Sunday, June 30, 2019

Peugeot tandem TM 8 - creative restoration

Peugeot Tandem TM 8 restoration


Tandem experience


During our summer holiday in the Grenoble region in 2017, we had rented a tandem for novelty and out of curiosity. After one week of riding in the mountains we were hooked. When it was time to give it back, the stoker asked whether we could rent it a few days more, and I started to search for a used one of the 'french-fendered' variety. We quickly settled on a mixed Motobecane Inter Club or a Peugeot TM 8 Grand Tourisme because of our size difference and a certain charm in their looks.

Peugeot Tandem TM 8 restoration


The perfect deal


We found our TM8 in Hannover for a very fair price, and arranged to make a small stop to pick it up at the central station right on the way home from our vacation. We were delighted to find out that the couple selling the bike had actually ridden it to the rendez-vous. There is certainly no better way to say good bye and show that everything is in working order. Once arrived home I immediately rode from the station to our house to get the car and fetch our remaining luggage. There can barely be a better way to take possession of a new bike.

Peugeot tandem TM 8
Peugeot Tandem TM 8.

Start of a long journey


The tandem had surely been ridden on and off over all its life which is good, as it allowed us to use it right ahead while working on different aspects, but many parts showed wear and tell-tale signs of previous generations and bike shops fighting with the ubiquitous french tandem idiosyncrasies.

Start of a long journey. The bicycle as advertised on ebay. We were delighted
to find out the couple selling the bike had ridden it to the rendez-vous. There
is no better way to say good bye and show everything is in good working order.

We had no illusion about the value of this bike. It is easily identified as a typical 10 speed bike-boom bicycle. And with this in mind we happily started experimenting, changing and repairing. When we understood that we would stick with tandem riding and wanted to restore this particular specimen, we decided to go for a creative restoration keeping the spirit, rather than originality.

Peugeot Tandem TM 8 restoration

Frame


The charming frame is fillet brazed and sports a few nice details, as the very french bi-plane fork crown, oval boom, eccentric bottom bracket and hellenic mixte stays. And while the overall alignment seems fine and it tracks straight, a closer look shows sloppy execution in many details and price cutting measures where possible. Maybe they knew exactly where to stop cutting before the ride quality suffers?


Peugeot Tandem TM 8 restoration


As the frame showed specs of rust, and we anyway wanted to make a few modifications, we did not hold back with the torch and decided to go for a re-paint. One key point we wanted to address was to remedy the lateral whippyness through triangulation of the mixte stays (more here). And while we were at it we would add decals of our own design (more here)

Peugeot tandem TM 8
Peugeot tandem TM 8.

Wheels


The wheels were re-laced using 36 hole silver polished Ryde ZAC 2000 rims. In the rear we kept the original Atom drum brake hub using Sapim Strong spokes on the drive-side and Sapim Laser spokes on the non-drive-side in a 2 cross pattern, in order to match the cross-sections to the tensions and to keep the spoke angles reasonable. The weak axle of this hub and resulting bearing issues appear to be legendary , but since the installation of a CroMo axle, Shimano cones, and new bearing balls we get away with it. The front wheel was build around a Shimano DH-3N80 dynamo hub in a 3 cross pattern with Sapim D-Light spokes.  The wheels have stayed true and not given any trouble until now. For the tires we went with the affordable Continental Contact Speed for their clean look despite the reflective sidewall that we wanted to have for this everyday bicycle.

Drivetrain and shifting


The TM 8 came originally equipped with the beautiful Stronglight 49 D crossover tandem crankset in 52/42 teeth double configuration with 32 tooth synchronization rings. Simplex Prestige delrin plastic levers (velobase) commanded a SX A22 delrin band double front derailleur (velobase) and a Peugeot branded SJ810 (velobase) in the back. The power is transmitted through a 14-28 five speed french threaded Atom tandem Freewheel which holds up well to the rigours of tandem riding with its large 4 pawl design.

