Hello

 

I am in the process of buying stuff for my partner's conversion of her Cube Mountain bike. She is dead set on a rack mounted battery rather than a downtube so my question is will that be too much on the rear of the bike and will it just wheelie all the time? I am only going to use either my Yosepower 350w 48v or an AKM-128 but even so will it be unstable?

 

At the moment the shortage in materials is making it quite hard to even find a rear rack mounted battery but want to know if in principle it would work and not be too light on the front wheel?

It probably depends somewhat on individual design, but my experience of a rear hub and rack battery compared to my first ebike (front hub downtube battery) was that the former was not as stable especially if I was using panniers with any sort of load in them.

Just my own personal opinion, of course.

Some rack batteries are not designed very well and overhang the back wheel, so always check that in the pictures. Most are adjustable, but when you bring the battery forward, it tilts the batteru up at the back. That's not functionally bad, but some people don't like the look. Whatever you do, get the battery as close to the seatpost as you can.

I was using a Yose 350w kit last year with the downtube battery mounted on the rear rack - I found it fine, stable, the power is useful but there won't be any wild uncontrollable wheelies.

 

I tried another bike with a pannier rack battery and found it handled terrible, the difference was that rack wasn't very secure so it allowed the battery to sway from side-to-side. Rear rack batteries can work well be make sure the rear rack is fitted securely.

 

One thing to think about, Yose use a "speed controlled" system, I changed the controller and display to a "current controlled" system and prefer the way the motor works now.

https://www.pedelecs.co.uk/forum/threads/yose-350-rear-hub-kit-onto-spanish-mtb-by-mondraker.37899/#lg=post-562644&slide=0

Thanks to all of you for your input. It looks like it will be less stable but not horrendously so. I will go back to the boss er I mean partner and see what she says. If it were down to me I would be tempted by a mid drive BBS02 with the rear rack battery BUT can appreciate that this is more of an investment. I am tempted to get her her own AKM motor and rear rack battery and leave my conversion as it is for now. We are only doing a conversion on hers to allow us to get out and about to walks without the use of the car and so it doesn't have to be amazing. My experience though is that once you start using it for errands and getting to places you start to quickly expand you horizons and so it isn't always a bad idea to invest in the better kit early on.

I was using a Yose 350w kit last year with the downtube battery mounted on the rear rack - I found it fine, stable, the power is useful but there won't be any wild uncontrollable wheelies.

 

I tried another bike with a pannier rack battery and found it handled terrible, the difference was that rack wasn't very secure so it allowed the battery to sway from side-to-side. Rear rack batteries can work well be make sure the rear rack is fitted securely.

 

One thing to think about, Yose use a "speed controlled" system, I changed the controller and display to a "current controlled" system and prefer the way the motor works now.

https://www.pedelecs.co.uk/forum/threads/yose-350-rear-hub-kit-onto-spanish-mtb-by-mondraker.37899/#lg=post-562644&slide=0

 

Thanks for this. I will make sure the fit of the rack is very snug. Don't need a big battery so that might help in some respects.

 

I have not heard of the speed controlled vs current controlled but will look into it.

Thanks for this. I will make sure the fit of the rack is very snug. Don't need a big battery so that might help in some respects.

 

I have not heard of the speed controlled vs current controlled but will look into it.

There are a few discusions about speed / current controllers if you use Search at the top of the page, eg

https://www.pedelecs.co.uk/forum/threads/lishui-controller-and-lcd-vs-kt-controller-and-lcd.36444/

 

Both types work and I was happy with the Yose kit for about a year on my first E-bike.

Now I've had experience of both I'd pick "current" control over "Yose / speed" control if I had a choice.

 

I'm still learning so other riders with more experience might have more advice for you. Have fun

My wife has a Wisper 705 with a rear hub motor and rear rack with a battery (375wh). She also uses a rack bag that has panniers.

 

It is very stable, even on loose gravel and she’s never done a wheelie.

My wife has a Wisper 705 with a rear hub motor and rear rack with a battery (375wh). She also uses a rack bag that has panniers.

 

It is very stable, even on loose gravel and she’s never done a wheelie.

 

Thanks Diggy that's good to know.