FSA K-Force bodge part II



Hi All,

A few months ago I posted about ideas to bodge an FSA K-Force crankset
that appeared to have damaged splines on the left crank arm. In
attempting various bodges I managed to ruin the special bolt that
holds the arm on so I dropped the project. I just got a replacement
bolt and decided to have another go. Upon closer inspection, it seems
the play that is felt in the crank arm is not from damaged splines,
but rather from the metal insert having come loose from the carbon arm
such tha the arm can wiggle a bit while the metal insert is held fast
by the bolt.

I was willing to ride a bodged crankset with worn splines, but I am
leery of trying something where it seems the crank arm is in the
process of separating from it's mount. FSA's warranty is specifically
just for the original purchaser (which I am not) so I'm looking for
suggestions on how to resurrect this crank set. My bike is on a diet
so I'd like to use this crankset to save a few grams, but I don't
really want to spend any (much?) money on it as I got it for free and
it will save at most 100g anyway.

Joseph
 
J

jim beam

Guest
[email protected] wrote:
> Hi All,
>
> A few months ago I posted about ideas to bodge an FSA K-Force crankset
> that appeared to have damaged splines on the left crank arm. In
> attempting various bodges I managed to ruin the special bolt that
> holds the arm on so I dropped the project. I just got a replacement
> bolt and decided to have another go. Upon closer inspection, it seems
> the play that is felt in the crank arm is not from damaged splines,
> but rather from the metal insert having come loose from the carbon arm
> such tha the arm can wiggle a bit while the metal insert is held fast
> by the bolt.
>
> I was willing to ride a bodged crankset with worn splines, but I am
> leery of trying something where it seems the crank arm is in the
> process of separating from it's mount. FSA's warranty is specifically
> just for the original purchaser (which I am not) so I'm looking for
> suggestions on how to resurrect this crank set. My bike is on a diet
> so I'd like to use this crankset to save a few grams, but I don't
> really want to spend any (much?) money on it as I got it for free and
> it will save at most 100g anyway.
>
> Joseph
>

do your homework on the construction. iirc, the fsa is simply a carbon
outer on a skinnied down aluminum crank arm. if that's the case, you
could inject resin into the gap between the two just to stop the loose
carbon rattling about.

but but but, you have to ask yourself, wtf are you bothering? it
shouldn't have failed in the first place. it could be that the internal
aluminum has cracked already and it's only the carbon holding it
together. to be sure, you'd have to x-ray, and the cost of that
outweighs new purchase.

bottom line, unless you know for sure what the problem is, you're
setting yourself up to pay for your dentists' kids college. if you're
cheap, you're much better advised to invest in a new, known good crank
like a shimano 105. the weight gain won't kill you and the reliability
will keep your dentist merely well remunerated as opposed to wealthy.
winning is about the guy, not the gear.
 
J

Jay Beattie

Guest
On Jul 13, 7:09 am, jim beam <[email protected]> wrote:
> [email protected] wrote:
> > Hi All,

>
> > A few months ago I posted about ideas to bodge an FSA K-Force crankset
> > that appeared to have damaged splines on the left crank arm. In
> > attempting various bodges I managed to ruin the special bolt that
> > holds the arm on so I dropped the project. I just got a replacement
> > bolt and decided to have another go. Upon closer inspection, it seems
> > the play that is felt in the crank arm is not from damaged splines,
> > but rather from the metal insert having come loose from the carbon arm
> > such tha the arm can wiggle a bit while the metal insert is held fast
> > by the bolt.

>
> > I was willing to ride a bodged crankset with worn splines, but I am
> > leery of trying something where it seems the crank arm is in the
> > process of separating from it's mount. FSA's warranty is specifically
> > just for the original purchaser (which I am not) so I'm looking for
> > suggestions on how to resurrect this crank set. My bike is on a diet
> > so I'd like to use this crankset to save a few grams, but I don't
> > really want to spend any (much?) money on it as I got it for free and
> > it will save at most 100g anyway.

