Help needed with hardtail MTB conversion for wife

[Gabs]

Hi everyone,

My wife would like to be able to take out our two little ones - a 3yo and a 1yo - on bike rides in a kids trailer. We live on the top of a pretty steep hill and there’s plenty more around.

She has a nice enough hardtail MTB with 1x9 Deore groupset -with a Holllotech II bottom bracket - with some shimano hydraulic disc brakes.

She likes her bike and would prefer to convert it rather than getting a new ebike plus with the two kids we could do with keeping this on a budget.

She is pretty lightweight - about 60ish kg - and never been much of a fan of climbs even without towing two kids.

What I’m looking for is ideally
- rear hub motor - for disc brake and with a freehub body to accommodate a 9sp cassette and
- battery to give her a range around 20-30 miles
- PAS

I saw that one of the guys here did a neat trick with a PAS disc with the magnets where he bolted it onto the Hollotech crank instead of the small chainring. My wife also has a triple crankset that I could do this, I think..

I also saw someone posting brake sensors that are for hydraulic brakes.

I don’t know a lot about motors but I was thinking about going 250w to stay road legal. I know little about batteries but I was thinking along the lines of 11-13is amp and I know and understand absolutely nothing about controllers and LCDs..

 

[Gabs]

If anyone could help with suggestions for compatible set ups (motor, controller, battery, LCD and possibly throttle) with actual sources that would be amazing.

One other thing that worries me a little is the placement of the battery and the controller. I’m not the biggest fan of frame bags and I would like to keep the conversion as tidy as possible.

We are also planning to go back to Wales for some mountainbiking without the kids for our wedding anniversary -squeezed a mini honeymoon out to Wales back in the day - so it would be nice if the kit was firmly attached and wouldn’t need to worry about it dangeling around.

I hope all of this makes sense and someone could point me towards a few different options.

Thanks for reading all this and l look forward to all the great ideas!

 

[Deleted member 4366]

The pedal sensor is straight forward if you get a normal cheapo one and the bike has a 68mm BB. 73mm is a bit more tricky.

For 68mm, you drill the magnet disc to 25mm and move the sensor to the other side of its bracket, then remove the BB, chuck the spacers, mount the sensor behind the LH shell, slide on the magnet disc and assemble the LH crank.

There's a choice of cassette motors, but you'll have trouble finding a high torque one in the UK. Ideally, you want a low speed one (201 rpm) for towing. That normally means buying from China.

 

[Woosh]

Hi Gabs,

Take a look at the XF08C kit on my website.
http://wooshbikes.co.uk/?hubkits

If your wife's bike is a step through, we can offer the kit with 13AH or 15aH rack battery.

 

[Gabs]

Hi Gabs,

Take a look at the XF08C kit on my website.
http://wooshbikes.co.uk/?hubkits

If your wife's bike is a step through, we can offer the kit with 13AH or 15aH rack battery.

Hi Woosh,

Thanks for your reply. The kit looks pretty much what I need.

Just a couple of quick questions.

Would I be able to drill the PAS magnet disc and fit it instead of the small chainring and keep the hollowtech bottom bracket and chainset?

If used with a single front chainring what size chainring is it recommended to be used with?

If I was to order the kit would there be an option to get some hydraulic brake specific stop sensors instead of the complete cable levers that are normally supplied with the kit?

Have you got any details on the LCD that it comes with?

What sort of mileage should I expect from the different battery options? Also is there much weight difference between the different batteries? This should help decide which one to go for.

Many thanks,

Gabs

 

[Woosh]

Would I be able to drill the PAS magnet disc and fit it instead of the small chainring and keep the hollowtech bottom bracket and chainset?

we supply the magnet disc precut to go over the external ball bearing and a 3D printed mounting adapter for the sensor head.
It is possible to fit the pedal sensor without removing the chainringbut fiddly.
You remove the triple chainring, cabletie the precut disc to the smallest ring, re-install the chainring then cabletie the sensor kit to the seat post.

If I was to order the kit would there be an option to get some hydraulic brake specific stop sensors instead of the complete cable levers that are normally supplied with the kit?

We don't keep them in stock but you can buy compatible hydraulic brake sensors on ebay.

Have you got any details on the LCD that it comes with?

We supply the King meter JLCD with kits.
http://wooshbikes.co.uk/manuals/King-Meter-J-LCD.pdf

What sort of mileage should I expect from the different battery options? Also is there much weight difference between the different batteries?

I can only give you a rough idea, allow 12WH per mile without towing, 18WH with trailer and the kids. A 13AH battery gives 36V * 13AH = 468WH, That is 39 miles without the trailer but as the battery voltage goes down with the battery being deplete, you have to lower the assist level to 1 or 2 to extract all stored WH, I usually say that you get 35-40 miles with a 13AH. Some people are good pedalers and can get 50 miles out of a 13AH battery. the 15 battery weighs slightly heavier and give you 15/13 the range above. They are made with Samsung cells.

 

[D C]

I have a Woosh XF08C kit with 15AH battery on my bike and I'm very pleased with it's performance and with the instant help, advice and after sale service from Woosh.
It's easy to fit a "kill" switch instead of brake sensors if you wish. The hydraulic sensors with magnets can be a bit awkward to fit depending on what sort of brakes you have.
I'm a big guy in a very hilly area (probably weigh half as much again as your wife) but the kit has plenty of power and is an improvement on the last one I fitted.
A definite recommendation from me.
Dave.

 

[Gabs]

I have a Woosh XF08C kit with 15AH battery on my bike and I'm very pleased with it's performance and with the instant help, advice and after sale service from Woosh.
It's easy to fit a "kill" switch instead of brake sensors if you wish. The hydraulic sensors with magnets can be a bit awkward to fit depending on what sort of brakes you have.
I'm a big guy in a very hilly area (probably weigh half as much again as your wife) but the kit has plenty of power and is an improvement on the last one I fitted.
A definite recommendation from me.
Dave.

Thanks for your feedback on this kit Dave. It’s nice to hear from someone who actually has this kit and has personal experience with it.

Just one quick question. Does the hub motor let you freewheel freely when you’re not using the assistance or does it have some drag/resistance?

Thanks,

Gabs

EDIT: and one more thing that I just remembered.. Do you use it with a single front chainring or a double or triple chain set? If single ring then what size ring do you use?

 

[Benjahmin]

That's a geared hub so the clutch will disengage when the power goes off - freewheel no problem.
Many will say that only a single front ring is needed on an electric bike. Me, I kept two 'cos of where I live. I'd say, as your wife will be towing, keep two. Shouldn't really need the granny ring whatever happens. Mine came with 48/38/28. I dumped the 28 and bolted the pas ring in its place, can't even see it. 48/38 gives good spin rate up to about 30mph, 28 gives good steep hill spin rate with 32 tooth bottom gear.

 

[D C]

ust one quick question. Does the hub motor let you freewheel freely when you’re not using the assistance or does it have some drag/resistance?
Do you use it with a single front chainring or a double or triple chain set? If single ring then what size ring do you use?

There's no discernible resistance at all when freewheeling, I have three chainrings, 26, 36 and not sure about the largest one, (think it's 42) the rear cassette is 11/32.
The 36 gets the most use and gives all the rear cogs. I almost never use the 26 and rarely go fast enough to need the large chainring.
Dave.