Advice please

[cogs]

I'm told there are gismos that prevent the front wheel twisting out of the forks under stress (it happened to me today - bafang motor). Anyone know what they are named and where they may be available please?

 

[NRG]

Torq arm.

type 'arm' into the search on here to bring some examples up:

The Grin Cyclery

 

[cogs]

Thanks very much NRG. That is most helpful. I am going to get one - it could save my life..

 

[cogs]

getting hold of a torque arm is easier said than done..

I have sourced one to the States (http://www.ampedbikes.com/). They are $24 with $27 postage! £33 in total, and that is for one. I assume that one would be adequate, but perhaps two are necessary?

At £66 I could get a new set of forks which may prevent the hub twisting out.

Any advice out there?

 

[Streethawk]

How about those washers with a tab that fits into the dropout on them? I dont knwo what they're called...

 

[jerrysimon]

Or make your own

Here

As I understand only one is usually required.

Regards

Jerry

 

[jerrysimon]

How about those washers with a tab that fits into the dropout on them? I dont knwo what they're called...

You mean like this

The ones that go in the dropout themselves would not really offer any benefit in terms of the motor shaft spinning out. The one shown on my Brompton are better (they go into a hole in the fork slightly higher up) but probably best is one that attaches further up the fork arm itself.

What is the power of your bafang i.e. is it greater than 250w ?


Regards

Jerry

 

[cogs]

its 250w Jerrysimon. It is powerful, but I'm about 15 stone

I can't work out why these torque arms are not widely available considering their life saving benefits etc.

 

[jerrysimon]

its 250w Jerrysimon. It is powerful, but I'm about 15 stone

I can't work out why these torque arms are not widely available considering their life saving benefits etc.

I agree its strange how they are not readily available here. The DIY one I linked to was on my first Ebike which had a simlar Bafang 250w motor. At the time I weighed 13 stone.

Most kit suppliers of 250w motors in the UK, don't include a torgue arm. There is mixed opinion about whether you need one on a 250w motor or not.

I took the safe root when I made one myself. If you don't fit one it is important to make sure that everything is seated in the fork dropouts properly i.e. the washers and nuts are flush against the dropout sides. I think the Bafang comes with some washers with lugs that locate in the dropouts. Some forks have raised edges around the dropouts and its easy to end up with the washes and nuts not flush against the fork sides and therefore not clamping the motor/shaft in tight.

If you look at my picture you will see the recess (common in forks with quick release wheels) I was talking about where it is easy to end up with the washer/nut not sitting flush when you tighten it up.

A small DIY torque arm like the one showed in my post, would be more than sufficient for a 250w motor.

Regards

Jerry

 

[NRG]

Peak power will be a lot higher than 250w though, even with the Bafang peaks of over 800w or even 1Kw are possible.


Another on-line shop in the US selling torque arms, not sure of their shipping cost.

Hub motors | ebikessf.com

 

[schoe]

I think that Wisper are selling one as part of their Daahub kit which is due out at the end of this month. If you contact David he may sell you the arm bit separately.

Regards Schoe.

 

[Deleted member 4366]

Some people have used an appropriate sized (10mm I think) open-ended spanner with the the other end cut off as a torque arm. It'll only work if you can find space for it. It probably needs to be a thin one. The open end goes on the axle and the shank runs up the fork leg, where you fix it with a jubilee clip. Best would be to use a pair - one on each side. If you can do it, it could be a temparary measure until you can get a more professional solution.

 

[jerrysimon]

Seems someone has these from ebikes.ca

and is pming people to see if they want one. Looks like a neat job.

Regards

Jerru

 

[theskip1]

a quick cheap alternative is an old spanner the size of the nut with the other end cut of and fixed with a jubilee clip.

 

[Trevor Holloway]

Shouldn't it be the size of the flats on the axle rather than the nut size ?

 

[Deleted member 4366]

Shouldn't it be the size of the flats on the axle rather than the nut size ?

If you had a spanner over the nuts, one side would have the effect of tightening the nut and the other would loosen it, so it might work on one side only, but there's a small danger of stripping the thread. A spanner on the flats would be better.

 

[theskip1]

Shouldn't it be the size of the flats on the axle rather than the nut size ?

sorry yes the flats of the spindle/

 

[Wisper Bikes]

Here is the image of the DaaHub torque arm, they will be available in the UK in early spring.



Regards

David

 

[jerrysimon]

Looks like a very professional job David

Regards

Jerry

 

[Wisper Bikes]

Hi Jerry, we were a little worried too, however after much scratching of heads function had to come before form in this case. The stainless steel adjuster has been utilised so the unit will fit on most bikes.

All the best

David