>
> > Joseph

>
> do your homework on the construction. iirc, the fsa is simply a carbon
> outer on a skinnied down aluminum crank arm. if that's the case, you
> could inject resin into the gap between the two just to stop the loose
> carbon rattling about.
>
> but but but, you have to ask yourself, wtf are you bothering? it
> shouldn't have failed in the first place. it could be that the internal
> aluminum has cracked already and it's only the carbon holding it
> together. to be sure, you'd have to x-ray, and the cost of that
> outweighs new purchase.
>
> bottom line, unless you know for sure what the problem is, you're
> setting yourself up to pay for your dentists' kids college. if you're
> cheap, you're much better advised to invest in a new, known good crank
> like a shimano 105. the weight gain won't kill you and the reliability
> will keep your dentist merely well remunerated as opposed to wealthy.
> winning is about the guy, not the gear.- Hide quoted text -


Crazy Glue. Really, throw it away and be happy with the fact that it
was free -- which is slightly below the real value of most FSA
components based on my (bad) experience. I broke my FSA ISIS crank
and got a nice Ultegra HollowTech for $200 plus $40 for the cups
(could have gotten it cheaper if I went internet). I know this is
more than you want to spend (which is zero), but it is sure nice
having a positive feeling crank with no mechanical problems and a BB
that will last for more than a few days.

P.S. -- I bought a new ISIS BB for my bike before learning that my FSA
crank was broken (cracked through the splines in the aluminum insert
that came loose on your crank). The good news is that the ISIS BB on
my x-bike is shot, too, so at least I can use my new ISIS BB in that
bike. When that goes, I'm switching to a cheap outboard bearing crank
-- maybe something from TruVativ or a low-end Shimano. -- Jay Beattie.
 
On Jul 13, 4:09 pm, jim beam <[email protected]> wrote:
> [email protected] wrote:
> > Hi All,

>
> > A few months ago I posted about ideas to bodge an FSA K-Force crankset
> > that appeared to have damaged splines on the left crank arm. In
> > attempting various bodges I managed to ruin the special bolt that
> > holds the arm on so I dropped the project. I just got a replacement
> > bolt and decided to have another go. Upon closer inspection, it seems
> > the play that is felt in the crank arm is not from damaged splines,
> > but rather from the metal insert having come loose from the carbon arm
> > such tha the arm can wiggle a bit while the metal insert is held fast
> > by the bolt.

>
> > I was willing to ride a bodged crankset with worn splines, but I am
> > leery of trying something where it seems the crank arm is in the
> > process of separating from it's mount. FSA's warranty is specifically
> > just for the original purchaser (which I am not) so I'm looking for
> > suggestions on how to resurrect this crank set. My bike is on a diet
> > so I'd like to use this crankset to save a few grams, but I don't
> > really want to spend any (much?) money on it as I got it for free and
> > it will save at most 100g anyway.

>
> > Joseph

>
> do your homework on the construction. iirc, the fsa is simply a carbon
> outer on a skinnied down aluminum crank arm. if that's the case, you
> could inject resin into the gap between the two just to stop the loose
> carbon rattling about.


The play is considerably less than 1mm (difficult to see, but easy to
feel) so there is no discernable gap to squirt anything into. The most
disconcerting part is that the play is most apparent in a rotational
direction. This leads me to think that the metal insert is just that,
and insert, not a long arm of any sort, or perhaps worse, an arm which
is broken.

> but but but, you have to ask yourself, wtf are you bothering? it
> shouldn't have failed in the first place. it could be that the internal
> aluminum has cracked already and it's only the carbon holding it
> together. to be sure, you'd have to x-ray, and the cost of that
> outweighs new purchase.
>
> bottom line, unless you know for sure what the problem is, you're
> setting yourself up to pay for your dentists' kids college. if you're
> cheap, you're much better advised to invest in a new, known good crank
> like a shimano 105. the weight gain won't kill you and the reliability
> will keep your dentist merely well remunerated as opposed to wealthy.
> winning is about the guy, not the gear.


