Advise with which Bike to convert

[paulhipwood]

Dear All
I bought my LAST bike just over a year ago. It was bought on the understanding that this was my last one.
I commute three times a week, 13 mile each way. I do not have the energy to do more. So I am thinking of converting one of my bikes to a front drive hub motor.
They are

Titanium 700c touring bike
Thorn Raven Sports tour (Rohlof hub) 26 inch wheels.
Moulton APB - did have 3 speed hub and 7 gear derailier, will convert to 9 or 10 speed. This has 20 inch wheels.

Oh there is a Dahon folder and an old tandem in the cellar as well.
I do not need too much assist so think a 9Ah battery will do the job. The idea is to power to work and then cycle home.

I do not want to convert the titanium bike, that is for nice days.
So the choice is between the Thorn and the Moulton.

The Thorn has carbon forks - not to sure if they are a good idea with the extra torsional forces from a powered hub. Its fairly heavy bike but has a very wide gear range, this is easiy to alter by changing the front sprocket.
The Moulton is also not light but has a very comfortable ride. My concerns are that the front forks have some suspension links that are within the 100mm spacing. There is a chance that they may foul the hub body.

Has anyone converted any of these bikes.

I am considering an 8Fun 250W 36V with a bottle cage 9Ah battery.

Any comments or suggestions.
I have been browsing the site and see there are some very interesting projects going on
regards
paul

 

[eddieo]

The Thorn silly.........NEXT!


joking apart: Hi Paul and welcome to forum! I thought about a thorn bike last year when going for a kit, but went for the specialised crosstrail ltd disc (cheaper, nice spec) the Rolhoff hub is a good match by all accounts and becoming popular on e bikes in Germany....

Wisper had a thorn bike with DaaHub kit fitted which I demoed before buying the kit, there are a few kits around some cheap some a good bit more.....but I like the DaaHub as it puts the battery weight in triangle and with front motor the bike is very well balanced compared to a lot of e bikes.

I think they are OK with carbon forks as well but best ask? not the end of the world changing forks anyway. you get the wheel in a bag and it is easy to swap back, remove battery, leave wiring loom in place and bike is non electric again...if you ever want this.

 

[Deleted member 4366]

It's not good to put a hub motor in carbon forks, so you can forget the Thorn. You don't want to convert the Titanium, so that only leaves the Moulton and even that won't be easy. have a look at this thread that will explain some of the problems:
http://www.pedelecs.co.uk/forum/electric-bicycles/10584-electric2011-dahon-jetstream-p8.html
Your best solution will be to buy a ready-made electric bike as it won't cost much more (if any) and it'll save you a lot of hassle and will be a better outcome. All the low cost ready-made bikes like the Ezee Sprint Primo, Various Kudos, Juicy, and Woosh bikes and others will do the job very adequately.

 

[paulhipwood]

Thanks for the input.
I need the bike to be used as a non electric bike and I think a ready made one will be too dificullt to ride on un assisted. Also I have too many bikes - did I really say that!!!!
I want to put a front hub motor in the bike.
After seeing the post about another conversion of a Moulton I think a 100 mm motor would be fouled by the suspension links.

I don't like the thought of using a carbon fork but can anyone explain why it would not be a good choice.
I am now thinking of possibly changing the forks to a Thorn steel touring fork with extra gussets.

regards
paul

 

[eddieo]

There are a few reputable dealers of good e bike kits on here, wisper, Ezee, oxygen. You would be better of asking them what you can and cannot do. I was told I could fit kit to carbon forks but in the end choose a different bike. it all depends on what motor they are using so no generic answer to your question.

I agree a lot of ready made ebikes (unless you spend a bit) would probably put you of e biking for life

 

[Deleted member 4366]

I don't like the thought of using a carbon fork but can anyone explain why it would not be a good choice.
I am now thinking of possibly changing the forks to a Thorn steel touring fork with extra gussets.

regards
paul

carbon forks aren't designed to resist the twisting forces from the motor.

Why would you want to use it as a non-electric bike? Most electric bikes work perfectly without power amyway.

 

[paulhipwood]

I am sure you are right about carbon forks - I always wonder about their life.

I do not have the room for another bike - so the thought of a project on one of them will end up like another new bike - if you know what I mean.
I want to keep fit so only want to use the electric power to assist me to commute five days a week.
I can only manage three days a week at present due to tiredness.

regards
paul

 

[Cyclezee]

Hi Paul,

Welcome to the forum. As the UK supplier of eZee conversion kits I can supply 20", 26" and 700c front and rear wheel kits from stock suitable for the majority of bikes on the market, but unfortunately carbon fibre forks are not suitable.

If however you changed the forks on your Thorn to steel, then one of our kits would be suitable. We did supply a kit to a customer with Thorn tandem last year and he has been very happy with it.

If you would like to know to install an eZee kit, send an email and I will send you a copy of our Installation Guide.

Regards,

 

[banbury frank]

Hi Paul

I am sure one off these forks will replace your carbon forks allowing you to fit super Ezee kits



Surly Forks | Cycle Products at Wiggle

Frank

 

[catsnapper]

I've fitted a motor to a Thorn Raven Tour with steel forks, also to the equivalent tandem. Thorn make several replacement forks for the Raven range, although plenty of other steel forks would do the job just as well, assuming they have the correct geometry.

The strong steel frame and general sturdy properties of the bike make it an ideal candidate for conversion. The Rohloff makes it easy to always have the right level of assist, without struggling or spinning out.

Alan

 

[paulhipwood]

I could fit this one, looks sturdy enough

Thorn 531 Steel 1 1/8 Inch Twin Plate Fork

regards
Paul

 

[catsnapper]

I could fit this one, looks sturdy enough

Thorn 531 Steel 1 1/8 Inch Twin Plate Fork

That's the one that was on my Raven, a similar heavier duty one on the tandem. I normally use fairly heavy disc suitable trials forks for front motors, but the Raven was fitted with a lightweight Tongxin motor, so I kept the standard forks.
I used it with the motor for just a few months as the frame was too small for me. I wasn't aware of any problems with the forks, although that's no guide to long term reliability.

Another member of the forum, Jerry Simon, has converted Moultons and has plenty of experience with them http://www.pedelecs.co.uk/forum/electric-bicycles/10131-new-project-portable-fully-suspended-ebike.html. Like several other members I've converted small and large wheel Dahons, although the 20" models with narrow forks means a limited choice of front motor.

Alan