Replacing BB and Crankset on Cheap Bike

[coffearobusta]

Hi,

Been commuting for over a year on a cheap Walmart bike:
http://reviews.walmart.com/1336/13398138/26-mens-roadmaster-sequence-comfort-bike-reviews/reviews.htm

In retrospect, I probably should have bought something better, but at least with this bike I haven't been afraid to tinker with it. Well anyway, I recently got a set of bike tools, and was set to do my first major repair - the BB, since it has been making noise and had a little play in it. Things never go quite as smooth as I'd like.

First, one of the crank arms had damaged threads so the puller had nothing to grab. So I had to remove the BB first. Oh my tool kit only has a tool for cartridge type BB? No problem, vice-grips and channel-locks removed the adjustable cup but damaged the threads in the process. Inspection revealed one of the bearing cages had nearly disintegrated and the grease had been replaced by road grime and metal shavings. So now it's all apart, except the drive crank is still attached to the spindle.

At this point, I figure replacing the crankset and replacing/repairing the BB is what I need to do. I would like to replace the crankset with one that only has one chainring, instead of three.

Choices:
1) repair/replace with cup and cone style
2) replace BB with cartridge style

Any feed back on what's better?

Questions:
1) Sizing of BB to match new crankset. How do I know what spindle length I need to match my bike?

Thanks,

[JohnV]

I don't know what you paid for the bike or what condition the bike is in, but depending on what you are going to replace your components with, it may be cheaper to get another bike. If you were looking to get a better bike in the first place and can still afford one, now may be the time to get it.

[DaveM]

JohnV has a point. But if the bike isn't too bad otherwise, it may be worth keeping it rolling.
Get a cheap cartridge BB, cup and cone is essentially gone.
If you can support the crank so that the old BB dangles underneath (like with two blocks of wood), then give the end of the spindle a couple hard taps with a hammer, you should be able to knock it out of the crank. The stripped threads would still be a problem next time. But by the time you wear out a cartridge BB, it will probably be the least of the problems on the bike.

If you do get a new crank though, just don't go nuts and get something nice. This bike isn't really worth "upgrading" parts on. But no reason to landfill it just because of a BB. The maker of the new crank should be able to recommend the right length BB spindle.

[coffearobusta]

Thanks for the replies, guys. DaveM had the preferred option, as my goal was to get back on the road cheap. I was able to take the crank down to my LBS, and the guy was nice enough to tap the old spindle out of the crank and sell me a slightly used cartridge BB for $25.

I've been commuting on my bike 3-5 days a week about 18 miles round trip, as the wife and I are trying to save some dough and it made sense to become a one-car family. Soon I will be able to get a new bike...soon.

Thanks again,
Bill

Attachment shows my bike with my DIY panniers.