I thought I might start this post with a joke about tight nuts.
But then I considered the gravity of the things that need to be said and the humour drained from my soul as if I’d been snogging a Dementor behind the bike sheds at Hogwarts.
You see, the problem is that, as manly men who like wielding spanners and tinkering with all things mechanical, we like to have good tight nuts and bolts. A job only feels well done if you push on the spanner as much as you can and everything’s well erm…. tight and secure. Bolted down, not rattling around, won’t come undone and is damn well in it’s place.
It’s all about control and I’ll tighten those damn little widgets, screws and nuts to within an inch of their lives! And therein lies job satisfaction, manly pride and order!
This is fine if you’re working on a tractor or to a certain extent a car or some other more robust piece of machinery but bikes, particularly road bikes, are a little more refined. Over tighten too much and you can easily shear off the threads, crack or snap a component, or tighten so much that over time the component simply won’t come undone again without damage to the bike itself.
This is particularly problematic on bikes with carbon frames. Of course carbon is extremely strong and extremely lightweight which is why it’s such a great material for building bike frames from. However, you might not realise that carbon fibre can also be extremely brittle and can crack relatively easily if force is applied incorrectly.
Essentially carbon fibre is like millions of tiny straws all glued together and in one direction it’s extremely strong but if you push or pull to the side it will collapse. Bike frame engineers exploit the strength of the material by making sure that load is applied in one direction only and in this instance it’s stronger than steel but, if a side pressure is applied it can collapse and fracture quite easily.
In contrast steel and aluminium are essentially equally as strong whichever way you push or pull them which makes their strength more predictable and stable.
You might have heard of carbon framed bikes being consigned to scrap after being in an accident as they are more easily damaged than steel or aluminium. They are also relatively easily damaged by over tightening components.
Just imagine the sickening scenario for a moment as you over enthusiastically tighten up the bottom bracket on your beloved carbon road bike without using a bike torque wrench………just one more push to be on the safe side and…….CRACK…….yes, it’s game over for that frame!
It’s unlikely (but not impossible) that you would crack a steel or aluminium framed bike but highly possible that enthusiastic over tightening might lead to sheared off bolts or, if they are left over time components that just won’t budge.
Depending on where they are this could make repair uneconomic – imagine again a completely jammed bottom bracket or headset where the bearings have completely gone and you can’t undo the component to replace them.
But, fear not. There is a simple solution on the form of a bike torque wrench!
What is a bike torque wrench and how do they work?
First of all the good news is that a torque wrench is a proper man’s tool. It’s the sort of tool that you can feel proud of walking into a shop to buy and asking about and drooling over. There’s something very satisfying and appealing about being able to announce to the family “I’m going out to buy a bike torque wrench – I may be gone some time”. It implies that you understand engineering, need a complex and technical tool and, instinctively you understand just what’s needed, how to apply the tool in any given situation and, well it’s just going to look great in the tool box.
And therein lies another problem because a budget torque wrench would probably do but the more expensive one is a thing of beauty and accuracy. The type of tool that will last a lifetime and that I can hand down to my……….actually I don’t think that any of my three post pubescent pre functioning adult daughters would do anything other than scoff in disgust if I left them a bike torque wrench in my will………
So, basically a torque wrench allows you to measure exactly the amount of pressure being applied as you tighten something.
Yes, it basically measures tightness!
And, unbelievably there are people whose job it is to provide information about how tight things should be in an ideal world ie tables of tightness (you can view one here) or tables of torque settings to be more technically precise!
So what’s torque?
I suffer from a lot of excessive talk (again referring back to the previously mentioned three teenage daughters!) but there is a big difference between talk and torque.
Torque basically refers to a twisting force and is measured in Nm or Newton Metres. Having had a quick check on Wikipedia (I was crap at Physics at school!) I can now confidently explain that a Newton Meter is the force of one Newton applied to a one metre long moment arm.
So that’s the force of one apple falling one metre from a tree (duh??)
And “talk” refers to the endless jabbering about boyfriends, memes, Instacrap, Crapchat, funny cat videos and Riverdale that I’m subjected to on a daily basis without the drawing of breath at unsustainably high volume and pitch and without any consideration that I just want to be left in peace IN MY MAN CAVE!
Do I need a specific bike torque wrench?
Once you start exploring the murky world of Newton Metres you will soon realise that all torque wrenches aren’t made equal and that some are designed for some jobs and others aren’t!
Basically the bigger the machine you are working on the higher the torque values you will be working at (broadly speaking) so, for example, a majority of the torque settings you might find on a car would probably go down only as far as around 25Nm.
This is far to high for working on a bike where settings as delicate as 3Nm might be required so you do need a dedicated torques wrench specifically for working on bikes.
You will probably find that you need more than one as the range of settings might be to great for just one tool and a set of two bike torque wrenches, one for low settings and one for higher, will cover all eventualities. If you own a carbon framed bike this will be especially important as you will probably want to use a torque wrench for every component on the bike. On a steel or aluminium framed bike you might well decide just to use a bike torque wrench for the most important and sensitive components and you could, therefore, possibly just buy a torque wrench for those only and save a bit of cash.
Bike torque wrenches v torque keys
Torque keys are cheaper but less flexible in their use as they generally come with a set Nm setting. You can get them set for 2Nm, 4Nm etc which is great if you know that you have a lot of nuts/bolts at that setting.
You might for example be able to cover a majority of the torque settings on your bike with a bike torque wrench but there might be one setting that’s outside of it’s range so, rather than buying a torque wrench for that single setting a single setting torque key will do the job just as well and be less expensive.
It’s horses for courses and bike torque wrenches look nicer and are nicer to use and have the flexibility but the fixed torque key is cheaper and can be more practical if you just have a single setting needed.
