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I'm thinking of getting a torque wrench (or something similar) for working on bikes. The ones I have for cars are pretty ungainly and I think I'd be at the low end of the range where they aren't too accurate most of the time.

So, does anybody know – or have ideas for how to find out – the range of torque values one would want to have covered? Also, how precise does the tool need to be? Wiha has some screwdriver & t-handle tools that are spec'd at ±6%. Is that close enough?

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    I'd be tempted to search for Nm on Shimano's website to get a feel for the numbers. Beats browsing aimlessly. Or just look for specifics, like Rohloff oil plug torque at the low end and something like BB cups for the high end. – Móż Nov 12 '15 at 0:05
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    See Park Tools. Claims +/- 4% – andy256 Nov 12 '15 at 0:07
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    Many of the things are 4 Nm or 5Nm when it matters (Ritchey makes torque keys for around 15 bucks each at both torque values). As for some other things, it depends -- they may have torque values written, but people may not follow them except in carbon fiber/high end cases. – Batman Nov 12 '15 at 0:37
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    @BEVR1337 So use a T-handle tool, as the question suggests, rather than a wrench that gives you a huge lever arm. And how is one supposed to get a feel for what 6Nm or whatever actually feels like without having some kind of device to measure it? How can you tighten by feel if you don't know what it's supposed to feel like? – David Richerby Oct 16 '17 at 10:31
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    My general rule is to tighten until the bolt breaks, then back off a quarter turn. – Daniel R Hicks Dec 31 '19 at 13:17
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I have 2 torque wrenches. One that goes up to 20Nm and another that goes from 20-60(ish)Nm. The little one is necessary for most of the things on my bike like my headset bolts and hollowtech crank bolts (around 7Nm and 14 NM from memory) and the big one is mainly for the cassette (40Nm) and bottom bracket (can't remember) and (just quietly) undoing stuck things (it's my longest spanner, so if I can't undo it with that I need to go get some pipe).

Unless you're doing super precise stuff with them a lot you'll probably be okay with cheap ones. I got mine when they were on special at Aldi, and probably use them less than once a month, but it's good to have them when you need them. I balked at the cost originally, until I ruined a set of cranks by over-torque-ing the bolts, which cost me quite a bit more than if I'd just got a torque wrench in the first place).

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    yeah, I'd back both the numbers and the approach. This is pretty much what I've done. Most of the time the big one sits in a corner. – PeteH Nov 12 '15 at 17:45
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Parktool had a PDF online (archived link) that says various numbers from 4 up to 700 inch-pounds.

You probably don't need to worry about 4 inch pounds required to screw the bottom bracket axle cap in correctly, so a tool capable of 30-700 would be perfect.

You don't need a torque wrench capable of anything above 700/800, because you do not use them to UNDO things. Use the correct tool at all times. If its a massively overtightened fitting, the correct disassembly tool is a big spanner or ratchet, not a torque wrench.

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    Er ... and what would that be in International (SI) units? I've only ever seen bikes specify Nm. – andy256 Nov 12 '15 at 0:59
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    @Criggie traditionally we use the furlong-fortnight-hundredweight system when forced to use imperial units. – Móż Nov 12 '15 at 1:37
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    "american units" - even the English are metric now. I used inch-pounds because that's what the park documentation listed, was summarising the info in case that document ever went off the internet – Criggie Nov 12 '15 at 1:49
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    @Criggie, except when we don't. ;) – alex Nov 12 '15 at 2:25
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    That link was broken. Fixed it using archive.org. I'd like to see other sources aswell. – try-catch-finally Dec 30 '19 at 11:08

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