I want to fix my friend bike, it skipps when she peddles, the chain wont stay on and the back wheel is wobbly. what can i do?

Any time a chain comes off it means there's slack in it or something's not tight enough. Not looking at your bike, I would have to guess that you need to loosen the bolts on the back wheels and then pull the wheel assemblies back until the chain is tight. This is probably a two person job, one to unbolt and bolt and one to apply tension. That being said, many years ago I remember bikes my friends used had a problem where if they were riding at a good speed and then stopped peddling to coast, then slightly reversed peddling, then started fast peddling again, that they would throw a chain. I think what was happening was they were creating slack in the chain by coasting, slightly reversing their peddling, then starting again. The chains were also slightly gummed up, allowing slack at this time.

If not too late return it to the place that sold it to you and request it be fixed to work properly. Otherwise take to a bike shop or bike co-op. Alternatively go to Repair Help or Sheldon Brown Bicycle Technical Information to learn how to fix it yourself

I’m happy to help further over the phone at https://www.6ya.com/expert/donald_f2ed37026a3ac881

If this is a coaster brake bike (single speed, no hand brakes) then the problem might be inside the rear wheel hub. If that is the case then you can only fix it by completely dis-assembling the rear wheel hub - or it might be simply that the chain is slipping, which would not happen unless the chain is too loose which would be indicated by the bottom of the chain hanging down too low. However, if this is a multi-speed bike, then it could be that the chain and rear-wheel cogs are worn - which can be fixed by replacing the freewheel and the chain - however, it takes a lot of use or rust and dirt before that level of wear happens.

Possibly. The pawls probably exploded. Not knowing what type of rear wheel/hub you have it's impossible to say but a Bike Shop would spot the cause in a heartbeat. The repair may involve something as simple as a spritz of lube in the right places to a complete new rear wheel (as hub replacement involves a lot of labor rebuilding the wheel and may not make economical sense).

Take it to a shop for a look-see.

The most likely cause of this problem is that the back wheel is not in straight. If you loosen the 2 nuts that hold the wheel in you'll be able to align it with the chain. When you stand behind the bike the wheel and chain should be parallell.

You should also keep the chain oiled as it helps to stop it hopping across the gears.

I think the clicking noise is caused by one of two common issues. The easiest is that the little black computer pickup is too close to the magnet located on the right plastic piece on the right side of the wheel and everytime the wheel makes a full circuit while peddling, that little black piece clicks as it actually hits the magnet. If that's the case, then pull the black magnet sensor away just 1/16 of an inch aways so it will not hit the magnet everytime it passes the magnet. You can tell what's causing the clicking noise by getting on the floor and pushing the pedal around with one hand slowly and looking closely at the tow places I will mention to determine where the clicking noise comes from and then making the adjustment to stop it. the other place the clicking can come from is the chain rubbing against the metal on the left side. It might be hitting the TOP of the metal cage when cycling OR the BOTTOM of the metal shield which covers the pedal assembly. Look closely at the left side of the bike while peddling the bike slowly to see if the noise is metal against metal. You can shift the cage slightly to take the pressure of the cage from scrapping the chain by sitting down in front of the bike facing the cage and placing both feet onto the left & right supports (they're what hold the bike up) and you grab the little black wheels on both sides with your hands and push down slightly but firmly to shift the cage a bit and it will move up or down depending on where the chain is scrapping it when you cycle. That cage will shift slightly over time and it can make a loud noise when it scrapes the chain. I hope this helps. If not, give me a reply with more details and I'd be glad to help you isolate and fix the problem. Leave postive comment on fixya if you like my solution. Luke [email protected]

It will entail taking the chain apart again (known as "breaking" the chain).
The chain feeds UNDER the lower cog on the derailleur, BETWEEN the 2 cogs, and OVER the top one... then BEHIND the gear cluster and back OVER it. Run the other end AROUND the front chainwheels, through the front derailleur and re-connect. You may find it helpful to lay the bike on its side (sprockets up) and have someone hold rear derailleur to keep tension off the chain.
Good luck to you.

If the chain has just slipped of the best way get it back on is to physically lift it into place at the top of the chain ring (the cog where the pedals are).
Then turn the pedals in the direction you would usually pedal (you may have to lift the back wheel off the ground).
This ought to pull the chain back on and let you get back on the open road.

Your rear freewheel (Gears) are broken and need replacing...this is not too pricey depending on how many gears and weather or not you have a freewheel or cassette system of gears....If your not a do-it yourselfer take it to your local bike shop....cost should be between 20-50 bucks....good luck to you friend....Tim

More than likely the wheel is out of true. There are 2 choices,

1 Buy a spoke wrench and attemp to true the wheel. You can do this by spinning the wheel to locate the spot where the wheel goes furthest to one side then tighten the spoke coming from the opposite side. Do this slowly 1/2 turn at a time. Do not over tighten the spoke. It may be necessary to loosen the other side slightly.

Alternate spokes between both sides of wobble.

2 Take bike to a good local bike shop to be tuned and have the wheels trued. Most shops offer a tune up at low cost. A well tuned bike will last a long time.

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