No torque wrench...axle nut question

[ebike11]

Hi guys
Is it fairly safe to tighten the axle nuts with an adjustable wrench without stripping the threads??
The motor is the qs205 that i just got. I compared the threads to my mxus 3000 and it seems the threads are much more deeper on the mxus. I was able to hand tighten those nuts as hard as i could.
Thx

 

[wturber]

Hi guys
Is it fairly safe to tighten the axle nuts with an adjustable wrench without stripping the threads??
The motor is the qs205 that i just got. I compared the threads to my mxus 3000 and it seems the threads are much more deeper on the mxus. I was able to hand tighten those nuts as hard as i could.
Thx

How strong are you? How long is your wrench? What kind of torque arms are you using?

Why not just get a torque wrench? They aren't that expensive and nice to have around if you work on your own stuff.

 

[dogman dan]

Well, a torque wrench won't solve a really shitty axle, machined so poor and loose it has no chance.

But a reasonable fit, I have not stripped one out by using a short handled adjustable wrench. One that is not as long as that size would be in a regular box wrench. About a six inch handle prevents me from over tightening a nut, and I'm an ex construction worker with a pretty strong arm. Totally guessing what torque I'm getting out of that, but for sure its no where near 100 ft pounds. But I am pretty sure its not less than 20.

If its critical, like really high power, and or using regen, then its up to the torque arms. Home make some of the type that actually clamp down like a vise on the axle flats, so the next thing that can give is twisting the axle in two.

 

[wturber]

About a six inch handle prevents me from over tightening a nut, and I'm an ex construction worker with a pretty strong arm. Totally guessing what torque I'm getting out of that, but for sure its no where near 100 ft pounds. But I am pretty sure its not less than 20.

FWIW, I routinely use a 6 inch adjustable wrench on my bike. But I'm only ever feeding my motor about 1000 watts of power and I have two torque arms. So all I really need is for the nuts to be tight enough so that they don't come off. But I think a person might want to be more nit-picky if they are dealing with a substantially more powerful motor.

I wish the shop mechanic that worked on my Honda CB-125 years ago would have used one when tightening my bike's swing arm bolt ... the one that came loose while riding home from the shop. Fortunately it didn't exit the frame and put me down onto the asphalt.

 

[ebike11]

Well, a torque wrench won't solve a really shitty axle, machined so poor and loose it has no chance.

But a reasonable fit, I have not stripped one out by using a short handled adjustable wrench. One that is not as long as that size would be in a regular box wrench. About a six inch handle prevents me from over tightening a nut, and I'm an ex construction worker with a pretty strong arm. Totally guessing what torque I'm getting out of that, but for sure its no where near 100 ft pounds. But I am pretty sure its not less than 20.

If its critical, like really high power, and or using regen, then its up to the torque arms. Home make some of the type that actually clamp down like a vise on the axle flats, so the next thing that can give is twisting the axle in two.

Im using just a 6 inch adjustable on the qs205 motor. I dont have clamp style torque arms. Its my firat time to install this big of a motor. I know its not recommended and i must be careful but at the moment i only have the M16 type torques on both sides that slide over the axle and wire clamps to the frame

 

[MadRhino]

If your dropouts were made good, the axle nuts could be hand tightened, or missing, NP. :wink:

Anyway, the axle nuts are not meant to hold the motor torque, and the axle must be held without them if it is secured enough to hold the torque. Then, axle nuts don’t need to be very tight. A second, thin nut can lock the first if you are worried that it unscrews with vibration or motor kick.

 

[ebike11]

If your dropouts were made good, the axle nuts could be hand tightened, or missing, NP. :wink:

Anyway, the axle nuts are not meant to hold the motor torque, and the axle must be held without them if it is secured enough to hold the torque. Then, axle nuts don’t need to be very tight. A second, thin nut can lock the first if you are worried that it unscrews with vibration or motor kick.

Thanks!
Yes i noticed the second thin nut. Ill try and use both nuts.
Do you put any washers on the inside, between the inside of the frames dropout and and motor?

