Ihor
New member
Does anyone use a digital torque wrench in their e-bikes?
Digital Torque Wrench
- Thread starter Ihor
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Atavar
Well-known member
I have had nothing but trouble with digital torque wrenches. I don’t trust them.
Good old click torque for me.
Good old click torque for me.
Ihor
New member
Thank you
DieselTech
Well-known member
I use a digital torque wrench, but it's not a cheap tool. It is a $400 torque wrench, does in/lbs, ft/lbs, Newton meters, & a couple other. Mine is always spot on. But I do have the torque wrench checked & calibrated yearly.
Ihor
New member
Thanks
Atavar
Well-known member
For pretty much everything on a bike ±10% is fine. The problem comes when tightening by hand it is easy to be off 100% or more. With the soft metal bolts and threads on these bikes the results could be disastrous.
You want Things to be tight enough to not vibrate loose but not so tight you are stressing metal.
On assemblies with bolt arrays and patterns it is more important that they are all the same than they are all exact. The goal is precision more than accuracy.
Oh yeah, blue loctite is your friend.
You want Things to be tight enough to not vibrate loose but not so tight you are stressing metal.
On assemblies with bolt arrays and patterns it is more important that they are all the same than they are all exact. The goal is precision more than accuracy.
Oh yeah, blue loctite is your friend.
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the blue loctite binds me up.
i like the red loctite on brussel sprouts though
i like the red loctite on brussel sprouts though
Ihor
New member
Really helpful. Thank you.
Atavar
Well-known member
For bikes and most car stuff I do great using the el cheapo torque wrenches from Harbor Freight. They’re close enough for the work I do. For $60 you can get three, a 1/4", a 3/8" and a 1/2".
If you want better ones you can spend multiples of that but IMHO those meet the minimum requirements for bicycle work. Just don’t expect them to be certified or come with a calibration document.
Do a bit of reading on how to use a torque wrench if you haven’t been trained. It is easy to use them wrong and get invalid results, even the good ones.
If you want better ones you can spend multiples of that but IMHO those meet the minimum requirements for bicycle work. Just don’t expect them to be certified or come with a calibration document.
Do a bit of reading on how to use a torque wrench if you haven’t been trained. It is easy to use them wrong and get invalid results, even the good ones.
DieselTech
Well-known member
Yes I guess I should have mentioned earlier I replace all my bikes factory hardware with hardened hardware.
Ihor
New member
What is hardened hardware and where is it available?
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Bolt Depot - About Fastener Materials
boltdepot.com
Black Steel vs. Carbon Steel: What's the Difference
Unsure of the difference between black steel and carbon steel piping? We break it down for you right here.
blog.thepipingmart.com
Ihor
New member
Great! My thanks.
m@Robertson
Well-known member
Thread lockers are a crutch shade tree mechanics use to make up for the lack of using proper torqueing on bolts. Don't do it. Almost nothing on a bicycle requires thread locker. Not even the brake rotor bolts.
If you look at a professional assembly guide for crankarms, for instance, they specify to use lubricant on the threads. The opposite of thread locker. Tons of amateurs will tell you how important thread locker is on crankarms and its terrible advice. Using thread locker, for example, on titanium crankarm bolts can introduce enough resistance to shear the bolt when doing a re-torque or removal.
A form of lubricant known as anti-seize is a better (but generally unnecessary) choice on a bicycle than thread locker. When using anti-seize, its generally considered a smart idea in the automotive world to back off your torque spec by 10%, but bicycle bolts are so low-torque I don't bother.
If you must use thread locker, look to Vibra Tite blue gel. It never hardens and is just gloppy enough to stop bolts from backing out even under sustained vibration, which is found in the aviation industry where supposedly it got its start.
I use three different torque wrenches. A small 1/4", a 3/8" and a bigass 1/2". The 1/4" (Wera) is enough to do everything but a crankarm on a bike, where almost every bolt is an M5 or an M6 which have a max torque value between 6 and 8 Nm, which is way milder than you'd do yourself. Wera's are expensive to be sure. But they are calculated to be within +/- 4%, and can be re-calibrated. Torque wrenches that get used a lot - especially cheap ones - go out of spec and can do more harm than good. I used one of these for a couple of years until I noticed it had gone WAAAY off and chucked it in favor of a new Wera.
