O Symetric Chain Ring swap

Jimmy Mac 65
Jimmy Mac 65 Posts: 3
edited May 2013 in Road buying advice
Just wondered if anyone could offer some advice on the following pls....................

Thinking of changing my chain ring to O symetric. I currently have a Tiagra Compact Groupset with 50/34 and 12/28.

If i was to change the Chain ring to O symetric which is 52/38 would i need to change the rear cassette as well to accommodate it??

Probably sounds like a dunce question sorry just haven't really got a scooby about the real technical things like that.

Thanks in advance!


  • Wooliferkins
    Wooliferkins Posts: 2,060
    Not necessarily it depends on the ratios and your legs. You'll need a longer chain and to raise your front mech. Not sure how you go about putting Osyms through a gear calculator to work out your progression though. Do you use the average chainring size or the virtual largest?
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  • Average I guess
  • Grill
    Grill Posts: 5,610
    Why are you going with O's? Do you TT?
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