Peugeot Tandem

Maintaining and Updating The Peugeot Tandem

Headset
The headset is another potential dead-end, being a long obsolete "French Tandem" size. However, due to a happy co-incidence, it is possible to use modern parts to replace the wearing surfaces. See details below:

Headset Details
The now obsolete French Tandem headset has the following dimensions:
Steerer O/D 28.04mm (ISO Standard 1" threaded = 28.6mm)
Steerer I/D 22mm (approx=ISO Standard 1" threaded)
Steerer Threads 1mm (25.4 tpi)
Frame cup O/D 34mm (= 1 1/8" standard)
Crown race I/D 30mm (= 1 1/8" standard)

How to Service or Repair
From the above data you can see that you can use the frame cups, crown race from a standard 1 1/8" threadless headset. In practice it is only the lower bearings that wear as they bear the weight and you can just replace the the crown race, lower frame cup and the bearing and re-use the upper bearings already fitted to your tandem. In practice you can replace both upper and lower bearings, by using the locknut from the old headset to pre-load the bearings (see photo) the brake cable hanger acts as a lock washer.
It is best to use a high quality headset due to the extra stresses of a tandem. Also pay attention to the stack height to ensure a good fit.

The inside diameter of the steerer is close to the ISO 1" standard (just 0.2mm smaller) so in practice you can use a standard stem for a 1" threaded headset. You might have to remove 0.2mm of metal from the stem with emery cloth, but on my bike a standard stem fitted perfectly.