Torque wrench ... ? nm value

[robgul]

Father Christmas is probably going to buy me a basic torque wrench for cycle stuff .... some have variable settings, some have a single setting of  nm  - most are 5 or 6

If I am to get a single value model what should I get?  - bikes are a mix of steel classics (Galaxy, Mirage etc) and fancy Ti Van Nicholas (one road, one touring)

... and any recommendations on models etc would be welcome

Thanks

Rob

[Kim]

Most of the bolts that specify a low torque setting that I've encountered on bike stuff are 5Nm.  But surely a variable wrench is much more useful?

I've got one of these: http://www.madison.co.uk/products/cycling/tools-maintenance-repair/multitools-torx-hex-wrenches/torque-wrench/ which seems to work well.

[Biggsy]

A long heavy-duty variable torque wrench is great for square-taper cranks, but don't expect the same wrench to be accurate for your small stuff as well.  Personally I'm happy to carry on with my human torque wrench for stems, etc.

[Kim]

A long heavy-duty variable torque wrench is great for square-taper cranks, but don't expect the same wrench to be accurate for your small stuff as well.

This too.  I also have a cheapo one of those from the days when I had a car to fettle.  It's mostly useful as a long lever for un-sticking things, thobut.

[shack]

For lower value requirements I used one of the topeak combi jobbies, they cost about £15 and pretty useful rather than pure gimmick.

[Jurek]

Pushbikes are irritating.
I'm not sure you'll find one torque wrench to cover the 5nm required of stem bolts, as well as the 'lots' of n.meters required of bb bearings....

IME It requires more than one torque wrench......,

[T42]

Giant make a single-setting 5 nm wrench for 15€. Nice thing is that it takes standard electric-screwdriver bits, so you can use everything the DIY shop can provide. It's also small enough to carry in an HB bag.

I also have a wrench like Kim's there, from BBB I think - they're sold under different labels. Trouble with that is that it may be "computer-calibrated" but the scale in the wee window doesn't return to zero when you zero the setting knob, and it's so far below the red line that parallax is a real problem.  Nowadays I calibrate the BBB by first tightening something up to 5 nm with the Giant then undoing it with the BBB. Then I ignore the scale in the window and simply count the turns on the setting knob.  Piece of rubbish.

[Ham]

I've got a BBB too, along with a couple of BFO Norbar that do service on the higher echelons (up to half shafts and the like)

I don't regard the parallax as a problem, because you are holding it square on to set, not sure how you'd go about setting accurate  torque with release, as you have to go past the torque to know where the max is, and by definition you can't on release.

[Chris N]

Pushbikes are irritating.
I'm not sure you'll find one torque wrench to cover the 5nm required of stem bolts, as well as the 'lots' of n.meters required of bb bearings....

IME It requires more than one torque wrench......,

I'd buy a torque wrench for the little bolts and delicate components, but wouldn't bother for the bigger stuff.  IME you're more likely to damage small screws and carbon parts from over-tightening, and less likely to get a BB bearing wrong.  5 Nm is not very tight at all, and easy to misjudge.

[Polar Bear]

Torque wrenches need calibrating on a regular basis to retain accuracy.   At least, they did when I was spannering.   Once they're out you may as well use a bar as a torque wrench.

[Tim Hall]

A long heavy-duty variable torque wrench is great for square-taper cranks, but don't expect the same wrench to be accurate for your small stuff as well.  Personally I'm happy to carry on with my human torque wrench for stems, etc.

"Tighten it until it shears off, then back off a quarter of turn"?  Works for me.

[Andrew]

Torque wrenches need calibrating on a regular basis to retain accuracy.   At least, they did when I was spannering.   Once they're out you may as well use a bar as a torque wrench.

Or vice-versa! I'm of the same belief too; that regular calibration is needed.

I don't use one, trusting in feel instead, but probably would get one (for the small nm numbers) if I had carbon bling.

[mzjo]

re calibration: a few years ago the knife-edge broke on the little SAM Dynastop at work (little is a relative term; this one covered something like 20-500Nm with an extension bar. The big one went to 1700Nm and was 2.5m long when assembled). When we asked about a replacement knife-edge we were told that said part plus the necessary recalibration was about the same price as a new torque wrench.

I can't think of buying a single value torque wrench - too many different small bolts on the machinery I come across.

I always liked the american rule of thumb on steel fasteners - snug + 2 flats. Simple, easy to remember, easy to use and remarkably consistent with attention to fastener cleanliness. Wouldn't want to use it on expensive carbon though (but then I don't have any)

[T42]

I've got a BBB too, along with a couple of BFO Norbar that do service on the higher echelons (up to half shafts and the like)

I don't regard the parallax as a problem, because you are holding it square on to set, not sure how you'd go about setting accurate  torque with release, as you have to go past the torque to know where the max is, and by definition you can't on release.