I use a 3/8" only on the crankarms, which being JIS/square-taper on a Bafang mid drive, loosen every few months on daily-driver bikes. My 1/2" wrench is used on Bafang mid drive lock nuts only - so barely any need for one that big on a bike.
10% accuracy sucks, but considering how far off the normal person is doing it 'farmer tight' and hoping for the best is, 10% is still a big improvement. Buying inexpensive torque wrenches to start off with, living with the inaccuracy and instead taking advantage of the consistency is a good strategy. But note that even though I spent $50 above, I still didn't spend enough to get a good wrench. For a beginner, that Harbor Freight wrench is good enough but ideally you only use it long enough to be able to stomach spending a lot more for a wrench you can depend on for years.
That video on proper torque wrench use is missing a SUPER important step on his wheel tightening example, and not doing it is something everyone working at a tire repair shop knows. You do NOT just put the wrench on an already assembled nut and torque it until it clicks. If you are doing a torque check on a bolt, you put the wrench on, and first back it offa tad. Say an 1/8 of a turn. THEN you tighten until it clicks. It will ALMOST immediately click, but to get to that you've just added a little torque. Do it a few times over a few months and you're at risk of shearing the bolt. Also, if the bolt was over-torqued to start with, you'll never know because the wrench will just click and you'll think you are at say 35Nm but there's no way for the wrench to tell you its really at 45. The common risk on a bike for this is crankarms.
I like McMaster-Carr over Bolt Depot. McMaster seems to have a wider selection. Also, your local Ace Hardware in the USA often has a pretty decent selection of metric M5 and M6 bolts (M6 are brake mounts and M5 is almost everything else). Speaking of which, typically you aren't going to be using truly hardened, nuts, bolts and especially socket caps. When you get a look at the prices on the hardened stuff you'll see why. This M5 x 10 socket cap - basically thats a water bottle or rack bolt - is US$6.34 each.
Instead just buy stainless steel, which is corrosion resistant and a big step up from the chinesium stuff you get on Far East manufacture bikes. You'll find stainless socket caps at Ace, Home Depot and McMaster and they're like US$0.85 to US$1 each. Thats a lot when replacing all your bolt hardware, but well worth it.
If you look at a professional assembly guide for crankarms, for instance, they specify to use lubricant on the threads. The opposite of thread locker. Tons of amateurs will tell you how important thread locker is on crankarms and its terrible advice. Using thread locker, for example, on titanium crankarm bolts can introduce enough resistance to shear the bolt when doing a re-torque or removal.
A form of lubricant known as anti-seize is a better (but generally unnecessary) choice on a bicycle than thread locker. When using anti-seize, its generally considered a smart idea in the automotive world to back off your torque spec by 10%, but bicycle bolts are so low-torque I don't bother.
If you must use thread locker, look to Vibra Tite blue gel. It never hardens and is just gloppy enough to stop bolts from backing out even under sustained vibration, which is found in the aviation industry where supposedly it got its start.
I use three different torque wrenches. A small 1/4", a 3/8" and a bigass 1/2". The 1/4" (Wera) is enough to do everything but a crankarm on a bike, where almost every bolt is an M5 or an M6 which have a max torque value between 6 and 8 Nm, which is way milder than you'd do yourself. Wera's are expensive to be sure. But they are calculated to be within +/- 4%, and can be re-calibrated. Torque wrenches that get used a lot - especially cheap ones - go out of spec and can do more harm than good. I used one of these for a couple of years until I noticed it had gone WAAAY off and chucked it in favor of a new Wera.
I use a 3/8" only on the crankarms, which being JIS/square-taper on a Bafang mid drive, loosen every few months on daily-driver bikes. My 1/2" wrench is used on Bafang mid drive lock nuts only - so barely any need for one that big on a bike.
10% accuracy sucks, but considering how far off the normal person is doing it 'farmer tight' and hoping for the best is, 10% is still a big improvement. Buying inexpensive torque wrenches to start off with, living with the inaccuracy and instead taking advantage of the consistency is a good strategy. But note that even though I spent $50 above, I still didn't spend enough to get a good wrench. For a beginner, that Harbor Freight wrench is good enough but ideally you only use it long enough to be able to stomach spending a lot more for a wrench you can depend on for years.
