Posted on April 18th, 2013 by Broadway Bicycle School
Do you ride a Peugeot, Motobecane or Gitane that was made in the 1970’s!?
If you have an older French bicycle – you may find it difficult to repair or replace certain components. The most common issues that come up are when your drivetrain or steering need some attention. French bikes from that era had their own standards that differ significantly from the modern parts that would be available in most bike shops today.
Here’s a little peek into some of the differences:
- A stem must be compatible with the dimensions of the fork steerer tube. Steerer tubes come mainly in two common sizes: 1″ or 1 1/8″, French steerer tubes are 25mm (just slightly bigger than 1″) So if your original stem became damaged – it could be difficult to find a replacement that would fit. In addition, changing the stem would then impact your handlebars.
- On all bikes, your stem clamps onto the handlebars. The standard diameter for this area is 25.4mm, 26mm or 31.8. On an older French bike, the handlebar measures 25mm – just small enough to prove unsafe with available stems….
- Your headset is the bearing system that allows your fork to rotate in the bike frame. Common standards have been established, but once again these don’t apply to older French bicycles.
- French Pedals have a different threading than modern pedals – they are not interchangeable.
If you are considering having work done on your French bike – we strongly recommend visiting a bike shop and speaking with a mechanic about these and other issues that may pop up. Depending on your particular bicycle, sometimes these repairs can be quite costly! An experienced mechanic will be able to identify if your bike has special needs and provide an accurate assessment of the future costs of repairs versus the value of your bicycle.
If you are very attached to your older steed all hope is not lost – sometimes repairs can include replacing your fork with a modern one that will then remove the above incompatibilities – thus ensuring your bike will be future proof and provide years of service. The love of the french bicycle has a small following and there are companies like Velo orange now making a French Headset and French Bottom Bracket. Both of these components are available at Broadway!
For those of you who like solid numbers, here’s a handy chart to compare older French dimensions to the current standards available with modern parts.
|Fork Steerer Tube Diameter||25mm||1″ or 1 1/8″|
|Fork Threads||25 mm x 1.0 mm||1″ x 24 tpi|
|Pedal Threads||14 mm x 1.25 mm||9/16″ x 20 TPI|
|Bottom Bracket Threads||35 mm x 1mm (1.378 x 25.4 tpi)||1.3701/1.375 x 24 TPI|
|Bottom Bracket Fixed Cup||Right Threaded||Left Threaded (reverse thread)|
|Handlebar Stem Clamp Diameter||23.5 mm, 25 mm||25.4mm, 26mm or 31.8mm|
|Seat Tube Diameter||28mm||28.6mm|
Check out these French parts available in the Broadway Land of Used Parts! They might be just what you need …
**Please note that modern Motobecanes, Merciers and Peugeots have no relation to the original older French bicycles except in name. Speak to an experienced mechanic to determine if your bike has standardized componentry.
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