 

[fechter]

Thanks!
Yes i noticed the second thin nut. Ill try and use both nuts.
Do you put any washers on the inside, between the inside of the frames dropout and and motor?

I would avoid that. You want as much friction between the dropout and the axle as you can get. If it is necessary for proper fit, then use them.

 

[ebike11]

Thanks!
Yes i noticed the second thin nut. Ill try and use both nuts.
Do you put any washers on the inside, between the inside of the frames dropout and and motor?

I would avoid that. You want as much friction between the dropout and the axle as you can get. If it is necessary for proper fit, then use them.

Hi Fetcher..thanks again!
So would it be ok to put the inside of the frame dropouts onto these 2 surfaces? The reason i thought about putting a washer in between is to have more contact area with the frame and motor but if its not recommended then i wont. Thanks

https://ibb.co/q096pnx
https://ibb.co/GWqqfMJ

 

[wturber]

If your dropouts were made good, the axle nuts could be hand tightened, or missing, NP. :wink:

Anyway, the axle nuts are not meant to hold the motor torque, and the axle must be held without them if it is secured enough to hold the torque. Then, axle nuts don’t need to be very tight. A second, thin nut can lock the first if you are worried that it unscrews with vibration or motor kick.

Thanks!
Yes i noticed the second thin nut. Ill try and use both nuts.
Do you put any washers on the inside, between the inside of the frames dropout and and motor?

The problem with what MadRhino said is that he has not described what he means by "made good" and you haven't described what kind of bike you are bolting this motor into.

It may be true that the axle nuts weren't made to hold motor torque, but the reality is that they do. Take a look at this testing done by Justin. Axle nut torque matters a lot.

https://endless-sphere.com/forums/viewtopic.php?f=2&t=14195&start=100#p220366

And keep in mind that standard bike dropouts weren't designed to handle motor torque either. So if you are using a standard bike and not some special bike frame made for powerful motors, then axle nut torque matters ... a lot.

 

[ebike11]

If your dropouts were made good, the axle nuts could be hand tightened, or missing, NP. :wink:

Anyway, the axle nuts are not meant to hold the motor torque, and the axle must be held without them if it is secured enough to hold the torque. Then, axle nuts don’t need to be very tight. A second, thin nut can lock the first if you are worried that it unscrews with vibration or motor kick.

Thanks!
Yes i noticed the second thin nut. Ill try and use both nuts.
Do you put any washers on the inside, between the inside of the frames dropout and and motor?

The problem with what MadRhino said is that he has not described what he means by "made good" and you haven't described what kind of bike you are bolting this motor into.

It may be true that the axle nuts weren't made to hold motor torque, but the reality is that they do. Take a look at this testing done by Justin. Axle nut torque matters a lot.

https://endless-sphere.com/forums/viewtopic.php?f=2&t=14195&start=100#p220366

And keep in mind that standard bike dropouts weren't designed to handle motor torque either. So if you are using a standard bike and not some special bike frame made for powerful motors, then axle nut torque matters ... a lot.

Thanks for the feedback
Yes im using a standard aluminum 26inch bike. Yeah its probably gonna be a death trap do im gonna ride at moderate speeds

 

[fechter]

On my A2B, I have the axle nuts tightened to 50ft-lbs (67N-m) and they still move a little, but that's at 2.5kW.
Torque arms might be a good idea if you're planning to run a lot of amps. At 1kW, things are a little more tame and lots of people run that much power without torque arms.

It's also a good idea to frequently check the nuts until you get a feeling for how well they stay tight. If the axle moves at all, it will tend to gradually loosen the nuts.

There are some pretty long topics on ES about torque arms and all kinds of DIY versions. You might browse some of those to get some ideas.

 

[TommyCat]

Yikes aluminum...

Two torque arms
Proper nut torque with lock nuts or possibly Belleville lock washers. Leave nothing to chance!

Hard to see the double nut, but it's there above the OEM shouldered nut with the teeth cut in. (locking)

Be safe.

 

[Voltron]

Also sold under the Nordlock brand.



