Aznman

My cranks are finally wobbling and I have never replaced bottom-bracket bearings before. I needed new cranks anyway since my chainring has survived four chain/one cassette replacements and I want to add toe-straps for my harsh, mountain biking practice
This will be my final fix for this old bicycle (it was already "used" when bought); I would buy a new hybrid once I repass the fourth chain replacement.

Since there is - practically speaking - too many types of bottom-brackets to google on, I hope there is a 'Specialized' expert here who would instantly recognize the specifics tooling I would need. See the DSLR pictures attached. If it helps, the bicycle frame is a 'Specialized' and was designed on a 'Sun Microsystem'. Let me know if you require pictures from the chainring side.



Yes, the dust-cover has long been lost.

dedhed

looks like a standard cartridge square taper BB. If you're replacing the crankset you MUST buy the new BB that that particular crankset requires. You need to know shell width (likely 68mm or 73mm) and threading (almost certainly BSA/English) of the frame

Iride01 

As far as the wobbling goes, are you seeing it in the spindle going through the bb? Or are you seeing that between the crank arm and the spindle.

As for you saying you ride harsh.... if that's got to do with putting a lot of stress into the cranks, you might want to figure out if a bb with external bearings will work with your frame. That will likely require a new crank set as well. But if you aren't going to have it much longer, probably not worth it.

As always, more info about the exact model and year of bike you have would really be of more help. Specialized uses all sorts of BB types for their bikes.

Aznman

Thanks dedhed. Seems like my BB being the standard cartridge square taper is a good bet. Looking at YouTube right now to find the right removal tools.

The spindle through the bb. Thanks for the external bearing advice.

Bill Kapaun

That's a pedal issue, not crank.

fietsbob

https://www.parktool.com/category/crank-bottom-bracket

Wrench remove your cranks

Remove the BB

Go with external BB type ?, installation tool




Option: save on multiple tool buys , have Bike Shop do the work..




..

Aznman

Yeah, sounds like the better plan.

dedhed

While helpful, the exact make and model # of the existing crankset is more helpful, particularly if they plan to just replace the BB and keep the existing crankset

dedhed

This will be my final fix for this old bicycle What will be the final fix?

So is your intent to replace the current crankset? or just repair the BB and use the old crankset? Not really clear.

Just replacing the cartridge BB? a cheap Shimano UN 26 or similar in the proper shell width, threading, and spindle length

Replacing the entire crankset? Decide on a cheap replacement crankset based on your gearing needs and riding style. The crankset will determine what BB it requires. The "final fix" says to me - Just another cheap square taper crankset and cartridge. Not "upgrading" to an external BB crank unless you're going to remove it and use it somewhere else when getting rid of this bike.

You are also going to find out in the current world pandemic that supply chains are creating shortages of both cheap replacement parts and upgrade parts. there's a chance you can't do this even if you want to, because parts aren't available.

madpogue 

In that case, as mentioned above, it's a new BB you're looking for, and your crankset may be fine. You mentioned multiple chain/cassette replacements. If that means you're concerned about chainring tooth wear (a well-founded concern, BTW), the next important identification question is -- are the chainrings bolted on, or riveted? If bolted on, you can replace them and keep your crankset. If riveted, then indeed, it's the whole crankset you'll have to replace. If you're unsure, post a photo of the right arm with the chainrings.

Look on the inboard side of the right-side crank arm. That should have a model number.

revcp 

+1. If the cranks are wobbling then the issue is a loose crank bolt, maybe both. If the wobble has been allowed to go on to long, it's possible the square hole in the crank has been rounded and no amount of tightening will fix it. So check that. If it is rounded, it needs to be replace. If you do replace the bb, as noted above, spindle will need to be the same length as the existing one (and depending on the age of the bike the spindle could be symmetric or asymmetric, so check that), and if you have to replace the crankset, a new bb would have to be purchased to work with the new crankset.

dedhed

In post 4 he says wobble is at the bearings and the picture of the rusted bolt tells me that's likely tight, might even be hard to remove from rust.
One of the issues is the future status of said bike. That to me would determine how much time, money, and energy I'm expending on it.