Drilling chainstays to fit chain tensioner ?

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Comments

  • sugdenr
    sugdenr Posts: 69
    There are 2 issues with drilling chainstay - first is ultimate strength second is fatigue, esp. in Ally.

    On a hard tail I doubt the ultimate strength would be the problem but as I found out with v. expensive full susser, when you pedal hard the driveside chainstay actually flexes a little. If the chainstay is not strong enough (like weak spot caused by machining weight out of it or in your case drilling a hole in it) you will eventually get fatigue stress fracture at the flex (weak) point as the ally work hardens.

    For a pub bike I would say do it, for giving it beans down the trail you can probably induce the same amount of risk by simply not wearing a helmet :shock:
  • unityjon
    unityjon Posts: 27
    sugdenr wrote:

    For a pub bike I would say do it, for giving it beans down the trail you can probably induce the same amount of risk by simply not wearing a helmet :shock:


    funny how things change isnt it, i never wore a helmet unless in Comp or Demos when i rode BMX BITD at skate parks but my mates have donned me with a lid for trail riding and i dont regret it !

    this thread is pretty much redundant now as i've got a CAD drawing of a bottom bracket mounted tensioner in the waterjet right now. 8)

    Most things are restricted by manuf. costs and profit to be had which is why a lot of 'affordable' bikes could be improved, if you look at supposedly top end stuff and loss leaders they have all the bells and whistles that are current fashion, doesn't mean that us mere mortals with average wage packets cant enjoy the fun too.
    Dialled alpine mk2, ragley, shimano deore groupset, v8's, Mavice en521, High Rollers - Lovin' it!
  • Dick Scruttock
    Dick Scruttock Posts: 2,533
    I recall years ago a company making a chain tensioner that extended out from the drop out and had a spring mounted to the end of that and the other end of the spring went to the bottom of the mech cage.
  • Anonymous
    Anonymous Posts: 79,667
    unityjon wrote:
    this thread is pretty much redundant now as i've got a CAD drawing of a bottom bracket mounted tensioner in the waterjet right now. 8)

    Most things are restricted by manuf. costs and profit to be had which is why a lot of 'affordable' bikes could be improved, if you look at supposedly top end stuff and loss leaders they have all the bells and whistles that are current fashion, doesn't mean that us mere mortals with average wage packets cant enjoy the fun too.
    No, what's redundant is your BB mount "tensioner".
    Black%20spire%20stinger%20bb%20mount.jpg
    They already exist, they aren't expensive, and are very common.
    What they really do is stop the chain slack from making it to the chainring, eo even on rough ground, the chain doesn't come off.

    £20 seems a hell of a lot cheaper than CAD software and a CNC, frankly.

    The kinds of things that mounted on the chainstay went away because frankly, they didn't really do anything. I've not sen anyone with a DCD in years.
    Same reason you see far fewer downtube mounted crudcatchers than you used to. Eventually people cottoned on to the fact they don't work.
  • nicklouse
    nicklouse Posts: 50,675
    yeehaamcgee wrote:
    unityjon wrote:
    this thread is pretty much redundant now as i've got a CAD drawing of a bottom bracket mounted tensioner in the waterjet right now. 8)

    Most things are restricted by manuf. costs and profit to be had which is why a lot of 'affordable' bikes could be improved, if you look at supposedly top end stuff and loss leaders they have all the bells and whistles that are current fashion, doesn't mean that us mere mortals with average wage packets cant enjoy the fun too.
    No, what's redundant is your BB mount "tensioner".
    Black%20spire%20stinger%20bb%20mount.jpg
    They already exist, they aren't expensive, and are very common.
    What they really do is stop the chain slack from making it to the chainring, eo even on rough ground, the chain doesn't come off.

    £20 seems a hell of a lot cheaper than CAD software and a CNC, frankly.

