Why no N x 1 instead of 1 x N?
#1
extra bitter
Thread Starter
Why no N x 1 instead of 1 x N?
This is sort of a shower thoughts question, but why do bikes favor large numbers of gears in the rear vs the front? I understand why many prefer 1x setups, but when I underestimate a climb and need a bailout gear fast, shifting to a smaller chainring is just mechanically easier than having to push up to a larger rear cog.
I’m sure there’s a good reason that we have “1x”instead of “x1” and that rear clusters almost invariably outnumber chainrings, but I’m just curious what that reason is. Would the right foot hit the chain line? Something else?
I’m sure there’s a good reason that we have “1x”instead of “x1” and that rear clusters almost invariably outnumber chainrings, but I’m just curious what that reason is. Would the right foot hit the chain line? Something else?
#2
Senior Member
Join Date: Dec 2016
Location: Long Island, NY
Posts: 2,129
Bikes: Trek 800 x 2, Schwinn Heavy Duti, Schwinn Traveler, Schwinn Le Tour Luxe, Schwinn Continental, Cannondale M400 and Lambert, Schwinn Super Sport
Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 817 Post(s)
Liked 1,038 Times
in
674 Posts
It pretty much comes down to mechanics. It would be difficult to put a cluster of gears on the crank. The other issue is that when shifting the chain on the front derailleur, it is under tension whereas when shifting on the rear the chain is slack. The most we see on the front is three chainrings.
Now with that said, we could get a three speed bike with these three chainrings, but we will still need a derailleur like device to take up the slack.
There are some bikes designed with internal gearboxes in the bottom bracket. Whether this qualifies as a n x 1 is up to you. The only one that I know of is Pinion. There might be others. Shimano has a patent on a system using chains, however, it is not available for sale. Neither is/was the Honda.
Now with that said, we could get a three speed bike with these three chainrings, but we will still need a derailleur like device to take up the slack.
There are some bikes designed with internal gearboxes in the bottom bracket. Whether this qualifies as a n x 1 is up to you. The only one that I know of is Pinion. There might be others. Shimano has a patent on a system using chains, however, it is not available for sale. Neither is/was the Honda.
Last edited by Velo Mule; 07-15-23 at 10:32 AM.
Likes For Velo Mule:
#3
Over the hill
Join Date: Mar 2006
Location: Los Angeles, CA
Posts: 24,406
Bikes: Giant Defy, Giant Revolt
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 1011 Post(s)
Liked 1,235 Times
in
707 Posts
I imagine there isn't enough space to fit that many gears up front without riding bowlegged, and chainrings are bigger and therefore add more weight for each additional gear.
I wonder if you could make an internal gear bottom bracket.
I wonder if you could make an internal gear bottom bracket.
__________________
It's like riding a bicycle
It's like riding a bicycle
#4
Senior Member
Join Date: May 2021
Posts: 8,761
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 4566 Post(s)
Liked 5,097 Times
in
3,145 Posts
The rear derailleur is lightning fast and efficient at changing ratios, especially modern ones. The front derailleur is still relatively slow and clunky in operation, especially going into a higher gear. Do you really want a stack of 11 or 12 front chainrings with a super-wide front mech? The less chainrings, the better in my book.
Likes For PeteHski:
#5
extra bitter
Thread Starter
The rear derailleur is lightning fast and efficient at changing ratios, especially modern ones. The front derailleur is still relatively slow and clunky in operation, especially going into a higher gear. Do you really want a stack of 11 or 12 front chainrings with a super-wide front mech? The less chainrings, the better in my book.
#6
extra bitter
Thread Starter
I think the chainring size is probably the main point. We can only go so small for rear cogs, meaning the lower limit for chainring teeth still leaves us with big chainrings in order to hit reasonable gear ratios. A “front cluster” would need a lot of teeth, making it very heavy and also requiring a derailleur with a huge capacity due to a large difference in absolute tooth count between the low and high end.
Likes For kyselad:
#7
Senior Member
Join Date: May 2021
Posts: 8,761
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 4566 Post(s)
Liked 5,097 Times
in
3,145 Posts
Simply because the rear derailleur is inherently quicker and more efficient at swapping cogs. The tech has been developed as best it can for both. The front mech is IMO a crude device, which is why the industry is slowly moving away from them. I predict they will be history within the next decade. There is zero chance of the industry moving in the opposite direction toward Nx1.
#8
Senior Member
Join Date: May 2021
Posts: 8,761
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 4566 Post(s)
Liked 5,097 Times
in
3,145 Posts
I think the chainring size is probably the main point. We can only go so small for rear cogs, meaning the lower limit for chainring teeth still leaves us with big chainrings in order to hit reasonable gear ratios. A “front cluster” would need a lot of teeth, making it very heavy and also requiring a derailleur with a huge capacity due to a large difference in absolute tooth count between the low and high end.
