Shimano Recalled cranks

[bigbill]

My 8000 and 6800 cranks came back as okay. I checked the bolts with my torque wrench at 12 Nm and had no movement, good to go.

[windsurfer]

Originally Posted by bicycletricycle

Correct, Torque wrenches on bicycles are for weird fragile parts.

Which includes everything carbon or titanium plus the stem/handlebars/steerer tube.

[skouri1]

I know they have threadlocker. I have had trouble getting some old rings off. Like I thought the cranks were goners. Since then, I apply grease (though I use the bolts that thread together with two allen keys on opposite ends). Torque to 12, no problems. You should not be able to move by hand though. Not rideable if they are at that level. Also, there are only some people I trust to tighten bolts by feel. I dont even trust myself.

[benb]

Originally Posted by Mark McM

Cranks are subject to high magnitude fully reversed loading, so all crank bolts need to be tightened to the appropriate torque, and that is best done with a torque wrench. This includes square taper, Octa-link, Isis, HollowTech II, GXP, BB30/BB86, Dub, etc. A home mechanic might be able to get away with not using a torque wrench (at least some of the time), but any professional mechanic worth their salt will use a torque wrench.

When someone says they have never had issues with the big items you are mentioning (BB, Crank, Rings, Cassette) and torque wrenches are only for the delicate things they are just telegraphing how hard they ride or that they're a smaller rider.

IME you ride hard, any one of those things will quickly become a problem if it was not done 100% correctly.

As long as you don't break the delicate things they are not likely to come loose.

[wyatt_]

Originally Posted by benb

When someone says they have never had issues with the big items you are mentioning (BB, Crank, Rings, Cassette) and torque wrenches are only for the delicate things they are just telegraphing how hard they ride or that they're a smaller rider.

IME you ride hard, any one of those things will quickly become a problem if it was not done 100% correctly.

As long as you don't break the delicate things they are not likely to come loose.

lol

This is a bit much. Torque wrenches can be great tools and definitely help inspire confidence that you're getting it exactly right with a nice part, but many, many great bike parts are made to be wrenched on without that level of confirmed precision.

The idea that you need to torque wrench each part of the drivetrain if you're riding hard is just kind of silly.

To name one data point: I'm 200+ lbs and rode a fully loaded tour from Florida to California without touching the bike that I built for that tour once with a torque wrench.

That said, I always torque wrench the seat post clamp on carbon frames, because cracking a frame like that seems exactly like the dumb mistake I would make.

[AngryScientist]

Well old Ben has me there.

I certainly dont ride "hard", and I'm not too big.

Additionally, I can't think of one thing in life I do 100% correctly. I'm happy cruising along in the 90% range.

[benb]

Originally Posted by wyatt_

lol

To name one data point: I'm 200+ lbs and rode a fully loaded tour from Florida to California without touching the bike that I built for that tour once with a torque wrench.

You think you ride that type of ride the same way you behave in a fast group ride or racing, or intervals or sprint workouts?

I have never ever had a problem in that kind of application either. On a heavily loaded bike I do not go stomping on the pedals or riding up hills in the big ring standing. I do everything as smoothly as possible to avoid getting hurt and to conserve energy.

You do something like shift into a tall gear in the big ring and start a sprint effort at low RPM you get huge spikes of force through the drivetrain that you don't get when you try and ride smoothly.

Different types of riding.

FWIW I never said Shimano rings give trouble regularly. Every Shimano crank I bought new at Retail or came brand new on a bike seems to have the rings torqued perfectly from brand new and never gave any trouble.

[old fat man]

Did you have noise and reason to believe your cranks were failing? Or did you show up hoping your perfectly torqued equipment that never gives you problems would be warrantied with a spiffy new set of crankarms?

Sounds like you went looking for a problem and ended up with one, though not the one you hoped to find.

[unterhausen]

If you don't use a torque wrench on one of the Shimano cranks with the two cinch bolts on the NDS arm, it's likely to come loose. Found that out the hard way, and seen others do it too. This kind of thing often happens to me when I'm wrenching while not feeling well; throws off my internal calibration.

[wyatt_]

Originally Posted by benb

You think you ride that type of ride the same way you behave in a fast group ride or racing, or intervals or sprint workouts?

I have never ever had a problem in that kind of application either. On a heavily loaded bike I do not go stomping on the pedals or riding up hills in the big ring standing. I do everything as smoothly as possible to avoid getting hurt and to conserve energy.

You do something like shift into a tall gear in the big ring and start a sprint effort at low RPM you get huge spikes of force through the drivetrain that you don't get when you try and ride smoothly.

Different types of riding.

FWIW I never said Shimano rings give trouble regularly. Every Shimano crank I bought new at Retail or came brand new on a bike seems to have the rings torqued perfectly from brand new and never gave any trouble.

Sure, I can see your point in that they're definitely different types of riding.

That said, I don't really see how throwing down sprint watts in the big ring on a group ride could really be harder on a drivetrain than climbing a mountain pass with fifty pounds of extra gear pulling against the bike in every direction?

But if a torque wrench is what keeps your drivetrain happy, no reason for me to disagree with what works for you.

[GregL]

Very slight tangent: a torque wrench definitely should be used when tightening aluminum alloy chainring bolts. It's all too easy to overtighten and break this kind of bolts. Also of note: the published Shimano torque specs for both the FC-9000 and FC-R9100 chainring bolts are incorrect. If you torque those alloy bolts to the recommended 12-16 Nm, it is very probable that you will break the bolts. I learned this the hard way. After replacing the broken bolt, I used the Park Tool recommendation of 5-10 Nm. No further bolt breakage with the lower torque value.

Greg

[m_sasso]

Funny, I use Shimano and various other brand Al chain ring bolts on my track bikes and change my rings usually more than once daily and almost never use a torque wrench. Have I broken a bolt or two over the years, yes but a rare occurrence.

[Mark McM]

Originally Posted by wyatt_

Sure, I can see your point in that they're definitely different types of riding.

That said, I don't really see how throwing down sprint watts in the big ring on a group ride could really be harder on a drivetrain than climbing a mountain pass with fifty pounds of extra gear pulling against the bike in every direction?

Gear ratios convert the force/torque at the crank to a different force/torque at the rear wheel. Ultra low gear ratios used when climbing generate the biggest forces/torques at the rear wheel, but high power sprints generate the biggest forces/torques at the crank. Since we're talking about forces at the crank, short, high power sprint efforst can generate much larger forces at the crank than steady-state climbing, regardless of the how steep the hill or how much cargo is being carried.

[GregL]

Originally Posted by m_sasso

Funny, I use Shimano and various other brand Al chain ring bolts on my track bikes and change my rings usually more than once daily and almost never use a torque wrench. Have I broken a bolt or two over the years, yes but a rare occurrence.

I think we're talking (typing?) past one another with the same general point. Like you, I have only broken one alloy chainring bolt. It happened because it was overtightened to an incorrect published spec. Can you successfully tighten aluminum fasteners without a torque wrench? Yes. Does experience lower your chances of breaking a bolt? Yes. Will use of an accurately calibrated torque wrench and correct torque specs lower the chances of breaking an alloy bolt? Yes.

Greg

[cgolvin]

Originally Posted by AngryScientist

I can't think of one thing in life I do 100% correctly.

I can. Your pairing of handle and avatar is 100% correct.