How to measure crank pre-load on Hollowtech 2?

[Jules59]

This is my first bike with a Hollowtech 2 crank.
Shimano quote a torque range of 0.7 to 1.5Nm for preloading the Hollowtech 2 crank via the cap tool.
How do you actually measure that preload ? The tool itself (TL-FC16) has nowhere to attach a small torque wrench.
So how do people do it ? Do you just have to guess?

I believe the crank preload of my new bike was set too high at manufacture. I noticed it span poorly when I took the chain off for cleaning. The crank spins much better now that Ive reduced the preload.

[Jdsk]

This is my first bike with a Hollowtech 2 crank.
Shimano quote a torque range of 0.7 to 1.5Nm for preloading the Hollowtech 2 crank via the cap tool.
How do you actually measure that preload ? The tool itself (TL-FC16) has nowhere to attach a small torque wrench.
So how do people do it ? Do you just have to guess?

I believe the crank preload of my new bike was set too high at manufacture. I noticed it span poorly when I took the chain off for cleaning. The crank spins much better now that Ive reduced the preload.

I use the IceToolZ tool which fits both the bottom bracket end and the little plastic insert.

And a torque wrench. But people helping me with this recently suggested doing it by feel... the force is tiny:
viewtopic.php?t=150722

Jonathan

[TrevA]

I have the Ice Toolz tool that enables you to fit an Allen key into the back to tighten/loosen the cap, so it would be possible if you have an 8mm Allen key bit for your torque wrench. Have to say that I just do it up hand tight and have never bothered measuring the torque.

https://www.amazon.co.uk/IceToolz-Brack ... %3D&sr=8-8

Cross-posted with Jdsk.

[axel_knutt]

If you really want to measure it, screw a torque arm to the tool and use a spring balance. The only torque wrench I have is a car one which doesn't go below about 20Nm, so if I'm working on the bike I use a spring balance for most jobs apart from BB, cranks & pedals.

[Stevek76]

It's basically finger tight on the official tool (which is about a third to quarter lower diameter than that icetoolz one!).

However do make sure the crank and axle splines are nice and clean first.

[Stradageek]

Tool, Allen key, string, weight (lumps of metal or small bags of sugar etc.), ruler and a bit of maths worked for me.

[Paulatic]

Shimano quote a torque range of 0.7 to 1.5Nm for preloading the Hollowtech 2 crank via the cap tool.

They are telling you it’s not very tight. In speak terms that’s just a light nip up and don’t go swinging on it.

[Jules59]

Solved: my cap tool is plastic so I heated up an hex bit and melted a hex hole into the face. so now I can attach my wrench which reads down to 1nm

[jb]

The idea is to remove the play or end float and no more. So lightly holding the plastic tool and turning it until it stops is all that's required.

[toontra]

Absolutely no need for any kind of torque measurement. Make sure the arm is seated properly and security clip lowered in place, then hand-tighten with the plastic tool. Not as hard as possible - just reasonable force until you meet firm resistance. Then tighten the 2 opposing hex bolts alternately.

[slowster]

The idea is to remove the play or end float and no more.

That is my understanding too.

Not as hard as possible - just reasonable force until you meet firm resistance.

'until you meet firm resistance' suggests to me tightening beyond the point at which side to side play has disappeared, i.e. more than Shimano's specified torque range, and enough to cause damage to/premature failure of the bearings.

[Keezx]

Preload is basically just takIng out the play you can feel with your hands, nothing more..
No need of bothering about measuring or torque.

[Jules59]

Thanks everyone.
I've got it sorted now.
Adjusting the preload certainly makes a difference .