torque pressure for tightening quill expander bolt on top of stem
09-10-20, 01:43 AM
#1
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Thread Starter
torque pressure for tightening quill expander bolt on top of stem
Whats a general ballpark figure for reasonable Nm pressure to be applied to the quill expander bolt on top of stem?
I have a cube hybrid/fitness bike and being a tinkerer i losened this at one point to see what i need to highten the stem.
Its now tightened with a simple allen key by hand, not too tight and erring on the side of caution and its been like this without issue for months, but ive gotten access to a torque wrench so just want to give it a touch with that to ensure its tight enough.
The cube website helpfully tells me to never touch this bolt and only let a specialist shop mess with this part of the bike (if we didnt mess, how would we learn anything?).
I have a cube hybrid/fitness bike and being a tinkerer i losened this at one point to see what i need to highten the stem.
Its now tightened with a simple allen key by hand, not too tight and erring on the side of caution and its been like this without issue for months, but ive gotten access to a torque wrench so just want to give it a touch with that to ensure its tight enough.
The cube website helpfully tells me to never touch this bolt and only let a specialist shop mess with this part of the bike (if we didnt mess, how would we learn anything?).
09-10-20, 06:28 AM
#2
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I set quill stems tight enough that the bars will not move under normal loads, but loose enough that I can move them while holding the wheel still. This is referred to as "race tight". The idea being that in a crash the bar will move rather than injure my leg. I do the same with shift and brake levers.
09-10-20, 06:33 AM
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according to my notes from the Barnett's DX manual:
steel bolt: 145–180 inch-pounds or 16–20 Newton-meters
aluminum bolt: 145–150 inch-pounds or 16–17 Newton-meters
steel bolt: 145–180 inch-pounds or 16–20 Newton-meters
aluminum bolt: 145–150 inch-pounds or 16–17 Newton-meters
09-10-20, 06:53 AM
#4
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Thread Starter
thanks for the reply.
I just had a look at what i had it tightened at, and its around 8Nm and ive been cycling it at this for moths. This is about what it was, give or take 0.5 to 1Nm, as i remember loosening it and it was not difficult at all, i doubt it was much more than 8Nm from the shop.
Im a bit worried now as your notes say 16Nm+ but at 8Nm it feels very tight and solid.
I just had a look at what i had it tightened at, and its around 8Nm and ive been cycling it at this for moths. This is about what it was, give or take 0.5 to 1Nm, as i remember loosening it and it was not difficult at all, i doubt it was much more than 8Nm from the shop.
Im a bit worried now as your notes say 16Nm+ but at 8Nm it feels very tight and solid.
09-10-20, 07:07 AM
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if you're willing to take that risk, it's your bike. search out any manufacturers' specifications and other reputable sources and you'll find that 8Nm is far below what is recommended.
https://www.bikeride.com/torque-specification — 16–29 Nm
https://www.parktool.com/blog/repair...s-and-concepts 16–29 Nm
https://www.qbp.com/diagrams/Manuals...DIMAdjStem.pdf 16–20 Nm
Rivendell Torque sheet 16–20 Nm
https://www.bikeride.com/torque-specification — 16–29 Nm
https://www.parktool.com/blog/repair...s-and-concepts 16–29 Nm
https://www.qbp.com/diagrams/Manuals...DIMAdjStem.pdf 16–20 Nm
Rivendell Torque sheet 16–20 Nm
09-10-20, 01:42 PM
#6
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Thread Starter
Apologies, i got the taxonomy incorrect. What i am tightening is the stem cap. Ive watched a few videos on it and most leave it hand tight, enough so its not rattling but not so much that its making the steering tight and potentially crushing the bearings.
(38 seconds in).
Another article mentions that 3-5Nm is more than sufficient, and that feels about right.
Again, apologies for the incorrect termonology, no way anyone can give an informative answer with an incorrect question being asked!
Another article mentions that 3-5Nm is more than sufficient, and that feels about right.
Again, apologies for the incorrect termonology, no way anyone can give an informative answer with an incorrect question being asked!
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09-10-20, 01:49 PM
#7
Banned
3 bears ?
loosening the stem clamping bolts, the top cap is your headset bearing pre-load.. you tighten it for effect .. on ..
..
headset bearing, not too loose or too tight & binding, it's 'goldilocks', then
the 2 stem bolts that grip the steerer are tightened again, to keep your adjustment..
...
..
headset bearing, not too loose or too tight & binding, it's 'goldilocks', then
the 2 stem bolts that grip the steerer are tightened again, to keep your adjustment..
...
Last edited by fietsbob; 09-10-20 at 01:53 PM.
09-10-20, 04:28 PM
#8
Senior Member
I set quill stems tight enough that the bars will not move under normal loads, but loose enough that I can move them while holding the wheel still. This is referred to as "race tight". The idea being that in a crash the bar will move rather than injure my leg. I do the same with shift and brake levers.
