On 10/8/2019 9:08 PM, jbeattie wrote:
On Tuesday, October 8, 2019 at 4:16:36 PM UTC-7, John B. wrote:
On Tue, 8 Oct 2019 14:28:04 -0700 (PDT), Tom Kunich
wrote:

On Monday, October 7, 2019 at 10:41:59 AM UTC-7, jbeattie wrote:
On Monday, October 7, 2019 at 9:51:24 AM UTC-7, Tom Kunich wrote:
On Sunday, October 6, 2019 at 2:55:01 PM UTC-7, jbeattie wrote:
On Sunday, October 6, 2019 at 2:12:41 PM UTC-7, Tom Kunich wrote:
On Sunday, October 6, 2019 at 1:54:47 PM UTC-7, jbeattie wrote:
On Sunday, October 6, 2019 at 10:51:40 AM UTC-7, Tom Kunich wrote:
On Wednesday, October 2, 2019 at 10:31:32 AM UTC-7, jbeattie wrote:
On Wednesday, October 2, 2019 at 8:37:07 AM UTC-7, Tom Kunich wrote:
On Tuesday, October 1, 2019 at 6:18:01 PM UTC-7, jbeattie wrote:
On Tuesday, October 1, 2019 at 4:53:53 PM UTC-7, John B. wrote:
On Tue, 1 Oct 2019 15:26:40 -0700 (PDT), Tom Kunich
wrote:

I've been using FSA 10 speed Gossamer (aluminum) cranks. I have never had any troubles with them except wearing out the rings. The latest ones are really good - they have a 30 mm shaft and the bolt pattern is 110 mm so that you can use 53/39, 52/36 or 50/34 ring sets.

I bought a set of the carbon fiber cranks but that was quite a time ago. They were barely lighter than the aluminum cranks and at two or three times the cost.

Now they are also making the new 4 arm cranks that weigh the same as the old carbon cranks did.

Andrew and someone else here having a discussion about always using the recommended torque to tighten the locking bolts and rather than use my usual "by feel" method I used the torque wrench and rode it that way.

The locking bolt is on the left side and it uses a normal right-hand thread. Well, the recommended torque allows the left arm to move slightly. And this worked the right-hand thread off of the crank and today on the last hill into Moraga the left crank arm came off with my cleat still locked into the pedal. I walked it the rest of the way to the top of that hill and tried to re-attach the crank arm. Turns out that I had one of those one piece all-purpose tools that had one Allen large enough to get the crank screw started and about 2/3rds of the way in. Of course, it took me 20 minutes of messing about to get the thread started and to screw it in as far as I could with the wrong size Allen. That allowed me to go into town to the Ace Hardware and they had a box of "borrow" metric Allens that had one the correct size to tighten the crank nut my way.

Next time I'll know better than to use a torque wrench on an aluminum part. I had the same trouble with an aluminum on aluminum seatpost/seattube. I'll go back to my normal "as tight as it feels it should be".

See:
http://www.fullspeedahead.com/en/sup...-recall-notice

FSA: "Failure Shortly Ahead" The stems are O.K. The pedal inserts on my CF crank cracked along with the adjacent crank arm. The wheels were terrible -- the spokes kept going slack. And, BTW, with aluminum, you really need to follow torque specs.

-- Jay Beattie.

I guess you can't read. I don't know about the FSA carbon cranks since I see no reports of them breaking. An example of one is meaningless.

I guess you can't read the recall notice posted by JB. https://cpsc.gov/Recalls/2011/Full-S...o-Crash-Hazard Does that problem sound familiar?

Also, on a BB30 crank, looseness (lateral movement) means you need another shim and not that you have to wrench like a gorilla on the crank-arm fixing bolt. I would think with your massive brain, you would have known that -- and that you would know to follow manufacturer's torque specs.

-- Jay Beattie.

