1x vs 3x: The Maths

[joglo]

A triple is a pragmatic way to keep small gaps between gears AND a big range. Otherwise it's either-or.

Interesting discussion, but too me one important aspect hasn't been mentioned at all here.

3xX offers typically still a better range and theoretical small gaps, it's a fact.
But this comes along with the biggest disadvantage for the a set-up with a front mech, the large overlaps.

Just another way to visualize this (there are plenty nice tools like this one BTW):
3x9 vs 1x12 (used same wheel size but have adopted the front chain ring at the 1x12 to have an almost similar low gear)

Red an olive marked gears are overlapping and therefore redundant.
Having that in mind, also a 3xX setup offers only a gear selection of roughly 13-16 gears with a unique ratio.

If you're not constantly also flipping the front mech, just the gaps (or better call it ratio differences) on the small chaing ring are small. Gaps at the middle or big chain ring are similar if not wider than using the 1x12 set-up.

Maths aside, I'm personally a big fan of 1xX, because I'm simply fed-up of those overlaps and also the continuous considerations when to flip the right hand or already the left hand to adopt to chaining elevation conditions.
To me, it's so clearly better to have just one shifter and a constantly increasing or decreasing gear ratio.

 

[kingoffootball]

The first thing I think when I look at that graphic is the "redundant gears" take out the combinations that will give a horrible chainline.

 

[joglo]

The first thing I think when I look at that graphic is the "redundant gears" take out the combinations that will give a horrible chainline.

sure, the tool colors them differently also because they are technically not recommended combinations.

Still, doesn't make a difference to me, this is reducing the choice of a 3xX set-up or causing complexity to use it in an optimal way quite a lot.

I'm personally riding mostly with a speed of 25kmph +-10kmph (sorry missed to say the units at the graphics are metric speeds) and in some rare cases +-15kmph

Using a 3x9 setup like above I'm ending up mostly at middle or big chain ring, don't have smaller gaps compared to an 1x12, but I'm limited (in a way that i have to change chain ring with front mech) that the middle chain ring is used predominantly on smaller cogs and in some situations not fast enough, and the big chain ring runs predominantly a bit on the bigger cogs and there are situations I can't go slow enough.

 

[hamster]

The first thing I think when I look at that graphic is the "redundant gears" take out the combinations that will give a horrible chainline.

Exactly! My point. The redundant gears are also handy for that small dip or rise which saves swapping chain ring.
If you set your stall to minimise overlap then you pay for it with an almighty jump on swapping front rings.

Note that in the nice graphic from joglo, there are 16 usable gears compared to 1x12. That's a big difference in terms of steps.

If joglo is truly riding at 25mph +/- 10 then he is an elite athlete and any discussion of a triple is irrelevant. 40/11 is also far too small a gear for road top, something like 53-12 would be better.

 

[joglo]

If joglo is truly riding at 25mph +/- 10 then he is an elite athlete and any discussion of a triple is irrelevant. 40/11 is also far too small a gear for road top, something like 53-12 would be better.

oh, sorry, that was a typo, I'm used to km/h, but wanted to type kmph.

 

[hamster]

I only use the triple as a range selector - uphill offroad / offroad / downhill or road.

There again my most common geared ride is a 34/44 double with 8s 11-30. Tourer is 24/38/47 7s with 7s 13-30.

 

[albash82]

I get into gear ratio charts with customers that come in for services, wanting to know how much they'll lose out on by going 1x.
It's interesting to look at, but It always boils down to what you do on the bike. Most of the bikes we get in, are high end modern MTBs. So most folk we serve, are predominantly riding off road "trails". For that vast majority of these customers, a 32t ring with a dinner plate cassette, is going to be absolutely fine. When was the last time you spun out 32/10 riding some technical singletrack?

But if you're into different types of riding, where you do want a really high gear, for grinding out decent speeds on either tarmac, or forest roads etc, but also need a granny gear, then keeping a front mech is absolutely fine. Isn't it?

Of course none of the mountain bikes we actually sell in the shop are actually compatible with a front mech now are they?! Haha.

Edit: just realised I've stumbled across an old thread, sorry.

 

[legrandefromage]

I notice the neighbours' second hand dinnerplate cassette was completely worn at the bottom and nearly new at the top.

Watching him ride, it was almost like how we were told to never ride our bicycles - granny ring and small!

Anyway, he also had huge tyres and 29er wheels, made my bike look like a kids bmx

oh, and the chain line was bloody awful!

mumble mumble mutter mutter

staying with doubles and triples here, some for show and some for go

 

[albash82]

Not the chainline!

Heaven forbid

 

[Jamesbike]

I'd be tempted with a 40 /40-11 setup.

When riding long distances once I get to 20+ mph I tend to take a break and freewheel.

Therefore I would rarely use the 40 / 11 cogs.