Stronglight 49D tandem crossover drive
Sronglight 49d crossover drive.

The flexy Prestige levers tended to slip and were replaced by the amazing first generation Simplex SLJ levers (velobase).

Simplex SLJ retro friction levers
Simplex SLJ retrofriction levers.

As we found the gearing range too narrow for our strength and intended riding, we tripelized the chainset and added a 6-th cog in the rear.

Simplex rear derailleur
Simplex rear derailleur. A combination using the
parallelogram of a SX 410 and the long pulley cage from an
SJ810. (6-th cog not yet installed).

In the process we replaced the front derailleur by the excellent Simplex SJ A223 and modified the rear derailleur.

Simplex SJ A 223 triple front derailleur
Simplex SJ A 223 triple front derailleur.

The refurbished 52/42/30 chainset with 14/16/20/24/28/32 freewheel provides developments from 2m to 8.1m, and got us over many alpine passes with pretty reliable shifting. (more here). While we liked the original black rubber pedals with their reflectors, we have meanwhile swapped them for MKS sylvan touring EZY superior rinko pedals for quick disassembly for transport.

Brake systems


The TM 8 is equipped with 3 brakes: Weinmann cantilever brakes front and rear, and an Atom drum brake in the back. The Weinmann brakes are actuated via a MAFAC twin lever on the right, while the drum brake is operated with a MAFAC single lever on the left.

Weinmann cantilever brake
Weinmann cantilever brakes. They may or may not be original. As they are
mounted with MAFAC bolts, they were probably exchanged later.

The Weinmann cantilevers stop the tandem well, but braking on long downhills is limited by the heat capacity of the rims before they get too hot and potentially melt the butyl inner tube. Adjustment of the relative length of the two cables can be tricky.

Mafac twin brake lever for tandems
Mafac twin lever.

The Atom drum brake does not really stop the tandem and is probably not intended to. But the self amplifying action of the drum makes for a light feel in the lever and the brake still scrubs a lot of speed. At the same time it can take a lot of heat before fading. This is really useful on long descents, where we use the drum to keep the speed under control on the straights and the cantilevers to brake into turns.

Drag brake: Atom drum brake hub
Drag brake: Atom drum brake hub.
Up to grades of 6% we have a lot of fun, around 8% we start to manage the brakes, and beyond 10% we begin to worry and stop regularly to let things cool down. That said, tandem braking is both art and science and riding a loaded Peugeot TM 8 over alpine passes is probably somewhat stretching the envelope.

Lighting


If there is one place where progress of bicycle technology has been striking over the last 40 years, its lighting. I do not miss the faint glow and low lifetime of conventional bulbs and the slip-stick-skip behaviour of many bottle generators. With the bike's current home in rainy Hamburg, and the decision  to keep the spirit but not originality, we went for a hub dynamo and led lighting.

Busch & Müller EYC
Busch & Müller EYC headlight on custom mount.

The front light is the excellent B&M Eyc, modified with a polished top and a custom mount (more here) for seamless integration at the original position. The beam pattern of this light is a pleasure to ride with, and the total power is adequate for tandem night riding.

Schmidt SON fender mounted taillight und Busch & Müller Z-reflector
Schmidt SON fender mounted taillight and Busch & Müller
Z-reflector on custom mount.

In the back we opted for the beautiful fender mounted Schmidt SON taillight, complemented by a custom mounted large area reflector (more here).

Shimano DH-3N80 hub dynamo
Shimano DH-3N80 hub dynamo.

The lights are powered by a Shimano DH-3N80 hub dynamo, we chose for its wide flange spacing, large flange diameter, good bearings, and excellent sealing. Proper cable routing was fairly easy through the fork, inside the rolled edges of the Gilles Berthoud fenders, and with the help of the original cable eyelets along the frame - a  nice detail common on these old frames.

