RVD72

bought a brompton!

yes, i will upload pics when it arrives but i just got excited.

i read some other posts in here that basically said that eventually "all roads lead to brompton" in the folding world and i think that's correct. i spent most of the past few weeks agonizing over getting another bike (i already own 6) but justified this purchase by saying that i have my old road bike for sale right now and it should fetch more than enough money to cover this bike, i deserve another bike after living car-less for a few months, etc.

i bought a dahon speed d7 in late november and that was my first folding bike. i also like to mess around with electric bike conversions so i converted that bike to electric. it's pretty cool and i like it but i'm not that happy with the fold and i'm not crazy about it's lack of roll ability when folded. weight isn't great but i expected that when i put an electric hub motor on the bike, etc. but anyway...

i almost decided to get a bike friday because of the speed of the fold and how well it rides.

i almost decided to get a xootr swift because of the lower price tag, standard parts, etc. i could have gotten 2 xootr swifts for the money...

but i just think that the fold of the brompton is just way too cool and elegant so i decided to get one.

however, i didn't really want to buy a new one…even if i can save just a few hundred bucks i would prefer to buy used. there isn't a whole lot of used inventory on ebay, craigslist, etc. i would prefer not to buy used from the UK and ship it here.

anyway…in the end, i bought a used brompton and it is scheduled to arrive next week (2/20) via ups. it's a M6R and includes the brompton B bag, i didn't really care which handlebar i got but the M is pretty popular. i wanted a 6 speed. i wanted the R but could live with the L. i like having a luggage rack and like the better rolling with the luggage rack and ez wheels.

it's red/black and also comes with the telescopic seat pillar, schwarbe marathon tires, and ez wheels.

i have a nice brooks saddle from another bike that i will use on this one. it is currently on my dahon but i'll probably move my brooks to the brompton, dahon saddle from my full size electric to dahon, and put in a cheap saddle on the electric.

i may try to sell the B bag to help recoup of the costs as this was a little bit over my budget.

i don't need the telescopic seat pillar since i'm not that tall. anyone want to trade for the regular seat post + cash?

i'll probably get the brompton bike cover and maybe explore some other minor upgrades.

and yes, i will post pics when i get the bike! i know i know...pics or it didn't happen….

RVD72

and oh yeah, don't worry...i'm not gonna touch the brompton with anything electric. it'll be pristine...

Dynocoaster 

Congrats, did you get the orange Brompton with the Brooks that was on Ebay?

RVD72

Lol I was looking st that one. Orange is my favorite color but the girl raised the starting price from 1200 to 1300 and this other deal was better. Someone else bought it though on ebay anyway.

jerrysimon

My EBrompton has transformed my commute and my working day




Adds 3kgs to the weight including motor and small DIY battery.

Regards

Jerry

chagzuki

I wish I had the skills to replicate what you've done Jerrysimon, it looks awesome. Too complex for me, I barely know what electricity is. . . well, I saw a BBC4 program on the subject the other day and now I almost know.

RVD72

nice work jerry on the conversion.

i generally like the rear hub motors a little more than the front hubs because i prefer the weight to be more in the back.

i like my dahon electric conversion but the bike is a little heavy with the batteries. my hub motor is only around 3kg (6 pounds) but the batteries add another 5 pounds or so and the controller is fairly negligible but we're still talking over 10 pounds in weight which was the best i could do. my range is about 20 miles in this setup but i use lipo so i can add more for longer trips fairly easily.

anyway, i've seen a few other brompton conversions and they look nice but i think this time i'll resist the temptation to put an electric motor on it.

bdi121

Jerry, Could you show us your bike with the battery attached please. Thanks.

RVD72

i am pretty sure that his battery (and controller) will be in a bag that is attached to the front of the bike. the bag with batteries will add another 3-5kg (or more?) so the bike will be fairly front heavy since the hub motor is on the front wheel.

the bike when folded without the bag isn't too bad but if you fold the bike with the batteries in the bag, it will be pretty heavy. good thing you can cart the brompton around...

bdi121

I wonder , can we modify a power drill battery to run the electric bike motor ? It'll solve the weight issue, enough power for your daily short commute and attach another baterry the next day - most good power driil comes with two batteries. My Electric bike motor runs on a 36V battery.

RVD72

Yes, you can use a power drill battery. It's actually fairly common to use those as a battery source.

However, I believe that for the weight, using lithium polymer (lipo) is best. The only issue is that the chemistry is a bit volatile so you need to be careful when you charge. You also need to make sure that you don't discharge too much, etc. In short, there's no BMS (although there are some build it yourself type) that makes using lipo idiot-proof.

