Bafang BMX conversion

[sparkysx]

Trying to fit a bafang 500w 36v to a Haro BMX but I've got a mismatch with the teeth on the lekkie bling ring and the rear freewheel, also I'm not getting the best line for the chain so need to offset it more, any ideas?

Thanks!

 

[wheeliepete]

What do you mean by mismatch? As you have plenty of clearence on the chainstay, you could improve chain line by grinding the BB to bring the chainwheel inboard and adding spacers on the non drive side if needed. Looks like you could add 1-2mm spacer behind the rear freewheel.

 

[sparkysx]

What do you mean by mismatch? As you have plenty of clearence on the chainstay, you could improve chain line by grinding the BB to bring the chainwheel inboard and adding spacers on the non drive side if needed. Looks like you could add 1-2mm spacer behind the rear freewheel.

Sorry, what I meant by the mismatch is the pitch of the teeth are not the same so the chain doesn't fit both gears.

Thanks for the idea of putting a spacer behand the rear freewheel, that could buy me a few mm which would help but can't grind the BB of an original Mid School BMX, I also might want to convert it back at some point. Is there anyway of me putting a chain ring together that would allow me to get it a bit further in than the bling ring? and does anyone do rings that could match the rear free wheel or can I get a rear freewheel to match a chainring? The current one on the back is a dicta 14t.

cheers

 

[vfr400]

If you're talking about the thickness of the sprockets, it's no problem if you use a BMX chain. They should both have the same pitch as long as you don't have some weird freewheel on the back, otherwise change the freewheel for a standard one.

What chain did you try? Derailleur chains are normally too narrow for a BMX freewheel.

 

[sparkysx]

Right, the KMC bmx chain does fit but because the lekkie has wide teeth it makes it a tight fit, so thinking I should get adifferent chainwheel/ring combo and try to space it further towards the frame at the same time?

 

[wheeliepete]

Bmx chain, 1/2" x 1/8" will run fine on the Bling Ring, i've used it myself. The tightness you desribe could be down to your bad chainline. I can't think of any chainring setup that will be an improvement on your present setup. That Dicta freewheel looks quite deep in your photo, measured a SA one I have and it's around 20mm.

 

[sparkysx]

I've taken the dicta off now and it died in the process so need to get another one, no big deal as it probably needed changing anyway, it's not the chainline though as it's tight if you just flop it over the chainring on its own, atm the chain is actually too short so I haven't been able to see how it runs anyway.

 

[wheeliepete]

it's tight if you just flop it over the chainring on its own

The bling ring has a narrow/wide tooth setup, you have to match a wide tooth with a wider link, if it's tight, move the chain along 1/2 a link.

 

[sparkysx]

Cheers! Don't know why I didn't notice that!

 

[sparkysx]

Made some m30 washers to go behind the freewheel, ordered a new chain and freewheel, just trying to find a reasonably priced c965 display and it will be finished! will post pics when it's done, it's looking quite nice and have only seen one other mid drive BMX. Also waiting for the bottom bracket spacers from Luna, should be here next week.