The real reason for torque arms

[docnjoj]

I was rebuilding my wife's front brakes (V-brake) on her Sun USX delta trike when I happened to check the wheel nuts. Both were really loose. Had she not had 2 torque arms, she could have lost her front wheel.

Yes it is a steel fork, but having both torque arms saved her from a serious accident. Yes it is a front DD motor.

We will now check them on a regular basis, since it is quite easy to tell if they are loose.

Just a word to the wise.

otherDoc

 

[Deafcat]

Time for some blue loctite...

 

[Ykick]

Regen enabled?

 

[pdooley]

i'll stick with a rear hub motor, thanks.

 

[gogo]

We are pilots with as much to lose as those who fly off the ground. Pre-flight checks pay dividends. Even quick visual-only checks are worth the effort.

Thanks for the reminder.

 

[MrDude_1]

i'll stick with a rear hub motor, thanks.

You still need the torque arms, for the exact same reason.... except if you dont do it, you trash the whole frame. He just trashes a fork. Considering that both of you crash the same, I think he wins... :lol:

 

[MrDude_1]

Time for some blue loctite...

or nylock nuts... or some other thread locking nuts.
better than locktite as you can take them off and on without having to have a tube of it handy.

 

[flathill]

Get some nord-locks and make sure to also mark your nut with a line for visible indication of movement

 

[danielrlee]

Get some nord-locks and make sure to also mark your nut with a line for visible indication of movement

This.

Nord-lock washers have completely solved my issue with axle nuts loosening on a 2800W bike with regen. They may seem expensive at first glance, but considering the ease in how they solve the problem, they are worth their weight in gold. Also the tip about marking the nut provides an easy visual check without needing to get yer' spanner out.

 

[WoodlandHills]

If we really want to pretend that we are pilots why not go to Aircraft Spruce and order AN or MS locknuts or drilled nuts and use safety wire? Or is that too authentic/expensive? Racer supply houses also offer titanium hardware with safety wire holes to replace clunky Chinese hardware on axles.

 

[The fingers]

Get some nord-locks and make sure to also mark your nut with a line for visible indication of movement

I mark problem nuts with a little nail polish or white out for an easy visual check. :wink:

 

[MrDude_1]

If we really want to pretend that we are pilots why not go to Aircraft Spruce and order AN or MS locknuts or drilled nuts and use safety wire? Or is that too authentic/expensive? Racer supply houses also offer titanium hardware with safety wire holes to replace clunky Chinese hardware on axles.

honestly?
Its not safety wired because there is nothing convenient to wire it to.
My sportbikes have the axles, brakes and oil filter and oil drain plug safety wired. :lol:

 

[pdooley]

i'll stick with a rear hub motor, thanks.

You still need the torque arms, for the exact same reason.... except if you dont do it, you trash the whole frame. He just trashes a fork. Considering that both of you crash the same, I think he wins... :lol:

no, you don't for a steel dropout bike frame below 1000w. 6k miles later and no issues at all.

 

[pdooley]

how many thousands of miles do you have to ride to no longer be new? i thought i needed a TA when I first built my bike, but some seasoned people on this forum said I don't for a steel dropout frame. So I went without it, and he was right. if i ever do have a problem, i'll be the first to admit it right here.

 

[Sean9002]

i'll stick with a rear hub motor, thanks.

You still need the torque arms, for the exact same reason.... except if you dont do it, you trash the whole frame. He just trashes a fork. Considering that both of you crash the same, I think he wins... :lol:

Ive experienced a snapped swing arm, rear wheel and fork in different crashes. I will take the swing arm or rear wheel failure ten times out of ten.

loosing your front wheel or fork means hospital time and rehab.

 

[Sunder]

Maybe I'm talking out of my *cough* here, but I've accidentally rode a (non-electric) road bike with no skewer in the wheel, and well, I'm still alive. I didn't even notice until I put the bike away.

No, seriously guys. I fit the wheel, forgot to put in the skewer, and it was totally fine. Unless I got air (not likely on a roadie), I can't see how the wheel can come out, and even then, the V-Brake would have provided some resistance along the tyre (28mm on a 19mm rim).

I can imagine that it might not be quite as safe with an electric bike, especially one with suspension, but seriously, when I need to service the eBike, I need a hammer to get the motor out of the dropouts. While I'm not advocating running without nuts, I can't see this being as suicidal as people are making it out to be.