I doubt you'll ever strip the axle threads.. You're more likely to round off the corners of the nut. One thing to look out for is that some axles have a step that rests against the inside of the dropout, and it's not very tall on a lot of them. Overtightening can drive the dropout over the step, and damage the dropout.

 

[Voltron]

Just saw the question about washer between the frame and axle. That's fine, but only if it's the ebike washers like these.


A regular round hole washer is only touching the axle step on less than half it's circumference, and will squish over the step, making the axle nut get loose.

 

[ebike11]

Just saw the question about washer between the frame and axle. That's fine, but only if it's the ebike washers like these.
41WKYN4q48L.jpg

A regular round hole washer is only touching the axle step on less than half it's circumference, and will squish over the step, making the axle nut get loose.

Yes i have 2 M16 ebike motor washers with the lip that matches the dropout opening. But they are about 3mm thick each so 6mm will require me to stretch my dropouts further. Its a tight fit already with a qs205

 

[999zip999]

Aluminum frame 2 torque arms. A must

 

[amberwolf]

Also sold under the Nordlock brand.

Actually the Belleville are different. They don't have a pair of interlocking surfaces like NOrdlock, they just have a segment of a dome shape, so pressure on the center as you tighten it pushes down on that, pushing outward on the rest of it, stretching it's springy metal outward, so all that pushes up on the nut to help hold it in place.

 

[ebike11]

Also sold under the Nordlock brand.

Actually the Belleville are different. They don't have a pair of interlocking surfaces like NOrdlock, they just have a segment of a dome shape, so pressure on the center as you tighten it pushes down on that, pushing outward on the rest of it, stretching it's springy metal outward, so all that pushes up on the nut to help hold it in place.

These sound good....where can u easily get them from? Would it be best on the inside or outside of the dropout?

 

[wturber]

Getting back to your original point of not having a torque wrench, both of these washer typed should be torqued appropriately. So the use of these does not really eliminate the usefulness of a torque wrench. Sure, you could use either without a torque wrench. But it would be better if a torque wrench was used.

https://www.ecmweb.com/content/how-use-belleville-washers-correctly

https://www.nord-lock.com/nord-lock/products/washers/
[youtube]IKwWu2w1gGk[/youtube]
also worth listening to ...
[youtube]VINYUXFtnw0[/youtube]

Two 3/8" or 1/4" torque arms with appropriate axle torque is probably all you need. Just check your nut tightness from time to time.

 

[MadRhino]

That is a way nut to bother about torque.
If washers were required, they’d be inside to tune spacing.

 

[wturber]

That is a way nut to bother about torque.
If washers were required, they’d be inside to tune spacing.
DF993167-E2D7-45AF-B168-57A9981B86D7.jpeg

Assuming those are steel "dropouts", then yes, tightening to feel is probably just fine.

 

[MadRhino]

That is a way nut to bother about torque.
If washers were required, they’d be inside to tune spacing.
DF993167-E2D7-45AF-B168-57A9981B86D7.jpeg

Assuming those are steel "dropouts", then yes, tightening to feel is probably just fine.

They are, and you can speed mountain trails, not even noticing a loose axle nut.

 

[TommyCat]

Hi ebike11,

Sorry for the late reply to your P.M. question. Those are home made torque arms made out of 1/8th thick mild steel.

My best tip would be to be very careful on matching the axle profile with it in the correct position. Get perfection all around.
And tweak it so it slightly binds CW on the drive side, and slightly binding CCW in the other side. To produce a slight tension holding the axle secure with no load.

To see more about the fabrication, go here... https://electricbike.com/forum/foru...r-bottle-batt-52v-11-5ah-huffy-parkside/page2

 

[wturber]

My best tip would be to be very careful on matching the axle profile with it in the correct position. Get perfection all around.
And tweak it so it slightly binds CW on the drive side, and slightly binding CCW in the other side. To produce a slight tension holding the axle secure with no load.

I think a better tip would be to use 3/16" or even 1/4" steel. I base this on the testing that Justin did and that I posted to earlier.