Installing New Crankset

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Jdsk
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Re: Installing New Crankset

Post by Jdsk »

cycleruk wrote: 16 Sep 2021, 8:59pm My only thought about torque wrenches is how do you know that they are accurate and how can you test them?
You can have them checked commercially. Or DIY by rigging a known force at a known distance.

Jonathan
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Paulatic
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Re: Installing New Crankset

Post by Paulatic »

Jdsk wrote: 16 Sep 2021, 9:00pm You can have them checked commercially. Or DIY by rigging a known force at a known distance.
You can but unless you’re a serious engineer how often do people do it?
I’ve only ever used one fitting cylinder heads and never once felt the need for a bicycle. As for hollowtech it’s the first I’ve heard about regular checking. I usually fit, check a week later, and forget.
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Jdsk
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Re: Installing New Crankset

Post by Jdsk »

Yes, we can have the whole discussion again. And every time that torque wrenches are mentioned.

I think that it's one of those situations where having the right tools and following the instructions is the best approach for those with little experience.

And those with lots of experience certainly don't need any advice from me.

Jonathan
Stevek76
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Re: Installing New Crankset

Post by Stevek76 »

For all the chat about torque wrenches or not I'd just like to highlight this part which I think is quite key!

"The two left crank arm mounting bolts should be tightened in stages rather than fully tightened at once. "

Don't just whack one straight up to 13Nm (or the equivalent 'about that much') while the other's still loose, and certainly don't do that and then do the 2nd up to 13Nm and ride away as the first will definitely be loose again and there'll likely be some odd stresses on the crank as well.
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Jupestar
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Re: Installing New Crankset

Post by Jupestar »

Stevek76 wrote: 16 Sep 2021, 10:44pm For all the chat about torque wrenches or not I'd just like to highlight this part which I think is quite key!

"The two left crank arm mounting bolts should be tightened in stages rather than fully tightened at once. "

Don't just whack one straight up to 13Nm (or the equivalent 'about that much') while the other's still loose, and certainly don't do that and then do the 2nd up to 13Nm and ride away as the first will definitely be loose again and there'll likely be some odd stresses on the crank as well.
Definately. I also recommend the same when taking them off. There is better designs in my opinion.
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Chris Jeggo
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Re: Installing New Crankset

Post by Chris Jeggo »

Many years ago our cycling club treasurer was a very senior engineer at British Aerospace, who said he could not understand why the majority of bicycle cranks were still (1970s) secured by cotter pins. Splines were much better. But he had in mind one large pinch bolt, not a pair of little ones.
fredN4
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Re: Installing New Crankset

Post by fredN4 »

irc wrote: 16 Sep 2021, 1:55pm While Shimano may recommend regular checks I have never done (wasn't aware of the need) a d haven't had any problems.

I have also fitted the cranks without a torque wrench just judging tight but not too tight by hand.

One advantage for touring is they are easy to remove with minimal tool. Useful, I found, when packing the bike for return from the USA and could only get hold of a very small cardboard box. The frame with bars, wheels, and seatpost off still needed the cranks removed to squeeze in.

All that said at £22 I may try the torque wrench.
me neither. save your money.
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