Some conversion help please

[Shazbag]

Hi hoping you can help,

I will be blunt, I am very overweight, I have a carerra
subway ltd bike which I love, and I enjoy cycling about with my toddler on the back
in a seat, Although I was about 24 stone and now 22, (i hope to be 20 by the time I do the conversion) I can happily cycle 5-12 miles and not be in too bad of shape, its pretty flat round here thankfully but I average 6-7mph and I want to get that higher which I cant at the moment (without help).

Anyway cycling is helping the fat fight, but come September I will HAVE to use my bike
to commute and its a total (there and back) of 25 miles.

I have been chatting with Electric bike conversions who have been helpful and recommended this

http://www.electric-bike-conversions.co.uk/acatalog/electric_bike_rear_hub500w_kit_details.html

I am not bothered about top speed, just to help me go the
25miles without looking like I need 999 at a decent spend (15mph ish?) so it
doesnt take too long, there will be one steep hill but the rest is flat. I also still need to be able to have my toddler seat. (I know 500w is illegal on the road but I can go off road for large sections)

My main worry is spending out ALOT of money for it not to work well as I am
so big, I was just hoping that some people could reassure me it will work and my bike wont break, I see things about toque and stuff but I am clueless. I wont be doing the conversion but paying them to.

Many Thanks

 

[Deleted member 4366]

It looks like that kit in your link has a direct drive motor. You need a geared one for the speed you ride to get enough torque. The motor should be a 201 rpm one, which will reach just over 15 mph.

Are you competent to do the conversion yourself?

I've converted a Carera Kraken before. It has the same frame as yours, but different forks. There's no problem fitting the motor or battery. Does yours have combined brakes/shifters or separate ones? I've seen both on Subways.

The mountings of that rack don't look strong enough. As far as I can see, all the weight is on two 5mm bolts with a shear and twisting load on them. One good bump and they'll snap.

 

[Shazbag]

Thanks for your reply, I have to say I am not very technical so its all a mine field, I dont think I could do it myself it looks complicated!

The cycle shop put the rack (for baby seat) on should I take it back?

The breaks/ gears are combined I think, you have the break and above that is the gears one on each side

Thanks for your help

I have just seen this http://www.50cycles.com/product/612027100 but its only a 250w battery and I would need to see if I can get finance but I do love my subway

 

[selrahc1992]

Hi hoping you can help,

I will be blunt, I am very overweight, I have a carerra
subway ltd bike which I love, and I enjoy cycling about with my toddler on the back
in a seat, Although I was about 24 stone and now 22, (i hope to be 20 by the time I do the conversion) I can happily cycle 5-12 miles and not be in too bad of shape, its pretty flat round here thankfully but I average 6-7mph and I want to get that higher which I cant at the moment (without help).

Anyway cycling is helping the fat fight, but come September I will HAVE to use my bike
to commute and its a total (there and back) of 25 miles.

I have been chatting with Electric bike conversions who have been helpful and recommended this

http://www.electric-bike-conversions.co.uk/acatalog/electric_bike_rear_hub500w_kit_details.html

I am not bothered about top speed, just to help me go the
25miles without looking like I need 999 at a decent spend (15mph ish?) so it
doesnt take too long, there will be one steep hill but the rest is flat. I also still need to be able to have my toddler seat. (I know 500w is illegal on the road but I can go off road for large sections)

My main worry is spending out ALOT of money for it not to work well as I am
so big, I was just hoping that some people could reassure me it will work and my bike wont break, I see things about toque and stuff but I am clueless. I wont be doing the conversion but paying them to.

Many Thanks

I have a hub kit (relatively underpowered one) - I'm very happy with it, but I don't think it would work with 25 stone - if it's really flat where you are a more powerful hub drive would do the trick I imagine - but will semi serious and serious hills ever be part of things? I'd - moreso perhaps given you may want to average lower speeds (my hub drive is happiest above 10mph, and manages that easily, but i tend to have to hurry) with a baby on the back consider a crank drive

 

[Shazbag]

My trip will involve one short hill, say 100m thats it so very flat, just want to go 15mph max really, if I am in traffic I will have to stop start anyway.

any recommendations of crank drives? so I can look at them?

now 22st, will be 20st by the time I do this so atleast its going in the right direction

 

[selrahc1992]

My trip will involve one short hill, say 100m thats it so very flat, just want to go 15mph max really, if I am in traffic I will have to stop start anyway.

any recommendations of crank drives? so I can look at them?

now 22st, will be 20st by the time I do this so atleast its going in the right direction

I was factoring in the weight of the baby - if its only one short hill - apologies for backtracking - a relatively powerful hub drive (like a bpm as I think d8veh is suggesting) may be best - others on the forum may have better ideas, but in my experience a hub drive can be easier to live with

 

[selrahc1992]

I was factoring in the weight of the baby - if its only one short hill - apologies for backtracking - a relatively powerful hub drive (like a bpm as I think d8veh is suggesting) may be best - others on the forum may have better ideas, but in my experience a hub drive can be easier to live with

stop staring with a crank drive in traffic can be a PITA

I was factoring in the weight of the baby - if its only one short hill - apologies for backtracking - a relatively powerful hub drive (like a bpm as I think d8veh is suggesting) may be best - others on the forum may have better ideas, but in my experience a hub drive can be easier to live with

sorry - stop starting in traffic with a crank drive on a derailleur can be a complete PITA

 

[Shazbag]

oh yes I totally forgot about the weight of the 2stone 4lb 2 year old behind me lol

 

[Deleted member 4366]

Without being able to see it in detail, it's difficult to comment further, but I must admit that from what I can see, it gives me a very uncomfortable feeling.

