Folding electric bike

[Woosh]

To me at 18Kg with battery, its pretty much the limit of what can be picked up, put in the back of the car etc. Even without the battery pack (-2Kg) its still a struggle to handle.

True. The Brompton is particularly easy to carry using the saddle as a handle, the weight front/rear distribution is pretty much balanced.
The Rambletta is not too bad on this regard, it has a carrying handle built into the frame:

You still need two hands to lift it up, one hand holds the handle, the other the saddle or the rack.

 

[StillFindingMyWay]

The larger the rear sprocket (number of teeth) for a given chain ring at the front, the faster you have to spin the pedals.

For example, with the 14 tooth rear sprocket on the Stow Away and Basis, for 15 mph you will be spinning the pedals at nearly 80 turns per minute, nearly one and a half times per second, which some find too fast for general riding.

With the 11 tooth rear sprocket on the Rambletta, for 15 mph you will be spinning the pedals at about 59 turns per minute, once per second, a comfortable speed.

It all depends on how happy you are with spinning the pedal fast in your usual riding
.

Thank you for your explanation of this. That helps. I appreciate it

 

[StillFindingMyWay]

I have a folding eBike, a Swytchified Brompton.

To me at 18Kg with battery, its pretty much the limit of what can be picked up, put in the back of the car etc. Even without the battery pack (-2Kg) its still a struggle to handle. Maybe its old age.

Thank you. I thought Brompton were the ideal. It wouldn't have occured to me that they could be heavy. A lightweight bike is key for my search as it needs to go into my Motorhome and of course, there will be times when I need to lift it, in and out of my home

 

[StillFindingMyWay]

I have a folding Basis Finch from eBikes Direct and this uses a 'universal' battery which can be bought relatively cheaply from eBay and shared with my bigger eBike. It offers good performance, accommodates a +34" inside leg (which the Rambletta disappointingly doesn't) and cost about £749 at the time of purchase.
I take a smaller 10Ah battery on camping trips then use it with a 15Ah (£299) battery at home.

I have to say, that this idea of switching batteries is really appealing to me. However, the Basis Finch is not in stock. I wonder if there are any other bikes that can do this?

 

[StuartsProjects]

Thank you. I thought Brompton were the ideal. It wouldn't have occured to me that they could be heavy. A lightweight bike is key for my search as it needs to go into my Motorhome and of course, there will be times when I need to lift it, in and out of my home

A Brompton Electric C-Line is quoted at 17.4kg plus;

Brompton Electric C Line | Electric Folding Bike

Foldable electric bike from Brompton - the C Line electric. Compact, light and powerful you'll arrive in style on a C Line folding e-bike. Shop Now.

www.brompton.com

So by the time you add the rear rack and some better easy wheels, my Swytchified one is around the same weight. Although with the battery bag removed its around 2 - 3Kg lighter.

However, that for all Steel Bromptons.

There is also a P Line Electric, Titanium rear frame, 16kg at only £3775.

There is a full titanium\carbon non electric Brompton, only 8Kg and a mere £4,400. But its got Carbon forks, so its not suitable for adding a front hub motor, and even if you could, by adding the titanium forks for instance, you would loose the 7 year warranty.

18Kg is too much for me, so I have just bought a second hand Brompton, 3 years old, that had a lot of titanium stuff on it. Currently making some changes, and the finished Bromton, as a non-electic should be around the 9Kg mark. I will likley ride it a bit as non-electric to see how I get on, but converted that could be an 'electric' weighing a bit over 12Kg, if the battery is small.

 

[guerney]

18Kg is too much for me, so I have just bought a second hand Brompton, 3 years old, that had a lot of titanium stuff on it. Currently making some changes, and the finished Bromton, as a non-electic should be around the 9Kg mark. I will likley ride it a bit as non-electric to see how I get on, but converted that could be an 'electric' weighing a bit over 12Kg, if the battery is small.

It's good to hear you've gone titanium with your Brompton, as you've mentioned being interested in doing so on earlier posts. An electrified 12kg is very light. The lightest titanium folding bike I've ever seen is the Panasonic Traincle 6500/7500 at 6.5kg/7.5kg, but single speed, sold only in Japan, only suits riders less than 5'5" in height and weighing less than 80kg. Although not titanium, there's also the rarely mentioned Fnhon Gust (Fnhon used to make frames for Dahon), which someone might be able to make quite light. It's available as frame only, the advantage of which is that standard gearsets can be fitted. But an electrified Gust wouldn't be anywhere near as light as 12kg. I do hope you'll upload photos of your conversion, if you convert it.

 

[StuartsProjects]

It's good to hear you've gone titanium with your Brompton, as you've mentioned being interested in doing so on earlier posts.

I was tempted to buy the T - Line, but an electric conversion does not seem possible. Apparently the titanium forks that are available from Brompton wont fit on the T-Line. The Velospeeder possibly, but that would void the warrranty, which potentially is a lot of money to through away given the Bromptons 7 year warranty.

I will have titanium forks and titanium rear fram, bottom bracket, seatpost and most steel bolts replaced with titanium.

Its not clear if the titanium forks can handle the torque of a front wheel motor. The steel forks seem to, given the number of conversions that are done, but were not designed to, and on the Electric Brompton they use a different steel fork, getting rid of the hole for the tab washer in the drop out blade.

One big weight saver is to dump the 3 speed Sturmey Archer type hub gear. The standard two speed wheel that uses a pusher arrangement for the derailleur can be fitted with a 3 speed setup. 3 Speeds might not seem a lot, but on the Swytch Brompton I rarely change gear anyway and had recently been using it for shopping trips and only after a couple of days noticed the gear changer chain was disconnected at the hub.

The Brompton seems very popular out in the far East, with a huge variety of spares and replacements available. You can even get 7 speed derailleur setups for the rear, carbon wheels, all sorts.

Whether I will pay the circa £1000 for a titanium main frame or £500 for the steering tube, will depend on the weight the pre-conversion bike gets down too.

 

[guerney]

Its not clear if the titanium forks can handle the torque of a front wheel motor. The steel forks seem to, given the number of conversions that are done, but were not designed to, and on the Electric Brompton they use a different steel fork, getting rid of the hole for the tab washer in the drop out blade.

Titanium flexes more than steel - would the hub at high torque cause the fork to twist, and twist back again after power is reduced? If so, that would of course change the bike's trajectory a bit, but hopefully not much?

The Brompton seems very popular out in the far East, with a huge variety of spares and replacements available. You can even get 7 speed derailleur setups for the rear, carbon wheels, all sorts.

That's very interesting, and good to know in case I ever consider buying a Brompton. I can't cope with the idea of coping with 16" wheels, fearing they'd be too squirrely for the impaired sense of balance I appear to have these days, due to my failing eyesight. I'm ok with 20", think I'll stick with those.

Whether I will pay the circa £1000 for a titanium main frame or £500 for the steering tube, will depend on the weight the pre-conversion bike gets down too.

I'm looking forward to seeing a thread detailing your build.

 

[StuartsProjects]

Titanium flexes more than steel - would the hub at high torque cause the fork to twist, and twist back again after power is reduced? If so, that would of course change the bike's trajectory a bit, but hopefully not much?

Possibly. When I got the 2nd hand Bompton it came with all the old stuff too, so I have a spare set of steel forks, in case.