Atom 77 Compact Freewheel Rebuild

In the previous post, I reviewed how I disassembled, cleaned and lubed the Atom 77 Compact freewheel of the PB 12 as a precaution against failure like I had seen in another 77 which my brother had given me. I decided that I would tear down and examine that freewheel to see if it could be restored to function or if I would simply disassemble it for spare parts. The tear down procedure was exactly the same as for the previous freewheel and ended up looking like the photo to the right.

Fully taken apart, there was no immediate visual cue as to why the freewheel would intermittently fail to catch the pawls and drive the freewheel body. A really close look at the pawls revealed that one of the pawls was not being held out from the body to allow the ratchet to function. I assumed that the issue was poor spring tension on that side. The photo to the left clearly shows a pawl protruding from the the freewheel body and that was not happening. I carefully removed both pawls and using a thin, straight bladed screwdriver, bent the springs upward to add tension to the pawls as I had done with the original Atom 77 Compact. I then tested the pawls for range and smoothness of motion. One worked perfectly and the other would snag, catch, and release functioning  intermittently, at best. The pawls themselves look like little metal flags on a short flag pole and I thought there might be a problem in the pivot hole drilling in the body not allowing the pawl to rotate. I removed and checked the roundness of both drilled holes and there was no roughness or binding. Next, I checked the pawls themselves. One of the pawls was rough along its upper surface

 

and when fitted back in the body, the roughness would snag and hold the pawl away from the ratchet steps. There was also slight roughness on one side of the pivot shaft. I took out a flat profile file smoothed down the roughness on the top of the pawl and the shaft. I also ran it over the top of the machined groove that the pawl moves in to be sure there were no snags or roughness there. ( I didn’t find any.) After that, I added Park grease to the springs, grooves and pivots as well as the bearing races and then reassembled as I did the last time. Once everything was snugged down, a quick spin gave out a quiet buzz from the freewheel and positive, sharp engagement of the pawls within the freewheel. Success! I now have a second, working, Atom 77 Compact instead of spare parts.

Note: Please be aware that some mechanics do not like to use grease in freewheels. They are concerned that grease, in low temperature applications, causes the freewheel to lock up with the pawls not engaging due to thickening of the grease. A thin grease layer in the bearing tracks and liquid lube on the pawls and ratchet teeth are an alternate lube strategy if you regularly ride in low temperatures.

Atom 77 Compact Freewheel Service

Once I had purchased the Peugeot, I went over it for safety issues and, once satisfied, I took it for a test ride. Several items got added to the mental to-do list which have been discussed previously. One thing I did notice was the near absence of any freewheel buzz. Many freewheels make a distinctive clicking or buzz as they freewheel when you are not pedaling. My narrow spaced/Compact/Ultra type Maillard 700 and Helicomatic  freewheels are clearly audible but not so with the Atom 77 Compact. I simply considered it odd and carried on with planning and completing the PB 12’s restoration. Even after the freewheel was removed, cleaned, flushed and lubed, it was still nearly inaudible when remounted and test ridden.

However, just after all that was done, my brother and I went out for breakfast. He is a professional bike mechanic and had a customer come into the shop complaining that the freewheel on his bike was not working. It was an Atom 77 Compact with the same gear range as mine. The Atom would happily freewheel in both directions, intermittently, but would sometimes then catch and so it was replaced. Knowing that I was working on the Peugeot, he passed the junked Atom on to me .

I cleaned, flushed and liquid lubed it, sure that it was merely plugged up with 35 year old dried grease. There was some improvement after several weeks of soaking in CitriSolv , drying and lubing but, at best, the freewheel would give off the same quiet buzz of the PB 12’s freewheel and would then, without provocation, freewheel forward and back. Then, spontaneously, the drive would re-engage. All this is fine in what is, after all, spare parts. However, the same noise from two freewheels with one exhibiting intermittent failure was not a comforting  situation.  I determined that the only way around a potential future problem was to remove the Peugeot’s Atom 77 and tear it down for examination and service.

This Maillard/Atom product uses a grooved, dedicated freewheel remover as seen previously when I described the initial freewheel service during the restoration process. The details are here, if you need them.  Once the rear wheel was off the bike, the dust cover on the front of the Atom needed to be loosened for removal and access to the bearings and pawls. These are reverse threaded and need to be turned to the right with a pin wrench to undo them. Unfortunately, in that uniquely French manner of design, the dust cover does not unscrew and lift off the body. It does not do this because the hole in the two outer cogs is too narrow to fit the dust shield through. To remove it, you must undo the 2 outer cogs which are in a unit, remove them from the freewheel body and then finish unscrewing the dust cover.

