Hi, first time bike mechanic here. Currently “”restoring”” a 70’s city bike to learn some basics, but its got some strange standards, like futura cranks that required an m12 bolt to remove.
I am almost done with disassembly, but the one thing holding me back is this bottom bracket. How do I go about removing it? Both sides are like this. Do I just tap it out, or is there some magic I’m not aware of?
by AbashedAlbatross
6 Comments
This [https://www.parktool.com/en-int/product/bottom-bracket-tool-bbt-18](https://www.parktool.com/en-int/product/bottom-bracket-tool-bbt-18)
Or this [https://pedros.com/products/bottom-bracket-wrench-shimano-8-notch](https://pedros.com/products/bottom-bracket-wrench-shimano-8-notch)
The square bit is not the bottom bracket, it’s the axle. Definitely do not just tap it out, because that will still leave the bottom bracket behind.
It’s hard to tell which tool you need because you have taken your photo from the worst possible angle. However it might require an “8 notch” tool.
That’s a Spanish bearing. It’s a press fit. Never seen on a square. Does the axle pull out? If not then it has a shoulder to prevent over pre loading. You can tap it and push the opposite bearing out.
It’s a very loose interference fit so a tap should do it.
A Spanish bb is two bearings a preload sleeve and a few cone washers to adjust chain line.
https://winstanleysbmx.com/superstar-spanish-bottom-bracket
If the bearings are good leave it alone
It’s a press-fit BB, the cartridge bearings press directly into the frame and the axle has shoulders for the bearings. Ritchey/Gary Fisher, Klein and a few other top quality US builders used the same standard, along with the cheapest possible Euro bikes
You can drift the axle out with a hammer but be very careful not to damage the axle – if you do this fit a scrap crank bolt and hit that. The better way to do it is to use the axle and a hollow cylinder to pull the bearing out – if you’re lucky you might own a socket or other tool that is the right size to do this. Some press fit cartridge BBs have circlips on the axle or frame but I doubt this one does. I agree with the other poster that it looks like someone has peened the edge of the BB shell possibly because the fit was poor
I’ll say it again – if the bearings are good leave it alone
Wrench
Imho what we see here is a damaged English threaded bottom bracket fixed by hammering in a slightly larger bearing around the axle. This bearing has 35mm diameter, english threaded is 34.8. I am not aware any press cup BB this size, those are almost always 38 or 40mm. It can be factory made, but damage is suspicious.