stems: how tight should i go?

Rudd

Hello all,

I need to pack my bike for a trip to the alps so need to remove and reassemble my stem. I have a torque wrench and note that my deda stem stipulates a max torque of 8.8nm. The trouble is when i'm tightening up 5nm feels plenty tight enough to me and I'm nervous about exceeding that. Irrational perhaps but if i didn't have a torque wrench and was just going by feel this is as much as i would go, so I was wondering if any ace mechanics out there would be able to comment on how tight they go? Presumably 8.8nm is the max but what drives the minimum? If it makes a difference i have a carbon steerer.

Any comments much appreciated.

David

AK_jnr

Its not going to go anywhere if you have tightened everything in the right order especially once the top cap is on. 5nm for me.

nicklouse

The minimum is where the stem no longer moves on the steerer.

sungod

before shipping...

once the stem is off, it's a good time to check steerer for any wear/damage

after shipping...

make sure the clamping area is clean/grease free - if the steerer slips down during transit it may pick up grease from the bearings

then as above, tighten bolts until the stem is secure - usually there are two bolts, don't just tighten one fully, do them 'together' in increments so that clamping force is evenly distributed as you go

fwiw mine is secure around 5Nm, but it'll vary with the stem etc.

Rudd

thanks all - 5nm is what i'll go for. I've got some carbon gripper paste too which i guess is a little extra insurance.

sungod

personally i never use carbon paste on a steerer clamp

a) never needed it

b) if the gritty bits get washed down into the headset bearings it won't be good

fenix

So 8 is the max. It doesn't mean to use 8 all of the time.

My car has a max speed of 120. I never go that high.

(no idea about the car just used that as an example)

Rudd

Sorry, i should clarify. Its a deda stem and just says "8.8nm", not "Max 8.8nm". You could easily take this as a minimum.

I guess i could have read the manual too!

David

homers_double

Rudd wrote:

I guess i could have read the manual too!

Good heavens man, don't resort to that!

singleton

homers double wrote:

Rudd wrote:

I guess i could have read the manual too!

Good heavens man, don't resort to that!

Just what I thought - have some self respect....

fenix

I've never had a torque wrench and been messing with bikes for 30 years. Probably won't get one either so I'll live in ignorant bliss.

AK_jnr

^^ I bought a torque key after 3 years of having a carbon bike. I dont think I was a mile off when guessing before, possibly under tightening most of the time but I feel bloody lucky not to have cracked something!

Rudd

ha - you also need to care of internet forums - this very one had a long discussion from members trying to work out how to get to 8nm without their titanium bolts failing.............careful twisting and good use of grease was the solution.

I know nothing, I admit to being a dreadful mechanic :oops:

itboffin

Singleton wrote:

homers double wrote:

Rudd wrote:

I guess i could have read the manual too!

Good heavens man, don't resort to that!

Just what I thought - have some self respect....

it's a slippery slope you'll be asking strangers for directions next