FSA Crankset Issues
#1
Senior Member
Thread Starter
FSA Crankset Issues
I am having some issues with the SLK front crankset.
Initially it was fine and quiet.
Recently is has been noisy.
When pushing hard while seated it makes a knocking sound, like marbles.
When standing it makes a loud creaking noise.
When I installed it I used a torque wrench so I don't think any thing is loose.
It could be the eccentric, I have not taken things apart to investigate yet.
I know FSA isn't known for being super reliable so it could the bearing is already failing.
Another issue is the crank spacing. Since this bike has a 145mm rear wheel vs. 160mm on our Santana I thought the cranks would be closer together. I measured them and compared to my road bike they are 20mm further apart which would be about what the Santana was. I am finding it feels awkward and may be aggravating some knee pain.
For some reason it never was a problem on the Santana. I am thinking about replacing the FSA crankset with a standard Ultegra installed backwards with Helicoils to reverse the pedal threads. This was an idea I had when building the bike but opted to go with FSA so I would have a perfect chain line. But now i think my knee comfort is more important than the chain line. My understanding is that the timing chain can have lots of offset without it being a problem since it is much longer than the rear which of course works with plenty of offset.
Initially it was fine and quiet.
Recently is has been noisy.
When pushing hard while seated it makes a knocking sound, like marbles.
When standing it makes a loud creaking noise.
When I installed it I used a torque wrench so I don't think any thing is loose.
It could be the eccentric, I have not taken things apart to investigate yet.
I know FSA isn't known for being super reliable so it could the bearing is already failing.
Another issue is the crank spacing. Since this bike has a 145mm rear wheel vs. 160mm on our Santana I thought the cranks would be closer together. I measured them and compared to my road bike they are 20mm further apart which would be about what the Santana was. I am finding it feels awkward and may be aggravating some knee pain.
For some reason it never was a problem on the Santana. I am thinking about replacing the FSA crankset with a standard Ultegra installed backwards with Helicoils to reverse the pedal threads. This was an idea I had when building the bike but opted to go with FSA so I would have a perfect chain line. But now i think my knee comfort is more important than the chain line. My understanding is that the timing chain can have lots of offset without it being a problem since it is much longer than the rear which of course works with plenty of offset.
#2
Senior Member
I had a Santana and the crank spacing was about 20 mm wider than my Co-Motion. Like you, my knees notice the wider spacing. Teflon tape on the bottom bracket threads will sometimes stop the creaking of the bottom bracket.
#3
Senior Member
Thread Starter
Is your Co-Motion standard road crank spacing?
#5
Senior Member
Thread Starter
I just made some measurements and it turns out that the chain line would be perfect by mounting the 40T chainring on the outside of the Ultegra cranks.
The FSA cranks have to 40T ring on the inside.
I think I am going with the Ultegra's.
The FSA cranks have to 40T ring on the inside.
I think I am going with the Ultegra's.
#6
Senior Member
#7
Likes to Ride Far
Use some loctite on the BB threads when installing, this should prevent it from creaking. However, as you said, it could also be coming from the interface between the eccentric and the frame.
#8
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Another issue is the crank spacing. Since this bike has a 145mm rear wheel vs. 160mm on our Santana I thought the cranks would be closer together. I measured them and compared to my road bike they are 20mm further apart... I am thinking about replacing the FSA crankset with a standard Ultegra installed backwards with Helicoils to reverse the pedal threads....My understanding is that the timing chain can have lots of offset without it being a problem since it is much longer than the rear which of course works with plenty of offset.
Originally Posted by Sheldon Brown
Q Factor/Tread: The lateral distance between the pedal attachment points on a crankset. For most cyclists, the narrower the tread the better....
#9
Senior Member
Thread Starter
[QUOTE=Ritterview;10848948]By crank spacing you are referring to the Q factor?
Yes (aka Tread) , It's 164 on the FSA SLK tandem and 147 on the Ultegra.
Yes (aka Tread) , It's 164 on the FSA SLK tandem and 147 on the Ultegra.
#10
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I pur an FSA SL-K crankset (spindle attached to spider) on our new tantem and we both noticed the wider Q factor right away. The spindle comes in one length and you make up the difference with the spacers so no matter what your bottom bracket width or rear spacing is you get the wide Q. The wider Q hasn't caused me any problems but my stoker is having knee pain when we ride the tandem. A new crankset will be costly but it's not worth risking knee injury.
#11
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The Cyfac used by the French racing team has a square taper Stronglight Impact Tandem crankset. These are really inexpensive. I don't know the Q-factor, but sans external bearings it might be favorable. The weight is 1350 grams, figure 400 grams for two bottom brackets, and at 1750 grams your roughly on par with the FSA. A review of sorts on the triple version here. If this solved your crankset and Q-factor issues for less than $200 would be a nice resolution.
_________________________________________________________________edit.
Upon further review, the Stronglight is not the answer to your Q-factor woes. It is 168 mm.
Last edited by Ritterview; 05-24-10 at 11:27 PM.
#12
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FSA says to use Loctite 641 on the spindle itself. However, I've never been able to find the stuff locally. Here's a web link. https://www.shoplet.com/Loctite-641-R...S44228802/spdv
I have used Loctite blue (242) on the threads of the bolt, and it seems to help.
The inherent problem in the FSA design is that one bolt tightens the crank, as well as setting the preload on the bearings.
The shimano approach of one bolt to set pre load, and another two to hold the crank arm in place is a much better design IMHO.
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You could get lost and die.
You could hit a tree and die.
OR YOU COULD STAY HOME AND FALL OFF THE COUCH AND DIE.
#13
Senior Member
Thread Starter
I think I can get an Ultegra crankset for around $100 - $150 and then $50 to helicoil both arms, so similar in cost to the Stronglights
#14
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Go for the reversed Ultegra. I have done the same thing with an older DuraAce crank on the front of our tandem. Didn't use helicoils, just (with the help of a mill to keep everything square) put new, reversed threads right over the original. It has served me well for several years -- but I'm only ~150 lbs, so YMMV.