mwkeefer
1 MW
Hello all,
As many of you have found out the offering of only 48 or 46 tooth chainrings is not the only issue with the bafang drives for your bikes... I have several bikes from Hard Tail mtn bikes to many, many 20" folders and I can say that yes chainring availability is a pain in the ass!!! My Dahon MU wants a 52t to perform properly (As it was designed) and my Vietesse 7H wants a 38t drive feeding a 16T rear sprocket... My MTN Bike wants 38t also feeding up to an 11t.
Problem is so far this isn't really possible, I think etard or someone created some adapter spiders but I've contacted everyone I could seek out to obtain these to no avail (I am not the most patient person on earth)... so I started sketching on a pad (Im no artist but I can make things make sense)...
After about 1/2 an hour looking at the face of the motor, a mounted assembly, the existing chainrings and my beloved 130mm BCD chainring cranks I decided there were actually 2 problems to conqur because the chainlines were very badly out on several of my builds... by badly I mean outset 1/4" or more and no wonder I'd had such issue shifting. Now a properly designed spider must have 2 parts - the mount face which attaches to the motor plate and 5 arms which clear the motor but allow a back spider to be attached, this back spider can be spaced or not and in either direction and will then take a normal mounted chainring of 130mm bcd and likely there will be room to bore mounts for the BMX and Downhill style chainrings as well.
I've contacted a local machine company about manufacture of both a replacement, 1/4" inset 52t chainring with the motor bolt pattern - they have water jets and CAM so this is actually quite an easy process for them to cut from 6061 alum stock.
The adapter I imagine will take a bit more time, perhaps I'm wrong - machine shops always amaze me when I can take them a sketch, a few parts and a crappy (imho) explanation of what I want and they produce a work of art almost every time.
While I am there I will have them look at my crappy handy work at making a front luggage truss for any and all bikes (bolt on but able to support 20 lbs easily) and see what they can make of it - who knows, it could become a new product on a coming website - more on that later.
Today I build interation #1 of a Bafang 500w 36v Dahon MU P8 - with my 48t chain ring my top speed at 36v should be 30 mph in top gear (48/11) with a few days patients it will again be 52 or perhaps I'll go mad and hit for 54 teeth..
Actually looking at one of my 130 mm bcd chainrings next to an installed unit, I can't see any reason why any shop can't drill and taper mount holes to the back side of the stock chainring so that normal mounting spacers and bolts can be used to attach a 130mm bcd chainring? Anyone else done this yet, if these adapters aren't needed I don't want to put money into them.
Give me some feedback about what you need to make your kit complete and better integrated with your build and let me see if there is enough demand for things like these spider adapters and other addons and enhancements for the stock Bafang Kits.
As many of you have found out the offering of only 48 or 46 tooth chainrings is not the only issue with the bafang drives for your bikes... I have several bikes from Hard Tail mtn bikes to many, many 20" folders and I can say that yes chainring availability is a pain in the ass!!! My Dahon MU wants a 52t to perform properly (As it was designed) and my Vietesse 7H wants a 38t drive feeding a 16T rear sprocket... My MTN Bike wants 38t also feeding up to an 11t.
Problem is so far this isn't really possible, I think etard or someone created some adapter spiders but I've contacted everyone I could seek out to obtain these to no avail (I am not the most patient person on earth)... so I started sketching on a pad (Im no artist but I can make things make sense)...
After about 1/2 an hour looking at the face of the motor, a mounted assembly, the existing chainrings and my beloved 130mm BCD chainring cranks I decided there were actually 2 problems to conqur because the chainlines were very badly out on several of my builds... by badly I mean outset 1/4" or more and no wonder I'd had such issue shifting. Now a properly designed spider must have 2 parts - the mount face which attaches to the motor plate and 5 arms which clear the motor but allow a back spider to be attached, this back spider can be spaced or not and in either direction and will then take a normal mounted chainring of 130mm bcd and likely there will be room to bore mounts for the BMX and Downhill style chainrings as well.
I've contacted a local machine company about manufacture of both a replacement, 1/4" inset 52t chainring with the motor bolt pattern - they have water jets and CAM so this is actually quite an easy process for them to cut from 6061 alum stock.
The adapter I imagine will take a bit more time, perhaps I'm wrong - machine shops always amaze me when I can take them a sketch, a few parts and a crappy (imho) explanation of what I want and they produce a work of art almost every time.
While I am there I will have them look at my crappy handy work at making a front luggage truss for any and all bikes (bolt on but able to support 20 lbs easily) and see what they can make of it - who knows, it could become a new product on a coming website - more on that later.
Today I build interation #1 of a Bafang 500w 36v Dahon MU P8 - with my 48t chain ring my top speed at 36v should be 30 mph in top gear (48/11) with a few days patients it will again be 52 or perhaps I'll go mad and hit for 54 teeth..
Actually looking at one of my 130 mm bcd chainrings next to an installed unit, I can't see any reason why any shop can't drill and taper mount holes to the back side of the stock chainring so that normal mounting spacers and bolts can be used to attach a 130mm bcd chainring? Anyone else done this yet, if these adapters aren't needed I don't want to put money into them.
Give me some feedback about what you need to make your kit complete and better integrated with your build and let me see if there is enough demand for things like these spider adapters and other addons and enhancements for the stock Bafang Kits.
