Help on new motor choice needed....

[NRG]

I'm a bit stuck and need the thoughts of the experts please! As much as I love riding my converted Peugeot with the Conhis motor it's just too darn heavy! It's not a nice experience trying to ride it without assistance and I feel it needs to go on a diet.

So I'm looking for a lighter and better motor, a geared one that would save me about 5~6Kg but still provide useful assistance on 14~15% hills with a 700c wheel....plus a reasonable freewheel...

My Alien with 26" and Bafang motor gives OK hill climbing ability with a good amount of input from myself...so I'd like to have similar ability on the Peugeot.

First thoughts would be the Bafang and I have talked to Frank about one but there is a concern that with a 700c wheel it would not be a good match and that I'd have to keep speed above 7.5mph on the hills otherwise all the motor would be doing is producing heat and not forward motion.

So he recommended I look at the Puma motors...I know nothing about these or if they would be overkill...they are also 1~2Kg heavier than the Bafang...

....or would one of the 'Cute' motors work?

My main aim is to lower the weight and I think this would offset to some degree any loss in torque due to the 700c wheel but really I'm going around in circles and need some help please!

 

[flecc]

I don't think a Puma would suit, heavy and high powered, usually Direct Drive I think, so better for speed rather than hill climbing.

Only the Tongxin Nano really fits, but chosen as the lowest revs version to suit the 700c wheel. It's the lightest and has virtually no rolling resistance so ideal for pedalling without power. Not particularly powerful, though giving useful assistance on hills.

The Bafang is a good second choice though and has more power.
.

 

[eddieo]

a few nice looking choices here if you follow Dan's Link's

http://www.pedelecs.co.uk/forum/electric-bicycles/4971-hub-motor-kit-handlebar-backlit-display.html

 

[NRG]

Hmmm, they look good, thanks for the link Eddieo. Cheers Flecc, the Bafang kit from Frank is very competitive price wise although I'd need to build my own wheel... apparently he can tweak the controller current and also says they work well at higher voltage if I feel its not strong enough...

 

[NRG]

I've played safe on gone for the Bafang from Frank as the offer was good. Only problem is I will have to build my own wheel so I'll give Daniels wheel building thread a good read.....however, what rim do I go for.

I see a variety of 700c touring rims on SJS that range from about £17 to £65...I was thinking a midrange one at £30 would be more than good enough or is this overkill?

 

[jerrysimon]

Yes lots of choice. Good on you for having a go at building it yourself. Getting the right spoke lengths is the key. I like the Sun rims I have for my Brompton, but not sure if they do a 700c/36h one.

Remember you will need one with 36 holes.

Hmm here is one

I am sure others will advise.

Regards

Jerry

 

[Herb]

however, what rim do I go for.

When I bought a Bafang motor from Frank , I had SJS cycles make up the 26” wheel for me, they were keen on a Sun Rhyno 559 ATB Alloy.

They also wanted ( and did ) use 14 gauge spokes with brass washes on on hub end.

I have spoken to SJS today to try a find out if 13 gauge spokes if available would be a better fit.

Their wheel builder was on holiday but I shall speak to him another day to unravel the mystery.

Herb

edit - I see Jerry's link above is for the same make of rim.

 

[flecc]

I've used these 14 gauge spokes on Bafang hubs with no resulting problems. The build quality is more important.
.

 

[Mussels]

When I bought a Bafang motor from Frank , I had SJS cycles make up the 26” wheel for me, they were keen on a Sun Rhyno 559 ATB Alloy.

They also wanted ( and did ) use 14 gauge spokes with brass washes on on hub end.

I have spoken to SJS today to try a find out if 13 gauge spokes if available would be a better fit.

Their wheel builder was on holiday but I shall speak to him another day to unravel the mystery.

Herb

edit - I see Jerry's link above is for the same make of rim.

13g spokes don't have as much give in them as 14g so despite being thicker then can be more liable to snap, even more so with the short spokes required for hub motors. The washers are because SB hubs aren't the best quality and poorly fitting holes can cause spokes to snap.
SJS rebuilt my wheel using 13g spokes and a Sun Rhino rim and it has been fine for a few thousand miles, prior to this I did a huge amount of reading about spoke design trying to stop my wheels falling apart and there are a lot of causes of broken spokes.

 

[Herb]

The build quality is more important.
.

Agreed, The guy who laced my wheel was SJS Cycles master wheel builder, and even then he discussed the build with the owner and the guy in the shop.

I hope this wheel is of the highest quality, but I do remember part of the discussion was about the use of 13 or 14 gauge spokes.

Herb

 

[Herb]

Just to add to my post above, SJS Cycles has a very strong online presence but they are also very helpful over the phone, keen knowledgeable people field the queries - Well worth a phone call.

But if you are ever in a position to visit them, I can only compare the service to an appointment with a bespoke tailor.

Herb

 

[eddieo]

SJS built my rear wheel using a RHYNO rim for my 905 SE and it was bomb proof ever since, a fantastic job.......... I am 17 stone and never a loose spoke in 12 months

 

[NRG]

Thanks Guys, thanks Herb, very good advise. I'd like to try this myself but I think I'll call them next week and talk things through....

 

[Mussels]

SJS built my rear wheel using a RHYNO rim for my 905 SE and it was bomb proof ever since, a fantastic job.......... I am 17 stone and never a loose spoke in 12 months

After SJS rebuilt my wheel I did get loose spokes but this is fairly normal on the non drive side, spokes should still be checked and adjusted and it doesn't necessarily mean there is a fault.