Conversion Kit Gearing.

[JohnD135]

I am considering converting an MTB to electric. I already have an old Oxygen with a rear motor, but this is not so good on very steep hills. Otherwise it is brilliant! Is it possible to have two main cogs on a mid mounted motor please? So that I can manage very steep off-road?

 

[Nealh]

Yes but will need some tinkering to set up for both the ring spacing/adapter and derailleur . For spacing longer rings bolts may be needed and some 1mm spacer washers.
Cross chianing may be an issue with gears and the chain line but in essence one should be able to use most of the gears available esp the small small for climbing.

 

[saneagle]

I am considering converting an MTB to electric. I already have an old Oxygen with a rear motor, but this is not so good on very steep hills. Otherwise it is brilliant! Is it possible to have two main cogs on a mid mounted motor please? So that I can manage very steep off-road?

Rather than buy a new kit, it would be cheaper to upgrade your Oxygen by any of the normal methods:
1. Add a blob of solder to the shunt. Cost zero. 25% improvement in hill-climbing. Many older Oxygens have potted controllers, so not easy to achieve, but most post 2016 ones might be OK.
2. Change the controller to one that gives more current and get a better control system at the same time. Cost £80. 30% improvement in hill climbing.
3. Swap your battery and controller for 48v ones. Cost about £300. Up to 50% improvement in hill-climbing.

Without you saying which Oxygen you have and exactly what type of hills you need to tackle, I can't go any further.

 

[JohnD135]

Thanks Nealh, it is a relief to know that this is possible, although, as you say, alignment may be an issue.
As to the Oxygen bike that I have Saneagle, it is very old and I was thinking it might not stand the strain! As to the hills, I climb a few of them now but am now not so fit as I was so looking for a way to stay in the hills for longer. I supose that I will find out what is possible for me later on. I rebuilt the battery myself (37V and measured at 17.6 AH) so was hoping to use that. I enjoy a project and am fairly competent. Not sure which mid-drive to choose as yet. Am I correct that prices are higher now than they were?