Singlespeed & Fixed Gear - Crankset doesn't fit bottom bracket

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seanile
01-24-09, 11:54 AM
I got a 170mm sugino xd 46t crankset and a shimano bb-un54 bottom bracket 110mm for a 68mm bb shell.
the crankset doesnt fit all the way down the tapered spindle, leaving a good centimeter to go before they fit flush against the bb.
how can i get the right size crankset? what numbers am i looking for?
larsalan
01-24-09, 12:00 PM
sounds like it fits.
peabodypride
01-24-09, 12:08 PM
I got a 170mm sugino xd 46t crankset and a shimano bb-un54 bottom bracket 110mm for a 68mm bb shell.
the crankset doesnt fit all the way down the tapered spindle, leaving a good centimeter to go before they fit flush against the bb.
how can i get the right size crankset? what numbers am i looking for?
The gap is perfectly normal.
seanile
01-24-09, 12:10 PM
http://i12.photobucket.com/albums/a234/sreilly845/P1241827.jpg
really? if so, awesome
peabodypride
01-24-09, 12:13 PM
Actually, I lied. You need a 103mm bottom bracket for a good chainline. Also, the BB isn't in all the way. So, you will have some space, but that BB is too long.
seanile
01-24-09, 12:14 PM
****
seanile
01-24-09, 12:38 PM
i have a 130mm rear spacing if that helps narrow down what kind of bttm bracket i need
Spacing isn't an issue with chainline - it's the hub that matters. If you have a normal track hub you want a 42mm chainline, which would be a 103mm BB spindle, even if it's spaced out to 130 (it matters where the cog is, not where the chainstays on the frame are). If you have a bigger hub like the surly 135mm hub, that has a 47mm chainline so you'd want a 108mm BB spindle or something close to that. Also, there's about 5mm of difference between the inside and outside of a double crankset, so if you have the ring on the outside of the spider, you can move it to inside and be 2mm off with your current BB, which really won't cause any issues.
One way or another, make sure the cartridge unit is tightened as far as it'll go. If the loose cup side doesn't thread in all the way it's fine.
mr_macgee
01-24-09, 01:17 PM
You have a JIS BB with a JIS crank, that sounds fine. Sugino xd requires a 103mm BB with the proper torque (approx. 350 inch/pounds) on the crank bolt to get a 45mm chainline. You have 110mm bb that may not have enough torque, this will put your chainline way outside of normal. 130mm spacing shouldn't matter if the wheel was properly built up for fixed gear (42mm chainline). 1st Check/measure the chainline at the wheel, when you know what number that is then you'll have a better idea what to do next. Make sure the cranks have the correct amount of torque. As stated in post above, you most likely need a 103mm BB and the gap of non drive side is normal But I would add that since there is no lock ring for this BB, be careful that it has not come loose.
seanile
01-24-09, 01:35 PM
excellent, that really helped me out..i read around on some other forums and i do need a 103mm..thats kinda whats required with that model crank..and its a flip flop hub...anddd i just measured the chain line to be in between 40mm and 45mm
thanks for everything guys, much appreciation
Did you tighten your crank bolts yet?
If you didnt, your crank arms will come in closer...
If you did, need a shorter bb.
I just put a 110 on my 68 and on the non-drive side the crank is about 1 centimeter away. I've tightened everything and it won't get closer. The drive side is tight. If I went for a narrower BB, say a 108 or a 103 I am concerned that the drive side would be too close and the inner ring would hit the chain stay.
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