Mafac LS, LS 2 and LSX Brake Pad Replacement Part 2

Once the restoration of my 1973 Carre/Bertin C 37 was finished, it only took until the first ride to discover that the stock OEM Mafac pads were hard, high effort and unsatisfactory, especially compared to my 1960s C 37 equipped with Mafac Competition centerpulls with aftermarket black, Kool Stop pads. The search was on to try and find some kind of workable replacement.

Mafac Pad Front View

The Mafac LS series shoes are angled to create toe-in when the shoe is mounted on the LS caliper arm. In addition, they have a nut inside the OEM alloy brake shoe to accept the brake shoe attachment bolt which means a replacement pad has to have a notched or relieved center section to fit. See the accompanying photo on the right of the screen to view both of these features. Also problematic are the tight tolerances in the brake shoes and pads themselves. Having measured pads around the workshop like generics as well as Weinmanns, I could not find an exact dimensional match to the Mafac LS pads. Consequently, I decided to take the easy way out and simply replace the whole shoe/pad assembly.

The easy way was not easy. I ordered, on line, an inexpensive set

Mafac Pad Side View

of YST shoes with chevron shaped braking surfaces to echo the Mafac pad shape. Once they arrived, the steel brake shoes looked comparatively poorly finished and once installed they did not toe in well or look the part of a high end brake as one might expect with such an inexpensive product. However, the pad rubber was soft and once sanded clean of mold flash, the shoes did stop the bike better than the 40 year old OEM Mafac pads. Brake feel and modulation was not great but the bike would stop and did so with less lever effort than the original pads. Faint praise.

YST Pads On Jagwire Bag

Part 2 of the easy way was to order another shoe/pad combination set but this time from Jagwire in the Weinmann X pattern pad configuration. A big name in brake components should yield big results. Not so much. The Jagwires were better finished and cleaned up the mold lines with relatively little sanding. However, even with the LS caliper arms designed in toe, the Jagwires were still nearly parallel to the rims’ braking surfaces. The stopping was adequate, better than the OEM but not enough and they didn’t look right as mounted.

Part 3 of the easy way was an attempt to open up the Jagwire pads and extract one to test fit in a Mafac alloy shoe. The steel shoe on the Jagwires was reluctant to open which basically meant destroying the shoe to get the rubber brake pad out only to find the pad dimensions wrong for the Mafac shoe. At that point, I determined to find a pad that would fit the OEM Mafac shoe.

I searched through the technical specs for pads on the Kool Stop site but found nothing that looked close enough. While searching on the EBay USA site for Kool Stop, I came across a Scott/Mathauser ad offering Type M pads specifically for Mafac and and early Dura Ace. They could not have been for regular 4 dot Mafac centerpull brake shoes because the photos of the package clearly showed a Campyesque pad that looked quite different from the usual 4 dot Mafac pads found on Racers, Competitions and 2000s. So, I ordered a set which were quickly delivered from Ebay by Canada Post. When I opened the package, the Scott/Mathausers had a superficial look of compatibility with the Mafac LS OEM pads. Like I did with the Mafacs, I measured the Scott/Mathauser pads with my digital calipers.  I found the measurements to be slightly larger but within .5 to 1 mm of the Mafacs’ measurements. The one exception was the relief area on the top of the pad which in the Scott/Matthauser pad was 15 mm long compared to the 12 mm for the Mafac.

While I waited for the Scott/Mathauser pads to arrive by mail, I had been cleaning the Mafac shoes and removing the original pads. Removing the pads entailed levering them up at the end with a straight bladed screw driver followed by using pliers to wrench the pads the rest of the way out of the shoe. The shoes were wiped down and then run through an ultrasonic cleaner with some dish soap. The result was as set of clean shoes ready for the installation of the new pads. When the pads showed up, I checked the details on the reverse side of the plastic pack before attempting a trial fit or the installation.

Once the shoes were cleaned and ready, I attempted a trial fit of the Scott/Mathausers in the Mafac LS shoes. Even with the use of dilute dish soap as a lubricant, the pads did not fit into the shoes since the angle of entry of the pad was too extreme, the pad edge hung up on the round nut within the shoe and the pad would not settle under the rear stop at the back of the shoe.

The failure of the easy fit lead me to a few conclusions: that the .5 to 1 mm oversize difference of the Scott/Mathauser pads made a difference and you might want to do a little file work on the pads; the forward edges of the new pads need to be angled or rounded off to fit over the embedded nut within the shoe and finally, the rear tab of the brake shoe must be broken off to fit the new pad.

