Originally Posted by
elcruxio
I had to go and try this on my wife's mountain bike which still has a triple and a normal rear mech. Having the chain on a large or small ring does absolutely nothing to retain the chain or prevent chain slap. Having the chain on a larger chainring changes the geometry a bit but if you ride over even moderately sized roots at speed it's ring ding a ding and goodbye paintwork.
Been doing it for almost 40 years. I will point out that nearly every mountain bike made in the last 20 years has a chain protector on the driveside chain stay. Even 1x sold today have them. Chain slap probably can’t be completely eliminated due to physics and the freewheel mechanism. Changing into a larger rig tightens up the system and reduces chain slap just like the clutch does.
I had my fatbike with 1x and Sram clutch rear mech next to it and it does in fact eliminate even the remote chance of chain slap. This is because clutch mechs have a friction element at the first pivot point which holds the mech arm static when riding. When testing a non clutch and clutch rear mech side by side it's night and day difference. The clutch mech does have stiffer springs as well but it's mainly the friction element, ie. the clutch which is doing the work.
If the clutch eliminates chain slap, why do mountain bikes still come with chain guards?
Now that I think about it I did try 1x with my previous mountain bike and didn't use a clutch mech then. It didn't work, because the chain kept falling off. Not sure if I used a narrow wide chainring. But when I used a double before that I would have dropped chains during downhill runs. Also had the chain wedge itself between chainrings once or twice again on downhill runs. And a broken chains as well. Note that I would not pedal on downhills because it would not be possible. The reason for that is below.
You’ve just admitted that the narrow wide is necessary to keep the chain from falling off of single speeds.The clutch mechanism is less important than the stronger springs now being used. Very early rear derailers had very weak springs which is why many of us used the upshift to higher gears. Derailer springs have gotten stiffer and the latest iteration is very strong, indeed. But that is all because of the need to keep the whole system much tighter on 1x so that they don’t throw the chain all the time. It’s also more important on dual suspension bikes because the chain is constantly loosening and tightening as the suspension extends and contracts.
If you have had a chain drop without shifting, your bike is adjusted wrong. I’ve done 30 mph on washboarded roads as well as rough downhills and have
never dropped a chain off of the crank. It would be almost impossible given that the front derailer is acting as a chain keeper in addition to it’s other purposes.
Actually I think one thing needs to be made clear here. Mountain biking and cycling is confusing with all the terminology and terms that are specific to a discipline of cycling but also have common language equivalents. So to define trail I mean the mountain biking definition of trail, ie. rougher than XC single track but not quite as bad as technical downhill runs. Trail bikes typically have 120-160mm of travel and tend to be full suspension. Actually trail bikes are pretty much the same as enduro bikes but not competetive. It's really silly.
Anyways I've been riding these kinds of trails starting with a 100mm hardtail, then a 120mm hardtail and now with a 120mm front suspended fatbike. I'm a little undergunned to be honest but 140mm at the front was too much for climbing on the fatbike.
I don’t need a definition of a “trail”, thank you very much. I don’t break down trails into cross country and
real trails. Trails I’ve ridden all my life have smooth bits and rough bits. I started riding the trails around Colorado and the western US on trails that were designed for hikers and carved by motorcycles and 4 wheel drives. Most everything that people ride now on bikes with 140mm of front and rear travel, I was riding 40 years ago on bike that was one generation away from a modified cruiser. Rocks and drops are just a way of life here.
Why I haven't been riding something faster and more fun you may ask? Well, Finland's terrain is kinda unique since it was under the glacier during the last ice age. This means that the natural granite was ground to stones in varying sizes and those stones are literally everywhere. Every single trail is littered with these head sized boulders. Secondly our forests are heavily pine and fir based, both of which are surface root trees. This in turn creates trails which are nothing but technical. There's no speed here. Just rock and root gardens.
The environment really is unique because go only a hundred miles south to estonia and they don't have these boulders littered everywhere. Their forests are sand based and a travelling boulder the size of a small car was an actual tourist attraction.
Not unlike mountains that are only 55 million years old and actively growing. Our forests may be a bit drier but we still have plenty of roots.
And our mountains haven’t been flattened by sheets of ice.
Having that context thing out of the way when I look at trail pictures of Colorado or anywhere in the US rockies all I seem to find are these glass smooth flowy single tracks you could ride a cyclocross bike down. If your experience is with relatively smooth singletracks especially if you don't do jumps then I can understand why you might not see the need for better chain retention current 1x systems provide. I've seen only a limited amount of single tracks in the european alps but the ones I have seen have all been pretty darn smooth and nicely built.
Mind you, there's nothing wrong with that. I'd love to be able to ride hours and hours of fast downhill singletrack. In fact that's probably the most fun a person can have. But that's not what we have here.
Oh please!. Our trails aren’t “glass smooth”. Please quit being insulting. I’ve already said that when I do 30 mph, it is usually on a connector
road. Yes, we have some flowing trails. I suspect that you have some to. I’ve been on enough mountain bike trails (probably close to 30,000 miles of them) to know that trails have a mix of baby heads and smooth bits. For every mile of smooth dirt, there’s a mile of boulders. I wasn’t born at night and I certainly wasn’t born last night.
It would seem that at least some shimano clutch mechs are compatible with multiple chainrings. Maybe it's a sram thing that you can only use 1x with them. At least sram road clutch rear mechs are completely incompatible with multiple chainrings
Sorry but you have no idea what you are talking about. The only bikes I have have triples and I have more than one with a clutch rear derailer and they all work perfectly fine. There is nothing about the clutch that makes them unusable on multigeared cranksets. The clutch isn’t some kind of magic mechanism that explodes when it gets close to a crank with 2 or 3 rings.
Correction. The front mech keeps the chain relatively secure if it does fly off a chainring, but the chain can fly off if the going gets rough. The narrow wide keeps the chain in place even if you shift during rough stuff. But the narrow wide doesn't have any detrimental effects so it's really a non issue. Other way to achieve the same thing would be to use a chain guide and front pulleys to retain the chain but those add friction and do no favors to shifting performance.
No, not a “correction”. In nearly 40 years of mountain biking, I have
never thrown a chain off a chainwheel unless I was shifting. Even then it was only on the inner ring and was due to a misadjustment.
Yes, the narrow-wide chain ring keeps the chain on a 1x without a chain keeper but you have to have the narrow-wide to do so...by your own admission. The continued use of chainstay protectors on 1x bikes says to me that chain slap hasn’t been eliminated either.
Not doing wrong per se but riding trails that would in other places be considered technical downhill sections (mtb discipline downhill) with a hardtail can and will wreak all kinds of havoc in the drive line.
Then again haven't had a single issue after I went with a proper 1x system so there's that. Then again the fatbike does have a bit more rear suspension than your typical hardtail but it still gets bounced around quite a bit.
Quit considering your local or your riding experience “unique”. I ride in mountains which has uphill and downhill sections. I’ve got nearly 40 years of experience with mountain biking. And, I assure you, that Colorado’s mountain bike trails aren’t the equivalent of a ride on a bike path. Technical downhill sections are mostly innocuous when it comes to damage to the drivetrain unless you dump the bike on those rocks. Even then, the damage to a chain would be minimal in almost all cases. Chains break under tension and, most of the time, you are coasting on a downhill which puts zero tension on the chain.
Chain stress come from using it under power either on the flats, which causes minimal damage, or while climbing which puts much more stress on the chain. Even then, breaking a chain is more user error than it is something the chain does. In all honesty, I’ve carried a chain tool on every ride I’ve done over the last 35 years or so in anticipation of a chain break. I’ve used it once on someone else’s chain.