New Project - Portable fully suspended ebike

[jerrysimon]

Ok as promised here is a taster post of my latest project.

I have ridden it on my work commute a couple of times now and here it is shown stowed in my work office

Those are 20" wheels. More to follow ..........

Regards

Jerry

 

[jerrysimon]

The donor bike

It is a Moulton TSR 2. It has a Sturmey-Archer S2C, 2-speed, "kick back" hub which also has a back pedal brake incorporated into it. As the bike splits in the middle this helps as there are no cables running to the rear of the bike.

This model also has a belt drive fitted which again makes it excellent for transportation when split, as there is no oily chain.

The spaceframe design is unusal and its often a case of you either love or hate it. Being fully suspended the ride is very comfortable, again unusal for a smaller wheeled bike.

Regards

Jerry

 

[morphix]

How cool is that!? The big question, how much does it weigh fully kitted out? You're leading the way in ultra portability Jerry! I'm planning to have a go myself eventually so I'm taking notes. The SA hub gears is a sensible approach to this kind of usage.. I've been thinking along the same lines for my next bike..but I'm also considering no gears at all and a rear hub motor.

 

[jerrysimon]

Thanks

On my EBrompton I actually went from a 3 Speed S/A hub option to the two speed derailleur gear option. This saved about 0.5kg.

The Brompton TI with the derailleur gear option and a Tongxin would be around 12kg plus 3kg of luggage with controller/battery components. A truly ultra portable Ebike!

On the TRS 2, the S2C hub is heavier as it has the anti rotation arm for the brake. Thus the TSR2 is heavier than my Brompton at about 15kg incl the Tongxin. The advantage being that it splits in two and thus carried in both hands, 6.5kg front 8.5kg rear. A further 3kgs of leccy gubbins/battery are carried in a back pack . I will post some more pics later to show how I have done it.

The problem with a single speed is finding the right gear. Too high and starting off will be difficult, too low and you will spin out, though with a more robust rear motor it may work.

The whole thing is a balancing act. The Brompton definately has it on portability I love nipping in and out of shops with it, though I would not like to cycle on it more than 15-20 miles with its small wheels and being suspended only on the rear.

The Moulton whilst portable is more bulky and could not be easily carried in and out of shops, however it is a dream to ride being fully suspended and I would happily cycles miles on it. I think two gears is the ideal, one to start off with and one for cruising, though again I am not sure that would be ideal in a very hilly arear.

Regards

Jerry

 

[kitchenman]

... you either love or hate it....

I love it!

 

[eddieo]

I love it!

Me to.......!

 

[jerrysimon]

Thanks for your comments.

I have had the bike for nearly a year now and although I have used it quite a bit in the summer, having some lite assist will hopefully mean I can use it more often or work commutes in the winter weather.

I also hate it when my EBrompton is down for maintenance and I have to use the car. Having two ebikes is the answer

Regards

Jerry

 

[jerrysimon]

Just for comparison I cycled my EBrompton into work today. Here it is shown folded and stowed in the same spot in my office

Regards


Jerry

 

[morphix]

Thanks

The problem with a single speed is finding the right gear. Too high and starting off will be difficult, too low and you will spin out, though with a more robust rear motor it may work.

The whole thing is a balancing act.

Absolutely. I have it just right on my current folding 26". I use the highest (6th) gear and have the chain on the largest crank sprocket (it was originally a 21-speed but I downgraded it to free up handlebar space).

Using the highest gear and large crank wheel is only way I can keep up with the motor when pedaling on highest power and I never usually move from the highest power setting. It's just the right balance for me and has made the rest of my gears redundant, I just don't use them. I don't have any problem starting off even unpowered, although it is a bit more effort..but cycling the bike any distance unpowered is virtually impossible. If that happens on my present bike, although I can't adjust the gears on the highest sprocket, I can always slip the chain onto a smaller sprocket and regain the use of my gears in an emergency if my electrics failed. That is something to consider I guess. With a single gear so highly geared I might be up the creak without a paddle if the electrics failed.

