Take the 2-minute tour ×
Bicycles Stack Exchange is a question and answer site for people who build and repair bicycles, people who train cycling, or commute on bicycles. It's 100% free, no registration required.

I want to put a new Sram X7 instead of killed one, should I open the chain (if I have no chain lock) or it's better to open the derailleur?

share|improve this question
3  
Personal opinion - Much better to open the chain. It's easier, and that's how it's designed to be. –  JohnP May 23 '13 at 17:59
    
Agreed. Opening the chain is infinitely easier than trying to open the derailleur. Especially if you have a master link, but even without one it's not hard. –  sevargdcg May 23 '13 at 19:41
    
@JohnP that is the answer. You should post it as such. –  jimirings May 23 '13 at 21:31
    
@jimirings - done. –  JohnP May 23 '13 at 21:35
1  
Old derailers (20-30 years ago) were designed to be opened. New ones, not so much. –  Daniel R Hicks May 23 '13 at 21:49
add comment

1 Answer

up vote 8 down vote accepted

It's much better to open the chain. Derailleurs are not really designed to be opened repeatedly, and doing so inexpertly can potentially ruin the derailleur. Chains might have either a lock link or a master link of some kind, find that open the chain and then thread the chain through the derailleur. If the chain does not have one of these links, you will need a chain tool to split the chain. DIY grade ones are quite cheap and do the job well, but you will need to read up on how to use it properly.

Also consider that if the size of the derailleur arm is different, your chain may need either fewer links or more links to fit properly.

share|improve this answer
    
And, if your chain didn't come with one, buy one of these. chainreactioncycles.com/Models.aspx?ModelID=871 –  alex May 24 '13 at 1:53
    
Are you saying new derailleurs aren't designed to have jockey wheels replaced or their bearings greased? Because that would suck. –  armb May 24 '13 at 10:36
    
@armb - No, I edited the answer slightly. However, removing a chain is basically just pushing out a pin. Here is a link showing derailleur maintenance and all the springs/parts involved: parktool.com/blog/repair-help/rear-derailleur-overhaul –  JohnP May 24 '13 at 14:29
    
But most of that isn't relevant to just opening it enough to put a chain through. If you don't have a master link, some modern chains have pins designed for single use only. Once you've got the chain the right length, if he's replacing like for like, undoing the dérailleur is probably as easy as splitting the chain, especially if he doesn't have a suitable chain tool. We're not talking about opening it "repeatedly", just once to fit it. On the other hand, he'll need a new chain sooner or later, and then it will need adjusting to length. –  armb May 27 '13 at 21:18
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.