That video on proper torque wrench use is missing a SUPER important step on his wheel tightening example, and not doing it is something everyone working at a tire repair shop knows. You do NOT just put the wrench on an already assembled nut and torque it until it clicks. If you are doing a torque check on a bolt, you put the wrench on, and first back it offa tad. Say an 1/8 of a turn. THEN you tighten until it clicks. It will ALMOST immediately click, but to get to that you've just added a little torque. Do it a few times over a few months and you're at risk of shearing the bolt. Also, if the bolt was over-torqued to start with, you'll never know because the wrench will just click and you'll think you are at say 35Nm but there's no way for the wrench to tell you its really at 45. The common risk on a bike for this is crankarms.
I like McMaster-Carr over Bolt Depot. McMaster seems to have a wider selection. Also, your local Ace Hardware in the USA often has a pretty decent selection of metric M5 and M6 bolts (M6 are brake mounts and M5 is almost everything else). Speaking of which, typically you aren't going to be using truly hardened, nuts, bolts and especially socket caps. When you get a look at the prices on the hardened stuff you'll see why. This M5 x 10 socket cap - basically thats a water bottle or rack bolt - is US$6.34 each.
Instead just buy stainless steel, which is corrosion resistant and a big step up from the chinesium stuff you get on Far East manufacture bikes. You'll find stainless socket caps at Ace, Home Depot and McMaster and they're like US$0.85 to US$1 each. Thats a lot when replacing all your bolt hardware, but well worth it.
Ihor
New member
Whoah! Thanks for such useful information.
I appreciate it.
I appreciate it.
m@Robertson
Well-known member
I came back from camping a day early and still had the day off
F
Freddy1
Guest
You don't need a torque wrench for anything on a e-bike. You'll actually do more damage than tightening things by feel using the correct size spanner for the job. When you rely on a torque wrench you are disregarding that all important 'feel'.
For small fasteners get a el cheepo set of 1/4" drive sockets. To strip a thread with those short 'bars' you have to seriously be trying to strip it. Same deal with a basic Allen key.
For small fasteners get a el cheepo set of 1/4" drive sockets. To strip a thread with those short 'bars' you have to seriously be trying to strip it. Same deal with a basic Allen key.
Atavar
Well-known member
Really bad advice. If you strip or break bolts with a torque wrench you are doing it wrong or using the wrong specs.
I know a lot of guys live by “snug and an eighth” but torsion is nowhere close to repeatable doing that.
F
Freddy1
Guest
What you really mean to say is YOU have no feel for how tight a small fastener should be, so rely on a torque wrench as a crutch. And if you continue to rely on that crutch you will never develop a feel for how tight is appropriate, or when a fastener in a failing thread is pushing its limit.
I've been in the engineering field for 50+ years, I'll guess you work in a clerical field.
The ONLY place a torque wrench is necessary is for an assembly that requires a uniform precision fit eg. a motor cylinder head. You ever see a professional tyre person use a torque wrench to tighten wheel nuts? NO, only pure amateurs.
Atavar
Well-known member
lol. I worked as an engineer in the aerospace field for 20 years. If they ever caught us assembling without a torque wrench they would give us hell and write us up.
You do realize that when you overtighten a bolt and stretch it that it gets weaker and should never be trusted again , right?
Every professional tire guy I know under torques on assembly and finishes with a torque wrench. If they don’t I know they are not professional’s and I never use them again.
Every car manufacturer I know specifies lug torque, usually 90-100 lbft. I have never read in an owners manual to tighten until it feels good. In fact when I get my tires changed I am instructed to come back in 50-100 miles to have the lugs re-torqued.
Using measuring tools to verify your work is a mark of the professional and differentiates them from amateurs.
Fairly often powered assembly tools (like pneumatic or electric lug wrenches) are designed so that they can be adjusted to slip at a specified torque. Just because you don’t see a separate wrench doesn’t necessarily mean they aren’t following torque specs.
You do realize that when you overtighten a bolt and stretch it that it gets weaker and should never be trusted again , right?
Every professional tire guy I know under torques on assembly and finishes with a torque wrench. If they don’t I know they are not professional’s and I never use them again.
Every car manufacturer I know specifies lug torque, usually 90-100 lbft. I have never read in an owners manual to tighten until it feels good. In fact when I get my tires changed I am instructed to come back in 50-100 miles to have the lugs re-torqued.
Using measuring tools to verify your work is a mark of the professional and differentiates them from amateurs.
Fairly often powered assembly tools (like pneumatic or electric lug wrenches) are designed so that they can be adjusted to slip at a specified torque. Just because you don’t see a separate wrench doesn’t necessarily mean they aren’t following torque specs.
