Tag Archives: 650b conversion

Reconversion Therapy: 700c to 650b to 700c

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I’ve had a long and interesting relationship with this early 1980’s Meral Sportif.  It’s actually the bike that inspired me to start this blog.  I acquired it as a frame and fork back in 2012.  It was going to be the platform for a 650b conversion – the first one I had attempted.

While the conversion to 650b went fine, there were some issues with the bike:  the frame was slightly too small for me, and the bike had serious toe overlap with the fenders I had installed.  I later changed the build in a number of different ways, installing upright bars and different fenders that had a flush connection to the front stays, so as not to engage my shoes.  I put a lot of miles on the bike, and enjoyed tweaking the components, but a couple of years ago I stripped it down to the frame, and set it aside, not knowing what I would do with it.

Recently I have been searching for a project that I could actually start and finish within a reasonable period of time, having become frustrated with a number of other vintage builds presenting road blocks at every turn.  And, I have been wanting to move toward selling many of the bikes in my too large collection.  Due to the pandemic there’s not only a shortage of new bikes and parts, but also a renewed interest in cycling.  So, this seems the perfect time to thin out the stable.

My first thought was to accept the bike as it is:  a small frame designed around 700c wheels. I focused on making the bike true to its French heritage and to its original purpose as a sport riding machine, but with enough all-rounder gear to make it useful for all kinds of riding.

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I was pleasantly surprised to find that even with these 32mm Paselas, there’s enough room for fenders at the fork crown and rear brake bridge.  I installed a set of beautiful Shimano 600 side pulls, which work very well with the Dia Compe levers on the Phillipe bars.  The bike has its original Shimano 600 headset, French sized, so I didn’t mind mixing all kinds of components, both Japanese and French.

The drive train consists of a Sugino GT crankset with 50/45/34 rings, paired with a NOS Suntour Ultra 13-30 6 speed freewheel.  This gives a wide gear inch range of 30 – 104 – perfect for full speed blasting and hill climbing.  I used a Shimano Deore long cage rear derailleur, the same one I have always used with the bike, as well as a vintage Shimano front derailleur.

Gear changes are seamless with these Suntour stem-mounted ratcheting shifters. It’s nice to have the shifters close at hand rather than on the downtube.  Previously I had installed a converted Huret shifter clamp, allowing Shimano pods to be mounted.

The “new” 700c wheelset consists of vintage Campagnolo Record hubs laced to new Mavic Open Pro rims, a set that I built a while back.  As expected, these wheels are smooth running and spin forever.

The rear rack adds utility, but with the porteur bars up front, a front rack would fit nicely as well.  The frame size is 49 cm (seat tube) X 51 (top tube), perfect for someone about 5’2 to 5’4, but with a shorter inseam than my 30 inches.  I’ll be listing this bike along with some of my others over the winter months and I hope its new owner gets to enjoy it as much as I have.

 

A Sunday Ride to Oaks Park

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Care for a dance?

Sunday rides are a ritual for me, even in winter.  But today’s glorious sunshine accompanied by a warm spell (60 degrees!) made getting out on a bike today a real delight.  I often ride out Springwater Trail, along the Willamette River, to visit Tadpole Pond, and the wetlands of Oaks Bottom, accompanied by a swing through Portland’s bustling Sellwood district.  Today, I decided to stop in at Oaks Amusement Park, one of the oldest continually operating parks in the U.S.

Being an amusement park, there are fun rides, including this swooping roller coaster which now induces a slight feeling of nausea, even though I once relished joining my pals for a spin on this magnificent, multi-colored joy machine.

But in addition to having the option to get sick, Oaks Park also offers picnic areas along the river, an historic wooden-floor roller rink complete with a Wurlitzer pipe organ, and is the home of the Herschell-Spillman Noah’s Ark Carousel, which is itself listed in the National Register of Historic Places.  I like visiting the park in the winter, when it’s closed, to enjoy the quiet river views and to marvel at the nostalgia-inducing feel of the place.

I’ve been riding my 1975 Centurion Semi-Pro, which I converted to 650b about a year ago.  I re-used the Sunshine Pro-Am hubs, laced to V-O rims, and installed Mafac Raid brakes to accomplish the conversion.

