Torque wrench or not?

kleinstroker

I'm just about to put together my new bike, carbon frame/forks/bars etc, and I haven't got a torque wrench. So how important are they? Is it going to make any difference to the build? Obviously there is some risk of over tightening, but fork has alloy steerer, so I'm wondering where the problems might come from?

cheers

Dmak

There is a risk. I would buy a good torque wrench but the below may be fit for purpose.


Ritchey Key

kleinstroker

Yeah I had seen those before, but being fixed at 5nm I wasn't sure how useful they would be. What range would be suitable for all bike applications?

sungod

sealey stw1012

covers 2-24Nm, ideal for the majority of bike stuff

includes a good storage box and calibration certificate, can be had for a smidge under 30 quid including delivery

http://www.amazon.co.uk/gp/offer-listin ... dition=new

kleinstroker

nice find sungod!

Looks like with that and the bits that'll be a gnats whisker under £50 though!! When will the expense ever end?

sungod

for bits, this set is excellent...

http://www.amazon.co.uk/Draper-Expert-2 ... B0001K9R6W

some draper tools are a bit crap, but these are great quality, i've been using my set for years and no signs of wear at all

thescouselander

A lot of torque wrenches are miles off calibration and aren't much use. I'd only recommend a torque wrench if you're a bit ham fisted. Otherwise just take a bit of care when tightening things up.

rolf_f

thescouselander wrote:

A lot of torque wrenches are miles off calibration and aren't much use. I'd only recommend a torque wrench if you're a bit ham fisted. Otherwise just take a bit of care when tightening things up.

For building from scratch there is something in this - presumption of calibration accuracy might be risky though I have no idea if the calibration tends to drift randomly or towards the side of caution.

However, I think it's very wrong to assume that duff calibration means a torque wrench isn't of much use. The absolute value might be wrong but they do provide consistency. If I need to remove a part from my bikes, I'll check the torque according to my wrench before I remove the bolt (and the value does match the correct settings so I can assume that my wrench is reasonably accurate).

As long as I know how tightly a part was fitted before, I can re-tighten it confidently and consistently to that same setting with the torque wrench. I once overtightened a cassette and wrecked the tool trying to remove it. Now I use a torque wrench and never have any trouble. I don't take seriously the setting on the wrench but I do know that if I stick with that setting the cassette will be properly tight but still removeable (note - this is a big torque wrench I got for £15 from Lidl - it's a nicely made thing. For most bike work I use the BBB wrench)

As for being ham fisted - apparently research indicates that people who think that they aren't ham fisted habitually over-tighten small bolts and undertighten large bolts. Mechanics instinct is basically crap in most cases!

sungod

As for being ham fisted - apparently research indicates that people who think that they aren't ham fisted habitually over-tighten small bolts and undertighten large bolts. Mechanics instinct is basically crap in most cases!

^^^ this is me

i had years of precision work on fiddly electronics and optics, but i can still snap a stem bolt, the precision comes in handy when drilling the bolt to take the screw extractor

now i use torque wrenches, one for small stuff, one for big stuff

Secteur

The only time I have ever broken something on my bike by over tightening something was with my new Park Tools torque wrench.

It was user error as the torque click was so subtle I didnt feel it, and the screw sheared. Have been riding with 3-and-a-half bolts on my stem/bar clamp since!

I rarely bother with it now, preferring to go with feel, though I dont have a carbon bike.

Blacktemplar

Secteur wrote:

It was user error as the torque click was so subtle I didnt feel it, and the screw sheared

I do have a carbon bike, and the small torque wrench I bought sounds like yours..... I can't tell when it's reached the required torquiness.. I thought it would just ratchet freely when it did? Haven't used it as I'm scared to overtighten the seatpost bolt. Is this common?

sungod

many torque wrenches just 'give' slightly with a click

if the torque is high it's quite clear, but at low torque it can be much easier to miss

tightening slowly and steadily makes it easier to feel when the set torque is reached

g00se

I've got this one for a similar price.

http://www.chainreactioncycles.com/Mode ... tedKingdom

It works well and gives a very definitive click even at low torques. Looks identical to the previous one linked.

I got this tool set to go with it:

http://www.diy.com/nav/build/motoring-w ... t-11377934

So it does come out near £50 but you get a reasonable bike-sized socket set too.

rolf_f

Blacktemplar wrote:

Secteur wrote:

It was user error as the torque click was so subtle I didnt feel it, and the screw sheared

I do have a carbon bike, and the small torque wrench I bought sounds like yours..... I can't tell when it's reached the required torquiness.. I thought it would just ratchet freely when it did? Haven't used it as I'm scared to overtighten the seatpost bolt. Is this common?

This may help. Set the wrench to tighten and put a low torque on it. Apply it to a bolt (a biggish one!) on your bike. You'll know that there is no chance that the setting will be sufficient to move the bolt. You should feel the click and see the movement in the head before you feel the pressure against your and again. If you keep pressing now, you will have gone past the torque setting and if you press hard enough, you will move the bolt. You can then ramp up the torque towards the correct setting for the bolt and then, when the setting is higher than the current setting of the bolt, you'll be able to move it without the click and head movement. But probably don't move it far!

A torque wrench isn't a licence to be cack handed - you still need to be ready to feel for the click. I'm sure this is an appropriate time for a Swiss Tony line but I'll leave that for someone else!

thescouselander

Rolf F wrote:

thescouselander wrote:

A lot of torque wrenches are miles off calibration and aren't much use. I'd only recommend a torque wrench if you're a bit ham fisted. Otherwise just take a bit of care when tightening things up.

For building from scratch there is something in this - presumption of calibration accuracy might be risky though I have no idea if the calibration tends to drift randomly or towards the side of caution.

However, I think it's very wrong to assume that duff calibration means a torque wrench isn't of much use. The absolute value might be wrong but they do provide consistency. If I need to remove a part from my bikes, I'll check the torque according to my wrench before I remove the bolt (and the value does match the correct settings so I can assume that my wrench is reasonably accurate).

As long as I know how tightly a part was fitted before, I can re-tighten it confidently and consistently to that same setting with the torque wrench. I once overtightened a cassette and wrecked the tool trying to remove it. Now I use a torque wrench and never have any trouble. I don't take seriously the setting on the wrench but I do know that if I stick with that setting the cassette will be properly tight but still removeable (note - this is a big torque wrench I got for £15 from Lidl - it's a nicely made thing. For most bike work I use the BBB wrench)

As for being ham fisted - apparently research indicates that people who think that they aren't ham fisted habitually over-tighten small bolts and undertighten large bolts. Mechanics instinct is basically crap in most cases!

I did a bit of research work on torque wrench settings for a subsidiary of GKN. We went into it in quite some depth and there are so many variables that affect how tight a bolt clamps onto something - the accuracy of your torque wrench is only one factor. Even if you have got a decent torque wrench the results are quite variable. Just consider at 5Nm a 1Nm difference is 20% out. 1Nm is nothing and you could easily be out either way by much more than this.

If you're not used to torquing bolts regularly a torque wrench will probably help prevent accidents from over tightening but once you get enough experience you might as well just do it by feel.

thescouselander

Duplicate

Bozman

I've never used one, i just use common sense and i've yet to have an issue, you don't grab a fist full you use a finger and thumb to tighten.