BMSBattery torque arm

[casainho]

Hello.

I would like to say that BMSBattery started to sell torque arm for $15 a pair, which is probably the cheaper in the market. I bought and received 2 pairs (26.03.2012) and I am sharing here some pictures.

They are stainless steel and very strong.







And here a picture showing one torque arm on a Bafang BPM 500W motor (not enough axle to hold the torque arm and the nut...):


They seem to be similar to e-bikekit.com torque arm:

 

[DAND214]

Axle size looks small. $15 a pair and NOT $30 but $41 shipping?
Hope they are good enogh to use, safely.
AM I JUST SEEING THINGS? $41 TO SHIP A COUPLE LBS IN AN ENVELOPE?
Keep us posted, on the quality.

Dan

 

[motomech]

From their Department of Metallurgy and Fine Cheeses :lol:

 

[amberwolf]

Personally I expect those are basically clones of the ebikekit ones, but I have no idea what metal they're made from. Could be recycled beer cans.

 

[dogman dan]

Likely Justin never bothered to patent his torque arm design.

Chances are, thick enough even if somewhat lower quality steel. But 41 bucks to ship? Ouch!

Bear in mind this is the version one torque arm, that is suitable only for non suspension front forks. Alloy front forks have larger diameter, and require Justins second version design to fit well, and definitely you also require c washers for an alloy front fork.

Sometimes the axle piece of this design can be used on the rear. Very often people bolt them on the rear, but it's done in a way that renders the install more or less decorative. What I mean is, if you look at it closely, you see that any rotation of the first piece applies a load to the second piece that will merely slide the hose clamp down the stay. They need to weld the two pieces to prevent this, or have it bolted to the stay, not hose clamped.

They can be used if you have metal under the bolt hole, and can simply bolt the axle piece to the dropout metal. The other alternative requires you to fabricate your own second piece, perhaps to bolt to the disk mount on that side.

 

[casainho]

About the shipping price, I am in Europe and most shipping price from USA shops are higher. Also I buy from BMSBattery all components needed for the electric bicycle, like the motor, battery, controller, throttle, etc, so the shipping is not important if I add the torque arms in a package with the electric kit.

Chances are, thick enough even if somewhat lower quality steel. But 41 bucks to ship? Ouch!

I will use an hammer to find if the metal is hard or soft. I bought 2 pairs to be able to make tests in one pair and destroy it if necessary.

Bear in mind this is the version one torque arm, that is suitable only for non suspension front forks. Alloy front forks have larger diameter, and require Justins second version design to fit well, and definitely you also require c washers for an alloy front fork.

Sometimes the axle piece of this design can be used on the rear. Very often people bolt them on the rear, but it's done in a way that renders the install more or less decorative. What I mean is, if you look at it closely, you see that any rotation of the first piece applies a load to the second piece that will merely slide the hose clamp down the stay. They need to weld the two pieces to prevent this, or have it bolted to the stay, not hose clamped.

Many thanks for the explanation of the possible slide of the hose clamp!! I will for sure weld the both pieces so I have a only one torque arm.
I were decided to built my own torque arms by welding the washers that came with the motor:

Happens that BMSBattery just started to sell the torque arms after I told them about my accident of front fork dropouts broken.

 

[Russell]

Apparently the minimum shipping charge has gone up dramatically since my last order from them. The charge appears to be $41 for many items, like a $19 controller now costs $41 to ship when previously it was around $25. The idea then is to wait until you need several items or one big item then tack on the smaller item in the shipment. Add the torque arms to an order you're already placing, for example a BPM kit at $179.00 + 122.92 shipping, raises the shipping to $126.15, a $3.23 upcharge. Same goes when ordering a battery for $259 + 84.72, adding the arms raises the default shipping charge $3.87. Or...order 100 SETS of the arms at $1,500 and the shipping is $158 reducing the cost to $16.58 per set. :wink:

-R

 

[Racer_X]

One of the most important things is that it is STEEL and not aluminum. I heard of a EU ebike kit seller selling aluminum torque arms, that I would not trust.

 

[casainho]

I will test them and report later.

 

[rojitor]

Good luck with that meu amigo.

 

[miuan]

Guys don't forget these are 12mm arms only suitable for geared motors like bafang and mac! No good for 14mm axles.

 

[rojitor]

Don't worry miuan, casainho is a bafang user.

 

[casainho]

Jack Xie ecitypower@gmail.com told me on an e-mail:

1. what metal are the torque arms ? stainless steel
2. What thickness ? 3mm.

 

[dogman dan]

Should be good. A bargian if you are already having a box sent. For 14mm axles, it should be easy enough to ream one out to 2mm longer hole.

 

[casainho]

I received 2 pairs (26.03.2012) and I am sharing here some pictures.

I were told by Jack from BMSBattery that they are stainless steel. They seem to be very strong, I am very happy with them for now.







And here a picture showing one torque arm on a Bafang BPM 500W motor (not enough axle to hold the torque arm and the nut...):

 

[Russell]

I bought some of these torque arms when I placed my last order with BMSbattery. They have both 12mm and 14mm versions now so I picked up 2 sets of the former and 1 of the latter for a total of 6 arms. I ordered some other stuff too so these ended up running me about $10 a piece. The 12mm versions measured in right at 10mm wide and 12mm long but the 14mm arms were a bit long at about 14.8mm. About half of the arms came with philips head bolts and none had lockwashers. They aren't the best design but they are decent quality and I only really wanted the main torque plates anyway.

I'm using these t-a's on my current work in progress, a Mongoose full-suspension with a rear Bafang BPM motor. The BPM is a torquey motor and while the 'goose has a steel rear triangle the dropouts aren't especially deep so I wanted some added protection. The BPM also only has 12mm axles which are small for this size motor. The 12mm torque plates however fit nice and snug around the BPM's axle. I drilled and tapped a 5mm hole to secure the plate;

View attachment 1


I repeated on the freewheel side...now the Bafang is good and secure :wink:

-R

 

[neptronix]

Oh, they finally have 14mm ones for rear motors. Those might actually be worth buying, then.

I dig the idea of drilling them right into the frame. If you could drill another additional hole to increase amount of torque that can be leveraged, that would be even better.

Do those fit snug on the axle, btw?

 

[Hyena]

I bought a set of these to try a month or so ago with some chargers so the extra shipping was negligable. However the ones they shipped me were tiny and don't even fit a 12mm axle :?
As stated though the design and material seems to be sound enough if it suits your purpose ( and might be half useful now if they offer sizes - silly me for assuming they'd be a common size)

 

[Russell]

Do those fit snug on the axle, btw?

I bought a set of these to try a month or so ago with some chargers so the extra shipping was negligable. However the ones they shipped me were tiny and don't even fit a 12mm axle :?

I bought 4 pc's of the 12mm arms and picked two that just fit the axle. They are snug around the entire axle, which is great, though I can still wiggle them on and off by hand. The other two pieces will need slight massaging to get them to slide on but I prefer that to being too loose.

-R