The sequence then, is this:

      1.  Remove the rear wheel from the bike;
      2.  Undo and remove the quick release from the rear axle;
      3.  Unscrew the spacer from the rear axle and remove;
      4.  Hold the wheel in place, insert the pin wrench lugs into the dust cover body and unscrew the body to the right; (use a punch and hammer if too tight for pin wrench removal) Instructional video here.
      5.  Really, just break it loose and do a half turn or so as the cover will bind against the back of the nearest cog on the Atom Compact;
      6.  Use the Atom freewheel remover and remove the freewheel from the rear hub;
      7.  Put the freewheel in a freewheel vice or screw it down to a board as I did;
      8.  Using a chainwhip, break the two outer cogs loose on the freewheel body and then manually remove the two cogs;
      9.  Use the pin wrench and unscrew and remove the dust cover (which also acts as the outer bearing cone);
      10.  This allows you to remove and set aside the upper ball bearings and clean the race. Be sure to remove the 2, thin, circular shims (spacers) and carefully reserve them in order to reinstall. These act to fix the proper spacing for the bearings to move freely;
      11. The upper bearing race is visible in this photo as is the mounting board. Use 4 hold down screws not the 2 as shown.
      12.  Loosen the hold down screws from the board and lift the cogs and body off of the back of the freewheel. Do this on a towel or in a large tub with no outlet – bearings will roll. Collect and clean them and keep them apart from the upper bearings. Even though these are the same size (yes, I measured them) other freewheels bearings  may not be.
      13. Clean the bearing race and the areas around the pawls.
      14.  The springs that tension the pawls and press them against the ratchet in the freewheel body may have lost or never had much tension. I noticed that these small, leaf springs needed an assist so with a fine bladed screwdriver, I bent the spring slightly outwards so it would add tension to the pawl and then did the same to the other one.
      15. Use your grease of choice to cover the bearing track both top and bottom  and then lay all the ball bearings back in place in each location using tweezers.
      16. Carefully, lower the body down over the lower section being careful to not disturb the lower ball bearings while rotating the body counter-clockwise to go over the pawls. Place the shims back in place, grease and insert the upper bearings, grease and counter-clockwise, screw in the dust cap with the pin wrench.
      17. Screw on the two outer cogs, snugging them tight with the chain whip.
      18. Then, as they love to say in technical manuals, “installation is the reverse of disassembly”.
        (Remember to re-coat the hub threads with anti-seize or grease.)
        Once the freewheel was completely reassembled, the wheel quick release re-assembled and everything re-installed in the rear dropouts, I noticed a more pronounced buzz from the freewheel while coasting. There was no change in the behaviour of the freewheel while it was under drive.So, it’s nice to know that this Atom 77 is fine and that just leaves me the dead one to look at and fix.

Michelin Dynamic Sports 700C x 23 and the Peugeot Course

Right below this introduction is a photograph of the Course taken in December of 2017. It shows the substantially restored state of the Peugeot, minus a few adjustments to seat height, toe strap length and such like. It also shows, if you zoom in by clicking on the photo, the pale blue logos of the original Michelin TS 23 tires in 700 C x 23 sizing. These tires were the OEM equipment installed on the Course at the factory.

Peugeot Course Dec. 2017

I had ridden the Course for assessment purposes when first acquired and I had ridden it to test changes to equipment and the frameset during the restoration process. In all these cases, the bike had been on its original Michelin tires. These inflated to 80 PSI (5.5 Bar) front and 90 PSI (6 Bar) rear with no problem and they rolled along as one would expect.

However, if one looked closely, short, fine cracks could be seen in the side walls and in the tread.  During a normal service life, these type of cracks have never been a problem on any Michelin I have owned but the TS 23s were installed around 1983 judging from the low tread wear and overall condition of the bike at time of purchase. Given the age of the casing and tread, I checked the tread rubber with a fingernail pressed against it. The rubber was hard and did not yield to the nail nor did it leave a groove in the rubber surface. As well, deflating the tire slightly and squeezing the tread yielded a series of parallel lines in the tread rubber that opened  down to the fabric cords beneath the rubber. The rubber did not chunk or flake and retained its integrity when re-inflated but it was obviously time to replace the tires.

