3x10 to 2x11 change

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pickerd1
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Joined: 31 Mar 2014, 5:05pm

3x10 to 2x11 change

Postby pickerd1 » 19 Sep 2015, 10:17am

Not sure why but I really fancy changing my 3x10 to a 2x11 set-up.
I originally set-up the 3x10 as below to find out which gears I sue most.
- chainrings = 22 / 32/ 42
- cassette 12 to 23
The 22/23 low gear is good so I would like to keep a 1:1 ratio.
I use the 32/16 and gears around it a lot and like the close ratios in this region. So I would like to keep ratios from about 1.6 to 2.4 with close gaps between gears.
I don't use the 42t ring very often - only for downhill and I am quite happy to roll. I don't want to give uo the higher ratios but would be happy with less gears.

Any ideas for an 2x11 set-up?

Brucey
Posts: 34218
Joined: 4 Jan 2012, 6:25pm

Re: 3x10 to 2x11 change

Postby Brucey » 19 Sep 2015, 10:57am

Blimey.

I just ran your present gearset through a gear calculator and I found that there are no fewer than 13 gears that give ratios between ~50" and ~70" (including 49" and 71" ratios) of which there are four pairs of near-duplicate ratios.

I don't think I've ever seen so many 'midrange ratios'.... :shock:

I think if you want the same gear range with a 2x11 gearset you need to use an 11T top sprocket (say a 11-23 cassette) and (say) a 38T big ring, 22T small chainring.

This will give fewer midrange gears and those you do have (near 32/16, i.e. 38/19) will be kind of cross-chained, and the next downshift will have a big interval.

If you go to a 11-28T cassette and 38, 26 chainrings, this gives the same range and improves the chainline in the favoured gears a bit, but it will leave you with bigger intervals in the gear range both at the top and the bottom.

Personally I'd not bother with 2 x 11; on an upright solo I can get all the gears I need with a 3x 7, 8 or 9s setup. But each to his own, eh? :wink:

cheers
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foxyrider
Posts: 4454
Joined: 29 Aug 2011, 10:25am
Location: Sheffield, South Yorkshire

Re: 3x10 to 2x11 change

Postby foxyrider » 19 Sep 2015, 12:55pm

I'm currently using a 2x11 set up on my utility/touring bike. It's a standard 50/34 compact with 12/29 cassette. My flat tour had me sat in a comfortable 50x15 for three weeks! When I fetched the shopping last night the 34x25 was low enough to get me up the 150m gain 2 mile ride home without me breaking into a sweat (we are talking 10% climbs of half a mile each for most of the gain).

It may not offer enough range for loaded alpine climbing but they'll get me up pretty much anything else I want to tackle. I think too much emphasis on low gearing when a smaller jump between the gears will generally be more efficient IME.

If you want those low ratios you will need an MTB double as the road versions won't take you lower than a 32 inner!
Convention? what's that then?
Airnimal Chameleon touring, Orbit Pro hack, Orbit Photon audax, Focus Mares AX tour, Peugeot Carbon sportive, Owen Blower vintage race - all running Tulio's finest!

TrekMad
Posts: 373
Joined: 2 Jun 2015, 10:17am

Re: 3x10 to 2x11 change

Postby TrekMad » 19 Sep 2015, 1:47pm

If you are using a Shimano 11 speed set up and fitting it yourself be aware that setting up the levers is very tricky and time consuming. 3 ( count em!) tiny screws require removing and replacing , just to insert the brake cable!!

Come on Shimano...

pickerd
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Joined: 22 Mar 2015, 7:01pm

Re: 3x10 to 2x11 change

Postby pickerd » 19 Sep 2015, 3:18pm

Thanks everyone. I realise the present set up is a bit excessive in the ratios department but I did it so that I could try them all. I'm now thinking of going back to a double.
If 2x11 is awkward I might try 2x10. I also probably have enough parts in the garage to do it where as 2x11 will cost.

Brucey
Posts: 34218
Joined: 4 Jan 2012, 6:25pm

Re: 3x10 to 2x11 change

Postby Brucey » 19 Sep 2015, 4:45pm

FWIW the last time I looked at this for a touring style double, I concluded that something like a 44T big ring (and a small ring to suit) then a 13,15,17,.........24,28,(32) cassette would do the trick. This gives you as many midrange gears as you can be bothered to have, all with a reasonable chainline, and you can choose to have the 32 sprocket or not, and to vary the inner chainring as necessary. The larger gaps in upper range and lower range of the gears I find less troubling than lots of gaps in the cruising range.

For some reason if you presented me with a 46T chainring, I might choose even numbered sprockets instead up to about 20T, but the principle is about the same.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

reohn2
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Joined: 26 Jun 2009, 8:21pm

Re: 3x10 to 2x11 change

Postby reohn2 » 19 Sep 2015, 5:37pm

pickerd wrote:Thanks everyone. I realise the present set up is a bit excessive in the ratios department but I did it so that I could try them all. I'm now thinking of going back to a double.
If 2x11 is awkward I might try 2x10. I also probably have enough parts in the garage to do it where as 2x11 will cost.


If a 2x10 gives you the range without overlaps it makes a lot more sense than spending money on a completely new drivetrain for the sake of 2 ratios.
It's just a matter of choosing the gaps to suit on the cassette,which shouldn't be difficult with 10 sprockets.Then picking the two rings up front,the inner/smallest that offers the lowest set you need for climbing and the outer/big ring to suit the best cruising/top end range.
You'll need to make sure the front mech will handle the difference between the two ring sizes though.

FWIW I find a 3x8sp offers enough spread and close enough gaps for me(two tooth in the cruising range and three teeth difference at the lower end),but two are duplicates which=22 ratios,although the duplicates can come in handy,especially when climbing,as they can save me a front change at times.
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pickerd
Posts: 104
Joined: 22 Mar 2015, 7:01pm

Re: 3x10 to 2x11 change

Postby pickerd » 20 Sep 2015, 8:26pm

I've put together a 30/42 chainset and a 12, 13, 14, 15, 17, 19, 21, 23, 25, 27 cassette from parts in the garage. I'll give this a try.
If I like it I'll consider a smaller inner chain ring - maybe a 26.

pickerd
Posts: 104
Joined: 22 Mar 2015, 7:01pm

Re: 3x10 to 2x11 change

Postby pickerd » 7 Oct 2015, 9:52am

Update: I've ended up with a 2x10 setup. 30/42 chain rings and 12 13 15 17 19 21 23 25 27 30 hybrid tiagra cassette.
This gives me the close ish ratios I need around the middle of the cassette on the big ring and plenty of climbing on the small ring with a little overlap between them.
The shifting with the hybrid cassette is good.

Samuel D
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Joined: 8 Mar 2015, 11:05pm
Location: Paris

Re: 3x10 to 2x11 change

Postby Samuel D » 7 Oct 2015, 12:37pm

That’s a range from about 26 to 92 gear inches with narrow road tyres. It’s not a bad range at all, albeit with about four gears replicated on the two chainrings (at least one of them too crossed to count as practical).

Whether it would work well would depend on your average speeds and cadence. No doubt you’ve thought it all through.