Hollowtech II bottom bracket torque

[Osprey]

I'm just replacing my hollowtech II bottom bracket but not too sure how tight they should go. Shimano are quoting 30/35kn torque but my torque wrench won't fit with Shimano,s tool. I've tightend it by hand but I assume the question is how do I know if its tight enough? Any advice appreciated.

 

[Pale Rider]

Can't help directly, but I reckon frame material might come into it, so best post that as well.

 

[Pikey]

I've always just used the shimano tool and tightened them up by hand. Tbh if it's too loose, it will probably let you know within the first km or so of your ride.

 

[400bhp]

As tight as you can do it, with a handle on something around about 30cm, to get enough torque.

 

[Osprey]

Can't help directly, but I reckon frame material might come into it, so best post that as well.

Good point. It's a Reynolds 725 steel frame and the cups are tiagra.

 

[Yellow Saddle]

It is impossible to describe torque in words but I'll try, It is uurgh, not oooomph. I you pop a vein, it was too much. Go to your nearest garage and ask them if you can practice for a few minutes on their torque wrench on a bolt in a vice. Hold the wrench at the same length as your spanner at home when you practice. The latter is important because the longer the lever, the tougher Tarzan becomes.

 

[DaveS]

Actually, it always surprises me how little torque they need. Make sure you grease the cups well and that they screw in all the way to the shell smoothly. Then just tighten firmly, no heroics. It is way better to err on the safe side and not overtighten. You can always go stronger if they come lose.

 

[moo]

I went a bit overboard on one side when fitting a 105 bottom bracket. The tool slipped and damaged the thread. It's on tight enough, but removing at a later date will be interesting.

 

[zacklaws]

Just checked my Hollow tech 2 instructions and it says 35N - 50N. I used to torque them down to 40N

 

[slowmotion]

If you don't have a torque wrench you can use a spring balance hooked on the end of the tool.

Torque= Force x lever arm distance.

Edit: with a Cyclo BB tool, the centre of the BB is 190 mm from the hole in the end of the handle.

If you pull the spring balance at right angles to the handle, applying 18kg force will give you 35 Nm

 

[PatrickPending]

I can't rightly remember but aren't the threads designed so they would be always screwing in when you are pedalling forward if they could (like pedals themselves). I did mine tight but didn't go mad....hard to quantify that in torque terms.......

 

[DaveS]

I can't rightly remember but aren't the threads designed so they would be always screwing in when you are pedalling forward if they could.

Unscrewing I think

 

[PatrickPending]

unscrewing wouldn't make any sense...

http://forum.ctc.org.uk/viewtopic.php?f=5&t=71657

 

[Osprey]

Thanks guys for your responses. I'm not the most practical person but I've enjoyed trying. The bottom bracket is creaking so I guess tighten it a little more.

 

[Moodyman]

with pedals and BBs I tighten until I can't turn anymore (using slight pressure)

with nuts/bolts I tighten until I start meeting resistance - then back off a quarter turn.