250w vs 500w for 120kg person + panniers!.

[ALTrooperUK]

Hello,

My preferred choice of motor was a 500w but upon checking the UK law it seems you can only get a lousy 250w motor which is a big disappointment!. I am still keen to purchase a 500w kit and ride it to use as my transport i am against petrol based systems and do not support 2 stroke vehicles either i think they should be banned!.

Apart from the latter i am in need of some help!.

My budget is £500 for the motor and accessories. I can always purchase the battery at a later date when needed of course.

Thank you for looking at my post i would highly appreciate some help from the community. Thank you, have a nice day.

 

[Deleted member 4366]

Nobody is checking at the moment. Nobody has been prosecuted for having a motor of too much power.If your £500 includes a battery, you''ll struggle to find anything in the UK, except from Woosh. They've recently started stocking high torque kits ask them about their front BPMkit and their BBS01 crank-drive kit.

http://www.pedelecs.co.uk/conversion-kits/front-bpm-kit/

There's loads of options from Chinese suppliers. Check out the rear BPM kits from BMSBattery for which you need a high discharge rate battery to get the power. If you know how to handle lipos, you can do it fairly cheaply to get started.

 

[trex]

as d8veh has pointed out, you can't be 100% legal any way - for that, you need certification to EN15194, not doable for individual conversions.
The BS01 is easiest to fit, only requiring standard bottom bracket shell, 64-68mm in length. Hub motor kits need a bit more attention to the donnor bike. If you fit a front hub motor, you'll need to make sure that the fork has standard 100mm dropout and is strong enough, especially if you want 500W motor, not only you need to fit torque arms but also it's man enough to take the power and weight. Similar considerations if you want to fit rear hub motor. Most kits require 135mm rear dropout, 500W motors will require fitting torque arms. If you have disc brakes, you need to buy the hub motor with disc brake bolt holes. Most conversions go with seat post mount 'frog' battery or downtube mount bottle battery. The new square bottle battery is better than frog battery or round bottle because you can buy larger capacity 48V 10AH or 36V 15AH.
Some of the points that you should also consider are:
- is the frame strong enough to mount and carry the battery weight?
- are the brakes good enough for conversion? you are adding FIVE times the average pedalling power to your bike, the stopping power of normal rim / disc brakes is just about enough to cope with 350W power, 500W motors require hydraulic brakes.
Ready built bikes are so cheap nowaday. Are you sure you want to convert your bike?

 

[ALTrooperUK]

Don't know where to start.

Seems a 500w motor is not necessary. I could live with a 300w motor as long as she can pull me and the panniers. I am 5 foot 8 1/2 at 120kg built with tone little flab lmao.

If i can find a good 300w - 350w motor that would suit my bike would be enough 500w is not exactly an absolute must but 250w is taking the **** a little IMO.

Would you gents suggest a bike that would be compatible with a 300-500w motor then seen as i have absolutely no clue at all what to go for!.

My local bike super store is halfords.

I could buy an already built electric bike but they are to much money and i want to mod my own bike an awful lot .

Cheers have a nice day .

 

[trex]

something like this £299 Carrera Vengeance with £549 Woosh BPM 15AH kit (plus lights, bell, rear rack, paniers, puncture proof tyres and mudguards):

http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_810721_langId_-1_categoryId_165499
http://www.pedelecs.co.uk/conversion-kits/front-bpm-kit/

The £849 ready built Woosh Big Bear costs rather less.

 

[Deleted member 4366]

If you want a high-torque motor, you'd be better with a rear one for safety. You need a bit of experience to install a high torque front motor unless you have steel forks.

 

[pn_day]

Depending on how technically adept and up for a "project" you are may drive you down the ready-built path. If you are more time-starved than money starved you may need to increase the budget.

I'm in the process of building up an 8Fun/Bafang CST 500W kit which will be great when finished, but is taking more time than my wife thinks it should Of course it doesn't help that I decided to do other tweaks to the bike at the same time (lots of lights, big tyres that barely squeeze in etc etc).

Woosh Big Bear looks like a decent thing to try if you can, or the eZee range which are also quite beefy engines.

Of course if you like to tinker then go for the kit - you can join me in asking really naive questions to kind gents like d8veh & trex when you are half-way through the build!

BBS01 or BBS02 for crank drive
Bafang BPM or CST for hub drive.

 

[wehey]

I can vouch for the Ezee conversion kit. I have had mine for 2 months now and am sooooooo glad I spent that bit extra and got something capable.
Nothing worse than spending all your had earned ££ only to find you want more.
The beauty of this kit is that it's a 500w kit but if your feeling a little soft you can restrict it to 250w in 30 seconds by just joining two connectors together and become a decent law abiding citizen again

 

[jackhandy]

And the after-sales service is Superb

 

[friendly1uk]

120kg rider plus panniers sounds a bit much for an 80kg bpm. You should probably forget hub motors and get a mid drive. Rear suspension too, as bikes are not usually designed for that weight but will fair better with some cushioning.

250w is very little, but at least you can put this average cyclists worth of power through some gears.

 

[Alan Quay]

... an 80kg bpm...

80kg? Surely not?

 

[friendly1uk]

Sorry about the long delay Mike. Shortly after me reading the spec on bmsb it was pulled. It has taken till now to find it again. Though this seller says 75kg.
http://www.evassemble.com/index.php?main_page=product_info&products_id=158

 

[Alan Quay]

Oh, now I see. That's the loading weight of the wheel, and as the seller points out, a bike has two wheels so you can double that to get total weight the machine can take.

My CST bike (basically same motor) is rear wheel drive. Most of the weight is over the back wheel - 20 ah battery is on rear rack. I also tow my son on his bike, and this connects to the seat post. Then there's me, 120k or so. It's fine.

 

[Geebee]

If you are concerned about the weight on the wheels, buy a bike that can cope ok and fit a BBS01, a side benefit will be better hill climbing.