Which Kit?

[John L]

hello John,

I haven't got a cassette motor in 29".

Yes I got an email from Tony telling me that he could do a 700c freewheel motor. I'm still considering all options. Thanks.

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[John L]

Hi D8veh

This is my Lapierre. To me it looks sturdy enough to take a front hub. Woosh tells me he doesn't have a front BPM motor but he has a front 700c SWX motor. Its a 29er but I presume that the difference is so small that it doesn't matter?

What do you think?

John

 

[Deleted member 4366]

That should be OK. The drop-outs have dimples around them. When you put the motor in, the axle won't be central because it has a 12mm diameter instead of the present 9mm. That means that the washer will be on the edge of the dimple on one side. when you tighten the nut, the drop-out will pop. to avoid that, you have to either file the drop-out deeper or file the washer eccentric so that it fits cleanly.

I'd use a torque arm for security, but you haven't really got any easy way to anchor it, which means that you have to choose the right type or make your own.

 

[Woosh]

you don't need torque arms with the 120mm SWX, but if you still want them, I have torque arms for your bike. The kit comes with 13AH HL battery, Samsung cells, King Meter LCD, 17A controller, Julet cableset, PAS, thumb throttle and brake levers. Price including delivery is £499. With 17AH HL battery £599,

 

[John L]

I didn't fully understand when you mentioned dropout dimple before. I get you now though. Filing the dropout or the washer would be relatively easy. A torque arm is a bit more problematic tho.

Seems like there's no easy option at the moment

The bike has a rear Shimano HG 8 speed cassette 11-34t. It works very smoothly. But most of the rear hubs are only compatible with freewheel sets. If I fit an 8 speed freewheel to a rear hub can I expect the HG drive train to work smoothly?

 

[Woosh]

I use this 8-speed freewheel:from DNP because they offer 11T-32T while many others (Ventura, Sunrace, etc) only go down to 13T. May be that does not matter much on a 29" bike.
They all work well.

 

[Deleted member 4366]

Nothing is easy. The problem with the 8-speed freewheels is that they make your axle too wide on one side. that means you have to dish your wheel or put spacers on the other side of your axle. With the spacers, the disc won't line up with the caliper, so you need to deal with that, plus the hole lot is wide, so you have to stretch the frame a bit. 7-speed is much easier, but then your gears don't index properly.

Basically, if you have an 8 speed cassette, you should use a cassette motor. All the time, you're trying to make do with what is available. It would be much better to get the right stuff.

 

[anotherkiwi]

Has anyone had a bent or broken axle with an 8 speed freewheel on a hub motor? I keep reading about that happening with freewheels in non motor wheels.

Do you have the numbers for the added width of a 8 speed d8veh?

 

[Deleted member 4366]

On a bicycle, the rear axle is typically 9mm and hollow. we use 12mm solid ones, so not as likely to bend

 

[Woosh]

Nothing is easy. The problem with the 8-speed freewheels is that they make your axle too wide on one side. that means you have to dish your wheel or put spacers on the other side of your axle. With the spacers, the disc won't line up with the caliper, so you need to deal with that, plus the hole lot is wide, so you have to stretch the frame a bit. 7-speed is much easier, but then your gears don't index properly.

Basically, if you have an 8 speed cassette, you should use a cassette motor. All the time, you're trying to make do with what is available. It would be much better to get the right stuff.

From memory, I don't remember having to stretch anything to fit a BPM fitted with a DNP 8-speed 11T-32T freewheel to a bike that had a cassette.
For those who are interested, the thickness and gap between the cogs are the same standard for the DNP and Shimano 8-speed HG50, you don't need to touch the derailleur.
One thing to note though, the BPM requires a 180mm rotor.

