Im thinking of another bike build. Im running an old skool 3×9 at the moment which I find adequate. Would going 2×10 give me the same or very similar ratio on the granny ring ( I use the granny ring quite a lot!).

It can do if you want it to depending on the chainring ,casette and wheel size that you choose.Plenty of double chainsets come with a 22tooth inner and paired with a 10 speed 11-36 casettes mean you could well have lower bail out gears than you currently run .

Use the gear calculator to get your answer.

You should always be able to match a conventional triple granny gear to the same gear on a double. The question is if you lose any range in trying to keep the same granny gear when running the double.

To give an example, the standard triple granny gear is 22T chainring with a 32T sprocket. You could match this granny gear even with XX1 (42T biggest sprocket) by running a 28T chainring. You’ll lose out though in top end speed. It is up to you if it bothers you or not. If you are only worried about the granny gear then a double will be more than fine, or even 1x is possible.

Yeh. more interested in the granny ring. there aren’t too many occasions i ever use the large ring…

Try the Rotor UK website, they have their’s on offer at the minute, excellent cranks.
I run 40/28 up front with a 38T biggie at the back, no probs with any hills really, good range.
Good luck.

When I asked this question, the general consensus was that there was no point in 2* that it was either 3*10 or 1*11.

I subsequently bought two sets of 2*10 cranks for my bikes 🙂 40:28 up front, with 12:36 out back. Feels the same as my old 3*9.

One of my HTs is an old school 3×9 with 42:32:22 and a 11/34 cassette.

I have just converted my other HT from a 1×10 (32 chain ring) to a 2×10 (I got bored spinning out everywhere). The 2×10 has a 40:28 up front and a 11/36 cassette. Just been running this set up for a couple of weeks and it is considerably better (for me) than the 1x set up.

There are certainly more knee friendly set ups if you we’re concerned about loss of a granny ring.

I’d say if you desperately need the range of a triple, go double. There’s no need to lug around a big, ugly, heavy chainset any more so why would you?*

* unless you reguarly see 40+ mph downhill on the road

2x at something like 24/39 gives you nearly the range of a conventional triple. You can add a bash and guide to that. Just gone 1x with a 40t fitness not quite up there yet but still good. If someone gave me xx1 I’d take it in a second.

Is that an answer?

When I asked this question, the general consensus was that there was no point in 2* that it was either 3*10 or 1*11.

If anything I’d have said there’s no point in 3×10 so go either with 2×10 or 1×11. So many gear overlaps on 3×10 and you can get the same range on a double as a traditional triple. 1×11 will lose you some range for the same granny gear but most people are happy with that and only focus on the granny gear end of things when making a choice (which can be matched on all 3 options, just different compromises on range).

I’m on XX1 now with a 32T chainring and everywhere is more than climbable. What I dislike is the chainline on my frame which gives me issues and chain drops in the biggest sprockets (worse in thick mud). Seriously considering going back to 2x for improved chainline and keeping everything a bit smoother…

Gear overlap isn’t the issue, for me at least. Having just moved from 3×9 to 2×10 (it was what was on my new bike), the jump between the chainrings is bigger than I’m used to, 3×9 gave a much smoother transition. That said I’m sure I’ll get used to it, frankly unless you’re racing what does it really matter, a bit of speed limitation at one end or a bit more mashing at the other, it’s not the end of the world.