Originally Posted by
Bikedued
Doesn't Helicomatic have the ridges in the tips of the teeth? Anything with thinner plates will get caught in those ridges, rendering forward motion impossible. Just my personal experience.,,,,BD
My thought on those ridges is that it isn't so much about the side plate getting caught in the groove as it is that a pair of inner/outer sideplates on the non-driveside of the chain can ride atop the very wide overall width of the tips of the teeth.
So, if anything, the chain with thinner and more-knifedged sideplates may more easily fall to either side of these blunt teeth, with effective transmission of power interrupted over a smaller range of lever movement.
Perhaps the biggest advantage of modern chains is their relatively wide central openings as compared to their outer width, which in my opinion makes it easier for the chain to fall into mesh with the teeth.
Sedisport chain was the one that these cogs were usually paired with, narrow as it was, but those old Sedisport chains also had square-edged sideplates that would too-happily glide/skate along those teeth tipped with pairs of ridges.
The ridges assisted shifting, but at the expense of the occasional "skating" where the chain cannot transmit power.
Interestingly, Shimano at one point had freewheel cogs with a single ridge up towards the teeth's driveside edge, while Suntour had teeth with broad tips slanted upward towards the driveside edge, both designs seeming able to reduce the width of any possible skating platform atop the teeth. A finest moment finally came when Shimano put a twist into each tooth leading up to a relatively sharp edge atop of the tooth, called it Uniglide, and thus created the finest cogs to ever grace a friction-shifted bicycle.
Later Maillard cogs featured teeth with the ridges pinched together aft of the leading corner (that first meets the chain's sideplates), with the single, pinched trailing edge corner apparently helping the sideplates decide which side of the tooth to fall over.
I've used a few of the SRAM PC-951 chains and experienced a very low rate of wear, so I am anxious to hear how the 8-speed version (PC-851) compares, both in terms of wear and in terms of how well it works on these narrow-spaced Maillard Helicomatic freewheels.
Those KMC X-series chains are very high quality as well, and also feature a removable link.