The OEM Michelin TS 23s were a top of the line clincher when new given the file/rib tread design and the then new, high tech Kevlar folding beads. It is amazing such a premium tire would be fitted to an entry or aspirational level model as the Course but Factory specs from the period clearly list the tire as such. It seemed to me, however, that the replacements needed to be competent not elite and affordable at the same time. Since Peugeot retained an enduring loyalty to French component makers, I decided to replace Michelin with Michelin. The  Michelin TS 23s would be replaced with Michelin Dynamic Sport tires in 700 C x 23. The Dynamics have a mixed reputation when you read reviews but I had previously had Michelin Selects ( a predecessor tire) on a previous Peugeot and had liked them. As well, I choose the white wall Sports rather than the Classic with gum walls because of the better match to the frame colour. The tires were purchased through Pro Bike .ca and the $12 Cdn cost per tire was outstanding and so was the service. The tires arrived  together neatly packed in a cardboard box.

 

The steel beads made for a difficult installation but once on the Rigida 1320 rims with Velox rim tape, the tires seated cleanly and the Michelin A1 Airstop tubes pumped to pressure without problem. The matt slick tread was quite grippy and where the TSs would slide easily across wood or tile floors, the new Dynamics will grip without slipping and chirp when forced. They come with a pressure suggestion chart on the cardboard label matching pressure to rider weight.  I run mine at 80 PSI front and 90 PSI rear just like the OEM Michelin TS 23s. They are ridden on tarmac paving, chip seal and compacted gravel and provide a comfortable ride at the pressures mentioned with good grip. No rain riding so no comment on that. It is comforting to be able to look at the new tires and trust that they will remain on the rim with an intact tread just as installed. With a few set up tweaks and the new tires, the Course now looks like this:

The next post of the series will be regarding the Atom 77 Compact freewheel there was an issue that needed to be dealt with.

 

Simplex Derailleur Adjustments Front and Rear

The fine tuning of the Simplex LJ 1000 rear derailleur and the SJA 102 front derailleur is a fairly straight forward procedure. If you removed the derailleurs from the bike and did nothing to them except clean and the lightly lube them, then this step will go very easily.

I am assuming that both derailleurs have been returned to their pre-restoration locations on the bike as described in restoration previous steps. If so, the SJA 102 front derailleur should have its cage parallel to the face of the outer chain ring and be located about 2 mm to 4 mm above the chain ring teeth. The rear LJ 1000 should be hanging on the rear dropout tab and be able to move freely on that tab. Both should have the Sedisport chain threaded through them and then over the largest rear cog and the larger of the two front chain rings. This gear combination  (big/big) is never used in the real world because of the extreme cross chaining involved which accelerates chain noise as well as wear on the chain, cogs and outer chain wheel. The reason you use this as the default location for setting the derailleurs is that the system must be able to accommodate this maximum length of the chain in case the gear combination  is engaged inadvertently.  If this configuration cannot be adopted because you have changed to a larger freewheel or a new chain or both, you must lengthen the chain to accommodate  this arrangement. Failure to permit the system to engage the big/big configuration will result in difficulty shifting onto the big cog or an inability to shift onto the big chain ring. It’s the old story: change one thing, change many.

However, if all you have done is clean and lube and resisted the urge to fiddle with the derailleurs while off the bike, the next steps are straight forward as promised earlier. It is critical to be sure the inner and outer throw of the front and rear derailleurs are accurate. If you get the rear derailleur adjustment wrong, you can stuff the derailleur into the spokes destroying the wheel, the derailleur and possibly even bending the rear dropout and frame as well. If you permit over shifting at the front, the chain may land on the crankset gouging the finish. Worse, the chain could go between the crank arm and the spider jamming and  gouging up that side.

For the rear derailleur, you will need to use the adjusting screws on the derailleur body to adjust the inner and outer throw of the derailleur. The upper screw  controls the outward throw of the derailleur to access the high gear cog. The lower screw controls the inward range of the derailleur throw to allow low gear engagement.  To check the set of the derailleur range put the right Retrofriction all the way forward. Manually place the chain on the smallest cog. Turn the cranks and pull the gear lever back, sequentially selecting the next cogs.  As you approach the largest cog, be careful of the force you apply to the lever and select the largest cog. There should be no extra travel available which would allow over shifting the chain into the spokes. If travel is still available, use a small straight blade screwdriver to screw outward the upper travel screw. This limits excess motion and prevents disastrous overshifting into the spokes. Carefully re-try and test that the throw limit is correct.

