Help! Torque arms

[Neilgtis]

Hi
Just a question about where to place torque arm on front forks seen conflicting photos
Where they are in the same direction of rotation ie clockwise and sone anti clockwise see photos
Neil

 

[matthewslack]

Hi
Just a question about where to place torque arm on front forks seen conflicting photos
Where they are in the same direction of rotation ie clockwise and sone anti clockwise see photos
NeilView attachment 46889View attachment 46890View attachment 46891

The middle picture correctly shows the directions of driving torque and resisting torque.

With this design of two piece torque arm, it does not really matter which side of the fork leg it is placed. The small bolt linking the short arm to the long arm is essentially a pivot, not a torque transferring joint. Thus the hose clamp is not resisting rotation, but is there to stop the link sliding up and down the fork leg.

Behind looks neater, in front behind loads the long link in tension, which is kinder to thin metal, but the forces involved are likely small enough that that doesn't matter.

Edit: behind loads in tension, not in front. Duh! So no good reason to be in front.

 

[PC2017]

I think I have the last one, shame really. Are your forks steel?

Always a good idea to inspect cables...

Just a quick post, I am getting new steel(chromoly) rigid forks fitted, [oxford cheap(ish) make £40 but look really nice in person] to save the LBS some hassle I removed my motor and brakes etc. Upon inspection of my long motor cable I came across two areas of wear one inside the axle near to...

www.pedelecs.co.uk

2nd to last post my pics.

 

[Nealh]

If a one piece arm it matters not but with a jointed arm the then the center pic.

 

[Neilgtis]

Suntour xcm I think they are aluminium

 

[Bonzo Banana]

I think if you have a regen motor then the forces reverse so really its just a matter of removing as much play as possible or maybe having two torque arms one on the front of the fork blade and one on the rear of the other blade. Steel forks obviously help here. Where you might only need one torque arm or no torque arm depending on motor power with a steel fork you might need one or two with aluminium forks.

I may be shot down in flames for writing this but I would of thought the best fit so as to eliminate play as much as possible was the priority so getting the torque arm to line up as well as possible with the fork blade which might mean front or back depending on design and shape of fork blades especially with regen where forces reverse anyway.

 

[Neilgtis]

Thanks for all you comments
I understand what the bolt and clip are doing now
They are basically holding the plate that goes on the axle to stop the motor chewing the aluminium dropouts I will fit it behind
Neil

 

[Woosh]

Hi
Just a question about where to place torque arm on front forks seen conflicting photos
Where they are in the same direction of rotation ie clockwise and sone anti clockwise see photos
NeilView attachment 46889View attachment 46890View attachment 46891

you have to fit a pair of torque arms, so it does not matter (the torque on the motor axle is clockwise on the left side, anticlockwise on the right side) but for aesthetics, the middle picture looks better than the first.

 

[Bonzo Banana]

I have a question that seems a good fit for this thread. Some people use rubber matting or similar on the fork blade to secure the bracket. It's not included with any kit but what is the best material for this. A bit of old inner tube or just some thin rubber matting perhaps originally from bicycle light fittings etc. I've seen people secure them directly onto the fork but seems more likely to move under load.

 

[PC2017]

one piece arm it matters

I'll take it I am wrong again Not to fussed I just want to see if that t-arm worked + steel forks max 600w

rubber matting

I had some spare heat shrink, I did the t-arm and the clips, it may wear with time it seem to protect during install.

 

[Blox]

On a front fork, one side is trying to push the clamp up, the other to pull it down. If I was running a front motor I’d have two torque arms for what those thin cheap jobs cost, one side pulling, other pushing.