Torque arm needs for my rear forks.

[wonderer99]

Hey. So after eliminating a mid motor kit for my bike I am looking at getting a 250/1000w switchable rear hub and battery kit. So my research brings me to torque arms and their importance especially on aluminium frames which mine is. However I am still not 100% on how and where to fit them. Firstly am I right in thinking I should be using two, one on each side? If so will there be room for them and also I am not sure how I need to fix them for my bike. I have attached photos of my rear forks and I notice there is a threaded hole on each fork not being used (forgive my lack of knowledge) so is that where the arms can be secured to the forks?

Will two even fit based on 5-8mm each arm?

Looking at the images do you think the bike with torque arms will be suitable for the torque involved. For what its worth I will only be using the 250w mode 99% of the time and maybe have a little more fun on my brothers farm once in a while and maybe up any ridiculously steep hills once in a blue moon. I want distance over speed so the bike wont exactly be being thrashed at high power all the time.

Lastly can anyone advise any decent torque arms suitable for my bike.

Thanks guys.

 

[Nealh]

My feeling is you will regret buying a 250/1000w DD kit as you will need a very good celled battery (min £400 with low ah/wh )to get the best use of a 1000w power.
It is pointless riding around on a 250w hub that weighs 5.5kg, if you want a bit more power go for 48v and 17/18a.
A legal 250w 36v geared hub motor will be enough to suffice and more user friendly, if you want more power use a 22a controller and a good battery as above or you can buy geared hub in 350,500 & 800w all a lot lighter then 5.5kg.

You will need at least one TA for hub gear bike and two for a powerful DD hub, the use of them is to prevent torque from spinning the axle in ali drop outs, if this happens you will short the motor by ripping out/twisting the motor wire.

Geared hub use 12 x 10 axles so will need about 1.5 -2mm of the drop out seat filing out so the axle sits fully deep enough, DD hubs use a 14 x 10 axle so even more filing to go deeper.
A TA has the same hole profile as the axle which has two flat sides, on your bike a neat small home made one piece TA is best made to snuggly fit over the hub axle one or both sides. You can use 2.5mm or 3mm steel to make one and then utilise that threaded hole between axle and brake mount bolt to secure the TA.

Cut a piece of metal approx. the size of the Blue outline, make a hole for the axle and carefully file it to fit over the hub axle snuggly. Once this is done you can drill a hole for the bolt to screw in to the machine hole (Blue dot )in the drop out, then when done you can shape the metal better to match the frame drop out area.

 

[wonderer99]

@Nealh thanks mate your detailed reply. I guess with the 250/1000 kit it is a case of covering all bases should I need them for any reason. It was actually the Cyclotricity kit I was looking at and their 48V 16Ah battery to go with it. I dont mind the extra weight of the hub so much as long as I am covered for most occasions should I need it.

Appreciate the advice on the TA's. I will definitely be fitting two. Are you saying I can fashion those myself in the way you describe instead of paying for some or that purchased ones wouldn't fit on my bike? Sorry for the stupidity. I am happy to purchase a couple if it would be better and/or easier. Would shop bought ones be able to be attached to the forks using those two threaded holes?

Thanks again, the advice here is second to none!

 

[sjpt]

it is a case of covering all bases should I need them for any reason

A couple of important bases a 1000w motor like that rules out are
* Riding on the road without insurance, etc etc
* Riding on any bridleways (with or without insurance etc etc)

 

[Nealh]

Home fashioned ones are all I use so I can utilise one piece design and any nearby unused threaded hole for a tied fixing.
Most available TA are two or three piece items, each piece using a bolt/nut ok on low powered stuff but for 1kw a single solid one piece TA will be best.

 

[wonderer99]

A couple of important bases a 1000w motor like that rules out are
* Riding on the road without insurance, etc etc
* Riding on any bridleways (with or without insurance etc etc)

I appreciate that. I am a sensible guy and have no interest in being silly with the kit. As for the legalities of having the kit I will wait for the legal system and UK suppliers to sort it out amongst themselves. I'm not going to worry too much as I know I will only be using 250w mode anywhere public and be staying within the legal speed limits on road so won't be drawing attention to myself.

 

[wonderer99]

Home fashioned ones are all I use so I can utilise one piece design and any nearby unused threaded hole for a tied fixing.
Most available TA are two or three piece items, each piece using a bolt/nut ok on low powered stuff but for 1kw a single solid one piece TA will be best.

Brilliant, thanks mate. So I guess lastly, coupled with two fitted torque arms the bike itself looks capable of safely holding the hub wheel? Will that battery I mentioned do the job? It is the highest option available on their site for the hub. £400

 

[Nealh]

Do the work and a link to the battery and I will look.

 

[wonderer99]

The hub kit is this one.

High Power mid Drive Electric Bike for Sale | Deals on Cheap Electric Bikes

Powerful 48V 1000W kits from Cyclotricity will get you up a hill with ease, or keep you going strong on longer rides. All the components are designed to work together seamlessly—simply add your bike and ride!

www.cyclotricity.com

This is the 48v 16ah battery listed on their site.

High Power mid Drive Electric Bike for Sale | Deals on Cheap Electric Bikes

An enormous amount of power in a small package.

www.cyclotricity.com

I wanted to go the mid motor route but my bike just won't accept it due to the chainstay being in the way and so rear hub is next best thing. Due to my weight and hilly location this was the kit I thought best.

 

[jeff St.Clair]

Yeah I converted my Specialized Rockhopper with a 250 /1000 watt kit , and used one torque arm on the rear . I bought it on line it looks like this

 

[jeff St.Clair]

Yeah ,Three years ago I converted my Rockhopper with a 250 /1000 watt kit and use one torque arm that I bought on-line it looks like this

 

[wonderer99]

@jeff St.Clair are the forks on your bike aluminium?

 

[Nealh]

There is only a brief battery description, no actual specs for the stuff in side, so can't comment on it.
I still think for a hilly area a DD motor is not the best solution all I can say is buy it fit it then see how it goes, there have been a few who have bemoaned the lack of oomph from these kits on hills and off road.
The DD hub does work but you need ideally to give it more current and voltage above that which these kits are supplied with. I'm no expert on these but someone like danidl may come along with there input.

 

[Parsons]

I made these at work. Work perfect on my bike made some for a member on the forum don't know if he ad tryed them yet

 

[Nealh]

That is how a TA should be small inconspicuous with a flat side hole which is a tight fit over the flat sided hub axle.

 

[wonderer99]

There is only a brief battery description, no actual specs for the stuff in side, so can't comment on it.
I still think for a hilly area a DD motor is not the best solution all I can say is buy it fit it then see how it goes, there have been a few who have bemoaned the lack of oomph from these kits on hills and off road.
The DD hub does work but you need ideally to give it more current and voltage above that which these kits are supplied with. I'm no expert on these but someone like danidl may come along with there input.

Fitness is a big goal of mine as well so I intend in putting in the effort as much as I can when it comes to the hills. Appreciate your help fella. Will see how it goes.

 

[Parsons]

I reckon some of them from work that I can get might work

 

[wonderer99]

I reckon some of them from work that I can get might work

Happy to try mate if you can source a couple for me. How much?

 

[Parsons]

Get you wheel first so I could drill at the right size hole of the wheel axle you will have to line it up with the little hole on your frame and drill a hole on the torque arm as for cost Just something to cover postage

 

[wonderer99]

Get you wheel first so I could drill at the right size hole of the wheel axle you will have to line it up with the little hole on your frame and drill a hole on the torque arm as for cost Just something to cover postage

Thanks mate. I will update you when it comes and fitted (hopefully stress free). Appreciate your help.