terminatorsd

So I had quite the Saturday, I biked with my girlfriend and a few friends about 15 miles into Downtown. It was a leisurely ride, we grabbed lunch and some beers and made our way back...

Well, my bike was missing and stolen Luckily it was my junker "full suspension" mountain bike...at this time my girlfriend opted to take an Uber and I'd take her bike. I agreed, and gave her my phone and began riding.


Honestly...a little angry about my bike, I adjusted the seat and started pumping away...and I heard the chain go. I thought the chain fell off, so I stopped...and it did fall off...completely, and was lying on the floor in a straight line. So I ended up walking about 12 miles home...fun!


So my question is... is this fixable for someone with basic tools or do I need to visit the bike shop? She needs a tune up in general, but my girlfriend is gone for a week visiting family so I thought I learn some mountain bike maintenance. My first question is, can I simply replace the link pin? I didn't really investigate the chain much closer to see what exactly happened but figured I'd research a little bit.

I believe this is a derailer issue...but she can't get it into third gear, this is secondary but it sounds like some adjustments are necessary without too much of tinkering. I am getting back big into cycling, and would like to understand bike maintenance better and stop visiting the bike shop with every tiny issue.

Last question, has anyone done this before?

Wythnail

You may be able to reattach it. You'd need a chain tool though. The issue would be if a pin actually sheared apart, to reattach it the chain will be shorter than it used to be, which would mean adjusting the rear derailleur after. That is if its not too short.

As for what caused it I dont know, im not what youd call an expert mechanic, im just learning.

Given that either way the derailluer needs adjusting, and theres a special tool involved, I'd say this is a bike shop job.

cny-bikeman

Modern bike chains generally cannot be reattached by using a normal link. No way to tell what caused the problem, though one possibility is that someone already installed the chain improperly. Take it to a bike co-op or shop and ask what you need to fix it.

As for general maintenance - sheldonbrown.com or parktool.com/blog.

achoo

What's the chain look like, especially where it failed? Anything bent or twisted?

How many speeds on the bike? IMO, and admittedly without much data, I'd think you need to replace the chain with a new one. You need to match the speeds to get the correct chain width.

Best solution, IMO:

1. Get the cheapest correct-speed KMC chain you can find: https://www.amazon.com/s/?ie=UTF8&keywords=kmc+chain
2. Get a chain breaker: https://www.amazon.com/s/?ie=UTF8&keywords=chain+breaker

Use the chain breaker to cut the new chain to the same number of links as the old chain, and put it on using the KMC quick link. Should take just a few minutes.

cny-bikeman

Caution - if the bike has a lot of miles on it, and especially if your girlfriend leaves it on the small cog in back, the new chain may skip on the old cassette/freewheel.