FSA K-force Mega Exo compact crank

Fat Head

Does anyone have any experience of these cranks?

I have heard that they can be problematic, with the non-drive side crank coming loose and shredding the bottom bracket splines.

Was wondering as there is a good deal on them from the continent

turbo_tim-2

Fat Head wrote:

Does anyone have any experience of these cranks?

I have heard that they can be problematic, with the non-drive side crank coming loose and shredding the bottom bracket splines.

Was wondering as there is a good deal on them from the continent

I use the very simalar FSA SLK Mega Exo (same apart from rings, i think) chainset on my best bike. I was very careful on assembly to do everything right, so made sure BB shell was clean and sqaure, torqued up the cups, used the spacing washers as instructed. I too have heard of the LH crank coming loose, so I assembled that side with Loctite Threadlock on the central fixing bolt.

Done about 2000 miles and never had a problem of any description.

Fat Head

Thanks mate. Sounds like a job for the LBS who will be instructed to apply some Loctite!

regards

Brian B

Not had the above problems with mine but did have A LOT of creaking in the first few months and it was checked and put back together again and it still creaked. Ok now though but others have had the creaking problem.

IanTrcp

I have the compact setup on one of my bikes, and the triple on the other. I've never had any problems with either so would feel quite confident in saying that they're fine.

Fat Head

Brian B wrote:

Not had the above problems with mine but did have A LOT of creaking in the first few months and it was checked and put back together again and it still creaked. Ok now though but others have had the creaking problem.

thanks brian, did you use loctite threadlock also?

Brian B

Yes and have had no probs since - that was over a year ago.

Steve I

I've got the FSA Gossamer Mega EXO triple on my cross bike. The non drive side crank has just started to creak after 1500 miles of use. I know it's the left crank from single leg pedalling. I've only checked the bolts so far for tightness and they seem ok, looks like I need to take a further look.

rustychisel

Gossamer is a different system Steve. They use opposing pinch bolts on the non-drive crank whereas SLK and K-Force use a captive bolt to force the splined crank onto the oversize axle, applying sideload to the bearings.

Mine (SLK compact) creak a bit but have been no trouble whatsoever in about 18 months of riding, which I suggest is down to good installation technique (mine). IMO locktite is not needed, but others may disagree. Use the recommended torque rates. My only issue was with the teflon coated push washer (between the non-drive crank and the bearing shell) which rapidly became stripped of its 'tef'. It doesn't seem to matter much.

John Stevenson

rustychisel wrote:

Use the recommended torque rates.

Amen, for all two-piece cranks that don't have pinch bolts (and even those that do!)

I had another maker's crank that uses a similar single-bolt mounting of the LH crank. After a couple hundred kilometres, it fell off.

I actually read the instructions and got out the torque wrench when I fitted the replacement, and was rather surprised to find that for me, the recommended torque was close to the maximum I could exert with a Park torque wrench. Okay, I'm a wimp, but this felt like a lot more torque than used to be needed for square taper cranks.

Moral of story: RTFM.

Good job I don't claim to be a bike tech journalist very much these days

rustychisel

Ah well... yes, the recommended settings are very high, you're not the only one to strain.

80nM is a bucketfull of grunt (or should that be 30 Odd Foot Of Grunt?)

John Stevenson

rustychisel wrote:

Ah well... yes, the recommended settings are very high, you're not the only one to strain.

80nM is a bucketfull of grunt (or should that be 30 Odd Foot Of Grunt?)

Does seem like a bit of a design flaw to me. Home mechanics are likely not to realise just how much grunt you need.

Nobody needs 30 Odd Foot Of Grunt though

BTW, where in Australia are you, rustychisel?

rustychisel

I be in Adelaide. [fails to think of significant witticism this time around].