what exactly is a torque arm

truckerzero

100 W
Joined
Apr 9, 2008
Messages
286
Location
fenton ,mo (st louis suberb) USA
and more importantly do i need one and whats it for
 
LOL, you've been here this long and don't know?

It's a thing you put on the axle of a motor to keep it from destroying the dropouts. They transfer the torque of the motor to somewhere further away from the center of the motor. Even relatively small motors put loads of force on the drops. Doc's X5 setup sees 4,600lbs of force at the axle :shock:.

You need one because, if you don't, you run the risk of the motor's axle spinning in the dropouts, which can do considerable damage to the system. In a brushed motor, the most that should happen is the controller sees a massive short that looks like you're not moving and try to limit the amps. You're likely to let off the throttle pretty quick, so you don't have too much harm done. If it happens on a BLDC, it could short one of the hall wires and cause shoot-through on the controller, destroying it.

In a really bad case, the motor can split the dropouts (particularly on an aluminum frame) and fall out of the bike. This is bad enough if you have a rear hub motor, and positively disastrous if you have a front. :!:
 
i just wanted a better sum up makes perfect sense to me now
 
Actually, it is only for hub motors. Since you're planning on using a regular motor instead, you'd have no use for a torque arm. You just have to make sure your motor is mounted very securely or its torque will rip it off the bike.
 
thaks cgammer ill probably get a hub motor bike later on id like to have at least have one
"covert "ebike to sneek in and out of a town near me that has banned all electric vehicles from it
 
truckerzero said:
thaks cgammer ill probably get a hub motor bike later on id like to have at least have one
"covert "ebike to sneek in and out of a town near me that has banned all electric vehicles from it
Just put straight-pipes, a big amp and an mp3 player on it:

VROOOOOMMMMMM...
 
I have a Crystalyte system using a 408, and am looking to overvolt. This topic is relevant to me. As well, anyone using a hub motor should get a torque arm, whether they have the hub in the front or rear. Eventually the frame will fail. This is because the motor adds forces that the bike frame would not otherwise be subjected to.

For your safety, for your motor and parts and frame safety, and for the safety of others. It is the responsible thing to do.
 
Its just a wrench.
 
D-Man said:
Its[sic] just a wrench.

Here's my torque arm (I focused on the hub casing so the fancypants torque arm itself is a bit out of the depth of field, my apologies :x ):

IMG_4573.jpg
 
I like the 10 mm wrench!
here is one for like $30 bucks!
GEDC0102.JPG
 
My P2a final "death spin" occurred with just such a torque arm! They are too soft and to loose! Forget 'em!
David(other Doc)
 
Yes I here you (notice this one IS NOT on a bike). But at 72V and 30+ amps a torque arm is essential. I have yet to find one I like so off to the fabrication shop to make my own. Rear torque arms are soo custum also. It is clearly a weak link that I think of on every bump and while cruising fast. Yikes!
 
Toshi, that looks fantastic. Depth of field be damned.

Request more pics and at different angles too. Great design.
 
To put it simply, it takes the forward thrust of a hub motor and transfers it to the frame or fork of the bicycle, or bike, :wink: instead of the axle. Without it, the axle might unscrew, and ruin all the crucial wires.
 
docnjoj said:
My P2a final "death spin" occurred with just such a torque arm! They are too soft and to loose! Forget 'em!
David(other Doc)

Better with one then without.
 
Any good "WIPE OUT" stories out there? Front wheel flying off? Snapped forks at speed? Torque Terror?
Personally I like my NUTZ tight (ouch ... wrong nutz)!
If you are not using some form of torque arm the recommendation is to tighten your nuts "nose-bleed" tight. :shock:
 
diver said:
I like my nuts played with before they tighten up, but they still loosen back up after a wild ride
Is your drive detachable? Loose nutz will eventually lead to a detachable driveshaft!
Hear here http://98.131.176.65/endless-sphere/Detachable_Driveshaft.mp3
 
thanks for the feed back that black torque arm lookes like what was on my old dirt bike that has a rear drum brake(the kind you pedal backwards to apply)
 
the town that bands all our electric thins is arnold,mo 63026 usa. the actual law bans any motor driven vehicle ice or electric like 50cc scooters gocarts pocketrockets and the like so unless you can register it as a electric motorcycle (this can be done but it has to be very fast and it is a very long drawn out process like regerstering a custome built motorcycle)and plated and isured. My soulution is a ebike that has the batterys and electronics hidden well and just risk it the only reason i just dont avoid the town is my folks live just inside the city limits
 
this is off topiv but sometimes i spend all night trying to get to this site but every link fails to get here and i cant get on the site does anyone else have this problem it is usally from 12 midnight to 6 am i have this problem and only some nights otherwise no problem
 
Back
Top