Torque???

COVEC

Hi,
I have recently picked up a carbon fibre roadie and am concerned about how tight I will need to do bolts etc. up without damaging the frame or components.
In the past I have kind of ignored the torque reccommendations and just tightened till I thought it was enough using a standard length allen key or spanner, will this tightening by feel be OK for the carbon or will I need to take a lot of care?
I am not Arnold Schwartzenegger(sp?) and tend to change the tightness depending on how much I think a slippage will cause major injury.
Do any of you have rules of thumb that you apply to get the tightness about right?

Cheers
COVEC

Garybee

It's a tricky one this as it's fairly easy to crush carbon tubes by overtightening. You don't need to be Arnie' to do so either. I tighten this kind of thing by feel, but if you are not confident would suggest that you buy a torque wrench (1/4" drive will probably be needed due to the low torque settings required) for this purpose. Many people will tell you to take it to the LBS but there is a fair chance that they won't bother to use a torque wrench so I would suggest it's better to do it yourself.

Monty Dog

Apart from doing some sort of engineering or mechanical appreticeship, it's hard to get a feel for how 'tight' is 'tight'. I worked with a mining engineer who's definition of tight enough was 'turn it until it gives and back-off a quarter-turn'. Get a tee-handled allen key - this often limits the force you can apply by twisting your wrist, not by leveraging an allen key. The difficulty is with things like carbon bars and 4-bolt faceplates on stems, where you want to get the 4 screws evenly torqued. The like of Ritchey and others now make a torque-key with a pre-set torque limit for about £12: http://ritcheylogic.com/web/Ritchey~Log ... &live=true

APIII

I ordered one of these last week as I was a bit concerned about getting my build right
http://www.totalcycling.com/index.php/p ... _4_20.html

synchronicity

Yeah well I only ever stripped 2 bolt threads in 15 years of bike mechanics... and that was during the brief time when I was using 2 park torque wrenches... so I've completely given up on them.

andrewgturnbull

synchronicity wrote:

Yeah well I only ever stripped 2 bolt threads in 15 years of bike mechanics... and that was during the brief time when I was using 2 park torque wrenches... so I've completely given up on them.

Hi there.

I was talking about this with a colleague who's into motorbiking and uses a torque wrench for everything. The problem he pointed out is that torque settings on bicycle equipment are really pretty low (compared to wrenching a honda anyway).

Basically unless you're going to spend over a hundred squid on a torque wrench then the figures it gives at bicycle torque levels are going to be too inaccurate to be meaningful.

Which is why I've _never_ seen a mechanic in a bike shop using one,

Cheers, Andy

www.andyturnbull.co.uk

Gerry Attrick

andrewgturnbull wrote:

synchronicity wrote:

Yeah well I only ever stripped 2 bolt threads in 15 years of bike mechanics... and that was during the brief time when I was using 2 park torque wrenches... so I've completely given up on them.

Hi there.

I was talking about this with a colleague who's into motorbiking and uses a torque wrench for everything. The problem he pointed out is that torque settings on bicycle equipment are really pretty low (compared to wrenching a honda anyway).

Basically unless you're going to spend over a hundred squid on a torque wrench then the figures it gives at bicycle torque levels are going to be too inaccurate to be meaningful.

Which is why I've _never_ seen a mechanic in a bike shop using one,

Cheers, Andy

www.andyturnbull.co.uk

Not so. There are plenty of reasonably priced torque wrenches available, but I would not recommend the "bending beam" type as they can be very inaccurate. I recently bought a Sealey 1/4 inch square drive click type and it is superb. Bear in mind a crushed tube is going to cost you big style, the few quid spent on a decent torque wrnech is nothing.

Have alook at this one http://www.toolcrew.co.uk/php/showProdu ... plu=STW101

Garybee

andrewgturnbull wrote:

synchronicity wrote:

Yeah well I only ever stripped 2 bolt threads in 15 years of bike mechanics... and that was during the brief time when I was using 2 park torque wrenches... so I've completely given up on them.

Hi there.

I was talking about this with a colleague who's into motorbiking and uses a torque wrench for everything. The problem he pointed out is that torque settings on bicycle equipment are really pretty low (compared to wrenching a honda anyway).

Basically unless you're going to spend over a hundred squid on a torque wrench then the figures it gives at bicycle torque levels are going to be too inaccurate to be meaningful.

Which is why I've _never_ seen a mechanic in a bike shop using one,

Cheers, Andy

www.andyturnbull.co.uk

For most torque wrenches you're right but there are some reasonably priced ones available with very low torque settings. You just need to shop around a bit to find one where the torque you require is somewhere near the middle of the range.

weedy1

Yep thats the size of it
no use using a 0 to 200Nm and trying to get 5Nm on it.
Click ones tend to be best and some certified ones are very expensive, lucky me works in engineering and get to borrow what I want for our workshop.