I already have a nice Ultegra 6600 crankset on the bike. I'm only
bothering because I can't bring myself to just throw away this nice
shiny barely used crankset that weighs less than my current one when I
am trying to lighten my bike.

I know it's the guy, not the bike, but the guy (and the bike!) keeps
getting dropped on hills, so losing weight on the guy and the bike
helps. And if it's a free "upgrade" I'll take it. No way I'd spend
money on a replacement crankset only to save a few grams. I may go for
a Dura Ace 7800 but more because it is available in 180mm. But
unfortunatley nobody has given me a free 7800 180mm crankset, but they
have given me a damaged 175mm K-Force!

Joseph
 
B

bfd

Guest
On Jul 13, 10:28 am, "[email protected]"
<[email protected]> wrote:
> On Jul 13, 4:09 pm, jim beam <[email protected]> wrote:
>
>
>
>
>
> > [email protected] wrote:
> > > Hi All,

>
> > > A few months ago I posted about ideas to bodge an FSA K-Force crankset
> > > that appeared to have damaged splines on the left crank arm. In
> > > attempting various bodges I managed to ruin the special bolt that
> > > holds the arm on so I dropped the project. I just got a replacement
> > > bolt and decided to have another go. Upon closer inspection, it seems
> > > the play that is felt in the crank arm is not from damaged splines,
> > > but rather from the metal insert having come loose from the carbon arm
> > > such tha the arm can wiggle a bit while the metal insert is held fast
> > > by the bolt.

>
> > > I was willing to ride a bodged crankset with worn splines, but I am
> > > leery of trying something where it seems the crank arm is in the
> > > process of separating from it's mount. FSA's warranty is specifically
> > > just for the original purchaser (which I am not) so I'm looking for
> > > suggestions on how to resurrect this crank set. My bike is on a diet
> > > so I'd like to use this crankset to save a few grams, but I don't
> > > really want to spend any (much?) money on it as I got it for free and
> > > it will save at most 100g anyway.

>
> > > Joseph

>
> > do your homework on the construction. iirc, the fsa is simply a carbon
> > outer on a skinnied down aluminum crank arm. if that's the case, you
> > could inject resin into the gap between the two just to stop the loose
> > carbon rattling about.

>
> The play is considerably less than 1mm (difficult to see, but easy to
> feel) so there is no discernable gap to squirt anything into. The most
> disconcerting part is that the play is most apparent in a rotational
> direction. This leads me to think that the metal insert is just that,
> and insert, not a long arm of any sort, or perhaps worse, an arm which
> is broken.
>
> > but but but, you have to ask yourself, wtf are you bothering? it
> > shouldn't have failed in the first place. it could be that the internal
> > aluminum has cracked already and it's only the carbon holding it
> > together. to be sure, you'd have to x-ray, and the cost of that
> > outweighs new purchase.

>
> > bottom line, unless you know for sure what the problem is, you're
> > setting yourself up to pay for your dentists' kids college. if you're
> > cheap, you're much better advised to invest in a new, known good crank
> > like a shimano 105. the weight gain won't kill you and the reliability
> > will keep your dentist merely well remunerated as opposed to wealthy.
> > winning is about the guy, not the gear.

>
> I already have a nice Ultegra 6600 crankset on the bike. I'm only
> bothering because I can't bring myself to just throw away this nice
> shiny barely used crankset that weighs less than my current one when I
> am trying to lighten my bike.
>
> I know it's the guy, not the bike, but the guy (and the bike!) keeps
> getting dropped on hills, so losing weight on the guy and the bike
> helps. And if it's a free "upgrade" I'll take it. No way I'd spend
> money on a replacement crankset only to save a few grams. I may go for
> a Dura Ace 7800 but more because it is available in 180mm. But
> unfortunatley nobody has given me a free 7800 180mm crankset, but they
> have given me a damaged 175mm K-Force!
>

You stated that the crank is not under warranty since you are not the
original owner. Nevertheless, have you tried contacting the mfr (FSA)
to get their thoughts as to whether the crank is repairable? Perhaps
they could provide you with a "fix."

