I'm debating what to do with my current leave-outside/winter/daily commuting bike.

It started out as a Walmart Mongoose mountain bike circa 2001 but has few original parts left on it. It had the front suspension fork replaced with an equally cheap but non-suspension fork. The front wheel is nice quality after the original wheel cracked but the rear wheel is still original. The Nashbar bottom bracket replacement now appears to be even more than slightly wobbly and I'm wondering if that's contributing to the knock I hear each time I turn the pedals. The knock is new.

The chain/7-speed cassette are probably nearing the time for a replacement again and the shifting is worse than it's been in the past. The chainline has never been all that great on the bike in any event. I usually keep it in the largest chainring and shift in between the 2nd-5th gear on the cassette for around-town riding.

The V-brakes were Nashbar replacements, all brake pads are good (Koolstop salmon), all cabling was replaced in the last several years and appears to work fine. I've got a cheap but reasonably fitting saddle and there aren't any other major issues with the bike.

Overall the bike looks like junk which I like since it decreases my chances of having it stolen. I could take it back to the LBS whom I like for a 'tune-up' which I suspect will require at least a cassette and chain replacement if not a new bottom bracket. I'm not sure I'll ever get a better chainline and the derailleurs were "upgraded" from the Walmart unbranded stuff to the cheapest Shimano models which didn't seem like too much of a step-up.

If I were to look for a new/used bike I would like to spend to too much money and would prefer a bike with 26" wheels as that would allow me to reuse both of my sets of tires (Schalbe Marathon Plus & Schwalbe Marathon Winter - i.e. not cheap tires to replace with different sizes) and fenders. Grip shifters would be ideal since they're much easier to deal with when you're wearing mittens.

You might just wanna replace, try and get a used quality mountain bike i ride a 90's raliegh its no where near stock but you can get em used for 60-75 bucks, same with old stumpjumpers and giants or treks.

Acquaint yourself with the local bike co-op. You can probably get parts at a reasonable price, even wheels. I'd recommend what Fizzaly says, but leaving the bike outside all the time will be hard on any bike.

How much do you like the old frame and how well does it fit? I've got an old Schwinn that I'm in the process of replacing some of the components because even with the worn out components it is still a more comfortable ride than my newer bikes.

Thanks for the feedback so far. I'm considering a new frame but Craigslist hasn't been all that helpful thus far. One of the local bike co-ops wants way too much money for their rebuilt bikes. They're nice, but perhaps a little too nice for what I intend to use them for.

The old frame fits reasonably well I think. I don't ride long distances on this bike. I go about 3-5 miles on it usually with the longest ride about 10 miles each way. I do like the frame because it looks somewhat beat-up and ugly which helps quite a bit when I lock it up in public. I thought about trying to throw a Deore rear derailleur on it and seeing how much of a difference it made but can you find a 7 speed Deore derailleur?

Edit: I guess 9 speed is compatible with a 7-speed cassette and it turns out it's not Alivio derailleur but an Altus derailleur on the rear..

Rear derailleurs don't care how many speeds you have on the cassette. I have the same Deore derailleur model on both my 9 and 7 speed bikes.

Also, Alivio, Altus, Deore...it doesn't matter. The derailleur *size* matters as it relates to chain capacity and cassette size (of the largest cog). Within Shimano, you should be OK.

I think the other shoe finally dropped. The front wheel on the bike is cracked despite my best efforts to never ride off a curb if I could avoid it. Now the only question is, new from LBS or used from Craigslist.