Worn crank

Kieran_Burns
Kieran_Burns Posts: 9,757
edited July 2011 in Commuting chat
I'm amazed to find that I've worn out my big ring :shock:

I was cleaning the chain last night (as you do) with the chain on the middle ring - I noticed that many of the teeth on the big ring are now badly worn

So I need a new one. I am now in the land of the unknown....

It's for the Tricross and I've checked to see that mine has the FSA Vero Triple crankset

The question is: can you get these? I can't find one and which one do I get? There appears to be 3 to choose from (crank length)

Or.... what alternatives are there (52/39/30t)?
Chunky Cyclists need your love too! :-)
2009 Specialized Tricross Sport
2011 Trek Madone 4.5
2012 Felt F65X
Proud CX Pervert and quiet roadie. 12 mile commuter

Comments

  • alfablue
    alfablue Posts: 8,497
    Sorry if this is obvious, but when you say "many of the teeth" are badly worn I wonder if you are just noticing that as new, several teeth will have a lower profile to aid shifting. Normal wear is likely to lead to uniform wear on all teeth, where they start to get sharp and pointy. Is it really worn?
  • Kieran_Burns
    Kieran_Burns Posts: 9,757
    Told you I was in the land of the unknown - I didn't know that

    I'll go back and look more closely tonight and check.
    Chunky Cyclists need your love too! :-)
    2009 Specialized Tricross Sport
    2011 Trek Madone 4.5
    2012 Felt F65X
    Proud CX Pervert and quiet roadie. 12 mile commuter
  • veronese68
    veronese68 Posts: 27,776
    Sketchley posted a nice picture of his worn big ring a while ago. You could post a picture and await a critique of your ring.
    Kinesis Pro6
    Marin Nail Trail
    Cotic Solaris
  • EKE_38BPM
    EKE_38BPM Posts: 5,821
    edited July 2011
    You say your teeth are worn but then ask about having different lengths to choose from.

    Assuming it is the chainring that is worn, what has crank length got to do with it? Can't you buy a replacement chainring or do you have to buy a whole replacement chainset?

    If it is just the chainring that needs replaceing, you will need to know your Bolt Circle Diameter (BCD) and the number of teeth on that ring in order to buy the correct replacement.

    Edit: The BCD is 130mm for the big and middle rings and 74mm for the granny.
    You need to be looking for a 52T chainring with 130mm BCD. Job done.

    This would do. But others may be better/cheaper/more suitable/prettier/lighter.
    FCN 3: Raleigh Record Ace fixie-to be resurrected sometime in the future
    FCN 4: Planet X Schmaffenschmack 2- workhorse
    FCN 9: B Twin Vitamin - winter commuter/loan bike for trainees

    I'm hungry. I'm always hungry!
  • bails87
    bails87 Posts: 12,998
    Damn, EKE beat me to it. Yep, just replace the outer ring.

    Is your chain worn too? Do you have a chain checker? If your chainring is worn then the chain probably will be too.
    MTB/CX

    "As I said last time, it won't happen again."
  • Kieran_Burns
    Kieran_Burns Posts: 9,757
    The chainset apparently comes in 3 different crank arm lengths. I know it's a 52 tooth but don't know the BCD for that one (or if it can be be replaced on its own)

    I'll take a look when I get home
    Chunky Cyclists need your love too! :-)
    2009 Specialized Tricross Sport
    2011 Trek Madone 4.5
    2012 Felt F65X
    Proud CX Pervert and quiet roadie. 12 mile commuter
  • EKE_38BPM
    EKE_38BPM Posts: 5,821
    Kieran_Burns wrote:
    The chainset apparently comes in 3 different crank arm lengths. I know it's a 52 tooth but don't know the BCD for that one (or if it can be be replaced on its own)

    I'll take a look when I get home

    Crank arm length is irrelevant if you are only changing the chainring. See the edit to my previous post.
    FCN 3: Raleigh Record Ace fixie-to be resurrected sometime in the future
    FCN 4: Planet X Schmaffenschmack 2- workhorse
    FCN 9: B Twin Vitamin - winter commuter/loan bike for trainees

