Octalink 1 left crank keeps loosening

[silva]

How did the step manage to hit you?

I said that, young guy, rode fast forward between buildings, with his head down looking at some computer or so mounted in the middle of his handlebars. He was 2 seconds away, I gave a yell but time too short for him to brake and I could do nothing, not enough space, not enough time. I went around a corner intended to turn left, he came from the left, and slammed in my middle before I could turn. My bike and me were thrown to the right. An hour later my right pedal fell apart, and when I was replacing it, I noticed play on the left crank, being this story that apparently restarted, and is apparently again solved by trying to tension further a number of times, spreaded over a couple days.

 

[Ajax Bay]

Pedal spanner; not some weedy allen key; for the torque.

 

[silva]

The crank is an allen key big cross section, have to check what size it is.
The pedal is a 15, I keep a couple such flat keys in my tools bags and a couple spare pedals.
Because I try to live as cheap as I can (have to save for an own house that keeps increasing in price) and use parts nearly till failure so chance is along the road and then the tools and spares come in.
I keep two keys with me, because pedals can be very hard to loose, then I put 2 keys on it, and press both, to spread force and avoid tool screwed up before pedal loose.
Some pedals have to small space for that. I had one that I even couldn't tension normally because the standard 15 too thick already. Lol at the crap parts these days. I removed that kind from my stock pedals because it's too easy to overlook, never expected such a problem. A luck I discovered this problem at home

 

[keithmac]

If it had been tightened up properly with proper tools from the word go it might have had half a chance.

My crank specifies 50nm and there's no way I'd get near that will a normal allen key.

Torque wrench and Allen socket for that one..

 

[silva]

The dealer mounted the crankset, so I'd assume done like that.
It losened.
Dealer removed the crank, put it back on, tensioned it with that big allen key, again I'd assume tensioned like it should.
It losened again.
I tensioned it with a small allen key, repeatedly, upon every occasion along the road, during the first half dozen times I could turn abit, then not anymore. The crank ceased to lose, no further tensioning possible, and after a half dozen last attempts, I ceased trying and it stayed fixed.
Despite I did it with such a small key, and the dealer with a huge one.
That's just how it was and apparently now again.
The crank started losening again after that hit by the step.
A half dozen further tensionings / retensionings possible during the first 2-3 days.
And since, not anymore.
So the crank now stays fixed, despite my small allen key.
Apparently, further retensioning a certain amount times, works (the crank stays fixed for many months / forever?), and a single tensioning by a big key, done according to the specs, apparently not (crank starts losening after some weeks)..
That's just how it was.
.

 

[Titanium]

It might be useful to check on ebay for a replacement part (the crank, that is). Every few days do a search for an identical part; hopefully one will pop up sooner or later.

 

[Cycleops]

It might be useful to check on ebay for a replacement part (the crank, that is). Every few days do a search for an identical part; hopefully one will pop up sooner or later.

The only problem being it might have suffered the same fate as the existing, you can't tell just by looking, which you can't do anyway.
As said the OP is better off switching to ST or Hollowtech.

 

[fossyant]

The only problem being it might have suffered the same fate as the existing, you can't tell just by looking, which you can't do anyway.
As said the OP is better off switching to ST or Hollowtech.

He won't listen.

 

[silva]

Said here before: I asked the dealer for hollowtech 2 crankset, because my previous bike didn't have a chain tension variation, but dealer said my bicycle / bottom bracket (with the eccenter) doesn't have dimensions ht2 requires and mounted an octalink 1 instead.
Today I checked a last time if I could tension it further, no, so I will now cease to check, the problem apparently disappeared using that same repeated tensionings technique as before.
One thing learnt now: if the crank gets a bump from something (now it was a hit by a step, but a pedal strike might cause it too), check the tension.

 

[Ming the Merciless]

but dealer said my bicycle / bottom bracket (with the eccenter) doesn't have dimensions ht2 requires and mounted an octalink 1 instead.

Which you agreed to, yes?

 

[classic33]

Said here before: I asked the dealer for hollowtech 2 crankset, because my previous bike didn't have a chain tension variation, but dealer said my bicycle / bottom bracket (with the eccenter) doesn't have dimensions ht2 requires and mounted an octalink 1 instead.
Today I checked a last time if I could tension it further, no, so I will now cease to check, the problem apparently disappeared using that same repeated tensionings technique as before.
One thing learnt now: if the crank gets a bump from something (now it was a hit by a step, but a pedal strike might cause it too), check the tension.

If a piece on any bike I was riding kept on coming loose on a regular basis as this piece is on yours, I'd be changing it. Not moaning about how it keeps on coming loose.

If I were unable to replace, I'd be using something, threadlock maybe, to minimise the chance of it working loose. Until I could get it changed.

Suppose it comes loose whilst you're riding on the road, what then?

 

[fossyant]

Could be square taper instead, because Octalink is a cartridge BB. Square taper is more reliable than most BB's in terms of longevity.

Get rid of the Octalink and get a square taper BB and crankset. £100 - £150 max.

 

[silva]

Which you agreed to, yes?

All I was told was that HT2 wasn't an option.
When he brought the bike home, he said he gave a price me reduction because the crankset was a secondhand one. That was for me news too.
Later on I checked the price and I found cheaper new ones for sale.
What I agreed to was that he replaced my crankset, since broken.
I saw an opportunity / chance to maybe solve the chain tension variation by chosing a crank type that I had earlier and that didn't show such a chain tension variation.
So agree yes, to a octalink 1 no and to a second hand one also no.
For what it matters, since if I had specifically agreed, it would have been without having been told how prone that thing was to losening left crank.

 

[silva]

If a piece on any bike I was riding kept on coming loose on a regular basis as this piece is on yours, I'd be changing it. Not moaning about how it keeps on coming loose.

If I were unable to replace, I'd be using something, threadlock maybe, to minimise the chance of it working loose. Until I could get it changed.

Suppose it comes loose whilst you're riding on the road, what then?

Well it did came loose while riding on the road, 2 times. Meaning: the crank hung vertical.
Just like that. Because I was surprised, the very first time (didn't touch it before) and the second time after the dealer tensioned it with his big key. I thought that solved it but some weeks or month later, bingo again.
The other losening occasions were when checking the tension. See, if a crank came lose twice, a person that cares starts to check in order to prevent it (by tensioning again). I cared of course, and I did so.
So no accidents or so happened, it's not that the crank broke eh, I felt it moving in a weird fashion and slowing down goes by itself then heh.

 

[fossyant]

Are you going to get a square taper then ? Otherwise you'll be constantly adjusting the Octalink.