You may want to consider that even if you do figure out how to "fix"
your crank, the crank plus any repair may ending increasing the weight
of the crankset and weighing more than your 6600 crankset...
 
S

Sir Ridesalot

Guest
On Jul 13, 9:29 am, "[email protected]"
<[email protected]> wrote:
> Hi All,
>
> A few months ago I posted about ideas to bodge an FSA K-Force crankset
> that appeared to have damaged splines on the left crank arm. In
> attempting various bodges I managed to ruin the special bolt that
> holds the arm on so I dropped the project. I just got a replacement
> bolt and decided to have another go. Upon closer inspection, it seems
> the play that is felt in the crank arm is not from damaged splines,
> but rather from the metal insert having come loose from the carbon arm
> such tha the arm can wiggle a bit while the metal insert is held fast
> by the bolt.
>
> I was willing to ride a bodged crankset with worn splines, but I am
> leery of trying something where it seems the crank arm is in the
> process of separating from it's mount. FSA's warranty is specifically
> just for the original purchaser (which I am not) so I'm looking for
> suggestions on how to resurrect this crank set. My bike is on a diet
> so I'd like to use this crankset to save a few grams, but I don't
> really want to spend any (much?) money on it as I got it for free and
> it will save at most 100g anyway.
>
> Joseph



Hi there.

You might want to consider what can happen if that insert lets go
under a lot of pressure like when you are standing on the pedals going
up a hill or sprinting across a street. If this insert lets go you
could find yourself sprawled on the road. In traffic thtat could
result in a very run-down feeling. Is it really worth the risk?

Cheers from Peter
 
J

jim beam

Guest
[email protected] wrote:
> On Jul 13, 4:09 pm, jim beam <[email protected]> wrote:
>> [email protected] wrote:
>>> Hi All,
>>> A few months ago I posted about ideas to bodge an FSA K-Force crankset
>>> that appeared to have damaged splines on the left crank arm. In
>>> attempting various bodges I managed to ruin the special bolt that
>>> holds the arm on so I dropped the project. I just got a replacement
>>> bolt and decided to have another go. Upon closer inspection, it seems
>>> the play that is felt in the crank arm is not from damaged splines,
>>> but rather from the metal insert having come loose from the carbon arm
>>> such tha the arm can wiggle a bit while the metal insert is held fast
>>> by the bolt.
>>> I was willing to ride a bodged crankset with worn splines, but I am
>>> leery of trying something where it seems the crank arm is in the
>>> process of separating from it's mount. FSA's warranty is specifically
>>> just for the original purchaser (which I am not) so I'm looking for
>>> suggestions on how to resurrect this crank set. My bike is on a diet
>>> so I'd like to use this crankset to save a few grams, but I don't
>>> really want to spend any (much?) money on it as I got it for free and
>>> it will save at most 100g anyway.
>>> Joseph

>> do your homework on the construction. iirc, the fsa is simply a carbon
>> outer on a skinnied down aluminum crank arm. if that's the case, you
>> could inject resin into the gap between the two just to stop the loose
>> carbon rattling about.

>
> The play is considerably less than 1mm


i don't care if it's 1mm or 0.01mm! it shouldn't be there. and it will
get worse.

> (difficult to see, but easy to
> feel) so there is no discernable gap to squirt anything into. The most
> disconcerting part is that the play is most apparent in a rotational
> direction. This leads me to think that the metal insert is just that,
> and insert, not a long arm of any sort, or perhaps worse, an arm which
> is broken.
>
>> but but but, you have to ask yourself, wtf are you bothering? it
>> shouldn't have failed in the first place. it could be that the internal
>> aluminum has cracked already and it's only the carbon holding it
>> together. to be sure, you'd have to x-ray, and the cost of that
>> outweighs new purchase.
>>
>> bottom line, unless you know for sure what the problem is, you're
>> setting yourself up to pay for your dentists' kids college. if you're
>> cheap, you're much better advised to invest in a new, known good crank
>> like a shimano 105. the weight gain won't kill you and the reliability
>> will keep your dentist merely well remunerated as opposed to wealthy.
>> winning is about the guy, not the gear.