How do you actually use a bike torque wrench in practice?
I’d never actually used one until a few months ago as I have an aluminium framed road bike and had always been of the “tighten it until it’s within an inch of it’s life” brigade.
I had a crank arm that kept coming loose and I realised that there just had to be a better way of tightening it that using an Allen Key hooked around a spanner and a hammer to hit it.
Well obviously I was at great risk of over tightening the bolt which could have caused the crank arm to crack maybe or the thread on the bolt on the bottom bracket to shear off. Neither would be good and, me being me, I decided that I would try to fix the problem rather than just buy a new crank arm which is what I should have done at the beginning and ended up doing eventually anyway!
What I eventually did was get a new crank arm and borrowed a bike torque wrench. I checked the torque setting for the crank arm online, set the torque wrench up to the correct setting and voila! Tightened the thing up confident that it wasn’t going to be too tight or too loose and come undone again and it’s been fine ever since.
In theory at least you should know the torque settings for all of the components on your bike and tighten appropriately every time – especially if you are riding on carbon.
For us mere metal framed mortals it’s probably enough to use a wrench for the vital components and guess the rest – but a bike torque wrench is a nice toy to play wit and you might well find that you want to use it more than you really need to!
Splash the cash
So, which one to get? Obviously there’s literally hundreds of choices out there and, as with most things in life you get what you pay for.
My inclination is to go for a nice looking boxed set as, to me at least, it looks nice and will give me a sort of weird man tool pleasure owning it (geez that’s a strange sentence!). If you read through lots of reviews on this type of thing you will come across a number of “wrench enthusiasts” who have terrible tales of inaccurate cheap bike torque wrenches and sheared bolts and, to a certain extent, if you are going to own such a tool you may as well have a nice one and my life’s just too short to worry about wrench calibration!
If I had a very expensive carbon frame and I was going to do my own maintenance rather than be a big girl and send it to the bike shop I would invest in a high quality bike torque wrench as a priority just for my peace of mind.
However, I’m a metal framed carbon wannabe at the moment so I might have to just reign in my wrench spending budget a bit for the moment – decisions, decisions!
Anyway after a lot of in depth research and far too much time reading about and poring over wrenches I’ve come up with a bit of a short list which, if you are in the same market, will hopefully be helpful for you as well:
Venzo Bike Torque Socket/Allen key Set
I like the look of this a lot and it ticks a huge number of boxes. It’s really versatile, comes in a nice presentation box, looks proper and it has hundreds of really positive reviews. It’s talked about as being really sturdy, having a high quality feel and it has a little “click” sound as the correct torque is reached which is a popular touch. As ever there are some reviewers who are concerned about calibration and accuracy and some who say it’s more accurate than the more expensive Park Tools version. It has 68% five star reviews out of a total of over 400 on Amazon at the moment and, as the price is good as well, this really does have to be a very string contender!
Bikehand Bike Torque Wrench Socket?Allen Key Set
This comes in at a similar price to the above and Bikehand are a well known brand. I’ve had some of their stuff before and been happy with it. Again the set has the same number of pieces and a 2Nm to 24Nm range with an accuracy of +/- 4%. there are fewer reviews than for the Venzo set but again the five star reviews are in the high 60% range. Again users seem to either love it or completely hate it as with the wrench above. It seems that any adjustable wrench can suffer from adjustment and calibration issues and the only 100% way to get around this is to have the wrench calibrated before using and again at regular intervals. there are enough stories of smashed up carbon frames around for me to seriously consider this option if I was in the position of needing to work on an expensive carbon frame. the other option is to buy single setting torque keys which seem to be more consistently accurate due to their simpler mechanism and design.
Park Tools TW5 and TW6 Torque Wrenches
So, in the quest for peace of mind and accuracy you could splash out and but what are essentially seen as being the best in class torque wrenches and go for the Park Tools TW-5 and TW 6. They cover a wide range of torque settings between them – the TW-5 3-15Nm and the TW-6 6-30NM. Do you need both? maybe, maybe not. Perhasp one of them and a torch key might work well? However they are undeniably beautiful and ooze quality. They don’t come with any sockets or keys though so these will be an additional expense. You would expect at such a high price for the reviews to be outstanding but again they come in at the high 60% for five stars on Amazon and, although very positive are not 100% conclusive and reassuring as you might hope.
Bike Torque Wrench Conclusions
As ever, in trying to solve a problem and make life simpler I now only seem to have added complications and decision making stress! I was hoping that, by buying a torque wrench set I could be reassured about the tightness of my nuts forever but it seems not to be the case!
I’m riding an aluminium bike at the moment and so I’m not too concerned about torque settings so I think I’ll go for either the mid priced Venzo or Bikehand etc. When/if I upgrade to carbon I would probably aim to get them calibrated just to make sure or maybe supplement the set with a torque key or two if I needed to.
If I had an expensive carbon bike now I would go for the Park Tools ones and just bite the bullet. It seems mad to me to risk terminally damaging my frame by either not using a torque wrench or by risking using a really cheap one. I might go as far as having the Park Tool set calibrated before use just to be on the absolute safe side and for absolute peace of mind.
It sounds crazy but calibration is big business and it looks relatively straight forward and not too expensive to send off the wrenches for calibration before using them.
So, the bottom line is that, if you are riding an expensive carbon frame you need to factor in the expense of high quality torque wrenches and calibration as well – or simply let your bike shop worry about it when they service your bike. You either pay for peace of mind or risk the potential tears, trauma and expense of ruining your bike!
If you have any more experience of using bike torque wrenches or can recommend any other options it would be great to hear from you – just leave a message in the comments!