To get the pad rounded off like the center pad in the photo to the right, use a file or 120 Grit sandpaper as seen in the photo. It is also necessary to remove the rear retention tab of the alloy Mafac brake shoes. I tried a hacksaw but the result was poor and recommend bending the tab upwards with pliers until it yields and then snaps off. Once the retention tab has snapped off, put the shoe in a bench vice with padded jaws to avoid damaging the finish and take a fine file and dress the broken end thoroughly being sure it is de-burred and smooth to avoid fouling during the pad installation.

Be sure to carefully identify which end you will remove as the shoes are directional and the forward facing arrow must go to the front with a closed end but also to permit proper toe-in in combination with the LS caliper arm design. Once the shoes have been correctly opened and cleaned up, prepare a soap and water solution to act as a lubricant when installing the new pad into the Mafac alloy shoe.

Once you have lubed the inside of the alloy shoe, add the soapy mixture to the nose of the pad and to the crease along both sides. Slide the pad on an angle over the internal nut in the shoe until it is stopped by the front of the pad holder. It will now be sitting at an angle with the rear of the pad protruding from the  alloy shoe. Place the shoe/pad assembly into the padded vise jaws and slowly tighten down until the pad slips into place. (You may need to reverse the shoe in the vise to get the back section to fully seat.) Once the pad is seated, rinse the shoe to get rid of the soap solution from the installation and then follow the same procedure for the other three pad/shoe assemblies.

Having cleaned and dried  the assemblies, use your 120 Grit sand paper to abrade the braking surface of the Scott/Mathauser pads until the shiny surface is removed and the surface appears dulled to the eye.  Trial fit the retention screws and washers before doing an installation. The finished pad/shoe assembly should look like this:

 

The assemblies, once installed, should show an obvious toe-in when viewed from above. See the following photo:

 

 

Seen in profile, the installed assembly looks convincingly original and discreet except for that tell tale orange colour peeking through the brake shoes:

 

 

Conclusions:

The Scott/Mathauser M pad is the only one that I have found that installs properly in a Mafac LS, LS 2 or LSX alloy brake shoe. The fit is tight and installation could likely be eased by a slight filing along the edges of the pads in addition to the sanding described earlier. Toe-in is stock and so is the side profile appearance. Functionally, the pads are superb. There is no squeal, stopping remains higher effort than my Mafac centerpulls, as one would expect, modulation is easy and completely linear and progressive. Braking from the hoods is comfortably possible and is very strong from the drops. I highly recommend the conversion if you have Mafac sidepulls and wish to experience a major improvement in your braking quality.

Disclaimer:

The bike has not and will not be ridden in the wet so I cannot comment on that aspect of brake performance. Before the upgrade as well as after, the Carre/Bertin C 37 was fitted with Velo Orange lined cable housing and mandrel drawn stainless steel cables.

 

Mafac Spidel LS, LS 2 and LSX Brake Pad Replacement

The Mafac LS series of single pivot sidepull brakes was a response to the Campagnolo sidepull and its imitators which had become serious threats to Mafac’s acknowledged status as the premier bike stoppers available.  After the initial release of the Racer centerpull brake around 1950, Mafac had the dominant position in the later 50s and throughout the 1960s until Campagnolo released their Nuovo Record sidepull brakes around 1968. Much as Mafac had done through elite riders such as Jacques Anquetil and Tommy Simpson using their product in high level competition, Campagnolo’s extensive promotion of their expensive new sidepulls in competition by riders such as Eddy Merckx ensured that sidepulls, once again, returned to center stage as the fashionable style of stopper for riders of the pro peloton.

Mafac fought back, initially, with higher quality, better finished versions of the basic Racer design like the Competition and 2000. Even the use of those brakes at the highest levels, including Tour de France wins with Peugeot and Bernard Thevenet did not displace Campagnolo despite the Mafac’s superior stopping power. The only thing to do was compete directly and hence the design and marketing of the LS, the LS 2 and, ultimately, the LSX sidepull brake versions by Mafac/Spidel.

The LS version is easily identified by the black, highlighted Mafac name and LS model designation stamped into the brake arms and by the angular profile of the brake arms themselves. There are differences in cable fixing bolt design, brake arm contours,

Mafac LS

cable adjuster location and brake guide mounting on each of the three different versions.  The LS 2 is found marked either Mafac or as Spidel, the name of a short lived gruppo effort by French manufacturers to go head

Mafac LS 2

to head with Shimano, Campagnolo and Suntour. The back of the brake arm on the LS 2 usually has the LS 2 designation in raised letters. The LSX can also be found branded as either Mafac or Spidel with the lettering engraved into the front of the caliper arm. One important thing for the purposes of upgrading the LS series braking is that the shoe design is consistent throughout the production of the three related series of the LS design so that the process and shoe application discussed here are consistently applicable across the LS, LS 2 and LSX line of brake calipers. Equally important is that fact that the brake shoe and the brake arms are toed in by design from the factory. This means that the brake pads are designed to meet the rotating brake rim front first and gradually lay down against the rim as brake force is increased. This makes

