Viewing 16 posts - 1 through 16 (of 16 total)
  • Does gravel 2x gearing have a maximum gear range?
  • bri-72
    Full Member

    Having issues with slow non responsive gear shifting. No amount of tinkering sorting it. I think my move to 2x the issue.

    Is there a max gear range my setup can cope with that I’ve gone beyond?

    Is anyone else running 2x with same chainring and sprocket sizes as below?

    Bike has sram rival 11 speed setup.

    Originally was 1x with 10-42 cassette.

    Now 2x same cassette and 50/34 front as it’s what I had in spares.

    My feel is that the 50 front too big and too much range ie need too long a chain to cope with the range.

    honourablegeorge
    Full Member

    Sram say that capacity for the mech is 32t, which is just enough for 10-42. Those capacity numbers tend to be on the conservative side, but you’re asking it to handle an additional 16 which is probably pushing it a bit too far

    longdog
    Free Member

    Don’t know about SRAM but I had a 10sp 50/34, 11-42 Shimano setup on Vapour CX, but I used a deore shadow rear derailleur.

    bri-72
    Full Member

    That’s the bit I couldn’t bet my head round, or find any info on sram website. So need add the front ring differential to the cassette range?

    So on that basis a change to say 46/30 front chainring wouldn’t solve it? As it’s still 16t difference at the front, same as my 50/34.

    I’m debating whether a different double setup is the answer. 43/30 available but still +13t.

    Or go down route of a 10-50 cassette and Ratio expander to revert back to 1x with bigger range.

    phil5556
    Full Member

    11-46 1x works with Rival but I don’t think anything much above that does very well (maybe 10-46), so 35 or 36T max really, and you’re trying to do 48 I think.

    infovore
    Full Member

    Capacity = (difference between max and min chainring) + (difference between max and min cassette ring).

    So – 10-42 on a 1x system is (0) + (42-10) = 32.

    On your 2x it’s (50-34) + (42-10) = 48.

    System capacity amounts are often conservative, but that’s not going to go. SRAM 2x systems tend to end up with 11-36 out back at most.

    Similarly, the GRX 2x setups ship with 11-34 out back, even if they have 46-30 up front. Some people have pushed the range of Shimano setups before but to answer your question, yes, there very much is a limit, and if the factory recommended limit is 36 teeth, 48 is way, way over. Either scale back the rear cassette, or go to a larger one with the 1x setup.

    (There’s also the issue of max sprocket size on a rear mech, separate to capacity. SRAM Road and MTB are more cross compatible than Shimano were, so you might find that if a larger mech is needed, that’s not such a problem.)

    Turnerfan1
    Free Member

    Also check your mech is not 1X specific as in CX1 or Rival 1? That could be a problem if running 2 X.

    bri-72
    Full Member

    Cheers all, the capacity explanation above makes sense.

    Think I’ll give up on 2x as it will end up quite spendy as would be looking at a new more compact range cassette and lower tooth count chainrings to get a workable solution and still decent low end gearing.

    On looking into the Ratio conversion a bit more, per this vid below the tail fin mod alone allows use of GX eagle derailleur and cassette. But only 11 gears as an unmodded shifter obviously. I thought shifter mod was essential too but not if happy to live with only 11 gears out of your eagle cassette. As I’ve got used GX stuff siting spare, so for £24 price of the tail fin looks like I can test it out cheap. Reckon I can live without the 9t at bottom of cassette for now anyway, it’s lower gearing I need. I can always retrofit the 12sp shifter ratchet mod down the line.

    phil5556
    Full Member

    if happy to live with only 11 gears out of your eagle cassette.

    I’ve only briefly looked in to this, are you supposed to run an Eagle / 12 speed cassette or a wide range 11 speed? I thought 11 speed but might be wrong?

    My mate has just done the shifter ratchet mod and is very happy with his full 12 speed Eagle GX setup.

    bri-72
    Full Member

    Hmmm good point wasnt actually clear from the video. Shifter mod not too complicated from looks of it.

    slowoldman
    Full Member

    It is perfectly possible to get a workable 2x setup which exceeds the rear derailleur capacity. I think the most extreme I’ve seen is 46/30 front 11/40 rear Ultegra. rear derailleur has a capacity of 35, knock off 16 for the front leaving 19. That means you can use 11 to 30 on the big chainring or 21 to 40 on the small (i.e you can’t go big big or small small).

    Spa cycles in Harrogate even allow you to specify such options on their new builds, so it must work!

    finbar
    Free Member

    That means you can use 11 to 30 on the big chainring or 21 to 40 on the small (i.e you can’t go big big or small small).

    And if you forget and shift under load you snap your chain or your hanger or your mech – no thanks…

    scotroutes
    Full Member

    I’m running 50/34 and 11-40 using a standard Ultegra RX rear mech. No mech extender. I get full cross-chaining and it shifts faultlessly.

    finbar
    Free Member

    Fair enough. I bet the mech cage is horizontal in ****t gear 😀

    midlifecrashes
    Full Member

    I was reading/watching stuff about tour divide setups. Plenty running 2×11 as 48/31 or 46/30 with 11-42 cassette . Some with standard GRX setup, some with a goatlink adaptor. Considering it myself to move to hydro brakes and still have the gear range of my 48/36/26 triple setup, but at current prices I could have a new bike for the price of the groupset so I’m dithering.

    bri-72
    Full Member

    Well I get the full range and could even cross big big etc if wanted too. But only with a long chain and slow not great shifting. So I guess the capacity limits can be pushed, but I’d not recommend on sram rival anyway.

Viewing 16 posts - 1 through 16 (of 16 total)

You must be logged in to reply to this topic.

Thanks for popping by - why not stay a while?IT'S FREE

Sign up as a Singletrack Member and you can leave comments on stories, use the classified ads, and post in our forums, do quizzes and more.

Join us, join in, it’s free, and fun.