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Gitane 1973-74 TdF stem/handlebar question 
PostPosted: Wed Jul 16, 2008 6:53 pm Reply with quote
dbrakr
Joined: 16 Jul 2008
Posts: 1
Hello,
I have a brown 1973-74ish Gitane TdF in good condition. It has the Sugino crankset, so that is how I date it.

I want to swap out to the Nitto Albatross handlebar (25.4mm) but it looks to me that the handlebar clamp on the Gitane is 25mm. Will I need to change the stem (this may be another "French" issue) to suit, or just pick up the filing tool?

Thanks much in advance.
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French (metric) bars and stems 
PostPosted: Thu Jul 17, 2008 10:32 am Reply with quote
verktyg
Joined: 14 Jan 2007
Posts: 2814
Location: SF Bay Area
dbrakr,

If your bike has the original cast aluminum stem, I would seriously consider replacing it! They have a bad reputation for failing.

Metric dimensioned bikes like older French makes used stems with a 22mm quill diameter (the part that fits into the steering tube).

The current world standard for stems is a 22.2mm diameter quill. French or metric 22mm diameter stems are no longer being made but are still occasionally available on eBay. They will almost always take a 25mm bar.

All is not lost. Metric stems run 21.9mm to 22mm (.862" to .866). A 22.2mm ( .874") stem is only 2mm to .3mm larger ( .008" to .012"). You can easily sand down the quill on a 22.2mm stem to fit your steering tube. I've seen metric steering tubes with inside diameters of 21.9mm to 22.1mm so its a matter of sand and fit.

The ID of the steering tube is usually rusted. I clean out all of the "guck" and run a brake cylinder hone down the bore to smooth out the surface so that a proper sized stem fits easily. You can also roll up some sandpaper and use it to clean and polish the ID of the steering tube. You don't want to take off too much metal, just clean it up.

You can still find stems that fit a 25.4mm bar but a lot of the current road stems fit a 26mm or 25.8mm bar. Nitto makes a 26mm to 25.4mm sleeve.

Chas.
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PostPosted: Fri Jul 18, 2008 3:57 pm Reply with quote
Kinst VonSterga
Joined: 26 May 2008
Posts: 153
Location: Hillsboro, Oregon USA
I have a phillipe aluminum cast stem that came with my "Je ne sais Quoi" gitane. Is this stem subject to breaking too as it looks to be in excellent shape where the pressure nut fits into the bottom of the stem. Would drilling a hole where the aluminum expander "cut" ends help in reducing the chance of breakage, assuming that is where a break would start?
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Cast Aluminum Stems 
PostPosted: Fri Jul 18, 2008 6:03 pm Reply with quote
verktyg
Joined: 14 Jan 2007
Posts: 2814
Location: SF Bay Area
There were millions of French cast aluminum stems used on European bikes up through the mid 1970s. Most of them have never failed but all it takes is the one on the bike you are riding to break to ruin your day. Crying or Very sad

My guess is that the stems that were made from poor quality castings are more likely to fail. The same basic design was used by at least 7-8 French stem manufacturers for over 20 years. During the height of the Bike Boom some of these cast stems were very poor quality.

The most common failure is from cracks that propagate at the expander wedge slot. Drilling a hole at the top of the slot will reduce the chance of cracks forming.

Stem with cracks developing:



Chas.
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Gitane 1973-74 TdF stem/handlebar question 
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