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Kids bike bottom bracket (Raleigh)

Mike67Mike67 Posts: 585
edited January 2015 in Workshop
I bought my son a new (to him :D ) bike off of Fleabay.

It’s in pretty good nick and fairly light. (a Raleigh Zero G) even with the unnecessary miniature suspension forks.

My son loves it as it has ‘gears and everything’ and he was on a singlespeed before and struggling with the hills.

Only one thing bothering me about it (in my fussy cycling way) is the chainline seems way off. So much so that if you back pedal in the lowest gear the chain jumps down to the next smallest cog.
It doesn’t bother my son as when he pedals forward the chain jumps back up again.

It appears that the BB axle is way too long (still not in line in the highest gear).

So short story is I’d like to replace it with standard square taper BB with better axle length.

The current one has nuts under the crank arm dust caps as opposed to hex bolts which I’ve worked on before and know my way around.
Any special tips/tools required for removal etc?

Can the BB be swapped out for the hex bolt type or does that depend on the crank design?

Also is the Raleigh Zero G a standard BB shell size? For instance would a Shimano sealed BB fit.

I know it’s a long shot that anyone has worked on this bike in particular but I’m hoping most kids Raleighs are similar. Info on the web is pretty limited.
Mike B

Cannondale CAAD9
Kinesis Pro 5 cross bike
Lots of bits

Posts

  • nicklousenicklouse Posts: 81,520 Lives Here
    1 yes but you may also need the bolts.
    2 is it a Raleigh Zero G 16-20-24-26?

    most BB are standard BSA
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • redveeredvee Posts: 11,921
    Mike67 wrote:
    The current one has nuts under the crank arm dust caps as opposed to hex bolts which I’ve worked on before and know my way around.
    Any special tips/tools required for removal etc?


    A standard crank extractor too is all that is needed.
    Mike67 wrote:
    Can the BB be swapped out for the hex bolt type or does that depend on the crank design?

    Any square taper BB will fit with the correct taper.
    Mike67 wrote:
    Also is the Raleigh Zero G a standard BB shell size? For instance would a Shimano sealed BB fit.

    As kids bikes are built to a price point they will use the most common parts to save on production costs.
    I've added a signature to prove it is still possible.
  • Mike67Mike67 Posts: 585
    nicklouse wrote:
    1 yes but you may also need the bolts.
    2 is it a Raleigh Zero G 16-20-24-26?

    most BB are standard BSA

    Thanks.
    It's a Zero G 20 and I think I've got a few hex bolts lying around from previous crank incarnations :D

    Looks like there's plenty of clearance between the chainring and chainstay to go to a shorter axle. Not sure why the one in it is so long in the first place really...it seems to be all the original fitment.

    Guess I just need to get him off it for long enough to replace it then :D
    Mike B

    Cannondale CAAD9
    Kinesis Pro 5 cross bike
    Lots of bits
  • Sorry for the thread resurrection

    I'm rebuilding a Raleigh Zero G 20 for my wee guy

    Bottom bracket is shot and I am replacing it. I know what you mean about it being too long - Current one is 125mm or thereabouts, I'm wondering if I could get away with putting a shorter spindle in but worried the chainring will catch.

    Do you remember how you fixed your kid's bike?
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