In Praise of Nx1 - Forget Double, Triple, Compact!

[RecordAceFromNew]

Given there are constant discussions and debates around here about the relative merits of double, triple, compact etc., I think many of us who haven't before should probably stand back a little and consider slaughtering a sacred cow or two.

Of course, Shimano, Campag, Sram, Spesh, Trek, etc. will be the last people who are going to want you to consider it. Why shouldn't they capitalise on the mass' propensity to imitate the pros, dumping perfectly good stuff to be fashionable?

With single chainring and no front changer/shifter/cabling, I see no reason why a Nx1 arrangement shouldn't be the best for most on the road. Obviously it depends on the application but for people who don't race or take chain ganging seriously I think it can be a rather liberating experience for more than one reason. The challenge is of course to figure out which chainring to get, given there is only one.

I think the logical way to go about it is firstly to decide what is the lowest gear one needs based on where one rides and how one rides, e.g. say 30 inches is good for me. That tells me then that if I get a readily available 34T rear sprocket a 700x23c tyre will deliver that with a 39T front ring, which will also give me 93 inches with a 11T smallest rear sprocket, which in turn delivers 25mph at 90rpm at the pedals, and which is also good enough for me. Ok Cav might do 25mph average on tours, but when I looked into the mirror this morning I didn't look even remotely like him, not yet anyway .

You see I think what people also forget, is that in the days of Merckx etc. 52x13 was often the biggest gear on most bikes when everybody had freewheels. That translates to 29mph at the same rpm on larger 27" tyres of those days. I think I would be exceedingly happy, though probably dead just trying, if I could make 86% of the speed of those guys going downhill. I think the moral is, it is not the gears...

The rest, then is to decide how to spread the range. I make up my own cassettes, usually leaving a 10 tooth gap between the largest and the second largest since the largest is so rarely used and is just there as a bail-out (Sheldon discussed this Alpine arrangement). I don't think spreading the rest between say 11T and 24T gives one large gaps if one focuses on getting ratios constant (which is the thing to do) rather than tooth difference constant (which is pointless). Even if one had a close ratio cluster, big gaps will always exist between the smallest sprockets which, whether you like it or not, nobody, even Cav, can avoid since despite searching high and low I couldn't find any 11.5T sprocket in CRC! This is also the reason I don't always buy the bitching about big gaps, especially from those lycra-cladded macho men who say in the same breath they are forever wearing their smallest rear cogs out.

If the above range of 30 to 93 inches is not quite enough for you, you can rob/use a 36T sprocket/cassette to push the range further by another few inches (30 to 98 inches with a 41T chain ring and a 11-36T cassette on 700x23c e.g.).

Campag drivetrains are usually unsuitable for this though, unfortunately, since the largest readily available Campag compatible sprocket is only 29T.

 

[ColinJ]

An interesting idea but I'm waiting for someone to suggest 1x1!

It certainly saves on brake blocks - totallyfixed was telling us on Sunday that he has put in over 20,000 miles on one pair.

 

[GrumpyGregry]

42 x 18 (on 23mm 700c) works for my cross-country commute at the mo, possibly a bit undergeared actually, given I could probably pull a longer gear up the hills if it meant not having to pedal quite so fast down the other side. Of the two the downhills are harder. The 170 mm cranks feel weird though.

 

[PpPete]

An interesting idea but I'm waiting for someone to suggest 1x1!

It certainly saves on brake blocks - totallyfixed was telling us on Sunday that he has put in over 20,000 miles on one pair.

Chains last longer too (and are cheaper in the first place)

OTH operating a narrow chain more frequently at extreme chainlines - inevitable if I were riding a Nx1 set up - would wear chains and cassettes out more quickly, wouldnt it ?

 

[Rickshaw Phil]

I think the idea is sound and that a simpler gearing option like this would probably appeal to those who are new to cycling as well as those who don't necessarily need a complex gear system.

 

[astrocan]

OTH operating a narrow chain more frequently at extreme chainlines - inevitable if I were riding a Nx1 set up - would wear chains and cassettes out more quickly, wouldnt it ?

The answer to that is obvious, two identical chainrings.. or is that defeating the object of the OP?

 

[GrumpyGregry]

the obvs answer is surely "hub gear"

 

[tyred]

Try one of these, all the advantages of 1 x 1 but easier on the hilly bits.