There isn't really a lot going for the Nx1 concept, which explains why it isn't a thing.
#9
Pennylane Splitter
Join Date: Sep 2012
Location: Orange County, California
Posts: 1,895
Bikes: Yes
Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 1849 Post(s)
Liked 1,500 Times
in
1,025 Posts
#10
Pennylane Splitter
Join Date: Sep 2012
Location: Orange County, California
Posts: 1,895
Bikes: Yes
Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 1849 Post(s)
Liked 1,500 Times
in
1,025 Posts
This is sort of a shower thoughts question, but why do bikes favor large numbers of gears in the rear vs the front? I understand why many prefer 1x setups, but when I underestimate a climb and need a bailout gear fast, shifting to a smaller chainring is just mechanically easier than having to push up to a larger rear cog.
I’m sure there’s a good reason that we have “1x”instead of “x1” and that rear clusters almost invariably outnumber chainrings, but I’m just curious what that reason is. Would the right foot hit the chain line? Something else?
I’m sure there’s a good reason that we have “1x”instead of “x1” and that rear clusters almost invariably outnumber chainrings, but I’m just curious what that reason is. Would the right foot hit the chain line? Something else?
#11
Senior Member
Join Date: Apr 2007
Posts: 6,849
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 1139 Post(s)
Liked 1,243 Times
in
787 Posts
This is sort of a shower thoughts question, but why do bikes favor large numbers of gears in the rear vs the front? I understand why many prefer 1x setups, but when I underestimate a climb and need a bailout gear fast, shifting to a smaller chainring is just mechanically easier than having to push up to a larger rear cog.
I’m sure there’s a good reason that we have “1x”instead of “x1” and that rear clusters almost invariably outnumber chainrings, but I’m just curious what that reason is. Would the right foot hit the chain line? Something else?
I’m sure there’s a good reason that we have “1x”instead of “x1” and that rear clusters almost invariably outnumber chainrings, but I’m just curious what that reason is. Would the right foot hit the chain line? Something else?
Likes For Camilo:
#12
Senior Member
Join Date: Sep 2005
Location: In the foothills of Los Angeles County
Posts: 25,451
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 8378 Post(s)
Liked 9,253 Times
in
4,550 Posts
Likes For big john:
#13
extra bitter
Thread Starter
I've got one, its a 2x1; two-ring chainring (52/34) with a 16T single speed on back and the RD is now a dedicated tensioner. Works great for the occasional hill in my area. But weight saving is practically 'nil' vs the original 2x6. Bicycle was originally a Schwinn LeTour 2 from the late 1970s that I got for free.
#14
extra bitter
Thread Starter
That’s honestly super cool. I was specifically thinking that the front is mechanically easier than the rear for shifting to a lower gear with a derailleur drivetrain. Not sure if an internal hub provides a similar advantage for front vs rear of the drivetrain, I only know that the workings of internal hubs is above my pay grade.
#15
Senior Member
Join Date: Sep 2005
Location: In the foothills of Los Angeles County
Posts: 25,451
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 8378 Post(s)
Liked 9,253 Times
in
4,550 Posts
That’s honestly super cool. I was specifically thinking that the front is mechanically easier than the rear for shifting to a lower gear with a derailleur drivetrain. Not sure if an internal hub provides a similar advantage for front vs rear of the drivetrain, I only know that the workings of internal hubs is above my pay grade.
It would work on a road bike but it adds weight and is said to drag a little in certain gears/conditions. It's pretty tough to beat a derailleur for versatility.
#16
Senior Member
Join Date: Jun 2013
Location: location location
Posts: 3,035
Bikes: MBK Super Mirage 1991, CAAD10, Yuba Mundo Lux, and a Cannondale Criterium Single Speed
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 344 Post(s)
Liked 297 Times
in
207 Posts
#17
Senior Member
Join Date: Sep 2014
Posts: 3,893
Mentioned: 20 Post(s)
Tagged: 0 Thread(s)
Quoted: 1062 Post(s)
Liked 665 Times
in
421 Posts
The rear derailer functions as both a gear changer and chain tensioner. And the mechanism is on the low tension side of the drivetrain. The conventional front derailer still requires at the minimum a chain tensioner to function.
Thinking about gearboxes, maybe putting them in front ultimately makes more sense because you can put as much stuff in an expanded bottom bracket case as you want. But there's also more torque in front, and frames have not been standardized to receive front gearboxes... yet.
If there was a cheaper way to put a bunch of gears on a bike, we'd see it on cheap bikes.