If you're not very technical, it would be better to get a ready-made electric bike. A conversion kit will cost about £600 in total, so would be cheaper, but if you get the wrong one or it doesn't You out how you want it, it'll work out much more expensive.

The Kalkhoff will do everything you want, but I still have reservations about the rack.

What do other people think about these racks for childseats? I'd prefer to see some of the weight taken elsewhere like this one:

http://www.bikehacks.com/.a/6a0120a7ed5f9d970b0163058ab02d970d-800wi

 

[selrahc1992]

oh yes I totally forgot about the weight of the 2stone 4lb 2 year old behind me lol

I think as d8veh suggests a 201 rpm bpm kit then, there's loads of them, from woosh, oxygen, etc etc. I wish, as an aside, someone will make one of those downtube battery controller combos (having read above about the rack not being strong enough) that puts out 25 A instead of 15A at 36V - I have a diy bpm job that's crying out for one..

 

[trex]

sorry - stop starting in traffic with a crank drive on a derailleur can be a complete PITA

why? zillions of people ride CD without ever complaining about noisy gear change. If you are not facing up a steep hill at traffic lights, the gear change is just as smooth as with a normal bike as the motor only starts an instant after the bike has moved. For the uphill gear change, slightly blip one of the brakes if you think you need to.

 

[RobF]

Twenty plus stone and a motor is a lot for a rear wheel to carry.

A front hub motor would even the load and stresses a bit.

Have a word with Cyclezee.

The Sprint Primo is a ready made, sturdy front hub bike with a pokey motor.

Something of a bargain for under £800.

http://www.cyclezee.com/ezee-sprint-primo.html

 

[selrahc1992]

why? zillions of people ride CD without ever complaining about noisy gear change. If you are not facing up a steep hill, the gear change is just as smooth as with a normal bike as the motor only starts an instant after the bike has moved. For the uphill gear change, slightly blip one of the brakes if you think you need to.

I half agree: the problem is not changing up or down as one goes along - its stopping from cruise in a high gear: so, there you are, stationary in traffic in a high gear - unable to accelerate from a low gear unless you have consciously geared down before you stopped - getting from seven to one takes quite a few turns and the crank has put the chain under pressure by that stage - and its all grinding and protesting and sounds as if something is going to break

 

[Shazbag]

HI, firstly thanks for all your replies.

I would certainly get it fitted from the place I brought it as I would muck it up no doubt.

The only thing that worries me about the Kalkhoff is its only 250w, I kinda wanted a 500w being a chunk

you talk about bpm (I googled it and came up with Bafang) is that right? I saw this http://www.ebay.co.uk/itm/500w-Bafang-Mid-Drive-Electric-Bike-Conversion-Kit-with-Battery-/111695372321?pt=LH_DefaultDomain_3&hash=item1a01902021

 

[Shazbag]

I will also check out Cyclezee thanks

 

[Shazbag]

I am not sure I can stretch to a brand new bike, can anyone recommend a 201 rpm bpm kit that d8veh suggests?

any thoughts on these 2 and this company, they charge £100 to fit it which is what I need and its now a million miles away.

http://www.electricbikeconversions.co.uk/product/bafang-bbs02-500w-36v-conversion-kit-with-battery/

http://www.electricbikeconversions.co.uk/product/500w-front-wheel-including-downtube-lithium-ion-battery/

There is such a massive price difference!

I wish the Kalhoff was a 500w :-( not sure we would get finance anyway

 

[Shazbag]

and to say I really appreciate all your help

 

[trex]

how good are you with DIY? can you remove the bottom bracket of your Carrera for example?

 

[Deleted member 4366]

I wouldn't fit either of those kits. As already pointed out, with your weight, the crank-drive BBS02 is not going to be very pleasant. Your gears won't last very long either. As I said before, that hub-motor is a direct drive one. It won't have the torque you need, so it's likely to run too slow and overheat.

You would need a 48v code 14 (260 rpm)or 16 (201 rpm) Bafang BPM running at 20 amps minimum. I don't know of anybody in the UK that sells them. You have to get them from China. Another option is MAC kit from Em3v.com.

If you want legal, it has to be a Woosh Big Bear kit or an Ezee kit. They both have about the same speed and power. Ezee offer more battery options but are more expensive.

 

[Alan Quay]

What do other people think about these racks for childseats? I'd prefer to see some of the weight taken elsewhere like this one:

http://www.bikehacks.com/.a/6a0120a7ed5f9d970b0163058ab02d970d-800wi

With you on that. I'm even toying with the idea of using the steel part as a rack on its own (for an easily removed battery).