The blue Loctite seems to have cured the problem. Though the stuff over-the-counter is not like the putty-like blue stuff that is applied at the factory. By all means you can follow the manufacturers torque suggestions and I will do it my way.

You've probably munged the interface, and it will loosen again. IMO, you shouldn't have to use Loctite or any other kind of glue on a crank retaining bolt. If Loctite is needed, FSA should spec a steel bolt and a higher torque spec.

-- Jay Beattie.

You don't think I should use Loctite but the crank screw is on the left hand side of the crank and is normal right-hand threads meaning it cannot be held tight without Loctite and with which the new cranksets come already applied?

Jay - where are you coming from?

Where are you coming from? The right/left hand thread issue has to do with bearing precession and is a design consideration for bottom brackets not crank/axle interfaces. The last time I checked, there are no bearings in the crank/axle interface. Ordinary right-hand thread has been used on BOTH SIDES of cotterless cranks since forever -- without Loctite.

-- Jay Beattie.

Jay,

On a connection such as the cranks with a built in shaft, the cranks themselves move. Even the Campy cranks.

The rotational direction of the BB bearing is only pertinent to the cups themselves coming off. This is what caused the change from Italian threaded cups to push-in bearings. The chain-side cups would work off without a lot of torqueing of the cup. But the bottom bracket area is strongly reinforced and capable of taking a LOT of torque And Italian threads themselves are constructed different from English threads and have more surface area and hence rotational resistance.

Any motion of the cranks causes the left side clockwise threads to work their way off unless they are locked into place with either torque (which isn't possible because the light build of the cranks don't allow sufficient strength in the connection to forbid motion) or using Loctite.

Campy solves the problem with a slightly different construction so that they can put the standard clockwise thread on the opposite (chain) side of the crank which causes the connecting shaft motion to contra-rotate the screw so that it tightens rather than the FSA method which loosens.

While I prefer Campy cranks, the latest FSA aluminum cranks are nearly the same weight as the last generation of Campy carbon cranks and they cost less than 25% the cost of the Campy.

Seems sort of a no-brainer to me.

Seems like a no-brainer to me, too. Consider this: back in the day, did your Campy dust-caps unscrew? Were your crank bolts unscrewing? No. On square drive cranks, bolts loosened as the cranks crept up the tapers and not because of the direction of rotation. If you were right, why did the industry use right hand thread on both sides? They figured it out with pedals and BBs, at least in England. Why would FSA use right-hand thread on your crank retaining bolt? If they are so stupid not to see what you see so plainly, why buy their product? BTW, after falling off, the axle/crank interface on your FSA is probably so battered that it will never stay tight, even with Loctite. You should get in there and reshape the profiles.

-- Jay Beattie.

After the Loctite and a hard ride no problems. I took the correct size Allen along JIC. Though I'm pushing so hard that the cleats on my Sidi's are making noise and I have to tighten them.


Tom, have you ever thought that you must be using a crank made by the
most ignorant people on the planet? After all they fail unless they
are over torqued and thread locker applied and apparently the company
just keeps on churning them out even though they fall apart in use.

If you hunt around on the internet, there are second-hand reports that FSA was having problems with bolt loosening and did recommend Locktite, but they also had a recall for the same reason, so first off, TK should check to see if his crank has been recalled.

Frank and Andrew can check me on this, but the reason the bolts back out has nothing to do with the direction of the crank rotation but rather has to do with the application of any force to the crank and the resulting deflection at the crank/BB axle interface -- or a defective and recalled retaining bolt. Even with a non-defective bolt, the crank/BB axle connection is apparently too limber -- and probably more so after the crank fell off a couple of times. The splines are probably munged up. The splines are big on the FSA, so you can probably clean them up and get them to work.

I'm not familiar with FSA cranks, but the loosening mechanism you
describe sounds plausible to me. I heartily agree about checking recall
status of Tom's cranks.

I wouldn't be optimistic about cleaning up any damaged splines. To me it
sounds finicky and unlikely to succeed.


--
- Frank Krygowski