Torque on a rear-derailleur cable pinch bolt

dakidcp

Using the torque guide on the Park Tool website, I was doing the pinch bolt up to 7Nm and it's stripped the thread out of the derailleur [:(]

I'm obviously going to have to buy a new derailleur (next month when I have money - bike off-road until then then), but was that for some reason the wrong torque to use??

<hr noshade size="1">"Get a bicycle. You will not regret it, if you live."
<i>Mark Twain</i>

Unknown

finger tight then a smidge more is the right torque for pinch bolts

thats about the right torque for most things i find

Mleh Mleh Mleh

PhilofCas

without wishing to take the p*ss/be cruel/make you look a d*ck etc, do you really have to use a torque guide on a pinch bolt ?, just nip the bl**der up so the cable doesn't slip, surely ??!!

dakidcp

In the absence of any experience, and without anyone to ask whether I'm doing something right or not, a torque guide is all I have. Now I have some further experience from other people (some of it even polite) that I shall apply in future.

I've also now realised I in fact used the wrong torque setting, which is probably what caused the problem in the first place.

<hr noshade size="1">"Get a bicycle. You will not regret it, if you live."
<i>Mark Twain</i>

PhilofCas

Like i said, i wasn't wishing to make a fool out of you, i just found it difficult to understand that someone couldn't fathom out how to do that without having to resort to an instruction booklet.

Sorry that you've lost a good derailer finding out, in all fairness to you it sounds as though 7Nm is too much, unless your torque wrench is faulty ?

dakidcp

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">i just found it difficult to understand that someone couldn't fathom out how to do that without having to resort to an instruction booklet<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Simply because the whole world of mechanics is alien to me. I've never done anything mechanical before (building computers obviously doesn't count), until a couple of weeks ago when I did a bike maintenance course, so I simply don't know - when I'm doing stuff up - whether it's way too loose or it's way too tight. One man's obvious answer is another's popular misconception, so until I am told otherwise, I have to rely on someone writing down a torque value. Now I know better for cable pinch bolts at least [;)]

7Nm was way too high ... almost double the 4Nm it said when I checked later - I must have looked at the wrong item. My own fault for not reading it really.

<hr noshade size="1">"Get a bicycle. You will not regret it, if you live."
<i>Mark Twain</i>

PhilofCas

once again, sorry.

PHcp

It is easily done[:I]
Before you buy another mech, have a look to see if you could get a half nut (lock nut?) behind it. I've done that on an XT mech and it's been fine for 1000s of miles.

dakidcp

Now that's a bloody good idea. Thanks, PH [:D]

And no worries at all, Phil ... apparently I'll learn best through my mistakes [;)]

<hr noshade size="1">"Get a bicycle. You will not regret it, if you live."
<i>Mark Twain</i>

msb123

unless you are working with carbon or very lightweight components you should tighten by feel. as you now know, a pinch bolt only needs to be tight enough to hold the cable so it doesn't slip. a stem needs to hold the bars so they don't slip, etc