50-39 vs 53-39

Bozabyka
Bozabyka Posts: 252
edited November 2014 in Workshop
I have a bike with 50-34 chainrings
34 to too low
Could I run 50-39 with a 11-23
How would this compare to 53-39 with 12-23?
Bike will be used for old skool time trial

Comments

  • FatTed
    FatTed Posts: 1,205
    Probably No
    BCD is different for 53/39 from a 50/34 unless its a new Dura ace Shimano crank set
    http://home.earthlink.net/~mike.sherman/shift.html
  • Bozabyka
    Bozabyka Posts: 252
    thanks ted
  • mamba80
    mamba80 Posts: 5,032
    Buy a Stronglight ct2 inner 39t chain ring - bcd 110, I got mine from SJS cycles, I ve got the 36 on a compact and its perfect - the bcd issue is only when wanting to change a 39t 130bcd to say a 34.
    50x11 is slightly higher than 53x12
  • CptKernow
    CptKernow Posts: 467
    I put a 36t inner on a compact a while back and it vastly improved it IMO. 50/39 sounds a bit close to me
  • DCI Gene Hunt
    DCI Gene Hunt Posts: 138
    CptKernow wrote:
    I put a 36t inner on a compact a while back and it vastly improved it IMO. 50/39 sounds a bit close to me


    What type of 110mm bcd 36 tooth ring did you buy and where did you get it ? Is it specifically for 10 speed use as I know a 36 tooth ring for 9 speed would give problems .

    I think 36/50 would be so much better to use than 34/50 as (imo) a 34 tooth ring is too low.
  • DeVlaeminck
    DeVlaeminck Posts: 9,104
    I've used a 50*36 campag on a compact bcd and it works well, imo preferable to 50*34 99% of the time (although we are talking about small differences).

    Can't see why a 50*39 would give problems though if you can get a chainring to fit the chainset.
    [Castle Donington Ladies FC - going up in '22]
  • smoggysteve
    smoggysteve Posts: 2,909
    Have you considered a 52/36?
  • keef66
    keef66 Posts: 13,123
    50 39 would I'm sure be OK; it's what I have on my triple, along with a 30 inner ring for emergencies. Spend 90% of my time on the 39 chainring because we don't got no big hills round here.
  • smoggysteve
    smoggysteve Posts: 2,909
    keef66 wrote:
    50 39 would I'm sure be OK; it's what I have on my triple, along with a 30 inner ring for emergencies. Spend 90% of my time on the 39 chainring because we don't got no big hills round here.

    No hills huh? So when you gonna mtfu and spend 90% of your time in the 50? ☺
  • Bar Shaker
    Bar Shaker Posts: 2,313
    Bozabyka wrote:
    Bike will be used for old skool time trial

    Do you need a small chain ring for time trialling?

    50 and 11-23 should cover anything up to around 40mph.
    Boardman Elite SLR 9.2S
    Boardman FS Pro
  • Bozabyka
    Bozabyka Posts: 252
    Ride a lot of hilly time trials with no real fast circuits.
    At 20mph whats the difference in cadence between 50 and 53 ring?
  • FatTed
    FatTed Posts: 1,205
    Bozabyka wrote:
    Ride a lot of hilly time trials with no real fast circuits.
    At 20mph whats the difference in cadence between 50 and 53 ring?

    87/85 in the 17 cog
    81/77 in the 16
    117/110 in the 23
  • earth
    earth Posts: 934
    50/11 is a higher ratio that 53/12
  • cswitch
    cswitch Posts: 261
    Just get a 52/38 set, virtually double gearing and allows you to go down to 36 inner if you end up doing an alps trip or similar. Ive ridden 53/39 for years and recently went 52/38. Didn't really notice the change but I did go with a 36 when on a riding holiday and it made life a little easier / pleasurable when I was knackered.

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