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New school BB 1pc to 3pc tech question - 2011 Haro jr race bmx - cranks too long

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downlowmatt:
Hello!

I'm looking for shorter cranks and a lower gear for my daughter's 2011 Haro jr BMX (she's 6)

I bought it for Christmas, did a mild resto on it (after parcelforce lost it and smashed it up), anyway she loves the bike BUT being only 6 finds the cranks too long (155mm) and gearing too high. When she rides it her knees come up to her chest!

So,

There seem to be three options:

1. Keep the existing cranks, get some crank adaptors to make them shorter, and a bigger chainring (£50ish, will make the cranks wider which I'm not keen on) http://www.bikecare.co.uk/crank_shortners.html

2. Find some shorter 3 pc arms with a bigger chainring (not easy to find, guessing £50+)

3. Swap the BB and put in a 1 pc crank. Small 1pc cranks are cheap (£15ish) and common so this would seem to be a good option - but can you get a BB?

Here's some photos I've found online of the bike and a crank





Cheers

oldscool:
I could be wrong but if those are the cranks that came out with the bottom bracket reducer, it should take a standard cheap one piece bottom bracket and cranks. You will need pedals also as they will probably be 9/16. :daumenhoch:

downlowmatt:

--- Quote from: oldscool on July 10, 2015, 09:32 AM ---I could be wrong but if those are the cranks that came out with the bottom bracket reducer, it should take a standard cheap one piece bottom bracket and cranks. You will need pedals also as they will probably be 9/16. :daumenhoch:

--- End quote ---

Thanks.... I think it has a USA BB at the moment (smaller than the old school BB that I'm familiar with!)... but looking at that picture above there is an adaptor that takes a USA to old school bb

I guess I don't know what BB you can get to convert a new school frame to a 1pc crank

Gary72:
Get some pics up of the BB on the bike so we can tell what it has currently. The pics look like a race bike and I suspect it will have a euro BB.

downlowmatt:

--- Quote from: Gary72 on July 10, 2015, 11:56 AM ---Get some pics up of the BB on the bike so we can tell what it has currently. The pics look like a race bike and I suspect it will have a euro BB.

--- End quote ---

Thanks Gary... I messaged Alans and they said it's a Euro BB. Yes, it's a race bike. You were on the right track, thank you!

In the meantime I've found theses, which although won't change the gearing, are shorter cranks.... and only £2!


http://www.ebay.co.uk/itm/391194077334

In conjunction with a bigger freewheel I could be onto something.
Thanks again for your help

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