    The kinds of things that mounted on the chainstay went away because frankly, they didn't really do anything. I've not sen anyone with a DCD in years.
    Same reason you see far fewer downtube mounted crudcatchers than you used to. Eventually people cottoned on to the fact they don't work.

    and it will not stop the chain hitting the chainstay making a racket.

    when you do fit one dont forget to lengthen you chain.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Anonymous
    Anonymous Posts: 79,667
    nicklouse wrote:
    and it will not stop the chain hitting the chainstay making a racket.
    Nope. Not at all.
    Luckily, I haven't had chainstays on my main bike for over a decade.
    And no, I did not hacksaw them off :lol:
  • MattJWL
    MattJWL Posts: 147
    yeehaamcgee wrote:
    Luckily, I haven't had chainstays on my main bike for over a decade.
    And no, I did not hacksaw them off :lol:

    Yes, yes. We know you used a blowtorch :wink:
    Intense Carbine SL
    "Chinarello"
    Taylor Made
    Off to pastures new:
    CELL Team Pro
    Intense Spider FRO
    Giant XTC Composite Clone
    1992 Fisher Al-1
    1990 Raleigh Mirage
    1988 Cloria Italian MTB
  • MattJWL
    MattJWL Posts: 147
    yeehaamcgee wrote:
    Luckily, I haven't had chainstays on my main bike for over a decade.
    And no, I did not hacksaw them off :lol:

    Actually, technically it does have chainstays, they're just 'Elevated Chainstays'. Remember the old Alpinestars?
    Intense Carbine SL
    "Chinarello"
    Taylor Made
    Off to pastures new:
    CELL Team Pro
    Intense Spider FRO
    Giant XTC Composite Clone
    1992 Fisher Al-1
    1990 Raleigh Mirage
    1988 Cloria Italian MTB
  • The Rookie
    The Rookie Posts: 27,812
    MattJWL wrote:
    yeehaamcgee wrote:
    Luckily, I haven't had chainstays on my main bike for over a decade.
    And no, I did not hacksaw them off :lol:

    Yes, yes. We know you used a blowtorch :wink:
    He gnawed them off......

    Simon
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • Anonymous
    Anonymous Posts: 79,667
    MattJWL wrote:
    yeehaamcgee wrote:
    Luckily, I haven't had chainstays on my main bike for over a decade.
    And no, I did not hacksaw them off :lol:

    Actually, technically it does have chainstays, they're just 'Elevated Chainstays'. Remember the old Alpinestars?
    Nope. It's a swingarm.
  • MattJWL
    MattJWL Posts: 147
    yeehaamcgee wrote:
    Nope. It's a swingarm.
    Yeah, alright I'll give you that. Even if it is a 3-member swingarm that echoes the shape of the Hardtail rear triangle. 8)
    Intense Carbine SL
    "Chinarello"
    Taylor Made
    Off to pastures new:
    CELL Team Pro
    Intense Spider FRO
    Giant XTC Composite Clone
    1992 Fisher Al-1
    1990 Raleigh Mirage
    1988 Cloria Italian MTB
  • Anonymous
    Anonymous Posts: 79,667
    It echoes the hardtail triangle in precisely one way. It connects the rear wheel to the main frame.
  • stubs
    stubs Posts: 5,001
    I want to be watching when this botch job hits its first bump. :lol:
    Fig rolls: proof that god loves cyclists and that she wants us to do another lap
  • rhialto
    rhialto Posts: 277
    nicklouse wrote:
    and it will not stop the chain hitting the chainstay making a racket.
    Interesting. I fitted a double and bash and a ISCG mounted Stinger and I have noticed a reduction in chain noise. It hasn't eliminated chain noise entirely, and not on big hits, but definitely on washboard-like terrain. Maybe because of the shorter the length of chain in play?
  • nicklouse
    nicklouse Posts: 50,675
    dpaulett wrote:
    nicklouse wrote:
    and it will not stop the chain hitting the chainstay making a racket.
    Interesting. I fitted a double and bash and a ISCG mounted Stinger and I have noticed a reduction in chain noise. It hasn't eliminated chain noise entirely, and not on big hits, but definitely on washboard-like terrain. Maybe because of the shorter the length of chain in play?

    watch out for the reduced number of gears that can be actually used. and if a fully watch out on the drops when in the larger sized cogs.

    yes it can reduce it a bit by stopping the chain coming away from the bottom of the crankset but it is no wonder fix for chain and chainstay contact, there is no real fix for that.
    As i said at the start the best fix for that is something to reduce the noise eg an old inner tube/chainstay protector.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • 02gf74
    02gf74 Posts: 1,171
    wrap neoprence cusion around hte cin stay?

    re: welding aluminium - aluminium alloys are available in many grades by alloying different elements in different qunatities together. Some need heat trating to maintain their strength after heating (by welding), some not as much or one at all.

    You really should find out the grade the frame is made from before welding to it.

    Make sure you post photo of what it is you made as I am sure I am not the only who is puzzled, :?

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