FSA K-Force MeaExo Crank Problem

Sir Topham Hatt said:

The LH Crank bolt seems to loosen up a bit after a ride. Any idea
why this is happening?

thxs

Not torqued to required specifications?

Sir Topham Hatt said:

The LH Crank bolt seems to loosen up a bit after a ride. Any idea
why this is happening?

It's not tight enough.

Bill "well, you asked" S.

I did not use a torque wrech, but I did torque it to a point, that i felt was
safe. I'm a litle paranodi when torquing carbon fiber components.
After listening to my feeble explanation, I guess I should just invest in a
torque wrench. :-(

Dave Thompson said:

Sir Topham Hatt said:

The LH Crank bolt seems to loosen up a bit after a ride. Any idea
why this is happening?

thxs

Not torqued to required specifications?

Sir Topham Hatt said:

The LH Crank bolt seems to loosen up a bit after a ride. Any idea why this is
happening?

thxs

Actually, that is normal. It happens to me too.

Jobst Brandt wrote about it. His explination is at:
sheldonbrown.cominstalling cranks.htmlOpen ↗

I found that if I use a torque wrench to tighten them, the bolts do not loosen enough to unscrew. If I use an ordinary, L shaped 8mm wrench, it is not long enough for me to apply enough torque, and the screws, especially the left one will get quite loose.

Also, when I install the crank, I grease the square tapers of my bb axel and the drive side always returns to the same place, so I never have to adjust the fdr. That is with the Campy, Shimano and Sugino cranks I own.

Steve S.

Steve Shapiro said:

Sir Topham Hatt said:

The LH Crank bolt seems to loosen up a bit after a ride. Any idea
why this is
happening?

thxs

Actually, that is normal. It happens to me too.

Not quite. This is a 2-piece crankset with an external bottom bracket. It
works much like a headset, the left-hand crank pinching down on the
right-hand crank, both pulled together with a top-cap-like cover where the
left-hand-crank bolt normally goes. These shouldn't loosen up.

--
Phil, Squid-in-Training

quote='Phil said:

Sir Topham Hatt said:

The LH Crank bolt seems to loosen up a bit after a ride. Any idea
why this is
happening?

thxs

Actually, that is normal. It happens to me too.

Not quite. This is a 2-piece crankset with an external bottom bracket. It
works much like a headset, the left-hand crank pinching down on the
right-hand crank, both pulled together with a top-cap-like cover where the
left-hand-crank bolt normally goes. These shouldn't loosen up.

--
Phil, Squid-in-Training[/QUOTE]

Mea culpa for not keeping up with FSA's products. So, I looked. It seems like there are 2 Mega Exo designs.
fullspeedahead.comMegaExo%20BB%20Installation%20final%20040820.pdfOpen ↗
One with the left arm slotted and having a bolt to pinch it to the axle. It should not loosen in use. The other design, with a conventional looking, but large bolt that screws through the arm into the axle. If those splines are tapered, then my comments apply. If no taper, then the OP just is not getting it tight enough to start with. I agree it should not work lose. In any case, if the arm gets floppy during a ride, it's toast. So, the torque wrench sounds like a good investment.

Steve S.

Got this message back FSA ...

<quote>
Sorry to hear about your troubles. I think I know what's going on
here. It recently came to our attention that the first batch of
K-Force cranksets that were produced had an improper tolerance on the
spline, causing them to work their way loose. Sounds like you very
well may have one of the offending cranksets.
</quote>

Let also add that FSA, by far, has the most competent and responsive customer
service organizations I have ever dealt with!

Steve,
I got an offical response from FSA on what could be the problem.

At first, I did not have a torque wrech, just used a L-Shaped 8mm hex key to
torque down the arm. Even when torqued to the proper specs, via my new torque
wrench, it did loosen somewhat, so pehaps I have the batch of the crank arms
with the tolearance issue.

The crank was not toast after it worked itself loose. The splines still looked
good.

