bottom bracket spindle
07-30-18, 01:32 PM
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bottom bracket spindle
Hey folks, newbie here.
My brother gave me an old 96 Gary Fisher Wahoo that needs a new bottom bracket. Checking the factory specs it says I need a 73 x 120mm BB. I came across the Shimano UN55-- sizes 73 x 118mm and 73 x 122.5mm but I don't see 120. The 73 x 122.5mm should be okay, right?
My brother gave me an old 96 Gary Fisher Wahoo that needs a new bottom bracket. Checking the factory specs it says I need a 73 x 120mm BB. I came across the Shimano UN55-- sizes 73 x 118mm and 73 x 122.5mm but I don't see 120. The 73 x 122.5mm should be okay, right?
07-31-18, 05:56 AM
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The 122.5mm spindle will put the chainrings and pedals 1.25mm (~0.050") farther out than a 120mm one. The 118mm will put them 1mm closer. Which works better for you?
07-31-18, 06:52 AM
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07-31-18, 06:58 AM
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Ah, I see. Im not sure which would be better. I ride road bikes so maybe the 118mm? Might not be a huge difference either way.
edit: Bike tinker man-- thanks, I'll look into that if I run into any issues using the 118.
Thank you, gentleman
edit: Bike tinker man-- thanks, I'll look into that if I run into any issues using the 118.
Thank you, gentleman
Last edited by pillows_; 07-31-18 at 07:03 AM.
07-31-18, 09:46 AM
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Before you go any farther with this make sure that the crank is actually the one that the factory specification says it is. Different cranks can require different length spindles, so if the bike no longer has the original crank(not unusual in a 20+year old bike), the factory spec is useless. Best is to actually measure the spindle length to make sure what you have
