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Technical FAQ: Setting up an authentic vintage 650b

  • By Lennard Zinn
  • Published Jul. 10, 2012
  • Updated Oct. 11, 2012 at 4:51 PM EDT

Editor’s Note: Lennard Zinn’s regular column is devoted to addressing readers’ technical questions about bikes, their care and how we as riders can use them as comfortably and efficiently as possible. Readers can send brief technical questions directly to Zinn.
Dear Lennard,
I just came across your response in regards to the 650b wheel size question. I am currently restoring an old 650b Ritchey.

When I got it, it had a road stem, drop bars and the accompanying bar con shifters. Through a friend that knows Tom I heard that it should have Bullmoose bars rather than drops. Is this consistent with what you recall?

I can barely find the slightest bit of info on these early 650b bikes. One Bicycling article briefly mentions one and called it a “Competition,” does that sound right? Do you have any thoughts or recollections on how many were made, etc?

Here’s a picture of the current state of mine.

My goal is to get it back to how it was back in the day. I have a fairly large collection of early mountain bikes. Do you have any old pictures of your 650b off road bikes?
— Dave

Dear Dave,
Absolutely that bike needs a Bullmoose handlebar, and it should be a fillet-brazed one painted to match (as opposed to a welded and chromed one).

Mine was the superlight quill-less version too, of which not very many were ever made. Rather than having a quill going down into the steerer, Ritchey silver-soldered a 7/8″ stub of a tube into the top end of the steering tube so that it stuck out above the headset. The triangulated tubes of the Bullmoose bar met at a cylindrical clamp with a pinch bolt that clamped onto that stub.

It was very elegant, as well as being lighter and stiffer than a quill with an expander wedge. Tom Ritchey was far ahead of his time on that, as clamp-on stems did not come to the mainstream until threadless headsets arrived.

I’m a little confused about your fork, though. That one looks like it has a cast crown. Mine and all of the ones I saw at Ritchey’s were built with double-plate crowns; two steel plates about two inches wide and 1/8″ thick were bent at around a 120-degree angle.

The upper plate was bored through at the peak of the bend with a one-inch hole saw for the steering tube. The lower plate was mitered at each end to mate with the side of the fork blade, while the peak of its bend was machined for the bottom end of the steering tube.

The entire thing – steering tube, two plates bent downward, two fork blades, and a ring on top for the headset race – was fillet brazed throughout, making for a very strong crown. I’m sure I have one of those around here still.

I’m sure I do have a photo of my Ritchey 650b bike somewhere, because I rode it all over near Crested Butte during our honeymoon in 1983, and we have lots of photos somewhere of that trip. But I can’t seem to find any of our photo albums, and my wife is in Africa right now. We do not have any digital versions.

I had the same Super Champion rims you have. It looks like you have the Michelin 650b touring tires on there, which were all we could get after around 1984 or so.

You’ve got a Campy front derailleur; mine had a Simplex, I think, although I can’t be sure. My rear derailleur was a Huret, and yours looks appropriately old and French, but it’s different than mine was.

That Suntour crank on your bike didn’t exist yet when my bike was made; mine had a TA crank. I had Magura brake levers and the same Mafac cantilever brakes as your bike. I think mine had Hi-E hubs, at least in the rear.

My frame looked exactly like yours, with that slack seat angle, Campy 101B short dropouts, and big, smooth Ritchey brass fillets at every joint, except that it was painted with DuPont Imron Forest Green Metallic. So was my Bullmoose handlebar and my fork (built with Reynolds fork blades and a double-plate crown).
― Lennard

Read also:

Tech FAQ: What’s the big deal with 650b?

Turner joins the rise of the 650b

Dear Lennard,
I’m considering buying a used 2008 Specialized Stumpjumper Comp 29er HT with alloy frame, 9-speed cassette and M542 BB/Crankset but would like to upgrade it to a Shimano XT M785 2×10 drivetrain.  Can you please tell me, or direct me to the appropriate resource, if the 10-speed cassette will work on the factory 9-speed freehub body and if the M785 BB/Crankset will work with the frame’s BB shell?

I ride singletrack infrequently so I don’t think I need a new bike but the drivetrain on the 2008 should probably be replaced.
— Dan

Dear Dan,
Yes, the 10-speed cassette will work on the factory 9-speed freehub body. The crank will be a 24mm Hollowtech spindle, and, judging by the specs here, your bike probably has a BB30 bottom bracket shell. So you would need BB30 adaptors for the Shimano integrated spindle.
― Lennard

Dear Lennard,
Regarding SRAM 1 X 11, the only question I have is, “Will they offer a GripShift version?”
— Randy

Dear Randy,
There will be a Grip Shift and trigger version.
― Lennard

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Lennard Zinn

Lennard Zinn

Our longtime technical writer joined VeloNews in 1987. He is also a framebuilder, a former U.S. National Team rider, and author of many bicycle books, including Zinn and the Art of Mountain Bike Maintenance and Zinn and the Art of Road Bike Maintenance, as well as Zinn and the Art of Triathlon Bikes and Zinn's Cycling Primer: Maintenance Tips and Skill Building for Cyclists. He holds a Bachelor’s degree in physics from Colorado College. Readers can send brief technical questions to Ask LZ.

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