Harril
Well-Known Member
- Location
- East Sussex
Do I need to use a dual directional torque wrench for a Shimano BB-UN300? I've had to change a couple recently and it seems I am having to guess the amount of torque for the drive side.
Torque Wrench question.
- Thread starter Harril
- Start date
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Bristolian
Senior Member
- Location
- Bristol, UK
Hmm, I've been using torque wrenches for the past 50+ years and was under the impression that, except for some very specific models used in factory assembly lines, (e.g. engine, machine tool, aircraft undercarriage, etc.) they were all bi-directional. Am I wrong?
OP
OP
Harril
Well-Known Member
- Location
- East Sussex
Apparently not. The cheaper ones are clockwise only, the more expensive ones, of course, are dual/bi directional.
OP
OP
Harril
Well-Known Member
- Location
- East Sussex
The problem is I don't have enough experience to know when its at the correct amount without the a TW. With such precise numbers stated I'd rather not leave it to guess work.
figbat
Slippery scientist
- Location
- South Oxfordshire, UK
Mine only ratchets in one direction, but I can remove the driver and flip it to the other side to reverse the applied torque direction.
fossyant
Ride It Like You Stole It!
- Location
- South Manchester
UN300 - fairly tight. GXP BB's very very very tight ! Just use a big adjustable 12" spanner on the BB tool.
Ajax Bay
Guru
- Location
- East Devon
slowmotion
Quite dreadful
- Location
- lost somewhere
I've got a couple of thirty-odd quid Sealey wrenches. If you do up a nut to a given torque, it doesn't come free at the same torque.
presta
Guru
So what? Torque wrenches are for tightening not undoing.
figbat
Slippery scientist
- Location
- South Oxfordshire, UK
I may have used a torque wrench to undo a tight nut when I couldn't find a breaker bar...
slowmotion
Quite dreadful
- Location
- lost somewhere
I wasn't commenting on this behaviour, merely reporting it.
scotsbikester
Well-Known Member
If you are talking about ratchet "clicker" torque wrenches, then I think the opposite is actually the case.
I've got 4 torque wrenches, for the appropriate ranges. 3 ratchet "clicker" type, one beam wrench. The ratchet ones will all undo a nut/bolt, but the torque measuring mechanism doesn't work in that direction (anti clockwise). The two higher range ones are Teng, which I think is a fairly well respected manufacturer. I actually rang the to ask if they worked both ways. The chap went off to ask the technical people. They said they did. But either they are wrong, or they misunderstood my question.
It's very easy to test. Find a bolt that is already done up to a very tight torque. Reverse the ratchet (to undo) and set the torque to a very low setting. See if it clicks. It almost certainly won't. Even better find a LH threading fastener, which on a bike is probably BB drive side (RH) or the left hand pedal. See if the torque clicky thing "fires" on a low setting.
I bought a beam torque wrench specifically for those two LH threading components. I'm a bit OCD like that. Of course doing the normal threading side first, then using that as a guide to the correct torque, by "feel", might be more or less as good. Though BBs don't always need the same torque both sides, I'm told.
I think the Park Tools torque wrench is genuinely bi-directional, in terms of the torque "click". And although it's expensive, I wish I'd bought it, as I've ended up spending the same, probably more, to get the same range and bi-directionality.
https://www.parktool.com/en-int/pro...pe-torque-wrench-tw-6-2?category=Torque+Tools
presta
Guru
My Norbar torque wrench does both left and right hand threads by sliding the square drive peg through to the other side of the head, not by the ratchet or clicker mechanism reversing.
scotsbikester
Well-Known Member
Thanks, that's really useful.