Turning the cranks, shift back down the 6 cogs of the freewheel until you cautiously approach the smallest, high gear cog.  As above, if the cog engages without extra lever motion available, you are fine. If lever motion is still available, use the straight bladed screwdriver to screw the limit screw inward to prevent over shifting. Once the limits are set, it may be necessary to re-tighten the derailleur shift cable to eliminate slack.

To check the front derailleur throws, set the chain on a middle cluster cog. Using the left Retrofriction lever , carefully turn the pedals and gently pull the lever back. The chain should climb onto the big chain ring. If lever travel remains, use the straight blade screwdriver to move  down the screw limiting extra movement. Carefully turn the cranks and then gently move the left Retrofriction lever forward to derail the chain off the big ring. The chain should drop neatly onto the small ring with just enough extra lever movement to allow the front derailleur cage to clear the chain as the chain goes up the cluster and onto the big cog on the freewheel. If excess motion remains at the lever, use the screwdriver to screw down the inner travel limit screw to prevent the chain from derailing onto the bottom bracket shell or jamming between the inner chainring and the axle. Any excess cable slack should be removed if this adjustment was necessary.

Once you have completed all the basic adjustments while on the work stand, run the shifts up and down the cluster gradually increasing the loads and the speeds of the shifts. The derailleur should shift quickly and cleanly from low gear to high, up and down the freewheel cluster with no overshifts beyond the cogs. Do the same for the front chainrings. Then take the small screwdriver with you and one large enough to fit the Retrofriction screw and ride the bike outside or on a mag trainer. Run the same upshift/downshift tests you did on the work stand paying special note to the possibility of Retrofriction lever slippage under load such as sprinting. Tighten and fine tune as necessary. Once the Retrofriction lever tension is set, it should stay that way until or if you choose to change it. Watch after the first few rides and check shift lever cable tension. There may be some stretch and you may have to remove that from the cables to keep the shifting smooth and linear.

One further step needs to be taken. After test riding the PB 12, I noticed cracking in the Michelin TS sidewalls which is quite typical of Michelins in general. However, there were also cracks in the tread which, upon higher pressures and closer observation, were observed to extend down to the fibers of the tire carcass. Replacement of the tires was obviously going to have to happen next.

 

Peugeot Course: Lyotard 45 CA Pedal Rebuild

The PB 12’s drive train only needed the rebuilding and re-installation of the Lyotard 45 CA pedals to be complete. This design of pedal has a lengthy history extending back into the mid-1930s as the Velobase link here describes.  As received, the pedals were slightly oily and dusty with the toe straps installed backwards (photo shows corrected orientation) . As well, the Christophe toeclips were slight scuffed but the pedal cages and caps showed no sign of the bike having been laid down in an accident as they were clear of scrapes.

The pedals themselves were nicely made with no burrs or machining flaws. The bodies were pressed, chromed tubular steel with press fit anodized alloy cage supports and alloy cages. The pedal caps were faceted to allow removal with a wrench (I used a small adjustable wrench but  slip jaw pliers with padding on the jaws can work). Removal was somewhat stiff but rider serviceable pedals were not to be sneered at. Once the dust cap were off, a lock nut and removable cone were revealed on each pedal along with sludgy, dried brown grease. This serviceability is very atypical at lower price points, pedals usually having peened over lock nuts and little user adjustability.

The thick, nearly dry grease was wiped off the axles, off the cones and out of the races. Once this was done, the pedals revealed themselves to be in excellent condition. The forged axles had only the slightest of bearing tracks worn on the axle pedal ends and the adjustable cones at the outboard ends of the axles were the same. The chromed, pressed steel pedal bodies had been bulge formed to make cups and these looked merely broken in. The ball bearings were in perfect condition. Everything was wiped clean with CitriSolv, greased with Park grease and reassembled. The pedals adjusted without play in the bearings, locked down and have held their adjustment. Oddly, these nice looking budget pedals are 100 gm lighter than Campagnolo Record road pedals and about 15 gm lighter than the black alloy caged Campagnolo Superleggeri non-click in pedals.

Once reassembled and adjusted, chromed steel Christophe medium size clips were bolted on and new, black leather Christophe straps were inserted into the cages. Thankfully, I remembered to give the straps one full turn to prevent the straps sliding when snugged up with a firm pull. To aid that, excess length was trimmed and strap buttons were added to the end of each strap. The raw, light coloured end of the leather strap was coloured with a black, alcohol based marker. Both pedals were then re-installed on their crank arms using a 6 mm allen key, completing the drive train refurbishment.