Mafac LSX

the brakes easier to modulate and it also can assist in eliminating squealing. This feature is one of the reasons I have searched for a pad that will fit the OEM Mafac alloy shoes. One of the underlying assumptions here is that you have already upgraded your brake cables with lined housings and drawn stainless brake cables or with PTFE cables and lined housings. Given that these upgrades are invisible and don’t detract from the historical look of the bike, they should be done before or at the same time as the pad upgrade. The only down side to the pad upgrade is that Scott/Mathauser pads are only available in the high friction, orange coloured compound not black like the OEM Mafac pads.

Other brake pads such as the one piece molded types or the basic black ones in cheaply made stamped steel shoes will fit your caliper arms but they will have much less toe-in and a poorer but probably acceptable friction material. The OEM pads on my Spidel branded brakes had the original shoes and pads with the front pads worn down almost to the alloy shoe as you can see in the photo to the right. The pads themselves were probably 35 or 40 years old, hard, high effort and desperately needing replacement.  When removed from the shoe, they were crumbly and fibrous in composition and well beyond their “best before ” dating period. The typical replacement Mafac pads on the market are the 4 or 5 dot Racer/Competition/2000 style most easily available from Kool Stop. While I tried to source a replacement pad to fit the unique OEM shoes, I used a set of basic rubber brake blocks with the OEM wheel guides. They stopped the bike but the wheel guides did not lock onto them as on the original shoes and the clunky look did not really suit the bike. So the search was on to find a suitable, effective and good fitting brake pad insert for the Mafac’s alloy brake shoes. Part Two of the series will address that search and the results.

 

Bertin Poster Graphics

It is not a startling insight to observe that things change but is interesting to see those changes especially in such a highly competitive field as cycle manufacturing. In June of 2018, there was a Bertin Retrospective festival which had an on line “poster” which advertised the event. Many of you had seen it when I posted it here a year ago to support the event. If you missed it, this is the “poster”:

 

 

It is an interesting and evocative style using bold colours in large areas with little modeling on the figure. Forty years earlier, a Bertin poster looked like this:

 

 

And twenty or thirty years before that, a Bertin paper poster looked like this:

 

 

An interesting evolution in style.

LED Light Conversion Part 4

In the previous Part 3 installment of the LED lighting conversion, I had test ridden the realigned headlight / rack combination and found it satisfactory for lighting on a MUP (multi-use path) but did not test it on a suburban street with overhead, municipal LED lights or on an unlit rural road. As the season closed down and nights came on sooner, it became practical to, literally, do a road test.

I live in a small town with conventional sodium street lights as well as the newer LED type located near my home. About two blocks from home is the edge of the town site and with it the unlit dark you get on rural roads away from the ambient light of a town or city. By the time there was a moonless night, I had finalized the provisional aiming of the headlight and the set up was configured as shown in the photo below.

Configured with Soubitez headlight, LED light and new TA front rack

On the mercury vapour lit streets as well as the LED lit ones, the headlight made a barely discernible pattern on the tarmac paving which was irrelevant since the ambient light was more than enough to see and ride safely. The Bertin’s LED headlight and tail light/reflector were more about visibility to traffic in those contexts. Thankfully, for testing purposes, two blocks away was a stop sign with the utter dark of a rural road on the other side of the intersection.

Once passed the intersection, the road was chip sealed tarmac and the headlight pattern gave an abbreviated, short pattern showing a shadow from the front wheel. After a short distance, I stopped and realigned the  headlight and this got rid of the wheel shadow and opened up the beam pattern on the road. I turned and went back to the original intersection and as I approached the stop sign got a brief headlight flash from an oncoming car before I stopped and the headlight went out (only the tail light LED has a standlight function). Obviously, the headlight seemed bright enough to oncoming traffic on a lit street.

A  left turn took me onto a recently constructed road with smooth tarmac and freshly painted white center line and lines dividing the bike lanes from car traffic lanes. The area was completely dark but the headlight re-alignment and the non-relective white lines made visibility quite satisfactory. The horizontal spread of the beam neatly covered the roadway out to the center line and over to the right to the outside edge of the paved and lined bike lane. As my vision continued to night adapt, being away from vehicles and street lights, I was pleased by the quality of the beam pattern and the intensity. You should not assume that this is an equal of a modern multi-LED headlamp but it finally can be considered a usable and safe lighting system that is and looks period correct. Nonetheless, I wouldn’t recommend screaming down some Alpine pass with it although I am pleased with the end results.