FSA is standing behind their products and have issued me a RA number for
replacement.

Steve Shapiro said:

Phil said:

Steve Shapiro said:

Sir Topham Hatt Wrote:
> The LH Crank bolt seems to loosen up a bit after a ride. Any idea
> why this is
> happening?
>
> thxs

Actually, that is normal. It happens to me too.

Not quite. This is a 2-piece crankset with an external bottom bracket.
It
works much like a headset, the left-hand crank pinching down on the
right-hand crank, both pulled together with a top-cap-like cover where
the
left-hand-crank bolt normally goes. These shouldn't loosen up.

--
Phil, Squid-in-Training

Mea culpa for not keeping up with FSA's products. So, I looked. It
seems like there are 2 Mega Exo designs.
http://www.fullspeedahead.com/downloads/MegaExo%20BB%20Installation%20final%20040820.pdf
One with the left arm slotted and having a bolt to pinch it to the
axle. It should not loosen in use. The other design, with a
conventional looking, but large bolt that screws through the arm into
the axle. If those splines are tapered, then my comments apply. If no
taper, then the OP just is not getting it tight enough to start with. I
agree it should not work lose. In any case, if the arm gets floppy
during a ride, it's toast. So, the torque wrench sounds like a good
investment.

Steve S.

"Dave Thompson" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Sir Topham Hatt said:

The LH Crank bolt seems to loosen up a bit after a ride. Any idea
why this is happening?

thxs

Not torqued to required specifications?

How do you torque the external bearing cups for this bottom bracket?

I don't own this crankset/bb but the question I have applies both to my
crankset, Shimano Ultegra (6600) 10 speed, and the FSA K-Force Mego Exo and
several other "Shimano Hollowtech II" style external BB's. My new bike came
with the non-drive side external bearing cup loose. I took the crankset/bb
apart and reassembled it trying to follow the manufacturer's instructions.

The instructions list a torque spec for tightening the external bearing cups
to the frame. These bearing cups require something like the Park Tool BBT-9
(http://tinyurl.com/7c2fz), that is a wrench, not something like a socket
that I can put on a torque wrench. I mounted my torque wrench in a vise and
pulled on it get the feel for specified torque. I then tried to apply about
the same force to the Park Tool BBT-9 wrench. Obviously this was not very
accurate. The Shimano tool for this purpose, TL-FC32
(http://tinyurl.com/dlvwl), also looks like a wrench rather than something
that will fit on a torque wrench. Same for the Spin Doctor integrated
bottom bracket tool from Performance, http://tinyurl.com/colgd. Ditto for
Pedro's version, http://tinyurl.com/e47wt.

Does anyone know of a "socket" that will fit on a torque wrench and fit on
Shimano HollowTech II style external bearing cups?

BobT

Sir Topham Hatt said:

Got this message back FSA ...

<quote>
Sorry to hear about your troubles. I think I know what's going on
here. It recently came to our attention that the first batch of
K-Force cranksets that were produced had an improper tolerance on the
spline, causing them to work their way loose. Sounds like you very
well may have one of the offending cranksets.
</quote>

Let also add that FSA, by far, has the most competent and responsive
customer service organizations I have ever dealt with!

Great, glad to hear it was resolved successfully.

[quote="Sir Topham Hatt"]Steve,
I got an offical response from FSA on what could be the problem.

At first, I did not have a torque wrech, just used a L-Shaped 8mm hex key to
torque down the arm. Even when torqued to the proper specs, via my new torque
wrench, it did loosen somewhat, so pehaps I have the batch of the crank arms
with the tolearance issue.

The crank was not toast after it worked itself loose. The splines still looked
good.


FSA is standing behind their products and have issued me a RA number for
replacement.


I'm glad to hear that FSA is standing behind it. Most bike parts work fine. Some work fine and are beautiful too. I think your crank falls into the latter category. I hope it gives you enjoyment for many miles.

Steve