    I'm hungry. I'm always hungry!
  • asprilla
    asprilla Posts: 8,440
    Kieran_Burns wrote:
    The chainset apparently comes in 3 different crank arm lengths. I know it's a 52 tooth but don't know the BCD for that one (or if it can be be replaced on its own)

    I'll take a look when I get home

    BCD is 130 for the two outer rings and 74 for the inner.

    http://www.chainreactioncycles.com/Mode ... roducts-UK
    Mud - Genesis Vapour CCX
    Race - Fuji Norcom Straight
    Sun - Cervelo R3
    Winter / Commute - Dolan ADX
  • bails87
    bails87 Posts: 12,998
    If it's this one then it's 130mm BCD and the rings are replaceable. Only very, very, very cheap (And 40 quid for a chainset isn't expensive) chainsets have the rings riveted rather than bolted on.

    It might work out cheaper to buy the whole thing, than it would be to buy 3 replacement rings as and when you need them. You can flog the old/new arms too.
    MTB/CX

    "As I said last time, it won't happen again."
  • rick_chasey
    rick_chasey Posts: 75,661
    52?

    Pfftt. Strap on a pair.

    nick-bowdler-2.jpg

    big-chain-ring.jpg
    _
  • Kieran_Burns
    Kieran_Burns Posts: 9,757
    edited July 2011
    bails87 wrote:
    Damn, EKE beat me to it. Yep, just replace the outer ring.

    Is your chain worn too? Do you have a chain checker? If your chainring is worn then the chain probably will be too.

    The chain is a recent replacement due to my ham-fistedness when using a chain removal tool.

    Ham-fistedness that almost led to overthebar-edness when checking the chain for the first time.
    Chunky Cyclists need your love too! :-)
    2009 Specialized Tricross Sport
    2011 Trek Madone 4.5
    2012 Felt F65X
    Proud CX Pervert and quiet roadie. 12 mile commuter
  • bails87
    bails87 Posts: 12,998
    EKE_38BPM
    Asprilla
    Are those 4 arm rings? Is the FSA chainset 5 arm?
    MTB/CX

    "As I said last time, it won't happen again."
  • asprilla
    asprilla Posts: 8,440
    bails87 wrote:
    EKE_38BPM
    Asprilla
    Are those 4 arm rings? Is the FSA chainset 5 arm?

    I linked to the full replacement crankset so you can see they are 5 arm.
    Mud - Genesis Vapour CCX
    Race - Fuji Norcom Straight
    Sun - Cervelo R3
    Winter / Commute - Dolan ADX
  • Kieran_Burns
    Kieran_Burns Posts: 9,757
    Did I mention it needs to be in black? :P
    Chunky Cyclists need your love too! :-)
    2009 Specialized Tricross Sport
    2011 Trek Madone 4.5
    2012 Felt F65X
    Proud CX Pervert and quiet roadie. 12 mile commuter
  • sketchley
    sketchley Posts: 4,238
    Having just done this.

    Sheldon Brown will tell you how to measure BCD if not printed on the chain ring.

    http://www.sheldonbrown.com/gloss_bo-z.html.

    I brought one of these 50T for £17 delivered does the job

    http://www.spacycles.co.uk/products.php ... tronglight

    Also see

    http://www.bikeradar.com/forums/viewtop ... highlight=
    --
    Chris

    Genesis Equilibrium - FCN 3/4/5
  • sketchley
    sketchley Posts: 4,238
    I also replaced Cassette and Chain (in fact did this first then found problem with big ring).
    --
    Chris

    Genesis Equilibrium - FCN 3/4/5
  • bails87
    bails87 Posts: 12,998
    Asprilla wrote:
    bails87 wrote:
    EKE_38BPM
    Asprilla
    Are those 4 arm rings? Is the FSA chainset 5 arm?

    I linked to the full replacement crankset so you can see they are 5 arm.

    The chainrings were 5 arm anyway. I looked quickly, then tried to go back and check and CRC was playing up.