Contact points


Captain: The original stem had been swapped for one with higher rise, and road handlebar and levers were exchanged for a touring noodle with flat bar levers by one of the previous owners. While I mainly went back to the original configuration to restore the looks, it quickly turned out that this was a wise decision: The light 'Guidons Philippe Atax Professionnel' absorbs road buzz and shocks very well, the geometry allows riding the tandem without fatigue despite its small width, and the racing position I am used to from my randonneuring bicycle fits me well. I discovered, that the narrow diameter of the bar wrapped in shellacked Tressostar cotton bar tape and the MAFAC levers allow me to find positions without pressure points easily. But most importantly, the combination of a racing position for the captain and a more upright position in the back gives the stoker more room and a better view, all while fitting our respective preferences! The simple and cheap Specialized Riva saddle I also run on my commuter bike is and remains one of my favourites.

Stoker: In the narrow stoker compartment there is not much room for adjustment, and suitable stems fitting the 25.4 mm captains seat post are not easy to find (early MTB ahead stems!). After quite some iterations, it turned out, that the length of the original Pivo stoker stem was just right combined with a riser bar with some backsweep. Only the bar had to be changed, as it had quite some drop towards the ends and its curves swept too far forward into the captain's thigh before sweeping back. For the saddle, the stoker also chose the same as on her commuter - a Selle Royal Ariel.

Rack and fenders


Unfortunately, only the rear fender was original, and the front fender had been exchanged.  We replaced both with the long version of the Gilles Berthoud stainless fenders in 50 mm width. This leaves room for tires up to 35-622. We extended the front fender with an SKS mudflap as long fenders are key to keep the stokers feet dry, and securely riveted the front light mount to the fender. The rear fender had to be dimpled to clear the chainstays and connects to the chain- and seatstay bridges. It carries the SON rear light and a riveted reflector mount. We modified the Pletscher Athlete rack that had been retrofitted by one of the previous owners,  so that it sits directly on the fender and connects with an M4 screw. A custom M6 daruma bolt combines both the rack- and the fender stays on each side respectively, so that fender and rack can be removed as a monolithic assembly for transport by loosening only four screws and a SON coaxial connector for the taillight.  

Frame geometry


Peugeot TM 8 frame geometry
Frame geometry. Click to enlarge.

There is obviously the question about the bike's weight. When we bought it, it was 22.7 kg. After the restoration and repaint it now weighs in at about 22.5 kg including bottles cages, frame pump, and still some possible gains. This is certainly reasonable for a fendered tandem complete with rack and lighting, and is likely still not too shabby compared with some production tandems. Its perfect considering its price. But a high end touring tandem can probably be still 5 kgs lighter which amounts to roughly half of the luggage we carry on a longer tour.

Epilogue


After the complete restoration with many new and new-old parts, there is the elephant in the room of what is actually left of the original Peugeot. And this implicitly raises the question whether a new or higher level used tandem might have been a better choice? Acquiring the Peugeot had started a process we thoroughly enjoyed. Owning this affordable bike had us confirm that we would stick to tandem riding. The adjustments and choices we made during the restoration taught us what goes where and why. And if we were ever to commission a high end or custom tandem we now know what to look for. But a thorough comparison with a well equipped modern rental Tandem had us return to our vintage steeds and really appreciate their design choices even more. Yet still - is it justified to invest so much thought and time in a frame of sloppy construction from lesser materials equipped with obsolete components?  We actually like the feeling of connectedness resulting from the short stoker compartment. We found out that restoring the frame and components to perform in proper condition and context revealed a beautiful ride quality that lead to the great memories we have created riding this bike. And to come back to the question of what is actually left from the original, the answer must certainly be: its soul. About 40 years ago, french bicycle makers definitely knew a thing or two about what makes a good ride!

More build- and restoration-details:


Cyclotouring with the Peugeot TM 8


Touring the French Alps on a vintage Peugeot Tandem

A hanseatic autumn trip with the Peugeot tandem

Image gallery of this Peugeot TM 8: on Flickr



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