jerrysimon

This is my wheel. On the TopBikeKit website it says their motor is 1.6kg which is impressive. Are they quiet ?

I hope I am not hijacking this thread just say I use to post several times every day on this forum for years when I was learning this stuff. If you are interested here are my Tongxin 36v, 180w, 260RPM, 28h motors. Not sure if you can still get them. They are only three wire not hall sensored. The beauty is they have steel roller bearings inside not gears so are vertually silent when running. I use to purchase them in pairs as it was cheaper direct from China for shipping. No Paypal back then, so we paid up front directly into accounts and often waited 6 weeks for delivery with no guarantees! The Chinese to English transulation often ended up confused hence we ended up with motors with roller brakes on them, wrong number of holes etc etc. It got better and the sellers always delivered and were honest. It really was an act of faith sending them money. They were 80mm widebetween shaft bearings, 120mm diam and needed spacers to stop the forks fowling, so the Brompton forks needed to be spread about 8-10mm and fork cutouts widened for the larger motor shafts! Just over 2.1Kg, maybe new ones are much lighter now ? PS just re-read thread and looks like the ones you are using now are a little bit lighter. When we fitted these they were at least 0.5kg lighter than the equivalent traditional geared motors. Maybe the ones now are also higher than powered ? These draw about 2 amps when you pedal assisting on the flat and a max of about 6-7amps (set) when you are going up a hill. There's only one in Cambridge! With the controllers back then we could re-program it to ensure we kept the current down and stopped them slipping on their clutches etc.

If you want to learn how to build wheels then 16/20" is the place to start. Plenty of youtube howtos and info on line. Small wheel builds are easy. I had to learn as 13 years ago it was impossible to get anyone to do electric hub builds for Brompton/small wheels. Radial makes it even easier. Years ago we did posts on here about how we learnt. I can now do large wheels including rear wheels/dishing etc. I am not an expert, but have built loads for my various bikes which have performed perfectly well. Here is a few builds I have done on the Brompton wheels. From left to right SRAM auto change 2 speed which was on my Brompton for a while. Two speed rear Brompton wheel and a radial front on a double walled Brompton rim.

Looking again at SJSCycles it appears some Brompton rims are only suited for rear/hub builds and as the spokes are crossed I guess that is why the angles are more and thus the holes drilled at an angle. They specifically say not for front wheels/two speed rear wheels or radial built wheels. As I said as long as the spokes on the electric motor hub are built radial, straight drilled holes would be fine. I guess you could use the double rim Brompton front wheel rim shown below, but to be honest all mine are single walled and have lasted years. https://www.sjscycles.co.uk/rims-tape/brompton-16-x-1-38-349-standard-drilled-double-wall-rim-silver-28-hole/ We did also use the Sun CR18 double walled rims but they were a nightmare to get Marathon Plus tyres on!

Last post today We use to use these which are single walled but obviously now you can get better double walled ones for the Brompton. Back then all Brompton rim holes were drilled straight whereas now, for the rear at least, I think they are drilled at an angle. https://www.sjscycles.co.uk/rims-tape/16-x-1-38-349-standard-drilled-single-wall-rim-silver-28-hole/

When we first built them we use to lace them up 1X but soon realised that radial lacing was sufficient (strength wise) for such small wheels. This also made the spoke angle and building more managable/simple As you can see on the wheel in the front of the picture (black Brompton) this was a 36H motor hub. Back then we managed to get the last few 16" ETRO 349 wheels that were drilled 36h. That was one of the first wheels I ever built, but as I said later we got motors with 28H which made everything much easier.

All I recall (is was 13 years ago) the ones provided ready built from China use to have a generic 16" rim that had an ETRO of 305 whereas the Brompton rims are ETRO 349. The other challenge back then was the motors only came with 36h so could not be laced into a standard Brompton rim which was 28h. That changed later when they made us motors with 28h. As long as your motor is 28h you should be able to relace it up easiy in a stock Brompton rim Again with the angles of the radial lacing somtimes we use to put copper washers on the spoke head (on the hub flange) to help seat them properly. The countersink on the hub flages were not machined very well. I suspect things are better now in terms of the hole drilling and counter sink on the flanges.

Yes on my 100mm hubs from memory, I think they are around 118mm. Radial builds are quite easy just lace up, bring up to tension and then work round keeping the rim straight and circular as you can. Loads of youtube videos show you how

The eletric hub will be much larger than the stock one, so very unlikely.

Probably Lithium Polymer which I used a lot in RC Flight (super light) but prefer safer Li-Ion cells on an ebike. Mine are built into both the older and newer Brompton rims which is not difficult for radial builds, as long as you get the spoke length correct

Meant to add in Cambridge (very flat) I get between 10-15 miles depending on wind. If I go further I just carry a spare. The motor is only 180w so not power hungry, draws less than 5-6amps max and mostly when I am pedaling less than a couple of amps. The solution would not meet requiments of people in much more hillier places!

All my electronics go in one back pocket of the Brompton bag and the battery in the other (it just fits). This keeps everything light, the main bag empty.and means you can carry Brompton in one hand and bag in another We had all the same issues you have found buying ready made up wheel sets re tyres so in the end build our own wheels PS therer are newer versions of mowers and hence batteries around now.

There you go Good quality/safe Li-Ion Samsung Cells with a BMS built in. You'll need a charger and make some kind of connector (mine is also fused) as shown. Made by Spear & Jackson. These are from an older model lawnmower sold by Argos. I have four purchased off ebay as lots of the lawn mowers are returned and ebay sellers buy up old/unused stock and sell bits on ebay.

