The Genius of Narrow Wide Chainrings - Why they work!

back in 2012 sham introduced the first mountain bike chain ring with alternating teeth we now know these as narrow wide chain Rings actually this one here is about $3 on AliExpress which means it definitely infringes on one of sram's patents but back in the 2010s many bike companies came up with their own version of the narrow white chain ring some were sufficiently different to stand on their own some paid licensing fees and then other companies just had no respect for intellectual property whatsoever but they all had one thing in common this alternating tooth profile from narrow to wide narrow to wide all the way around the chain ring and back in 2012 this was absolutely revolutionary it's arguably one of the most important advancements in mountain biking of the 2010s but why oh yeah that is noisy so today I'm going to show you some footage that I captured to illustrate what a narrowe chain ring actually does but first let's talk about what led up to this advancement here's an old mountain bike from the early '90s with lots of Gears here's your cassette and derailer at the rear and you have three chain Rings up front and a front derailer by shifting through all these gears you can climb Hills go fast and have lots of fun but over the next two decades as mountain bikers began tackling tougher terrain it became clear that there were tradeoffs to having this whole mess of stuff up here I actually published an entire video about all the advantages of chain rings and derailers but at the end of the video I ultimately concluded that I'd rather have a modern mountain bike with one ring up front and so as time wore on it became more common to see only two rings up front instead of three and many of our mountain bike ancestors from the mid 2000s began diying their own one by drivetrains actually it looks like the previous owner of this bike attempted to do just that as recently as 2018 They removed the outer ring they use the limit screws to just lock the derailer in place and use it as a chain guide and they've only been using this one ring but these old front derailers actually did help keep the chain on it's almost like a built-in chain guide because it runs through it and so when the chain would pop off which it would you could kind of pedal it back on with a little bit of effort so then after removing two chain rings from the front of their drivetrain people would then introduce complexity back into it with chain guides and pulleys and all manner of things to help keep the chain on some people would remove huge sections of their chain to make the derailer cage get really tight and hopefully keep the chain on but then in 2011 Shimano introduced their Shadow plus derailer which featured a clutch see derailers have this cage which can move up and down to accommodate different gear sizes and it flies all around when you're on the trail and when you go over a lot of bumps it can just knock that chain right off the front chain ring but but shimano's derailer had a little switch that you would flip and it would tighten up the spring and put a little bit of friction on the cage so it wouldn't move around as much and pretty much all derailers today on mountain bikes have that if you take a look at this slow motion footage you'll see exactly what chains used to do before the clutch existed you can see it's just flying everywhere and then you can see when we engage the clutch it's still flying everywhere but way less so now to be sure the chain is still moving a lot but that clutch is a dramatic Improvement and really helps keep the chain on but at the time these shadow derailers were still being used with multiple chain Rings up front that clutch alone was not enough to keep the chain on it wasn't until the next year when SRAM introduced that new drivetrain which came with a narrow wide chain ring now Shams derailer did feature a clutch at the time but the real star of the show was that narrow wide chain ring if we're not talking about chain slap or noise or anything like that and we're just talking about chain retention this is just as important as the clutch it might even be more important and in fact my tests show that it is let me show you a little experiment I did here we have the Ozark Trail PR Max Ultra Studio it's a Walmart bike that we did a whole bunch of upgrades to one of those upgrades was a cheap crank set with a cheap narrowe chain ring and at the rear of this bike the derailer is actually quite nice is a Shimano Dior XT derailer with a clutch that we can switch on and off with this little Le right here so I rigged up a Contraption and pointed a camera at the drivetrain and I went through the same Rock Garden a number of times and I didn't go slow with the clutch on you can see the chain stays in place quite nicely as it should with a narrow wide chain ring and a clutch a mortal like myself is probably not going to drop many chains I could ride for weeks on end without droing dropping even one of them but then I turned off the clutch and guess what the chain still stayed on yes it flopped around a lot but it still stayed on the bike so I made things interesting I put one of these on the bike a stamped steel chain ring with the same teeth all the way around we'll call it a conventional chain ring and of course it didn't Faire so well the chain came off almost immediately all right that's not that surprising so I turn the clutch back on if we do that same run with the clutch engaged and see if we drop a chain I think there's a good chance it will cuz I'm not pedaling this is not a very long run oh W oh oh we have the beginnings of a drop chain right here we