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Shimano chainring combo

The usual combinations for front doubles are 53/39, 52/36 and 50/34. Shimano tech docs “recommend” that you don’t mix these about as you might ruin the shifting.

I’m wondering whether anyone successfully uses 52/34 though? It’s an Ultegra 6800 setup. I can’t find any specification for whether the front derailleur will cope with an 18T difference or not.

Not that fussed about the different jumps in overall gearing, but more to get the lower range option with the 34.

Anyone?
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  • I think you should be OK. I was going to do the same.

    The rest of the internet is quite a good resource of success stories, but mainly with Di2, unsure if it's ok with mechanical.
  • daniel_bdaniel_b Posts: 9,923
    The pro teams run some very extreme combinations, but then I suspect they have a fairly stocked parts cupboard, and can and will make frequent changes depending on the race, so not on there the whole time.

    I personally changed a 53/39 to run as a 53/36, and despite what people pipe up to say about extra wear/stress on the system, it feels like it's a factory spec change, it's seamless, and so slick and smooth, a real joy to ride, and has made the bike so much more usable than it would have been for me otherwise - and all for the princely cost of £36!

    Mine is mechanical 9100, and is in theory 1 tooth outside of the recommended max.

    Yours would be 2 teeth out - I'd be surprised if it caused you any issues, I'd be inclined to simply go gently with the pedalling as you change on the front, but then I suspect most of us who are not racing do anyway.

    Please do update should you go for it, would be intrigued to hear how it goes, as a 52/34 also appeals to me on another bike :-)
    Felt F70 05 (Turbo)
    Marin Palisades Trail 91 and 06
    Scott CR1 SL 12
    Cannondale Synapse Adventure 15 & 16 Di2
    Scott Foil 18
  • I’ll probably give it a go - I have some spare parts laying about I can do it with, just wondered if the faff would be worth the effort of pulling the cranks off. I’ve not really checked whether the chain might need shortening - dunno if there’s enough tension travel left in the rear derailleur to use a 34 ring with the smaller few cogs on the cassette, will check first. Am sure there’ll be a trade-off in noise or shift smoothness, and around here I tend to do a fair few changes between front rings. Lots of short steep hilly bits, up and down.

    If it’s no good I’ll probably switch to the 50/34 rather than 52/36 - need more help up hills than down for sure!
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  • pilot_petepilot_pete Posts: 2,119
    I run 52/34 on both my summer bikes (Rotor NoQ chainsets) with Dura Ace di2 front mechs. No problems at all. I find it gives me the best of both worlds in the hills. On the flat I find I have a very straight chain line at my normal cruising speed with the 52 chainring and 11-28 cassette.
  • daniel_bdaniel_b Posts: 9,923
    edited December 2021

    I run 52/34 on both my summer bikes (Rotor NoQ chainsets) with Dura Ace di2 front mechs. No problems at all. I find it gives me the best of both worlds in the hills. On the flat I find I have a very straight chain line at my normal cruising speed with the 52 chainring and 11-28 cassette.

    Do the rotor chainsets come with that tooth count, or have you modified them?
    Felt F70 05 (Turbo)
    Marin Palisades Trail 91 and 06
    Scott CR1 SL 12
    Cannondale Synapse Adventure 15 & 16 Di2
    Scott Foil 18
  • pilot_petepilot_pete Posts: 2,119
    No, they come with 52/36. I swapped the small chainrings for 34 tooth.
  • I run 52/34 and 11-30 Ultegra Di2, with a short cage rear mech
    No problems with gear changes, and rarely drop a chain. Chain would be a bit slack on the 34 when down towards the bottom of the cassette, but I never go down there anyway.
    Use 53/36 on another bike with similar results.
  • Mad_MalxMad_Malx Posts: 4,464
    Do you guys really get much use out of 52-11?

    I don't get much use of 50-12 and even less from the
    -11 but I'm feeble and don't have many long sweeping descents.
  • pilot_petepilot_pete Posts: 2,119
    Mad_Malx said:

    Do you guys really get much use out of 52-11?

    I don't get much use of 50-12 and even less from the
    -11 but I'm feeble and don't have many long sweeping descents.

    Yes, I live on the edge of the Peak District. Lots of descents where I can pedal hard in 52/11 and ride away from mates on 50/11.

  • Mad_Malx said:

    Do you guys really get much use out of 52-11?

    I don't get much use of 50-12 and even less from the
    -11 but I'm feeble and don't have many long sweeping descents.