The Grand Bois Cypres 650b 32 mm tires are holding up well.  They are a nice alternative to tires offered by Rene Herse and Pacenti.  However, it appears that these tires are no longer available, although some models can still be purchased on eBay.  Below are photos of the bike’s features and current components.  In addition to re-using as many of the original Dura Ace pieces as made sense, I tried to stay true to the bike’s 1970’s roots.

Original Dura Ace FD

SunTour thumb shifters with bare helical casing

Stronglight 99 with 47/34 rings

Mafac black washer RAID calipers

Fender spacers – split to facilitate the installation of wider tires

Frame transfers – Dura Ace, USCF, and Tange Champion #1 tubing (faded)

Wrap-around seat stay, chromed

Jim Blackburn rear rack

Tange Falcon headset

My ride was capped off by watching a hawk flying overhead, chased by a murder of crows, only to land nearby with its prey in its talons.  My iPhone camera was no match for that photo opp, but the memory of that scene will live on, accompanied by many other memorable Sunday Rides.

 

Sunshine Pro-am Hubs vs. Ofmega Gran Premio

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Front hubs – Sunshine Pro Am on the left.

Rear hubs, Sunshine Pro Am on the right.

I recently needed to build a wheelset for a bike with 122mm rear spacing.  That meant that I could re-use its original Sunshine Pro Am hubs (spaced at 120mm on the rear), taken off the original tubular rims, or select a NOS hub set of similar quality and from the same era (mid-1970’s).  This might expand my hub choice options, because I could probably more easily locate a 126mm rear axle set, which the rear dropouts can easily accept without having to spread the rear triangle.

I ended up locating a 1980 NOS Ofmega Gran Premio 6200 hubset, with low flanges and 32 holes front and rear.  I had previously restored a few bikes that featured Ofmega components, so was familiar with Ofmega’s quality.

Ofmega Gran Premio 6200

Both sets were similar in weight, with the Ofmega set being only slightly heavier, probably due to the longer rear axle and fewer holes in the flanges. To verify my initial impression of the quality of Ofmega components, I researched the history of the company and discovered that its beginnings are murky at best.

According to VeloBase, the Italian component maker was founded by Mario and Dino Perotti sometime in the 1960’s, when they obtained patents for various bottom bracket designs.  It is posited by the disraeligears site that Ofmega had a relationship to the OMG Company, which in turn may have included the Gnutti brand in its portfolio.  By 2006, Ofmega appears to have finally shut down, although the exact date and cause of its demise is unknown.  For better or for worse, Ofmega is best known for its colorful and strangely shaped rear derailleurs, which evoke derision or amusement, depending on your perspective.

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Sunshine/Sansin’s history is similarly opaque.  I had believed that Sunshine was somehow part of Maeda and SunTour, but I wasn’t sure.  After a number of failed English language Google searches, I tried searching on Yahoo’s Japanese search engine, and came across a Wikipedia post (in Japanese) that I used Google translate to read, then took a picture of the brief entry, shown above. This confirmed that Sunshine was indeed a division of Maeda industries, a company with a very long history going back to 1912. This lead me to focus on what Maeda was doing in the 1970’s when my Sunshine Pro Am hubs were made.

From there I discovered that Howie Cohen of West Coast Cycles (and creator of the NIshiki brand in cooperation with Kawamura of Japan), was instrumental in encouraging Japanese component makers to bring high quality bicycles and components to the US market. Howie has passed away, but a website dedicated to his work lives on.  Howie had personal relationships and went cycling with many of the leaders of Japan’s cycling industry, and successfully convinced them that Americans were sick and tired of riding our heavy one speed balloon tired clunkers.  He turned out to be right.

I ended up deciding to re-use the bike’s original Sunshine Pro Am hubs, which I built using Velo Orange 650b rims.  I had a set of Grand Bois 32mm tires that I had originally planned to use for another project which never materialized.  The tires were relatively easy to mount, although it did take a few inflation/deflation attempts to seat the tires correctly on the rims.  As you can see from the above photos, the highly polished V-O rims look quite fine.

I’m glad I went with the Sunshine hubs – this is my new (old) 1975 Centurion Pro Tour, converted to 650b.  I will share more about the conversion in an upcoming post, but let’s just say for now that I am having a blast riding this well-handling and beautiful old machine.