 

[dellzeqq]

I can only disagree. The closer the ratios, the smoother the ride. It may be that this is of greater importance in the relatively flat southeast, but my gear ratios are not about the top and bottom - they're about the gaps in between. So...to take the gear I use most often - the 53/16. If I change up the shift is only 6.7%. If I change down the shift is only 6.3%. And, with all of my gears on the small ring below the top five gears on the bigger ring I get a decent range - not quite as much as I'd like on big downhills (but how much time would I gain) and barely enough for some of the nasty little items in Surrey and Kent (although sufficient for touring).

53 39
12 116.1 85.4
8.3 %
13 107.1 78.8
7.7 %
14 99.5 73.2
7.1 %
15 92.9 68.3
6.7 %
16 87.1 64.1
6.3 %
17 81.9 60.3
5.9 %
18 77.4 56.9
5.6 %
19 73.3 53.9
10.5 %
21 66.3 48.8

 

[ColinJ]

53/16 - either you really like to get a move on, or you prefer a slowish cadence! (I make that 23-and-a-bit mph at 90 rpm.)

 

[PpPete]

I can only disagree. The closer the ratios, the smoother the ride. It may be that this is of greater importance in the relatively flat southeast, but my gear ratios are not about the top and bottom - they're about the gaps in between. So...to take the gear I use most often - the 53/16. If I change up the shift is only 6.7%. If I change down the shift is only 6.3%. And, with all of my gears on the small ring below the top five gears on the bigger ring I get a decent range - not quite as much as I'd like on big downhills (but how much time would I gain) and barely enough for some of the nasty little items in Surrey and Kent (although sufficient for touring).

53 39
12 116.1 85.4
8.3 %
13 107.1 78.8
7.7 %
14 99.5 73.2
7.1 %
15 92.9 68.3
6.7 %
16 87.1 64.1
6.3 %
17 81.9 60.3
5.9 %
18 77.4 56.9
5.6 %
19 73.3 53.9
10.5 %
21 66.3 48.8

And last time I rode with you, you were telling me about your bad knees ...

 

[dellzeqq]

53/16 - either you really like to get a move on, or you prefer a slowish cadence! (I make that 23-and-a-bit mph at 90 rpm.)

it's not really about the speed, more the jump from gear to gear. I can quite see me dumping the 53 for a 48 in a few years time - indeed I had a hybrid with the same cassette and 48/38/28 on the front

 

[Ian H]

I've only got a 53 on the TT bike. Road bike is 48/36 and audax/touring is 46/36/26. 12-26 9-speed gives nicely close ratios. So overall there are no big jumps. Even so I'm not that slow.

Fixed, by the way, is 43x18.

 

[RecordAceFromNew]

Chains last longer too (and are cheaper in the first place)

OTH operating a narrow chain more frequently at extreme chainlines - inevitable if I were riding a Nx1 set up - would wear chains and cassettes out more quickly, wouldnt it ?

I presume we all agree that comparing 1x1 with Nx1 is like comparing apples and oranges.

Regarding chainline, while #speed dependent chainring spacings are roughly 2x that of rear sprocket spacings. That means by centering the single ring on the rear chainline in the worst case scenariois a Nx1 arrangement should offer better lines by 1 rear sprocket compared to a double, and 2 rear sprockets for a triple.

But of course the issue with Nx1 is one has no choice which front ring to use the extremes with. I have always wondered if this poor chainline = poor efficiency = increased chain wear is myth or gospel. What I do know, however, is that the most extensive research I have come across on the subject suggests a lousy chainline has no effect on efficiency, and while it might not be true that no efficiency loss = no increased wear, I figure with the money saved on shifter/mech with Nx1 one could buy quite a few additional chains.

There is a possibility that the poor chainline = poor wear rate evidence comes from SS and fixed experience, which I am unsure how relevant it is here, given the chain's usage is very different.

 

[MacB]

Actually I think SS and Fixed comparisons, along with hub gears, are very valid in this discussion, as it is part of the how many gears do you need debate. If we're talking simplification via removal of the FD then the next logical step is removal, or minimisation, of the RD. I've spent a fair bit of time on these matters, as you know, and I've come to the conclusion that I'm generally more adaptable than my gearing systems. But this is only applicable to how I generally ride and could alter if my riding style/requirements alter.

For example what Dell considers a boon, close ratios and fingertip gear changes, could be a total waste to another rider who may prefer to vary their tempo more and thus change gears less and rely on bigger steps when a change is required. Both of which may seem like a total waste to the Fixed/SS rider where tempo variation is the only option and part of the attraction.

For utility or foul condition riding then I'd always favour the 1xX option or the hub gear, if it was for a regular ride like a commute, and the terrain favoured it, then I'd also consider SS or fixed. But these considerations would be around maintenance, reliability and ongoing costs. For other types of riding then it has to be down to personal preference.