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As some of you know I'm a rather vocal anti 2x10er. This afternoon work was a bit quiet so I decided to test if I was a jerk for being so anti...

 

I sat down and worked out the various ratios for 2012 Shimano XT's 26/38, 28/40 doubles and their 24/32/42 triple. To keep it nice and neat I used their "middle" cassette - the 11-34 10 speed.

 

I then put all the ratios in order from smallest to biggest.

 

I then highlighted all the overlaps in red (I considered an overlap as a difference in ratio of less than 5%).

 

Attached is the result.

 

On the face of it the 3x10 looks *** - 11 overlaps leaving only 19 "real" gears versus the 16 and 17 "rea" gears for the 2 2x10's.

 

So I'm an idiot for saying 2x10 is a stupid idea....

 

...or am I?

 

I did some thinking and I am an idiot - but not for saying 2x10 is a stupid idea - I'm an idiot because the range of ratios depends on the cassette not the chain rings! The chain rings only decide the position of the range not the spread of the range.

 

So what does that mean?

 

Well a few things.

 

1) The difference in teeth on the front chainring is effectively fixed - a front derailleur cannot handle a jump of more than ~13 teeth. This means you're locked into a range of ~13 teeth on a 2x10 and ~26 teeth on a 3x10 (two jumps of 13 teeth). So in theory you have twice the width of range on the triple.

2) The overlap is terrible in theory but it doesn't really matter in reality because we don't use our gears seqeuntially - we use them within each chain ring (ie: we won't go to the next logical ratio by dropping onto a smaller ring an popping 2 gears down on the cassette - we'll just drop one gear down on the cassette).

 

Ultimately the only difference between a 2x10 and 3x10 is the width of range. A triple has a short, medium and long range whereas a double will have a small/medium and a medium/large range. If you stick to commercially available doubles the triple will always have a shorter short gear and a longer long gear (better range).

 

So....in my opinion:

 

2x10 is a stupid idea :D

 

For a 40g saving you can climb less mountains and can't go as fast on the downhills.

 

Man was that a waste of 10 minutes of my life!

2x10 versus 3x10.pdf

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https://forum.bikehub.co.za/topic/110330-the-ultimate-2x10-versus-3x10-page/
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To be honest, I wished that Sram made a 3 x 10 XX, as I would have had it on my bike. Not that the 2 x 10 does NOT work for me, but I would rather have more options like you said.

 

But I am saying, if you really like the Sram XX groupset = dont be toooo woried about it being 2 x 10 only.

 

EDIT:

You also left out the 26 X 39 ratio....39 brings you closer to the 42

<_<

Edited by Niner

As some of you know I'm a rather vocal anti 2x10er. This afternoon work was a bit quiet so I decided to test if I was a jerk for being so anti...

 

 

So I'm an idiot for saying **** is a stupid idea....

 

For... you can climb less mountains and can't go as fast on the downhills. What was that you said about pump track?

 

Man was that a waste of 10 minutes of my life!

 

Sorry. Had to precis that. I'm working.

Edited by The Drongo

The ratios are pretty close, and its likely that you wont use all 30 with the 3X10 anyhow. Not knocking it as they all have their place... similar to the 26er vs 29er arguement? In the end its which you prefer/utilise better? Personally i agree with Dangle, in that the 2x10 has made my riding more efficient and if i need another gear, walking may well be faster.

To be honest, I wished that Sram made a 3 x 10 XX, as I would have had it on my bike. Not that the 2 x 10 does NOT work for me, but I would rather have more options like you said.

 

But I am saying, if you really like the Sram XX groupset = dont be toooo woried about it being 2 x 10 only.

 

EDIT:

You also left out the 26 X 39 ratio....39 brings you closer to the 42

<_<

 

Dood - you must warm up your calculator - I used the 40 tooth which brings you closer to the 42 than the 39. Meh - it's all about the range - if you prefer pedalling faster then use the 24/37 - if you like trapping like Herr Jan then the 27/40 is for you - hell yoou can get a custom 29/42 made so you can match the 42 on the triple BUT you're going *** on the climbs with a 29 as your smallest chain ring...

 

Thats what I like about triples - you don't have to compromise - you can have all the gears you want.

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