>
> I already have a nice Ultegra 6600 crankset on the bike. I'm only
> bothering because I can't bring myself to just throw away this nice
> shiny barely used crankset that weighs less than my current one when I
> am trying to lighten my bike.


how about if you knew it was planning on injuring you?

>
> I know it's the guy, not the bike, but the guy (and the bike!) keeps
> getting dropped on hills, so losing weight on the guy and the bike
> helps. And if it's a free "upgrade" I'll take it. No way I'd spend
> money on a replacement crankset only to save a few grams. I may go for
> a Dura Ace 7800 but more because it is available in 180mm. But
> unfortunatley nobody has given me a free 7800 180mm crankset, but they
> have given me a damaged 175mm K-Force!


eh? you'll ride 175 when it's free [but dangerous], but not if you pay
for it? that's illogical.

you go ahead and ride whatever you want. i'm 100% with sir ridesalot on
this one.
 
D

Donga

Guest
On Jul 14, 7:37 am, Sir Ridesalot <[email protected]> wrote:
>
> You might want to consider what can happen if that insert lets go
> under a lot of pressure like when you are standing on the pedals going
> up a hill or sprinting across a street. If this insert lets go you
> could find yourself sprawled on the road. In traffic thtat could
> result in a very run-down feeling. Is it really worth the risk?
>
> Cheers from Peter


I was wondering if there is a medical specialisation for burst
testicles.

Donga
 
On Jul 13, 11:37 pm, Sir Ridesalot <[email protected]> wrote:
> On Jul 13, 9:29 am, "[email protected]"
>
>
>
> <[email protected]> wrote:
> > Hi All,

>
> > A few months ago I posted about ideas to bodge an FSA K-Force crankset
> > that appeared to have damaged splines on the left crank arm. In
> > attempting various bodges I managed to ruin the special bolt that
> > holds the arm on so I dropped the project. I just got a replacement
> > bolt and decided to have another go. Upon closer inspection, it seems
> > the play that is felt in the crank arm is not from damaged splines,
> > but rather from the metal insert having come loose from the carbon arm
> > such tha the arm can wiggle a bit while the metal insert is held fast
> > by the bolt.

>
> > I was willing to ride a bodged crankset with worn splines, but I am
> > leery of trying something where it seems the crank arm is in the
> > process of separating from it's mount. FSA's warranty is specifically
> > just for the original purchaser (which I am not) so I'm looking for
> > suggestions on how to resurrect this crank set. My bike is on a diet
> > so I'd like to use this crankset to save a few grams, but I don't
> > really want to spend any (much?) money on it as I got it for free and
> > it will save at most 100g anyway.

>
> > Joseph

>
> Hi there.
>
> You might want to consider what can happen if that insert lets go
> under a lot of pressure like when you are standing on the pedals going
> up a hill or sprinting across a street. If this insert lets go you
> could find yourself sprawled on the road. In traffic thtat could
> result in a very run-down feeling. Is it really worth the risk?
>
> Cheers from Peter


Ideed not! That's why the damaged cranks are sitting on the shelf in
my shed.

