One thing to keep in mind: If the chain is so badly worn that it no longer meshes well with the chainrings the freewheel is probably very worn as well. Your neighbour may well like this bike, but if it has been ridden enough to wear out a chain it is probably at the end of its useful lifespan. You might be able to rehabilitate it enough so that it can be ridden again, but it won't be long before some other component,(wheels, suspension, shifters) fails at even greater cost. You are not doing this person a favour by fixing the bike no matter how much they like it. This bike was never intended to be a form of everyday transportation

Thanks guys. I'm gonna keep trying to convince him that the bike isn't worth the time/money/effort and her should get a nice used mountain bike to commute on.

I kinda figured the chain line was a large factor in the way the rear of the bike was malfunctioning.

I kinda figured wheelsets would be mentioned. I'll look into a set but I think that'll exceed his budget... Maybe it'll convince him to just get a better bike

Even if the upgrade is a waste of money, it sometimes has to be done. Some, like me, have to experience it to believe and understand it. So don't beat him up too bad because if they don't learn it on the cheap bike, they may try it on a much more expensive bike later where the components will cost much more.

Agree with both points above.

I'm not getting this to be consistent with inch measurement. 12-1/8 divided by 12 is 1.010. About 1% elongation.
That same percent stretch in 10 inches is 10.1 inches, which is 25.7cm (actually a little less, 25.66, but 25.7 is easier to read off a ruler).

But the OP says chain stretch is a known problem. Check with the methods HerrKaLeun suggests and if need be, replace the chain. THEN assess shifting. Also, inspect cogs: If the bike has been ridden a lot on one cog, it could have developed the notorious cog-hooks that impair shifting. But I think the smart money should be on chain.

It would be a bit crazy to spend money on an RD or rear shifter without seeing how well the thing works with a good chain, aside from all the knocks against Wally World BSOs.

Looking at a chain (10), shifters (25), rear derailleur (25), cables (20) and freewheel (15), your friend will be into this bike an additional $95.

Can you find an equivalent working bike on Craigslist for $95? Maybe not. Order the parts and fix your friend's bike.

Didn't read the whole thread, but maybe you can locate a used bike without much mileage for a reasonably low price and just transfer everything. Make sure the frame is the right size in case you need to transfer everything back :).

As a principled person, I cannot in good conscience reccomend spending any money to 'upgtrade' that bike, beyond replacing any broken or worn parts. You shouldn't either - put your foot down and tell him that there is no silk purse to be made from this sow's ear. The first time the bike needs major repairs (wheel bearings wear out, fork stops working properly, rear triangle deveops slop) he must take that opportunity to trash it and get something else - not necessarily 'better', but at least not a stupid $200 full suspension bike. Even a $200 rigid bike is a much better choice than a $200 full suspension bike.

However, one thing that will always need replacing is tires, and a set of proper tires with less tread will undobtedly make a difference that can be felt while riding.

As others have said, the Shimano TX50 derailleurs are likely the best part of the whole bike. If shifting is poor, check other related parts, such as the cables and housing, or perhaps wheel bearing or freewheel play (these will allow the rear cogs to move out of alignment with the chain and derailleur), and make sure the (nutted?) rear axle is tight in the dropouts and not bent or moving.

If he has money burning a hole in his pocket, your friend should buy a set of metric wrenches, metric allen keys, 13mm and 15mm cone wrenches, and a good floor pump so he can keep his cheap bike running as good as possible until it is ready for the dumpster.

here are a couple of possibles on craigslist phoenix.....likely to be less hassle and less overall cost than upgrading. I have worked on neighbors and relatives bikes and the BSO just don't stay adjusted....

gary fisher $120 seems under priced but don't have feel for the market
https://phoenix.craigslist.org/nph/b...873946730.html

specialiazed hard rock sport $90
https://phoenix.craigslist.org/evl/b...888946601.html

This type project can ruin a friendship!
You bust your butt doing the best you can and he still sees how much better your bike functions. He assumes that you just don't "care enough" to make his that good.

https://phoenix.craigslist.org/cph/b...887230262.html

https://phoenix.craigslist.org/evl/b...873345283.html

https://phoenix.craigslist.org/evl/b...888946601.html

https://phoenix.craigslist.org/nph/b...888941395.html

Sun Cruiser,
Here in Bloomington, In. we have a co-op that services our less than minimum wage population. That includes folks from working at poverty level and below. Most of our clients are just like your neighbor. They have to rely on a bicycle to get around, and B-town is cycling friendly. The bike project offers used parts for free and has an earn a bike program that involves 3 hours of volunteer work and then the recipient builds a bike from our ware house of donated bikes. The concept is to make folks capable of self repairs and use alternate transportation. I would look around your city and try to find a place like our Bike Project. If not try reaching out to other co-ops (even ours) and ask for help with parts. There is also the swap area of the forum where you might find a few treasures to help your friend out. Look to the local Goodwill Store and watch for donated bikes there, I found a Fuji mountain bike there for about free, that needed air in the tires and a seat post. It is now sporting a proud parent riding with his daughter, something I thought I wouldn't see(Smiles!).
I find that a good tune-up and repair to the braking system is mostly what our clients need. Pay attention to those areas in helping your friend out (some times it is just the simple stuff!). Let me know if you need help. Contact me off line, Smiles, MH

Thanks for all the replies guys. I've managed to convince him (with the help of showing him this exact thread) to get a better bike overall. Right now he seems interested in the old trek single track 930s we have been seeing on offerup and craigslist

Those Treks 900 series are solid. They will make a very good ride for him, and are worth the effort to repair (and maybe even upgrade).

If possible, see if there are any older ones available from around ~1992 or earlier... these ones are constructed with lugs and brazing and were made in Wisconsin. The TIG welded ones (everything past ~1993 I think) are Taiwanese made. There is no practical difference - both types are excellent quality - the lugged ones are just cooler, IMO.