34/50 v 36/52 crankset?

Cats Eyes
Cats Eyes Posts: 49
edited June 2011 in Road buying advice
Thinking of upgrading my crankset & found a good deal on a 36/52.
I currently have a 34/50 with a 12-25 cassette. Would I notice much of difference with a lowest gear of 36-25 v 34-25?
What size cassette would I need to compensate for the increase in size of the small chainring? 12-26, 12-27?


  • centimani
    centimani Posts: 467
    Without getting into gear/inches calculations (cos i never had to :P ) there's a few things to consider.
    Your front derailleur may be a compact type. It may not work well with a 52 and if it does, you'll need to reposition it on your downtube to accomodate the extra diameter of the chainwheel.
    Will you notice the difference ? depends on whether you regularly use either extreme of the cassette. Anything inbetween on the cassette would simply mean
    you'd use a different gear to maintain your original output.
    You may have to add a link on your chain, although for such a small increase, maybe not.

    Someone may correct me, i'm looking at it from a non technical point of view.
  • Rule74Please
    Rule74Please Posts: 307
    36 is the ultimate for compacts

    36/25 is what we all had to manage with as it is equal to 39.27 which was as low as you could go. with a 36 you will be able to use you small inner ring again as the cross over speed is about 20 mph instead of 17.

    52 is what 10 ears or so ago was the standard outside ring. you are only slightly increasing your top gear

    36/23 is low enough for the uk but just leave your 25 on
  • LangerDan
    LangerDan Posts: 6,132
    It would depend on how much you currently use the 34 x 25. If you have to drop into it frequently, the the 6% increase in the gearing with the 36 x 25 would be significant - almost, though not quite, like staying in 34 x 23 rather than shifting down to the 25.

    You'd need a 11-27 to restore the same lowest gear, though you'll probably exceed the total chain capacity of the rear derailleur.
    'This week I 'ave been mostly been climbing like Basso - Shirley Basso.'
  • maddog 2
    maddog 2 Posts: 8,114
    whatever the 'good deal' is on the 36/52 you'll need a new cassette to retain an equivalent bottom gear, so it'd better be a very good deal to make it worthwhile...

    all depends on how low you need to go.
    Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer
  • i've changed set up as my fitness has improved.
    started on 50/34 with a 12/25
    now i'm on 52/36 with a 11/23
    i find that my set up now gives me more top speed downhills and uphill the bigger gear means i'm cranking more than spinning on the steeper stuff.
    the bigger chainrings were a whole lot cheaper than a crankset.
    and i've still got all the old stuff as spares incase a huge hilly sportive comes around.