 

[jerrysimon]

Ok I took a few more pics now the bike is finished.

All the parts to make one portable Ebike. Rucksack on my back each half carried in both hands. Its not a Brompton but it works for my work commute.

Where the umbilical plug stores.

Inside the bag is a battery left (my DIY 2 * 6s1p pack) and the controller which is all mounted in a tupper ware container lol.

I could have had the controller loose but this keeps all contained and the joints neat. I wanted it to all be plug n play (ride)

Regards

Jerry

 

[jerrysimon]

Controll is a thumb throttle and cutout switch for emergencies. No brake cutouts. The bike only has one brake lever anyway as the back is a back pedal brake.

Fitting the hub motor was a challenge. There is a lot going on up front with the suspension.

I used one of my original spare 80mm wide Tongxins with the roller brake fitting that I have since cut down and trimmed the drive shaft. A 100mm wide motor would not go in and clear the suspension fittings.

Suitable spacers needed to go both sides.

Regards

Jerry

 

[NRG]

Neat Jerry, love the bike!

 

[jerrysimon]

Finally a couple more shots of the controller box.

The setup uses my favourite Bulgin and Speakon plugs from Maplins

Inside the box.

It will also mate with my battery in a box if I want it to keeping it all very much plug n ride.

Regards

Jerry

 

[jerrysimon]

Ready to roll with space in my rucksack for other bits and bobs.

Its faster and a much smoother ride (suspension at the front as well) than the Brompton. The compromise as I said being the Brompton is more portable.

Regards

Jerry

 

[kitchenman]

If you heat one of your plastic boxes I wonder if it could be made to be bottle shaped!

Had to find a new place for my controller due to more config changes!

 

[jerrysimon]

Thanks Alan,

As they are hidden its not really important. I doubt if I did then the lid would fit on

I like those original Tongxin controllers very small and neat to fit on the bike frame or under the BB like Cytronex do.

Regards

Jerry

 

[morphix]

If you heat one of your plastic boxes I wonder if it could be made to be bottle shaped!
View attachment 2898
Had to find a new place for my controller due to more config changes!

That's clever Alan were you lucky to get something to fit that small space or did you have it heat and change the shape? I initially tried to fit my controller like that on the frame as I had a gap but I could see no way to do it so ended up just putting it in my bag.

 

[morphix]

Nice job

Jerry your build looks great, bike looks really tidy and well done! Did you weigh it now its all finished? Also how much did your bike cost if you don't mind me asking, it looks quite expensive.

 

[jerrysimon]

Thanks Morphix. Its not as light as my Brompton. Bike weighs about 15kg incl motor and rucksack another 3kg. In some ways its easier to carry as wieght split in both hands is less than Brompton 13kgs in one. I could not carry it into a shop/coffe shop though like I do with my Brompton

This is currently the cheapest Moulton TSR at around £950. Definately a niche British product. I still think for a fully suspended, belt driven bike its not bad value though.

Regards

Jerry

 

[morphix]

Thanks Morphix. Its not as light as my Brompton. Bike weighs about 15kg incl motor and rucksack another 3kg. In some ways its easier to carry as wieght split in both hands is less than Brompton 13kgs in one. I could not carry it into a shop/coffe shop though like I do with my Brompton

This is currently the cheapest Moulton TSR at around £950. Definately a niche British product. I still think for a fully suspended, belt driven bike its not bad value though.

Regards

Jerry

That's not a bad weight at all, 18kg and it does make a lot of sense having the gear in the rucksack.

I just weighed my bike again and its now weighing 20kg which is not too bad either suppose considering I've 26" wheels and 10ah now. I still haven't finished the bag on mine to allow it to be removed, so all the weight has to stay on it which is not great going up 2 flights of stairs every day!

I would like to do the rucksack approach on my next build but I'm not too sure it would work for me as I carry all my daily mail and packages to the sorting every day in mine and there's usually a lot! Maybe I could start using a rear rack tho on a 20". I did fit a rack to my 26" but the damn thing fell apart and it also added another kg to the weight.