dropped the chain it improved dramatically the chain was way tighter it was slapping around way less and it held on for much longer but by the time I got to the bottom of the rock garden that chain had come off the bike you can see it sort of off the bottom of the chain ring and that was only a 30-second run and so while I didn't perform this test under conditions that could be even close to Scientific it does illustrate something very interesting and I suspect it's kind of a tossup as to what's more important for your chain retention your clutch or your narrow wi chain ring this particular test seems to indicate it's the narrow white chain [Music] ring so a $3 AliExpress chain ring did more for our chain retention than a Shimano Dior XT derailer with a clutch why is that well let's start with the fact that conventional chain rings are by Design able to dchain put any lateral force in the chain and it reliably pops off as it should that's what a front derailer is designed to do but take a close look at a chain you have these inner links which are really small and then you have these outer plates which make up kind of a bigger more substantial link so they're alternating from narrow to wide narrow to wide eh and so on a narrow wide chain ring these teeth alternate as well and so it's designed to make full contact with the chain the entire way around vastly increasing the surface area you can see here every single link has a tooth that is exactly its size and now we can make a few interesting observations first of all unlike your cassette which might have an 11 to Cog and a 13 tooth Cog you're not going to find any prime numbers on narrow white chain Rings actually you're only going to find even numbers 28 30 32 34 because they alternate having an odd number would just make the chain fall out of syn every revolution in fact if you've ever noticed when you install a chain on a narrow white chain ring if you try to install it like one half link over it won't actually push down onto the chain and you have to line it up for it to fall on and so the result is there's barely any lateral movement whatsoever and you might say well yeah of course there's double the surface area on the Chain but actually that's only telling part of the story you see here with a conventional chain ring it has to be made to the lowest common denominator it has to fit the smallest links because if they made the teeth bigger to fit the big links it should be obvious they wouldn't fit into the small links and so conventional chain rings are making contact with the smallest puniest links and leaving the larger more substantial ones pretty much untouched and so a narrow wi chain ring is not only making contact with all the teeth but it's taking full advantage of those larger more substantial links that conventional chain Rings barely touch at all so when you have a narrow wide chain ring and the chain is flopping around everywhere because that lateral movement is so limited the chain always ends up back on the Chain ring even if it's flopping around and even coming off at the bottom because the very next link is being held in place whereas with a conventional chain ring there's all this side to side play that allows it to just work its way off of the chain ring and actually that's not all because the space between every single link is fully occupied with a tooth there's really no room for dirt and so this actually helps clear dirt from the chain keeping it cleaner and keeping your drivetrain running better meanwhile conven chain Rings leave all this space on the inside of the links for dirt to accumulate and for the chain to wiggle around and so now it should be pretty clear why narrow ey chain Rings provide such a huge advantage and so if you were upgrading a really entrylevel bike like this one or an older bike like that GT I would actually recommend you upgrade that chain ring before you upgrade anything else and so with all the Innovations we saw in mountain biking in the 2010s the clutch The Dropper post countless linkage designs this is the smack yourself in the face simple Innovation that actually made one of the biggest differences and we have the narrow wi chain ring to thank for a lot of the innovations that came after including one by Drive trains pretty much becoming all but ubiquitous with this Innovation over 10 years behind us it seems like kind of a strange topic for a video but it's pretty clear to me that people think the clutch is doing all the work and so I wanted to do a deep dive into narrow white chain rings and G out and explain why they do so much for chain retention would you have liked this video 2 weeks ago recently burm Peak launched a page on substack which you can sign up for in the link below not only do we post all these videos here and the videos on my other Channel all in one place but they don't have any ads and you get them 2 weeks early but that's not even the main thing we're doing we are hiring independent journalists to write articles that only appear there so we've invited authors engineers Racers mechanics from all over the cycling world to write about what they're passionate about and it's all available now on the burn Peak substack I hope you'll check it out again everything is in the link below I hope you enjoyed this deep dive I hope you learned something and if you didn't I hope you at least found it entertaining thanks for riding with me today and I'll see you next [Music] time [Music] [Music] he

Channel: Berm Peak Express

Views: 693,688

Keywords: do it yourself, diy, tools, home, backyard, mountain biking, cycling, outdoors

Id: nZXzXH4gBfs

Length: 12min 9sec (729 seconds)

Published: Mon Feb 26 2024