Also, don't underestimate how much battery you actually will need. My commute is 16 miles each way so even at relatively slow speeds (20mph or so), it will require about 8ah or so of battery at around 44v. This is more than your typical single power drill battery.

In any case, I think I may fiddle around with an electric conversion after all. I will likely get a Crystalyte 206 or 209 front hub motor and lace that onto a 16" wheel. This will be my first time using a front hub motor kit but I think that's the best way to go for the way that the Brompton is made. The front wheel also makes it easy enough to just take the electric wheel off and put in the factory wheel when i don't want to run electric.

jur

Power drill batteries are usually lower voltage. I don't recall seeing one which has 24V let alone 36V. There might be 18V but that is too low.

RVD72

yeah, we just take those and put them in series to create the voltage that we want. We also parallel them for the range that we want.

My friend Ambrose takes the Bosch FatPacks and then takes them apart: https://ebikerider.blogspot.com/2010/...-fat-pack.html

He also uses the batteries off of Makita.

It's not hard but for electric bike usage, you really need a minimum of 36v. 24v systems are way underpowered and everyone will be unhappy with those.

bdi121

Great news , Hitachi has a 36V Lithhium Ion Hammer Drill model and probably have a built in LiThium Ion idiot-proof circuit.

I have a brushless motor which has almost no friction , allow me to pedal normally, use the motor only on hilly terrains and conserve my battery reserve.

My current convertion kit - full size bike - last me two weeks on a single charge . Commuting 12km return trip from the train station. My "brick" size battery weight 3kg , alone.

jur

What's the motor maximum rpm?

bdi121

Jur, i can't find the RPM info but it's a geared brushless 200W motor , 35km/h maximum speed and 10amp battery .

kamtsa

Lipo fire is one of You Tube more popular topics. For example https://www.youtube.com/watch?v=W0tE_ohirhI . Some tool manufacturers such as DeWalt use A123 chemistry which is considered to be safe.

BTW, Brompton are supposed to come with electric assist upgrade. Search for 'brompton project X'.

RVD72

yeah lipo fires are pretty fun. i wouldn't recommend it if you don't know what you're doing but luke (this guy in the endless-sphere forums) does some pretty cool lipo abuse videos.

a123 is the best chemistry out there when it comes to the balance of output, weight, and safety.

jur

My company developed LiPo batteries for military use in backpack radios (25 years ago now), and one of the tests involved a steel frame which dropped a sharpened rod onto a cell, to simulate a bullet striking a battery pack. Many of the cells exploded like a grenade. I was amazed when I saw it for the first time. Cells which just blew smoke or a gentle fire were considered acceptable.

RVD72

Ok my Brompton arrived today! It's nice. I bought it from a guy who also included the Brompton B Bag so he shipped it to me in the bag and the bag in a box. There was basically no padding in the box and we all know how rough the UPS guys can get with a box like this. I am pretty sure that the box was tossed from one side of the warehouse to another and tossed into the truck, etc.

Overall, the bike arrived in good shape. There were no obvious signs of damage. The fenders did get bent a bit so they rub against the tires. I am carefully trying to bend them back into the correct position.

The wheels are not totally true. This may be from the previous owner or it may have been from getting knocked around. Either way it's not that bad and something I can play with on my truing stand. The rims do rub slightly against the brake pads.

I do like the fold and the factory Brompton saddle seems fairly comfy. I have a Brooks saddle that I will likely put on but it's one of the Brooks saddles that also have a spring so I'm afraid that it will make the fold a little bigger since the saddle is higher. But I'll probably do it anyway.

I have the telescopic seat post. It's actually nice because I can just pull out the saddle and top part of the seat post while the main seat post stays in. I think I'll keep it.

I bought a S bag on ebay so I will likely have to get a mounting block soon. I also plan to get the Brompton cover as well.

I'm not convinced that this B bag is all that good. I think it will do a decent job protecting the bike if you also fill up the bag with lots of padding like clothes and stuff like that so that the bike can't move around. If you just stuck the bike in this bag and checked it in as luggage on an airplane, I'm pretty sure the bike will show up in pieces on the other end.

RVD72

Here are some pics starting with the bag, unwrapping, folded, unfolded, and lots of random bike porn.

2011 Brompton M6R with EZ wheels, telescopic seat post, Brompton B bag, standard saddle. Red frame, black handle/chain stays.

RVD72

continued...

RVD72

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kamtsa

Great pictures and great looking bike. Is that bag padded inside? Can you add a pic of the bag's inside. I have a hard case but it weight almost as much as the bike itself.

RVD72

No the bag is not padded. It is a strong fabric so it won't rip but there is no padding.