Thinking about gearboxes, maybe putting them in front ultimately makes more sense because you can put as much stuff in an expanded bottom bracket case as you want. But there's also more torque in front, and frames have not been standardized to receive front gearboxes... yet.
If there was a cheaper way to put a bunch of gears on a bike, we'd see it on cheap bikes.
#18
Senior Member
Join Date: May 2021
Posts: 8,761
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 4566 Post(s)
Liked 5,097 Times
in
3,145 Posts
Others have described how a multi chain wheel would be impractical. But, the triple crankset solves that bail out problem. Just getting a bail out gear in front - going from a larger chain wheel to a smaller- is very quick and easy with a triple. Going to a smaller sprocket or chain wheel is mechanically easier and quicker and the triple crankset provides that, at least to a small extent. But "they're too hard to adjust" (BS), they're too heavy (a little heavier), but mainly not fashionable.
Modern drivetrains shift effortlessly up or down. On rides I do still see plenty of guys ranting their gears on steep climbs, but that’s just poor technique.
So I’m happy the way drivetrain “fashion” has gone in recent years.
Likes For PeteHski:
#19
Senior Member
Join Date: Jul 2015
Location: reno, nv
Posts: 2,323
Bikes: yes, i have one
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 1151 Post(s)
Liked 1,193 Times
in
694 Posts
Simply because the rear derailleur is inherently quicker and more efficient at swapping cogs. The tech has been developed as best it can for both. The front mech is IMO a crude device, which is why the industry is slowly moving away from them. I predict they will be history within the next decade. There is zero chance of the industry moving in the opposite direction toward Nx1.
#20
Senior Member
Join Date: Oct 2015
Posts: 15,577
Bikes: 2015 Workswell 066, 2017 Workswell 093, 2014 Dawes Sheila, 1983 Cannondale 500, 1984 Raleigh Olympian, 2007 Cannondale Rize 4, 2017 Fuji Sportif 1 LE
Mentioned: 144 Post(s)
Tagged: 0 Thread(s)
Quoted: 7681 Post(s)
Liked 3,572 Times
in
1,880 Posts
Others have described how a multi chain wheel would be impractical. But, the triple crankset solves that bail out problem. Just getting a bail out gear in front - going from a larger chain wheel to a smaller- is very quick and easy with a triple. Going to a smaller sprocket or chain wheel is mechanically easier and quicker and the triple crankset provides that, at least to a small extent. But "they're too hard to adjust" (BS), they're too heavy (a little heavier), but mainly not fashionable.
The added ratios a triple would provide are beyond what most riders would use, and since rear shifting is quicker and easier, there really isn't a necessity for a triple .... maybe for touring, where a rider might want a really low option for hauling full kit up mountains, but for most riders, a triple offers no benefit over a double.
Also, with front derailleurs now handling a 16-tooth spread (or more) as opposed to ten .... (standard 10-speed gearing was what, 52-42x14-34? or maybe 12-25?) I toured flat lands with a 52-42-32 triple and a 34-toorh big cog. Now I can ride a 50-34 with 11x36 and get almost the same range. Only for mountain touring where a 22-tooth chain ring might be needed, can I see a triple really paying off any more ....
Back in the day when cross-chaining was a real issue and a six-cog cluster was cutting edge, a triple really made sense for a lot of applications. Not so much any more. A modern 1x12 offers 12 usable ratios ... and old 2x6 maybe offered eight (with high-low and low-high excluded due to insufficient chain flex, and some overlap with ratios barely different.) A 2x11 probably offers 14-18 distinct and accessible ratios.
I think triples fell out of fashion because most riders simple never used the small ring once they got seven or eight cogs in back.
Likes For Maelochs:
#21
Senior Member
Join Date: Oct 2014
Location: Portland, OR
Posts: 12,980
Bikes: (2) ti TiCycles, 2007 w/ triple and 2011 fixed, 1979 Peter Mooney, ~1983 Trek 420 now fixed and ~1973 Raleigh Carlton Competition gravel grinder
Mentioned: 131 Post(s)
Tagged: 0 Thread(s)
Quoted: 4860 Post(s)
Liked 4,005 Times
in
2,601 Posts
I've been running a triple on my Mooney to run with 3 fix gear cogs, two on one side of the hub, one on the other. Chainline is barely over the track standard (about 1mm) and Q-factor running old straight cranks is very low. (Shifting mechanism can be found sitting on the seat. Rider using a Pedros Trixie tool. But only when stopped. Not quite ready for the mass market.)