    KB: Just find a 52T (If you're sure it's that and not 50T) 130mm BCD 5 bolt chainring.....in black. Ta daaa. Although it costs as much as a whole new chainset.
    MTB/CX

    "As I said last time, it won't happen again."
  • Kieran_Burns
    Kieran_Burns Posts: 9,757
    *cough* 50 *cough*

    I'm going to get myself a coffee.... :oops:
    Chunky Cyclists need your love too! :-)
    2009 Specialized Tricross Sport
    2011 Trek Madone 4.5
    2012 Felt F65X
    Proud CX Pervert and quiet roadie. 12 mile commuter
  • EKE_38BPM
    EKE_38BPM Posts: 5,821
    Thought it would be a 50 if its a triple.
    So, to clarify: The topic is wrong (should be chainring, not crank), the number of teeth was wrong and Kieran's thinking that the crank length was important is wrong. Are you sure it is a black chainring that you actually want?

    Kieran, if DDD had written that there would be people queing up to take a D from him!
    I will be generous and let you off as you did say that you are in the land of the unknown in your OP.
    FCN 3: Raleigh Record Ace fixie-to be resurrected sometime in the future
    FCN 4: Planet X Schmaffenschmack 2- workhorse
    FCN 9: B Twin Vitamin - winter commuter/loan bike for trainees

    I'm hungry. I'm always hungry!
  • sketchley
    sketchley Posts: 4,238
    Oi, I was trying to help you!

    1st I run 50 x 11 on top gear
    2nd I hit 40 mph at the weekend and I wasn't spinning out
    3rd it replaced a 50T and I had already shortened a new chain while it may of worked and I shouldn't be running 50x28 anyway it was still wrong.
    4th If it's good enough on this http://www.evanscycles.com/products/pin ... e-ec023491 ......
    --
    Chris

    Genesis Equilibrium - FCN 3/4/5
  • EKE_38BPM
    EKE_38BPM Posts: 5,821
    So, Kieran, whats the verdict?
    FCN 3: Raleigh Record Ace fixie-to be resurrected sometime in the future
    FCN 4: Planet X Schmaffenschmack 2- workhorse
    FCN 9: B Twin Vitamin - winter commuter/loan bike for trainees

    I'm hungry. I'm always hungry!
  • Kieran_Burns
    Kieran_Burns Posts: 9,757
    EKE_38BPM wrote:
    So, Kieran, whats the verdict?

    I'm an idiot.
    Chunky Cyclists need your love too! :-)
    2009 Specialized Tricross Sport
    2011 Trek Madone 4.5
    2012 Felt F65X
    Proud CX Pervert and quiet roadie. 12 mile commuter
  • EKE_38BPM
    EKE_38BPM Posts: 5,821
    LOL. Chainring not worn at all, eh?
    FCN 3: Raleigh Record Ace fixie-to be resurrected sometime in the future
    FCN 4: Planet X Schmaffenschmack 2- workhorse
    FCN 9: B Twin Vitamin - winter commuter/loan bike for trainees

    I'm hungry. I'm always hungry!
  • ex-pat scot
    ex-pat scot Posts: 939
    The stock chainset on Tricross takes a 30-39-50 set of rings.
    The outer 2 are indeed 130mm bcd.

    I'm about to sell my black chainset & BB - identical to yours - done 175 miles (I'm swapping for a compact double, like on my other bikes). Interested?
    Commute: Langster -Singlecross - Brompton S2-LX

    Road: 95 Trek 5500 -Look 695 Aerolight eTap - Boardman TTe eTap

    Offroad: Pace RC200 - Dawes Kickback 2 tandem - Tricross - Boardman CXR9.8 - Ridley x-fire
  • Aguila
    Aguila Posts: 622
    alfablue wrote:
    Sorry if this is obvious, but when you say "many of the teeth" are badly worn I wonder if you are just noticing that as new, several teeth will have a lower profile to aid shifting. Normal wear is likely to lead to uniform wear on all teeth, where they start to get sharp and pointy. Is it really worn?

    +1, before I knew better I too once thought I had broken/worn a chainset. This is far more likely to be the explanantion. Chainrings take donkeys to wear, you would expect to go through quite a few chains and cassettes before touching the chainset.
    www.bikehike.co.uk/mapview.php?id=6277
  • Jay dubbleU
    Jay dubbleU Posts: 3,159
    Kieran_Burns wrote:
    EKE_38BPM wrote:
    So, Kieran, whats the verdict?

    I'm an idiot.

    +1 - sorry someone had to :wink:

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