fitting a BBSO2 to a Norco Fluid


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3:21 AM
May 20, 2021
I recently bought a new 2023 Norco Fluid hardtail. It's a mid level 29 er. It's reasonably spec'ed out with hydraulic brakes and has a dropper seat post which I find very useful. Rear 12 speed 12 - 52 gearing. The bike shop installed a rear rack that was going to hold one of my rack mount 48V batteries. My spare BBSO2 is a 68 to 73mm version and the bottom bracket on the bike measured 68mm so I thought it would fit.

However the chainstays flare outwards just behind the bottom bracket so once the motor was installed and shimmed enough for clearance 2 issues arose. 1st only enough threads to barely put the large nut on that keeps the motor tight to the bottom bracket. Then the chain line was way out of line. So a 18mm offset chainring was installed to see if the the chainline would improve. Still not great because the motor now needed a shim to move it away from the bottom bracket to keep the chainring teeth from rubbing on the chainstay. A solution I guess would be order a 100 mm motor or maybe a CYC but they are expensive. Anyone here try a CYC yet?
get some of that PEX pipe and cut it to length then slice down the middle to put over your chainstay...

it takes forever for the chain to eat through ;)
Thanks for the reply but I don't think I'll be doing that.
I went thru this, with a different bike and a BB30 bottom bracket, although there is a converter to BSA 68 and 73mm there is not enough clearance between the motor housing and the spindle assembly when the adaptor is used. This is due to the increased thickness of the BB walls with the adaptor fitted.

It meant a new bike. something to consider there.
I may have found a solution. There are kits to convert bikes to single speed. The ones I've found come with 16 up to 20 tooth gears. The kits include spacers and usually a new tensioner wheel to replace the derailleur. Based on my fat bike experience on the trails the motor allows me to mostly use just one gear and the speed can be increased by upping the power. Anyway I'm not going to convert it at this time but will research it some more.
Be wary of those single speed kits. Many are fixtie conversions with no freewheel so if the wheels are spinning the pedals are spinning.