Likes For 79pmooney:
#22
Senior Member
Join Date: Sep 2005
Location: In the foothills of Los Angeles County
Posts: 25,451
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 8378 Post(s)
Liked 9,253 Times
in
4,550 Posts
I've had 2 touring bikes, multiple mountain bikes, and 2 sport bikes with triples. Still have a road bike with an Ultegra triple but I don't ride it often. I have nothing against them but when I got the bike with the compact double I found it has enough range for what I do, even with the 34x29 low. Modern compacts have way more range than the one I have and more range than the road triples I used to ride.
#23
Senior Member
Join Date: Sep 2005
Location: In the foothills of Los Angeles County
Posts: 25,451
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 8378 Post(s)
Liked 9,253 Times
in
4,550 Posts
The RD's 90 year head start is hard to overcome. Q-factor (width distance between pedal-crank interfaces, right and left) would increase though maybe not as much as it would seem as there is not FD above the chainrings the crank has to clear and the chain in the outermost cog combo angles in toward the rear cog.
I've been running a triple on my Mooney to run with 3 fix gear cogs, two on one side of the hub, one on the other. Chainline is barely over the track standard (about 1mm) and Q-factor running old straight cranks is very low. (Shifting mechanism can be found sitting on the seat. Rider using a Pedros Trixie tool. But only when stopped. Not quite ready for the mass market.)
I've been running a triple on my Mooney to run with 3 fix gear cogs, two on one side of the hub, one on the other. Chainline is barely over the track standard (about 1mm) and Q-factor running old straight cranks is very low. (Shifting mechanism can be found sitting on the seat. Rider using a Pedros Trixie tool. But only when stopped. Not quite ready for the mass market.)
With my stance I don't mind a wide Q-factor, within reason. I run 20mm pedal extenders because of toe out.
#24
Dirty Heathen
Join Date: Oct 2015
Location: MC-778, 6250 fsw
Posts: 2,210
Bikes: 1997 Cannondale, 1976 Bridgestone, 1998 SoftRide, 1989 Klein, 1989 Black Lightning #0033
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 894 Post(s)
Liked 936 Times
in
548 Posts
Many single / FG hubs are threaded on both ends of the axle (aka flip-flop hubs) so you can run two different cogs, or a fixed cog on one side, and a single freewheel on the other, by flipping the wheel around; or what 79pmooney did, is got a second cog on one side, with the third on the other, giving three on the back wheel. I presume a conventional triple crank up front.
Good piece of work, that, getting all three to work, on the same chain, without running out of dropout.
#25
Dirty Heathen
Join Date: Oct 2015
Location: MC-778, 6250 fsw
Posts: 2,210
Bikes: 1997 Cannondale, 1976 Bridgestone, 1998 SoftRide, 1989 Klein, 1989 Black Lightning #0033
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 894 Post(s)
Liked 936 Times
in
548 Posts
I don't see the FD as 'crude' but at the same time, they're a lot more particular about setup and technique, especially when combined with indexed integrated shifters.
In the 7/8/9-sp range, RDs are pretty much universal, with a fair amount of overlap with 10-sp hardware as well. A FD has a much smaller 'comfort zone' that it'll work with; a 9- or 10-sp road FD will work satisfactorily on a 53-39 road double crank, but a 7-sp triple FD intended for a 42t big ring, will be a mess trying to shift a 9/10 chain on a big double.
Front shifting is much improved since the SIS era, with ramps and pins to help move the chain, but it still needs to be pretty close, and it demands that the rider pay more attention during the shift (soft pedaling) to effect a smooth shift (and a lot of casual riders don't know this) Adding wear / poor adjustment to unsympathetic technique (shifting under load, etc) on a RD usually results in some pops and bangs, but usually delivers a shift; a blown front shift will often throw / drop the chain, either to the outside, free-spinning the crank, or to the inside, where it's sucked into the chainstay, crank, rear wheel, or a combination thereof.
In the 7/8/9-sp range, RDs are pretty much universal, with a fair amount of overlap with 10-sp hardware as well. A FD has a much smaller 'comfort zone' that it'll work with; a 9- or 10-sp road FD will work satisfactorily on a 53-39 road double crank, but a 7-sp triple FD intended for a 42t big ring, will be a mess trying to shift a 9/10 chain on a big double.
Front shifting is much improved since the SIS era, with ramps and pins to help move the chain, but it still needs to be pretty close, and it demands that the rider pay more attention during the shift (soft pedaling) to effect a smooth shift (and a lot of casual riders don't know this) Adding wear / poor adjustment to unsympathetic technique (shifting under load, etc) on a RD usually results in some pops and bangs, but usually delivers a shift; a blown front shift will often throw / drop the chain, either to the outside, free-spinning the crank, or to the inside, where it's sucked into the chainstay, crank, rear wheel, or a combination thereof.