 

[amberwolf]

It depends on the fit of things, the depth of the dropouts, strength of metals, etc.

In the case of a non-motor front wheel, I imagine that hitting the "right" pothole or bump or curb at an angle sufficient to push the wheel sideways could push against one dropout and pull out of the other, if the skewer or axle nuts were missing or very loose, and the dropouts shallow. I also imagine the sudden stop this could cause might vault the rider over teh bars.

Thankfully that hasn'thappened to me yet.

For motors, I've experienced spinout of a small geared hub in teh front because of insufficiently tight (though not really loose) axle nuts, no torque arms (I might have had torque washers, can't remember, was first geared hub on DayGlo Avenger). Because the motor stopped working I was spared the possibility of it coming out of the fork...it did slightly spread the droupouts apart, too, so if it had been alloy it probably would have snapped them off and been much more likley fpr tje wheel to just come off the fork. :/ Luckly it was softe steel so it didn't do that, eitehr.



As for wehter toeque arms are reuqired or not, for any power level, that depneds on not just steel or aluminum and hardness of either, but also on widthe of teh axle flats, thickness of drpoputs, tightness of fit of axle into dropuots, whether or not regen is used, geared or DD hub if there's higher torque with one vs the other, etc.

 

[dogman dan]

I rode 2000 miles with no torque arms on a front hub. Steel fork. But it's kind of like wearing the seat belt with the air bags in your car. If shit happens, you are better off with both. So nothing happened while I rode those 2000 miles. What the hell does that prove, other than nothing happened to me?

Rear wheel a bit different, what happens if a wheel jumps the slot is not quite as likely to knock out all your front teeth. So a stout steel frame may not need torque arms so much.

I say always at least one torque arm on front hubs though, since if shit happens, an unexpected header over the bars to paved road usually hurts a lot. I did it 8 years ago for another reason, and I still feel pain every damn day. Buy hey, much better to save the $40 and take the risk.

Re the road bike and no skewer, that would not have worked riding dirt. I had my brothers loosen my front wheel nuts once. Riding the dirt track in the backyard, they thought what happened at the jump was really funny. I didn't. No brake calipers trapping in the tire though.

 

[Ykick]

So nobody suspects regen for loosening axle nuts?

 

[docnjoj]

Get some nord-locks and make sure to also mark your nut with a line for visible indication of movement

Yep it has Nordlocks and no regen. I believe it started the last time she had to ride home about 4-5 miles with a front flat. Shoulda done a preflight after but I thought I got them tight. I hate to use loctite cause even the blue stuff makes removing the wheel tough but if this happens again I will. The green loctite can be applied after the nuts are set, and holds quite well but is still removable without heat. Marking the nuts is a great idea and I will do it today with the Dremel. Thanks flathill and fingers.
otherDoc

 

[Ykick]

Are you sure about the regen? Many controllers apply a small regen 100% of the time.

With my setup(s) the CA can be in circuit with no battery connected. Pedal or roll the bike it (CA) will power up. Obviously, the motor/controller’s regenerating.

Maybe it’s not much or maybe it is, we don’t know without further investigation? But any rocking back/forth can eventually loosen axle nuts.

I’d venture to guess the number of people using any sort of thread lock compound is fairly small. Shouldn’t need it and if you do, it would warrant further investigation IMO.

 

[999zip999]

My Nordlocks are worn out and need replacing. I just forget.
Yes I'm more safety checks on my ride.
Just a reminder.

 

[MrDude_1]

My Nordlocks are worn out and need replacing. I just forget.
Yes I'm more safety checks on my ride.
Just a reminder.

yeah.. i didnt know what Nordlocks were.. so I googled it.
Good video here:
https://www.youtube.com/watch?v=mgwmuZuJ02I

 

[amberwolf]

Are you sure about the regen? Many controllers apply a small regen 100% of the time.

With my setup(s) the CA can be in circuit with no battery connected. Pedal or roll the bike it (CA) will power up. Obviously, the motor/controller’s regenerating.

That is different from regen--that's just the body diodes in the unpowered FETs rectifying the 3-phase AC from the motor into DC.

That is a fairly low voltage compared to what regen usually generates (which can be an active regen, switching FETs in a way that creates current/voltage spikes on purpose).

For the simple rectification to work and create any braking/feed current back to battery, the motor would have to be spinning faster than the battery voltage at that time would be able to spin it.

 

[rojitor]

Never ever mount front hub without C washers and dual torque arm. And nordlocks also highly recommended.