tubulars were glued, so I will probably install a clincher wheelset on hand for this bike’s first test ride.
The bars were upgraded to 3TTT, mated to a Cinelli stem. The original SR seatpost looks very nice with this Cinelli leather Unicantor saddle. Unicantors were the first plastic base saddles of this era. I haven’t ridden one before and look forward to trying it out. You’ll also note the Centurion’s impressive, chrome wrap around seat stay.
This Semi Pro has the following SN: M5J00027. Consistent with all Centurion frames I have encountered, and as documented by others, the first letter indicates the frame builder, but no one knows who that is. Since both my 1976 Pro Tour and this 1975 Semi Pro start with an “M” I will guess they were both built by the same manufacturer, probably Japanese. The second numeral is a “5” and that indicates the year built – 1975 – which is consistent with the bike’s components. Another way to date a bike without a reliable serial number is by the components.
I look forward to venturing out on this extraordinary bike, and will keep you posted on our progress.