    Yes, I live on the edge of the Peak District. Lots of descents where I can pedal hard in 52/11 and ride away from mates on 50/11.

    On the actual roads here, not so much for me, but on the smart trainer, quite a lot in 50/12 or 11. Its also one reason I want the extra low range - there’s plenty of routes on there with short ramps of 15% or more and the 34 helps.
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  • ballysmateballysmate Posts: 15,778
    To those that have mixed 52 and 34 rings, have you noticed any problems in shifting?
    I believe the 50 and 34 rings have an A tooth profile whereas the 52 and 36 have a B profile on some teeth to aid shifting.
  • WheelspinnerWheelspinner Posts: 5,699

    To those that have mixed 52 and 34 rings, have you noticed any problems in shifting?
    I believe the 50 and 34 rings have an A tooth profile whereas the 52 and 36 have a B profile on some teeth to aid shifting.

    Bally! Who the phark are you etc…

    An update - I’ve done this change to use 52/34, and front shifting seems almost identical - perhaps a smidge more noise and two nanoseconds slower to ramp up, but no issues. The downshift from big to small is noisier too, a bigger drop I guess.

    Only practical issue as expected is chain length and tension. Using an 11-28 cassette, on the small front ring the chain tension is a little slack in the 3 smallest cassette sprockets, so I just shift gears a bit more often to avoid that. Rarely used those ratios anyway.

    Otherwise seems fine. I’ve not fitted a chain catcher yet on the front mech, will do when I can find one in the lbs… but so far no dropped chains. (Not big miles yet though by any means)
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  • ballysmateballysmate Posts: 15,778
    Thanks for the reply Spinner.
    I had a 52/36 and needed to replace the 36. A 50/34 would be a better suit for my cycling... erm...I hesitate to use the word abilities. I toyed with the idea of just replacing the 36 with a 34 but with the chat about big drops and the difference between A and B tooth profiles, I changed both. Good to know that the 52 ring is not a scrapper and may come in useful in the future.
    I certainly had no need of a 52 x 11 combo.
  • secretsamsecretsam Posts: 4,891
    Funnily enough, I had the same query. For me, it's not so much keeping the 52/11 that's the reason for a 52/34, more that outer rings cost ££££ 🤣.
    However, I run a 11-32 rear, would 52/34 be pushing my luck??

    It's just a hill. Get over it.
  • ballysmateballysmate Posts: 15,778
    secretsam said:

    Funnily enough, I had the same query. For me, it's not so much keeping the 52/11 that's the reason for a 52/34, more that outer rings cost ££££ 🤣.
    However, I run a 11-32 rear, would 52/34 be pushing my luck??

    No idea what you are running, but I bought this. Arrived in a couple of days. Currently showing availability next week.

    https://www.mantel.com/uk/shimano-105-5800-chainring
  • WheelspinnerWheelspinner Posts: 5,699
    secretsam said:

    Funnily enough, I had the same query. For me, it's not so much keeping the 52/11 that's the reason for a 52/34, more that outer rings cost ££££ 🤣.
    However, I run a 11-32 rear, would 52/34 be pushing my luck??

    My guess is you’d have problems with chain tension. Even with (just) a 28 the chain length is not optimal. The extra couple of links you’d need to run the 32 safely would likely render your 4 or 5 smallest cogs on the cassette as useless.

    Dunno whether a medium/long cage derailleur would solve that to some extent though, if you can get the shifting to work. Not tried that on a roadie.
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  • secretsamsecretsam Posts: 4,891

    secretsam said:

    Funnily enough, I had the same query. For me, it's not so much keeping the 52/11 that's the reason for a 52/34, more that outer rings cost ££££ 🤣.
    However, I run a 11-32 rear, would 52/34 be pushing my luck??

    My guess is you’d have problems with chain tension. Even with (just) a 28 the chain length is not optimal. The extra couple of links you’d need to run the 32 safely would likely render your 4 or 5 smallest cogs on the cassette as useless.

    Dunno whether a medium/long cage derailleur would solve that to some extent though, if you can get the shifting to work. Not tried that on a roadie.
    Mmm. did wonder about that. Full 8000 Ultegra (mechanical), rear is medium cage.

    I might have to be less tight and just buy a 50 outer as well! Or I could swap in the cranks from another bike (wrong chainring type, tho', old 5 arm model)

    It's just a hill. Get over it.
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