Forum home Mountain biking forum MTB beginners

Changing chainring sizes ?

RandGRandG Posts: 779
edited March 2014 in MTB beginners
I'm looking to change the tooth sizes on my chainrings, but is it as simple as just buying the sizes I want and changing ?? Obviously they will need to be 2x10 ten speed to match what I have, but other than that, is there anything I need ??

Posts

  • oxocube1oxocube1 Posts: 651
    Yes, the number of chainring bolts needs to be the same on the new chainring as on your current i.e 4 bolt cahinrings can only be replaced by 4 bolt chainrings. Also you need to make sure that the BCD (Bolt Circle Diameter) is the same. A large majority of chainrings will be 104mm BCD which is what Shimano tends to use along with a few other brands.
  • cooldadcooldad Posts: 32,904
    Depends what you want to change to. Some might not fit, some might not work with your mech.
    Posting some specifics always helps elicit sensible answers.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • RandGRandG Posts: 779
    Shock horror: Cooldad in helpful posting drama !!!

    I have a Boardman fs team, 2x10 42/27 I want to change to 36/22.
  • nicklousenicklouse Posts: 81,520 Lives Here
    RandG wrote:
    Shock horror: Cooldad in helpful posting drama !!!

    I have a Boardman fs team, 2x10 42/27 I want to change to 36/22.
    and the cranks are?

    what bolt patten and BCD?
    is FSA 3 bolt then have fun dont think there are any available yet.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • oxocube1oxocube1 Posts: 651
    RandG wrote:
    I have a Boardman fs team, 2x10 42/27 I want to change to 36/22.

    Yea I think that chainset (FSA Comet) uses a 3 bolt chainring and by the looks of what Nick is saying it might be difficult to get hold of new ones for it unfortunately!
  • You'll also want to take a link or two out of your chain. The park website has a guide on how to size your chain properly.

    Do you really need to go to 22? I assume you have got a 36 at the rear so 22/36 is a very very low gear.

    26/38 would give you more usable range of gears.
  • RandGRandG Posts: 779
    oxocube1 wrote:
    RandG wrote:
    I have a Boardman fs team, 2x10 42/27 I want to change to 36/22.

    Yea I think that chainset (FSA Comet) uses a 3 bolt chainring and by the looks of what Nick is saying it might be difficult to get hold of new ones for it unfortunately!

    Yes it is that.

    What's the reason for not being able to get a hold of one of these then ??
  • nicklousenicklouse Posts: 81,520 Lives Here
    at the moment only FSA make them and you only do certain sizes.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Ben_.Ben_. Posts: 16
    Sorry to drag back a post from a month ago but...

    This may seem like a dumb question. If you're changing a chain-ring from one size to another woudl the front dérailleur need re-adjusting?
    I've only ever changed chain rings to replace them (like-for-like) before. I can envisage that if I change a chain-ring to one with fewer teeth - the dérailleur/shifting might "work" at first glance, but it might actually need some adjusting/fine tuning.
  • CqcCqc Posts: 951
    You'll have to change the height
  • cooldadcooldad Posts: 32,904
    If you can.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • Some boardman have direct mount front mechs. Not adjustable so have to get one that matches chainring size.
  • Ben_.Ben_. Posts: 16
    Cheers
Sign In or Register to comment.