Changing chain rings/gearing

mattylyden
mattylyden Posts: 3
in MTB workshop & tech
Hi, I've just picked up a hardly used Carrera vengeance 22inch MTB.

I've not done any fun cycling since before kids, I took my bike out for a few laps around the local reservoir the other day. I really enjoyed it... apart from the gearing. I was in the hardest to pedal (fastest)gears the whole time.

There are 2 front sprockets/chain rings-the smaller ring for going up hills, I'd ideally like to do away with... I doubt I will use it... the existing larger chain ring is about right, but then I'd like a bigger one for 8 extra faster speed gears. Would this be an easy job, are the parts universal? What do bike shops charge for the work?

The shift is a two position lever on the left. 2x8 gears. Or are there any other routes to go with better gearing?

My cycle style is mostly flat, fast and distance but I still love jumping off curbs and any minor hills or tracks carved out by other bikes so went for this MTB in stead of a thin wheel hybrid.

Thanks for any help 😎

Comments

  • me-109
    me-109 Posts: 1,915
    Chainring size might be limited by the ability to move the front gear mech (derailleur) higher.

    If it is a band-on type where the clamp wraps around the frame then it should have plenty of room for adjustment unless you have suspension or funny shaped tubes getting in the way. If it is bolted through a small plate on the side of the tube, then it will have limited scope to move, so you may only increase the outer chainring by a couple of teeth.

    Once you work that out you are then into a world of working out chainrings to fit your current cranks, or replacing the whole lot - which might need new bottom bracket (chain set bearings and axle).

    Of course, if you are only pedalling at 50rpm the answer is to learn to pedal faster. ;)
  • Mad_Malx
    Mad_Malx Posts: 5,183
    The current version of this 2x8 has 36 and 22 chainrings.
    36 at the front (with a 12 smallest cog on the back) is quite a low gear. You won't get a much bigger chainring on that crankset, the spider (that the chainrings bolt to) will be too small for a big chainring.

    It's listed as a square taper BB so you might be able to swap quite cheaply for a new or used compact road crankset (50-34 ). It's also listed as band-on front derailleur which means you should be able to move it up far enough.
    However there may be a problem with a bigger inner chainring clearing the chainstay, so you need to look at this.
  • mattylyden
    mattylyden Posts: 3
    Thanks for the replies and taking the time to check out the spec of my bike.

    50/34 sounds perfect!

    With the crank sets, are all the pedal stem lengths the same size and should I replace the chain aswell so the length is better?

    I'd really like to do this, just pricing it all up. Would you guys think a bike shop would be better or buy some crank pulling tools and try it at home?

    I will check the chainstay clearance. Did you mean the inner sprocket touching the metal work as it flares out into 2.

    Thanks for this, really like the bike but it just feels like gears are missing
  • Mad_Malx
    Mad_Malx Posts: 5,183
    Crank arm length is personal, but fwiw I have similar (within 2.5 mm) on my MTB and road bikes. That's what they came with and I don't notice any difference.
    You will def need a longer chain, best to measure this in situ (Google is your friend) .
    It's an easy job to swap the crank, with the right (cheap) pulling tool.
    Yes, I did mean inner chainring might catch the flared horizontal arm between bb and the dropout, because it will project further back and so closer. If it's already close then there might be a problem.
  • mattylyden
    mattylyden Posts: 3
    OK great thanks very much for your help, I'll select the parts I need

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