Li-Ion. Hold on I will take a photo and post.

Years since I posted here but nice to see people still converting Bromptons. I was one of the first on here using a lightweight Tongxin (almost silent) motor sourced and shipped from China in 2010. I'm retired now but the steel one is still going strong. I now use prebuilt 4Ah 36v lawn mower batteries (have quality/safe cells in them and no sag with my setup) which you can pick up from ebay for around £40 and just make a connector to fit the battery. Back then we use to build our own batteries and I did that to keep them light and as I live in Cambridge (its very flat) I didn't need to carry a massive 10-12Ah one. I also converted a Ti Brompton in 2012 with a very lightweight but subsequentally unreliable motor. Here are some pics of both bikes. I deconverted and sold the Ti years ago. This is my original steel brompton now 13 years old (upgraded with lots of newer Brompton parts). All the electronics and battery are in the front bag connected to the bike with an umbilical wire/plug. Back then we could legally use just a thumb throttle which kept it all simple. The Ti which I think was around 11-12kg excl battery ? PS if you want more info I will post details of battery and connector.

Sorry I only have spares left for myself and a few family/friends I have fitted them for. Oh I do still have the KeyDe motor and controller though

The bike stands fine though in its folded state it will sit wonky on the ground as the forks are wider. It does still fold ok but you may need to play around with the cable that exits the hub (cable tie the wire to the forks) as it can effect the clip mech. Yes widening the forks does seem a little blunt/industrial. I have done it several times now on others Brompton's as well. It does require a little brute force but you are only widening it by about 10mm (wider but it springs back) and these forks are steel and constructed well. Like you I was a little concerned when I widened mine but in the end just got on and did it. As I said you can always buy a new pair of forks if it all goes wrong. Would I recommend it ? Well as I said mine has been fine for 9 years and with 10K miles done on it, but at the end of the day its your bike and the choice is yours

Spread mine over 9 years ago now still going strong after over 10k miles of use.. As per my thread likely you will have to spread them more than 83mm as they spring back. Make up a threaded rod like many have done before. You may also have to open the dropouts a little for the motor shaft. I also adjusted (drilled out the holes for lock washer) so I could use the supplied wahsers with tabs. Unlikely that they will spread evenly and you may have to use washers to space the motor so it does not foul the fork sides. Brompton certainly don't recommend it and you will of course invalidate any warranty. You could always get another pair of forks if it all goes horribly wrong. Many have done it without any problems. I have even spread a set of £250 Ti forks though they failed when I had a crash. Also note the Tongxin motors are only 2kg in weight and rated at 180W over your 2.7kg and 250W motor.

I didn't get charged on the first Boss welder I purchased, but when it failed and I sent it back, I got charged on the replacement The replacement spent ages in customs and I guess they open some stuff up to check ? I usually find I get charged on anything over £50, again I guess it depends on what they put on the package value wise. Of course if they mark things down, then I am not sure where you/they would stand on any postal insurance claim.

Rode my "steel" Brompton to and from work for almost 10 years, though not in snow and ice. Someone commented the other day how good it still looked (Front wheel Tonxin conversion) after nealry 10K miles. I wont be using it daily this winter, as I was fortunate to retire early last March However I use it a couple of times a week now when I volunteer and do Samaritan shifts. My little electric Brompton changed my commute/lifestyle! PS and back in 2009 I have this forum to thank as I embarked on the electric bike adventure.

Saga but you have to be 50 or over

I have found the Tongxin motors ok providing you treat them with some care i.e. no powering up before starting to pedal or expecting it to pull you up hills with no effort on your part. I would admit they they seem to me more reliable in small wheels, at least that has been my experience. In terms of the exisiting electrics you are probably right, a like for like replacement as a simple swap out is probably the easiest route to get him back on the road.

I love how all these companies talk about adding assistance as if they are the first ones to do it or even invent it lol Same on TV. I watched an episode of poshpawn (you can tell I am retired) the other day, as a guy was trying fund a project to build/sell electric bikes. It spoke of him as inventing an eletric bike! This thing did 50mph. No one even seemed to recognise or acknowledge that it was illegal to ride on highways

If you want the same motor they will cost between £100-£130 direct from China, dependant on postage and duty tax. The exisiting motor should have markings on it but my guess would be 36v, 175RPM or maybe190RPM if you want a faster wheel. Again not sure if you need a 36 or 32 hole motor dependant on the existing rim. Send an email to sales@h9.com.cn telling them what you want. This is probably the motor http://www.h9.com.cn/product/?id=336 Thats the V brake one, they also do one with a disc brake fitting. Here is the link for all the motors in that range http://www.h9.com.cn/category/186/ Or as you say the easier route would be to buy a replacement wheel from Cyctronex but of course nearly twice the price. http://no-hills.com/electric_bike_shop/product.asp?strParents=0&CAT_ID=24&P_ID=159

Sometimes we wonder about Chinese and other oriental post but my parcel sat in the UK sorting office from 8/8/17 to today 16/8/17 before it was finally handed to the Korea postal service. That was after I chased them by phone and email to find out what was happening! On the up side Lee (Aulakiria) was so concerned with how long I have had to wait for a repaired unit that today he emailed me to say that he would send out a new unit before mine got back to him and he had time to fix it. Again you would be hard pushed to find a UK supplier that would do that Clearly a top guy!