Gearing Down

You may recall that I busted my front derailleur the other day and now have a 1X Bianchi whether I like it or not. Well, I like it because I’ve been thinking about having one for years, but a 50-tooth chainring with 11/27 cassette is not going to get me up many hills around here without blowing out a kneecap.


So I’ve been forced to do a little math. Luckily I was drinking a beer at the same time or it could have ended badly. As I write these words, I think I understand what I need to do. Don’t test me tomorrow.

Firstly, I determined my current ‘range’. My biggest gear ratio is 50/11, which comes out to 4.54. My smallest is 34/27, so that’s 1.26. The first number over the second gives me my ‘range’: 3.6.

This is what I would be looking for in top and bottom gears if I needed to replicate my 2X set-up. With me?

But really, how often do I use my 50/11 or even the 50/12? Not much is the answer. I do, however, find myself in the 27 plenty of times so I’m keeping that. Therefore, I can effectively shorten my range by deciding that I don’t need the two biggest gears.


So, now we are left with a virtual set-up of 50/13 (3.85) and 34/27 (still 1.26). The range I could live with is now 3.05.

There’s a whole section of the article I’ve just used that I haven’t told you about, but it involves cassettes and their ‘ranges’. An 11-34 cassette just happens to have a range of 3.09, which is pretty close to what I need…so there you go.

Now that I know what cassette I need on the back of my future 1X, I have to determine the size of the chainring on the front. For that I need to know the biggest gear that I want, which was 50/13, or 3.85, multiplied by 11, the smallest ring on the cassette. 3.85 x 11 is 42.

So, if my poor mathematics skills haven’t failed me totally, what I might be looking for is  a 42 chainring with 11-34 on the back and Bob’s your uncle.

It goes without saying that I’ve got no clue how to accomplish this, but I’ve got friends with technical smarts and the internet is never far away. If nothing else, it’ll be a nice confinement project.


15 thoughts on “Gearing Down

  1. He needs a whole mountain bike, so he can try the whole 1x experience in-depth and thus make an informed decision about whether he wants to carry that over to his road bike. Along the way he’ll learn some things and keep the folks who make adhesive bandages in business. I’m sure the other half will understand the need to for first-hand analysis. It’s part of being in the business.

    • Well, that would obviously be the cheapest way to go about it, but my wife can’t stand the look of blood, so I might have to forgo MTB for this lifetime.

  2. I like the math, Gerry! And this is also useful for me: I have a 1x crossbike. For cross, I put a 38 chainring with a 11×32 cassette. But for gravel, I used My 42 chainring and was riding a 11×28 cassette; for the steep short hills, I need could use an 11×34 cassette — is such one available? And would it fit my derailleur (which can handle a 32)?

    • All good questions, Jan! I haven’t gotten as far as figuring out what I can fit, but I’m sure there’s a way if there’s a will! How fast are you when you top out in the 42/11 by the way? Like Rich says below, this could a limiting factor on the road.

  3. I think 50×13 is too small for your biggest gear. At 50km/hr, you’re already over 100 cadence. Any downhill pedalling will be ridculously high cadence. I personally think even 50×12 is too small. Even if you get the top end and bottom end correct, you’ll still have some big ratio changes between gears compared to 2×11.

    • Yeah, I thought about that. I could go bigger for sure, unless it’s too complicated. I was thinking that this bike, being my ‘other bike’, I could get away with it. Wouldn’t use it for Haute Route! If I can do it cheaply I’m looking at it as a test.

  4. Ask Aqua Blue about their success with a road 1X..I think they had none…which is why other teams did not follow suit. I think you will be better served buying a new clamp and sticking with a 2x. But that’s just my opinion..I could be wrong.
    [Around the team’s closure at the beginning of September, rider Adam Blythe came clean about the 3T Strada bikes being a key reason for the team’s inability to get results. While designed by former Cervelo founder Gerard Vroomen with aerodynamics in mind, the missing provision for mounting a front derailleur meant it simply lacked the flexibility required to be competitive within the pro peloton, leaving its riders more tired from grinding out big gears uphill than other teams’.]

    • I remember that well. Maybe it’s something about Canadians and 1Xs! I know I’d be missing some gears, especially on the top end, so I’ll have to think more about it before clicking ‘acheter’. Knowing your experience with cycling, I’m sure you’re not wrong 😉

    • It’s also looking a little pricey now, so during these times it might not be a good idea for an experiment! Passes the time, though, so I’ll continue the research.

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