You creep up on it from below then back off a notch once it releases.  OK, you can worry about stiction & so forth and Loctite will bugger things up, but it's a smaller ballpark than poke'n'hope and within ±1 nm of nominal is usually OK on a bike.

[Jurek]

Pushbikes are irritating.
I'm not sure you'll find one torque wrench to cover the 5nm required of stem bolts, as well as the 'lots' of n.meters required of bb bearings....

IME It requires more than one torque wrench......,

I'd buy a torque wrench for the little bolts and delicate components, but wouldn't bother for the bigger stuff.  IME you're more likely to damage small screws and carbon parts from over-tightening, and less likely to get a BB bearing wrong.  5 Nm is not very tight at all, and easy to misjudge.

I mostly agree with that -I'd be far more concerned about stripping a small thread than a beefy on such as the BB.
I guess I've ended up using the high nm torque wrench because I had one, from my spannering days on motor vehicles.
What I didn't have until recently (coincidentally the same time I started to fit c/f components) was one to deal with small torques.

[P Walsh]

Do use a torque wrench! Back when parts were heavier and made to last you could get away with doing it by feel. But not now. I have cracked the clamp of a stem doing that. I have a small BBB adjustable that works well.

If you are away from your torque wrench and have to loosen a stem, just note how many turns of the allen key you use to loosen it and use the same number to tighten it.

You are supposed to have torque wrenches re-calibrated occasionally, but I haven't yet tried doing that.

[Vince]

"Tighten it until it shears off, then back off a quarter of turn"?  Works for me.

I may have been doing it wrong for years. Is shearing a higher torque than stripping (the threads)?

[spesh]

The issue of calibrating click-type torque wrenches is why I prefer Park's TW-1 and TW-2 beam-type wrenches, because the way they work means that you can check the calibration yourself, without having to spend lots getting them shipped off to a calibration service provider. Unfortunately, Park has recently seen fit to discontinue them.

http://www.parktool.com/blog/repair-help/torque-wrench-use#article-section-1

[Biggsy]

A long heavy-duty variable torque wrench is great for square-taper cranks, but don't expect the same wrench to be accurate for your small stuff as well.  Personally I'm happy to carry on with my human torque wrench for stems, etc.

"Tighten it until it shears off, then back off a quarter of turn"?  Works for me.

That's the calibration.  The human torque wrench then remembers how much is too much! 

[Ham]

The issue of calibrating click-type torque wrenches is why I prefer Park's TW-1 and TW-2 beam-type wrenches, because the way they work means that you can check the calibration yourself, without having to spend lots getting them shipped off to a calibration service provider. Unfortunately, Park has recently seen fit to discontinue them.

http://www.parktool.com/blog/repair-help/torque-wrench-use#article-section-1

One of the ways I used to supplement my income as a greasy layabout (aka, teen) was to write in to the DIY/Car/Whatever magazines who often used to have a feature "best idea of the month" or some such, that they would pay hard cash for (10s, £5, something like that). I remember one that got published, describing how to make a pre-set torque wrench out of a beam type, with the addition of a bulldog clip, battery and light bulb which apart from convenience eliminates parallax errors. Only, I never have owned or used a beam type torque wrench; every time I see one I always wonder if it was a good idea.

[robgul]

... so it looks like the answer to my question is a 5nm model

I do also have a great big long torque wrench with 1/2" drive - that seems to be useful to get a bit more leverage on BBs, crank-bolts and removing cassettes (with a large chain whip in the other hand)

My letter to Santa will be put up the chimney later today 

Rob

[Biggsy]

I mostly agree with that -I'd be far more concerned about stripping a small thread than a beefy on such as the BB.
I guess I've ended up using the high nm torque wrench because I had one, from my spannering days on motor vehicles.
What I didn't have until recently (coincidentally the same time I started to fit c/f components) was one to deal with small torques.

Except a torque wrench can be educational in preventing under-tightening as well as over-tightening.  I didn't realise how many gorilla-newtons were needed for square-taper cranks until I got one*.  It's nice to have a big long wrench anyway even when you don't need the torque sensing.

EDIT:  * I mean I didn't know what it felt like.

[Kim]

Except a torque wrench can be educational in preventing under-tightening as well as over-tightening.  I didn't realise how many gorilla-newtons were needed for square-taper cranks until I got one.  It's nice to have a big long wrench anyway even when you don't need the torque sensing.

See also: Cassette/Centerlock  lockrings.  Though I split the difference and only do them up to what I can reasonably achieve with a 6" adjustable, on the basis that at some point I might want to get them off at the roadside.

[zigzag]

i haven't bothered so far with the torque wrenches, but always try to use standalone allen keys which provide very good feedback re torque. multitool keys only as a last resort.

[Canardly]

At long Itchington we would not have got my pedals off without a torque wrench due to tissue paper pedal spanners. BFO pedal spanner purchased since.