Joseph
 
On Jul 14, 4:24 am, jim beam <[email protected]> wrote:
> [email protected] wrote:
> > On Jul 13, 4:09 pm, jim beam <[email protected]> wrote:
> >> [email protected] wrote:
> >>> Hi All,
> >>> A few months ago I posted about ideas to bodge an FSA K-Force crankset
> >>> that appeared to have damaged splines on the left crank arm. In
> >>> attempting various bodges I managed to ruin the special bolt that
> >>> holds the arm on so I dropped the project. I just got a replacement
> >>> bolt and decided to have another go. Upon closer inspection, it seems
> >>> the play that is felt in the crank arm is not from damaged splines,
> >>> but rather from the metal insert having come loose from the carbon arm
> >>> such tha the arm can wiggle a bit while the metal insert is held fast
> >>> by the bolt.
> >>> I was willing to ride a bodged crankset with worn splines, but I am
> >>> leery of trying something where it seems the crank arm is in the
> >>> process of separating from it's mount. FSA's warranty is specifically
> >>> just for the original purchaser (which I am not) so I'm looking for
> >>> suggestions on how to resurrect this crank set. My bike is on a diet
> >>> so I'd like to use this crankset to save a few grams, but I don't
> >>> really want to spend any (much?) money on it as I got it for free and
> >>> it will save at most 100g anyway.
> >>> Joseph
> >> do your homework on the construction. iirc, the fsa is simply a carbon
> >> outer on a skinnied down aluminum crank arm. if that's the case, you
> >> could inject resin into the gap between the two just to stop the loose
> >> carbon rattling about.

>
> > The play is considerably less than 1mm

>
> i don't care if it's 1mm or 0.01mm! it shouldn't be there. and it will
> get worse.
>
>
>
> > (difficult to see, but easy to
> > feel) so there is no discernable gap to squirt anything into. The most
> > disconcerting part is that the play is most apparent in a rotational
> > direction. This leads me to think that the metal insert is just that,
> > and insert, not a long arm of any sort, or perhaps worse, an arm which
> > is broken.

>
> >> but but but, you have to ask yourself, wtf are you bothering? it
> >> shouldn't have failed in the first place. it could be that the internal
> >> aluminum has cracked already and it's only the carbon holding it
> >> together. to be sure, you'd have to x-ray, and the cost of that
> >> outweighs new purchase.

>
> >> bottom line, unless you know for sure what the problem is, you're
> >> setting yourself up to pay for your dentists' kids college. if you're
> >> cheap, you're much better advised to invest in a new, known good crank
> >> like a shimano 105. the weight gain won't kill you and the reliability
> >> will keep your dentist merely well remunerated as opposed to wealthy.
> >> winning is about the guy, not the gear.

>
> > I already have a nice Ultegra 6600 crankset on the bike. I'm only
> > bothering because I can't bring myself to just throw away this nice
> > shiny barely used crankset that weighs less than my current one when I
> > am trying to lighten my bike.

>
> how about if you knew it was planning on injuring you?
>
>
>
> > I know it's the guy, not the bike, but the guy (and the bike!) keeps
> > getting dropped on hills, so losing weight on the guy and the bike
> > helps. And if it's a free "upgrade" I'll take it. No way I'd spend
> > money on a replacement crankset only to save a few grams. I may go for
> > a Dura Ace 7800 but more because it is available in 180mm. But
> > unfortunatley nobody has given me a free 7800 180mm crankset, but they
> > have given me a damaged 175mm K-Force!

>
> eh? you'll ride 175 when it's free [but dangerous], but not if you pay
> for it? that's illogical.


I meant that I would not pay money to change from my existing Ultegra
cranks (which I bought and I like) for any other same-sized cranks
just to save 100g. If the 100g weight reduction came for free I'd take
it, but in this case the 100g comes at the expense of risking a crash.
Obvioulsy not worth it. But if the crankset could be salvaged somehow
without adding lots of weight it may be worth it.

Joseph

> you go ahead and ride whatever you want. i'm 100% with sir ridesalot on
> this one.
 
P

Phil

Guest
> Upon closer inspection, it seems
> the play that is felt in the crank arm is not from damaged splines,
> but rather from the metal insert having come loose from the carbon arm
> such tha the arm can wiggle a bit while the metal insert is held fast
> by the bolt.


Not uncommon. We were sending FSA cranksets back (many carbon, some
aluminum) at a rate of once a week last year.

--
Phil