 

[Woosh]

Here are some pictures from johny's thread, he converted his bike (which had a cassette) with using a woosh kit, with SWX02 and DNP 8-speed screw on freewheel:

http://pedelecs.co.uk/forum/threads/cant-decide-what-kit-to-buy.27858/page-3

 

[Deleted member 4366]

From memory, I don't remember having to stretch anything to fit a BPM fitted with a DNP 8-speed 11T-32T freewheel to a bike that had a cassette.
For those who are interested, the thickness and gap between the cogs are the same standard for the DNP and Shimano 8-speed HG50, you don't need to touch the derailleur.
One thing to note though, the BPM requires a 180mm rotor.

I've fitted several BPMs with 7-speed. They all needed dishing. When you fit an 8-speed, you need a spacer on the axle on the drive side to stop top gear from touching the frame. That increases the off-set.

You can see the off-set in this drawing, though they don't say what it is. If i were designing an OEM frame, I'd offset the frame on that side, so it wouldn't be a problem, but on a normal symmetrical bicycle frame, you have to deal with the off-set somehow.

 

[Deleted member 4366]

Here are some pictures from johny's thread, he converted his bike (which had a cassette) with using a woosh kit, with SWX02 and DNP 8-speed screw on freewheel:

http://pedelecs.co.uk/forum/threads/cant-decide-what-kit-to-buy.27858/page-3

It looks like he's used two washers on the axle, so his offset would be bigger than with a 7 speed. Is his rim central in the frame?

 

[John L]

D8veh "I've fitted several BPMs with 7-speed. They all needed dishing. When you fit an 8-speed, you need a spacer on the axle on the drive side to stop top gear from touching the frame. That increases the off-set."

That would be a further problem for me as my rear forks are only 132mm.

 

[John L]

Nothing is easy. The problem with the 8-speed freewheels is that they make your axle too wide on one side. that means you have to dish your wheel or put spacers on the other side of your axle. With the spacers, the disc won't line up with the caliper, so you need to deal with that, plus the hole lot is wide, so you have to stretch the frame a bit. 7-speed is much easier, but then your gears don't index properly.

Basically, if you have an 8 speed cassette, you should use a cassette motor. All the time, you're trying to make do with what is available. It would be much better to get the right stuff.

Lol D8veh you're right! I'm whacking my brain trying to find a kit/setup that is close at hand. Maybe I should bite the bullet and order what you described as "ebike nirvana" from BMSB. I'll review that option again.

I appreciate everyone's comments and efforts on my behalf

 

[Woosh]

d8veh, did you fit one with 11T-32T? the 11T is important.
All the wheel need truing after installation anyway, I have not noticed any difference.

 

[Woosh]

If i were designing an OEM frame, I'd offset the frame on that side, so it wouldn't be a problem, but on a normal symmetrical bicycle frame, you have to deal with the off-set somehow.

It seems that the factory does it with an extra washer:

 

[chris_n]

I've fitted several BPMs with 7-speed. They all needed dishing. When you fit an 8-speed, you need a spacer on the axle on the drive side to stop top gear from touching the frame. That increases the off-set.

You can see the off-set in this drawing, though they don't say what it is. If i were designing an OEM frame, I'd offset the frame on that side, so it wouldn't be a problem, but on a normal symmetrical bicycle frame, you have to deal with the off-set somehow.

5mm, taking the 43.5 at the bottom and half of the 40mm between flange centre lines gives 63.5, take this away from the 68.5 centres between the nuts gives 5mm offset.

 

[John L]

Well after considering everything I decided to opt for the woosh kit. Swx front hub with 36v 17ah battery. There are some compromises involved but that setup should be more than adequate for what I'll use the bike for.

Getting back on a bike and slowly building my cycling legs up again. I should get decent range from the 17ah battery. There's enough of the summer left to enjoy it


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[John L]

I'm afraid this didn't work out that well after all.

Unfortunately the front motor hub delivered does not have the mounting for the disc brake rotor. I've contacted Woosh and I'm waiting to hear back about how we can proceed.

Hopefully we'll be able to organise something.